eChapters

8.1 INTRODUCTION

In developing countries like India, sustainable development of horticulture is a biggest challenge. There is need to formulate strategies for their management through “state of art” technologies for harnessing the naturally available resources in a sustainable manner to meet the ever growing demands of fruits. Canopy architecture has its role in influencing the productivity of fruits. It has been well highlighted by Halle and Olderman, (1970) and Halle et al. (1978). The emerging concerns in the area of canopy architecture and its management are the existence of large number of old senile orchards among the fruits crops and the development of a rejuvenation technology to restructure their canopy and enhance productive and remunerative plant life. Actually, canopy management “designing the plant as per need, using inherent plant characteristics in accordance with given set of conditions and resources to make the plant to perform maximum. As a result of canopy management, the trees acquire their natural shape which very often is not ideal for quality production. A majority of the trees attain tall, upright and curved growth structure and the canopy is marked with criss-cross branches leading to a highly dense vegetative mass with very poor penetration of active solar radiation. Such conditions not only affect the photosynthetic rate but also facilitate proliferation of pests as they prefer shady conditions. Consequently with pressure of pest abundance and poor photosynthetic efficiency over the years in want of due care of tree canopy architecture, the trees turn senile and unproductive and uneconomical.

Existence of such unproductive senile orchards has a telling impact on the socioeconomic as well as livelihood status of the farmers and consumers are equally affected with low poor production and poor quality of produce is the biggest problem with old orchard. Uprooting such orchards and undertaking new plantation may not be a wise option considering the long gestation period of orchard establishment and resulting impact on livelihood of farm families, environment health as well as the investment cost. Mass scale uprooting of trees for replacement of the orchard will also have very adverse impact on production scenario at the regional and national level.

9.1 INTRODUCTION

India is the second largest producer of fruit crops with annual production of 68.4 million metric tonnes from an area of 6.1million ha (Anon 2010). The national horticulture mission commenced in 2005 had fixed a target to double the horticultural production by 2011-12. According to the available production data of horticultural crops, it seems that we are very close to achieve our target. But, if the loss caused by biotic and abiotic stresses is accounted, a sound conclusion can be drawn that still there is a huge scope for productivity improvement in fruit crops.

Among biotic factors bacteria, fungi, nematodes, viruses and insect pests, diseases and other pests are widely recognized as the biggest threat to the sustainable production of fruit crops. Every fruit crop is infected with one or other pathogen/pest, which causes a significant reduction in yield. The disease alone both in field and storage accounts for 25-30 per cent losses (Rangaswami and Mahadevan 2002). Along with diseases, insect-pests also cause reduction in the yield. About 600 insect and mite pests have been reported in temperate fruits alone in India (Sharma and Singh 2006).

Beside biotic factors, abiotic factors (salt, drought, low and high temperature) also limit the potential yield of fruit crops. It is estimated that nearly 10 million ha is affected by salinity/alkalinity in India (Singh 2006). Moreover, fruit cultivars are also to be modified for yield and traits of consumers preference e.g. seedlessness in grapes and citrus.

Genetic improvement can be achieved by following the conventional breeding approaches, when the gene of interest is present in related cultivars/species and the crop is sexually crossable. But due to long juvenility and genetically prevalent problems like incompatibility, sterility in most of the fruit crops and apomixis in citrus, mango and apple, conventional techniques seem to have limited role in the improvement of fruit crops.

Various biotechnological approaches either alone or in combination with conventional breeding approaches can provide a direct solution for the genetic improvement of fruit crops.

10.1 INTRODUCTION

Agriculture is a very important sector for the sustained growth of the Indian economy. About 70 per cent of the rural households and 8 per cent of urban households are still dependent on agriculture for their livelihood. Though, industrialization of the Indian economy has adversely affected the share of agriculture in the GDP, the fact can not be ignored that India has undergone a series of successful agricultural revolutions-starting with the ‘green’ revolution in wheat and rice in the 1960’s and 1970’s, the ‘white’ revolution in milk to the ‘yellow’ revolution in oilseeds in 1980’s. As a result, India has achieved self-sufficiency in agriculture. Applications of agricultural inputs at uniform rates across the field without due regard to in-field variations in soil fertility and crop conditions does not yield desirable results in terms of crop yield. The management of in-field variability in soil fertility and crop conditions for improving the crop production and minimizing the environmental impact is the crux of precision farming. Geographically, India is widely distributed into several agro-climatic zones, and the information needs for the farming systems in these areas are entirely different. Integrating the application of available technologies to realize farmers’ goals requires a systems approach to farming.

11.1 INTRODUCTION

Citrus as a perennial crop occupies globally a place of prime importance amongst major fruit crops including India. The cultivation of citrus in India is dominated by three major cultivars viz., mandarin, sweet orange, limes and lemons occupying collectively an area of 9.23 lakh ha with a production of 86.08 lakh tonnes and productivity of 9.3 tonnes/ha. Nagpur mandarin in India is grown in 0.97 lakh ha area with total production of 8.81 lakh tonnes and productivity of 9.l tonnes/ha, respectively. The productivity of mandarins within the country is highly variable in space and time, the major constraint is inadequate and unbalanced fertilizer use. The commercial cultivation of Nagpur mandarin is extensively confined along the Satpuda foothills of central India comprising Chindwara region of Madhya Pradesh and Vidarbha region of Maharashtra. The nutrient demand is highly variable in space (due to heterogenous soils) and time (due to varying weather conditions). Therefore, determination of crop nutrient requirement is a subject of great complexity. Experiments have shown that soils initially rich in fertility developed a variety of nutrient constraints following the non-synchronisation in demand and supply of nutrients with the orchard age (Srivastava et al., 1998). For example when exchangeable K is not rapidly replenished, crops start drawing on the non-exchangeable K, resulting in soil mining and depletion in soil K reserve. A nutrient level sufficient for one particular productivity level may not hold sufficient for other higher productivity levels. An extensive survey of 18,000 ha area of Nagpur mandarin orchards of central India showed large scale deficiency of three nutrients viz., N, P and Zn, with most of the sites expressing multiple nutrient deficiencies (Srivastava and Singh 2002; 2005). Reduced longevity of commercial citrus orchards due to varying nutritional constraints is one of the major production related constraints highly responsible for poor orchard efficiency (Srivastava and Singh, 2008a; 2008b).

12.1 INTRODUCTION

Oil Palm (Elaeis guineensis Jacq.) is a heavy feeder and needs a balanced and adequate supply of nutrients for growth and yield. Fertilizer is one of the most costly inputs, which accounts for greater part of production costs in the cultivation of oil palm. Large amount of nutrients are removed by the fruit bunches harvested from the mature palms. It is estimated that 25 tonnes fresh fruit bunches per hectare per year removes 93.5 Kg Nitrogen, 11.0 Kg Phosphorous, 92.7 Kg Potassium, 19.3 Kg Magnesium and 20.3 Kg Calcium.

Economic yields of oil palm are achieved when the supply of nutrients from the soil, palm residues and fertilizers are properly integrated in required quantities. Leaf analysis is an analytical tool for detecting the nutrient requirements in oil palm and other perennial crops, which are slow growing and can provide easily, defined standard leaf material for analysis due to leaf phyllotaxis. Nutrient deficiency symptoms are also an important means for determining the nutritional problems in oil palm, since the crop presents easily identifiable N, K and Mg deficiency symptoms. However, by the time symptoms are evident, nutrient deficiency might have already affected growth and yield.

Also the nutrient supply may be insufficient before the appearance of leaf symptoms. So there is a need for a thorough inspection of the leaf canopy to corroborate the results of leaf analysis and identify the areas with severe nutrient deficiencies. The research on oil palm nutrition was carried out under rainfed conditions at Palode, Kerala and irrigated conditions at Pedavegi, Andhra Pradesh.

In India, a great variety of soils ranging from red sandy loams/sandy clay loams (Alfisols), alluvial silt loams (Inceptisols / Entisols), heavy black soils (Vertisols) and acidic red laterite soils (Oxisols) are put to oil palm cultivation. In Andhra Pradesh, it is grown in red sandy, red loamy, red loam with clay base, deltaic alluvium pH - 6.5 to 9.0. In Karnataka, it is grown in red and brown sandy loams and black clayey soils, with pH - 6.5 to 9.0. Red soils, red loamy soils and clay loam soils are used for growing oil palm in Tamil Nadu. Laterite soils are used for oil palm cultivation in Kerala.

13.1 INTRODUCTION

The hot arid regions are spread over about 31.7 million ha area mainly in the States of Rajasthan, Gujarat, Andhra Pradesh, Punjab and Haryana, which inhabit on an average 61 persons per square km making up a home for population of nearly 20 million people. The Indian arid zone is characterized by high temperature and low and variable precipitation which limit the scope for high horticultural productivity. However, these conditions greatly favour development of high quality production of fruits such as date palm, ber, pomegranate, citrus, aonla, bael, grapes, guava and vegetables such as cucurbitaceous crops, spices and some medicinal plants. The optimized technologies and inputs could increase the existing low productivity. It is now realized that there is a limited scope for quantum jump in fruit and vegetable production in the traditional production areas. The amelioration of the extreme conditions is also considered vital for life support to the inhabitants of this area. The recent awareness regarding the potential of these ecologically fragile lands for production of quality horticultural produce has not only opened up scope for providing economic sustenance for the people of this region, but also for bringing new areas to increase production through horticulture.

The arid horticultural crops have developed and/or modified to perform certain vital physiological functions even under stress. Strong deep root system (ber, bael, aonla, wood apple, jamun, etc.), moisture synchronous flowering and fruit development (ker, lasora, aonla, pilu, etc.) and other xerophytic characters i.e. leaf shedding in summer (ber), scanty foliage (ker), spiny cladode (cactus pear), mucilaginous sap in plant part (ker, gonda, pilu, bael, etc.), sunken stomata and fur/ hairiness and waxy coating on the leaf surface (phalsa, ber, gonda, fig, etc.) thorny nature, and selective or reduced absorption of cation (Na⁺) and anions (Cl^-, SO4^—) for survival under adverse arid conditions are peculiar adaptations. Therefore, cultivation of suitable species of fruit and vegetables in the arid areas will increase the sustenance of the inhabitants and provide the alternate sources of income through development of nurseries, small scale industries and exports.

14.1 INTRODUCTION

The efforts for harnessing the natural resources for sustainining the human race have been ‘on’ since the beginning of the civilization. The basic needs of food, fuel and fodder are obtained from the land resources with the combination of water and sunlight. The combination of information technology and use of hi-tech equipments paved the way for the introduction of precision horticulture. Precision horticulture may be defined as application of a holistic management strategy that uses information technology to bring data from multiple sources to bear decision associated with agriculture production, marketing, finance and personnel. Enhanced input efficiency is an important component of horticultural production under precision horticulture site specific management. Enhanced input efficiency in crop management can be obtained only when suitable varieties, desired amount of nutrients and water based on calculations, at right time and by proper method are used.

With recent advances in geographic positioning system, remote sensing, data processing, harvesting equipment, fertilizer and pesticide applicators, the approach can be used from a more practical stand point to identify variability and to use the variable rate of inputs over an entire field.

In recent years, there is considerable awareness about the nutritional security and food safety. More emphasis is given to underutilized fruits due to their high nutritive and medicinal value in addition to being resistant/tolerant to many biotic / abiotic stresses. The demand of these fruits are gradually increasing owing to tremendous potential for commercial exploitation aimed at improving the economic status of the poor and marginal farmers. An area, which needs immediate attention, is the collection, documentation, conservation and utilization for their sustained production and popularization.

15.1 INTRODUCTION

Vegetables are rich sources of many essential micronutrients, including vitamin C, vitamin K, folate, thiamine, carotenes, minerals, and dietary fibre. In addition, vegetables are rich in health related phytochemicals, such as antioxidants. Such phytochemicals play an important role in reducing the risk of many chronic diseases. Therefore, it is essential to produce more vegetables to feed our ever growing population. In this context, use of genetically improved, disease resistant and high yielding varieties in precision farming may play a significant role in increasing vegetable productivity and production.

15.2 EXPLOITATION OF GENETIC RESOURCES

The genetic resources of a crop may be defined as the sum total of hereditary material, i.e., all the alleles of various genes present in a crop species and its wild relatives. Genetic resources are broadly grouped into two major types (i) cultivated germplasm, and (ii) wild germplasm. Alternatively, they may be termed as (i) indigenous (from the country in question), or (ii) exotic (from another country) based on their place of origin. Genetic resources consist the following five types of materials: (1) land races, (2) obsolete varieties, (3) modern varieties or varieties in cultivation, (4) breeding lines, and (5) wild forms and wild relatives.

16.1 INTRODUCTION

The world floriculture business has reached to almost over a $ 40 billion mark. It is continuously going through the rapid transitional changes to have more unique and competitive products of wide choice to the consumers. Netherland is ahead in floriculture trade. Throughout the year, a large number of ornamental commodities are imported in Holland and exported back to the countries for its retail and consumption mostly to the countries in the Gulf, Middle-East Asia and America. According to the statistical estimates worldwide, a large quantity is consumed in US and the other countries. For an example, the US alone consumes 100 lacs of cut flowers a day and approximately 4000 lacs every year, though it ranks only 17^th in per capita cut-flower consumption. The average Swiss spends Rs 4500 a year on flowers, nearly four times than that spent by the average American besides the fact that the consumption of fresh cut flower and foliage plant is on manifold increase every year resulting in the competition worldwide for growing of exportable eco-friendly products. At the same time there is great environmental consciousness towards transforming floriculture with “natural and unspoiled” system of having the exportable produce into a mass and its ease to transport to any distant market. The system relies greatly on the industry with extensive network of breeders, greenhouse managers, field workers, auction houses, sales representatives, shippers, and florists to offer consumers a variety of choices matching their taste. This is the fact that in the recent times, the commercial growers don’t rely on the nature to introduce the genetic mutation that will make them millionaires but depends on the art and scientific knowhow to create a novelty in its own. This has resulted in the seriousness and painstaking effort of the growers to produce the plants in new forms and shape to put forward a new plant with extra-ordinary marketable characteristics every year, e.g. compact chrysanthemum, kalanchoe, bromeliads, orchids, etc (Plate1) are some of the common products with an unusual and eye-catching hue in the European markets. Similarly, the consumers can purchase gerberas with blooms as wide as salad plates and roses with yard-long stems perfectly suited for valentine-day gifts which mainly they get produced under the specific and artificial environment created for a specific growth stages of the plant.

17.1 INTRODUCTION

Flower consumption is growing at an alarming rate of 20 per cent per annum at global level and India is, today, one of the world’s largest consumer base and fastest growing retail destinations. Commercial floriculture is today a potential money-spinner and an economically viable agri-business.

Cut flower trade in terms of export oriented units dealing with rose and gerbera is flourishing. Other cut flowers like gladiolus, tuberose, lilum, chrysanthemum, etc. are also being cultivated along with traditional loose flowers like jasmine, rose, crossendra, marigold on a higher scale. However, growing awareness of Indian consumers and popularity for cut flowers is creating demand for diversified flower crops. Further, trade of some flowers in the market is responsible for gluts. Thus, there is an urgent need to diversify the floriculture industry by introducing and adoption of anthurium as a cut flower with unique shape and high longevity.

Precision farming is an advanced approach for the flower growers to enhance their income. It mainly includes information and technology of farm management system to identify, analyze and manage variability within fields for optimum profitability, sustainability and protection of the land resource. Precision farming is applied for increasing efficiencies that can be realized by understanding and dealing with the natural variability found within a field.

Anthurium is taking a good place in market with high value. Farmers are undertaking anthurium cultivation and in this direction, precise farming technology will help the farmers to grow the crop with good quality and higher production per unit area.

18.1 INTRODUCTION

Organic farming systems have attracted increasing attention over the last one decade because they are perceived to offer some solutions to the problems currently besetting the agricultural sector. In the western world, organic farming is catching fast (Malik, 2000). Indiscrimpte use of chemical fertilizers, herbicides and pesticides have resulted in environmental and health hazards along with socio-economic problems (Padmadevi, et al., 2008). India is bestowed with lot of potential to produce all varieties of organic products due to its diverse agro-climatic regions. In several parts of the country, the inherited tradition of organic farming is an added advantage. Organic farming is necessary to attain the goal of sustainable development. According to the Food and Agriculture Organization (FAO), sustainable agriculture “is the successful management of resources for agriculture to satisfy changing human needs while maintaining or enhancing the quality of environment and conserving natural resources”. All definitions of sustainable agriculture lay great emphasis on maintaining an agriculture growth rate, which can meet the demand for food of all living things without draining the basic resources. Organic farming is one of the several approaches found to meet the objectives of sustainable agriculture. Many techniques used in organic farming like intercropping, mulching and integration of crops and livestock are not alien to various agriculture systems including the traditional agriculture practised in countries like India. However, organic farming is based on various laws and certification programmes, which prohibit the use of almost all synthetic inputs, treated seeds and health of the soil is recognized as the central theme of the method. Adverse effects of modern agricultural practices on the farm resources and health and over all survival of living being have been well documented all over the world. Application of technology, particularly in terms of the use of chemical fertilizers and pesticides has been serious concern. Their negative effects on the environment are manifested through soil erosion, water shortages, salination, soil contamination, genetic erosion, etc. Organic farming has the potential to provide benefits in terms of environmental protection, conservation of non-renewable resources and improved food quality. It is very important to maintain long term soil biological activity, ensure effective peak management, recycle wastes to return nutrients to the land, provide attentive care for farm animals and handle the agricultural products without the use of extraneous synthetic additives or processing in accordance with largely acceptable standard and applicable standards of destination country/ countries. Organic farming has several advantages over the conventional one apart, from the protection of both the environment and human health. Improved soil fertility, better water quality, prevention of soil erosion, generation of rural employment, etc. are some of them.

19.1 INTRODUCTION

Indiscriminate use of agro-chemicals over the last five decades has adversely affected soil fertility, crop productivity, produce quality and particularly the environment. These degenerative effects of intensive agriculture have compelled to think for alternative and sustainable system of agriculture. As a result, number of alternative systems viz Biodynamic, Rishi Krishi, Panchagavya Krishi, Natueco Organic Farming, Homa Organic Farming, Natural Farming and Jaivik Krishi have emerged in different parts of the country. In organic farming production is achieved without use of chemical input (Singh, 2011 and Malik, 2000). In these systems, maximum reliance is placed on self-regulatory agro systems and locally available or farm derived renewable resources. Since the soil, water and environment have been contaminated, hence even organic production techniques once effective are now are not capable of mitigating these issues. This has created number of myths in the mind of policy makers and even large number of farmers.

20.1 INTRODUCTION

With rapid increase in area under micro irrigation, now fertigation is getting momentum in many states in the country. At present, most of the soluble fertilizers are imported in the country. Hence, these are very expensive and beyond the reach of common farmers. It is interesting to record that for number of nutrients, which are becoming constraints in most of the Indian soils, soluble formulations have yet to be developed. This calls for some alternative options. As an alternatives liquid manures like cow urine, biogas slurry, or fermented manures etc can be sprinkled on the soil, applied with irrigation water or diluted and sprayed as foliar fertilizers (Frank et al; 2005).To our understanding, organic fertilizers /organic liquid manures referred now as bio-enhancers are essential to maintain the activity of microorganisms and other life forms in the soil. These are prepared locally, can resolve number of apprehensions and will be helpful in boosting production and mitigating number of nutritional disorders in most of soils and crops. It is interesting to record that these can be prepared at the farm with some infrastructure facilities and hands on training. Most of these formulations are used through irrigation. These organisms (bacteria and moulds) improve the soil health by solubilzing the complex organic substrates into simple forms and make it available to the plant, resulting in increased productivity. If these are integrated with micro irrigation techniques after proper filtration their efficacy can further be improved.

Cow dung and urine are important component in organic farming. Cow dung is rich source of microbial consortia Actinomycetes, which are helpful in control of many plant diseases. A potential species Streptosporangium psedovulgare of Actinomycetes and four strains of Bacillus subtalis have been identified at CISH, Lucknow (Pathak et.al., 2009).These showed anti pathogenic potential against anthracnose gummosis, stem end rot and dieback pathogens. These were observed to attack mycelia cell wall and finally the host cell degenerates completely. Organic liquid manures play a key role in promoting growth and providing immunity to plant system ( Sreenivasa et al., 2010).

21.1 INTRODUCTION

High population pressure has forced us to plough 46 per cent of our country area for food production. The present productivity is 12.36 tonnes/ha of fruits needs to be raised to 40.0 tonnes/ha by using N : P₂O₅: K₂O with other inputs, since recommended ratio is 0.75:0.50:1.00 only.

Since cost of the inputs like fertilizers and manures are very high, hence, efficient nutrient management is essential for sustainable fruit production and protection of the environment from different types of hazards occurring due to misuse of costly fertilizers.

The soils of India and especially of arid and semi-arid regions are impoverished to plant nutrients. Considering economy, energy and environment, it is imperative to use nutrients effectively by adopting the appropriate doses proper, placement and correct timings of application and to sustain the available nutrients in soil at the optimum level.

22.1 INTRODUCTION

The life-styles, economic conditions and food habits have a great effect on food marketing. There is an increasing demand for fresh fruits and vegetables and their processed products. Fruits and vegetables are processed into a variety of products and it is required to be picked at its right stage. For making juice, fruits should be picked at ripe and soft stage, for canning purpose it should be picked at fully mature but firm just before ripe stage. Fruits and vegetables are passed through a long channel before their consumption; which may lead to a number of undesirable changes in their composition. Thus effective post harvest management of fruits and vegetables is essential to provide their acceptable quantity and quality worth consumption. In this regard handling, processing and preservation and value additions form important loci.

23.1 INTRODUCTION

Mandarin oranges are the most popular among the citrus fruits and alone occupy more than 50% share under widely divergent citrus crops grown across the globe. In India, oranges have a place of prominence among fruit kind after mango and banana. It’s delicious, relishing, nutritious and handy fruits offer best mouth feel especially during summer when other fruits fail to quench thirst of throat. There is a need of scientific handling so as to accentuate trade and to exploit market potential of mandarin fruit.

Country wide, orange covers an area of 5.02 lakh hectares and the production is of the order of 43.96 lakh tonnes accounting for 12.03% and 6.40 % share under total acreage and production respectively in the fruits (Anon., 2010). Orange’s production in developed countries is projected to grow at an annualized rate of 0.6 per cent and that in developing country at 0.8 per cent.

In Rajasthan, ‘Nagpur’ mandarin and ‘Kinnow’ fruits occupy a place of prominence among various citrus crops grown. Cultivation of ‘Nagpur’ mandarin is mainly concentrated to Jhalawar district where it covers about 6040 ha area producing 87586 tons fruits, annually. After the implementation of National Horticulture Mission the area is further increasing steadily in the district.

24.1 INTRODUCTION

Citrus fruits occupy third position after mango and banana in the country and ranks 6^th in the world citrus production. The productivity, however, is only about 40 percent of that in Spain, Brazil, USA or Japan (8.4 t/ha) only. Of the total production, mandarin contributes more than that of sweet orange in which major chunk of 57.72 per cent was shared by Maharashtra, followed by 19.81 per cent by Madhya Pradesh state. At present, the Brazil is the largest producer of citrus, followed by USA. There are number of issues which need to be addressed to make fruit quality comparable to the international standards. Post harvest losses of fruits are also enormous mainly due to unscientific method of harvesting, lack of utilization of post-harvest handling techniques due to which 25 - 30 per cent losses occur in developing countries in comparison to 5 - 10 per cent in developed countries. Synergistic effect of pre-harvest practices and post harvest handling is the key to get the fruit of high quality and enhanced shelf life.

Recent trends are emerging as use of less chemicals and Good Agricultural Practices (GAP) during cultivation. Maintenance of quality standards and regulations up to retail market level is of utmost importance. Whereas, in marketing sector, now-a-days participation of private players on large scale in retail marketing of produce is noticed.

Value chains have become the centre of considerable academic and practical interests. Part of the reason for the rapidly growing interest in value chains in the citrus sector has been the result of changes in global retailing. In a large number of countries, supermarkets chains now dominate food retailing. Supermarkets have increasingly integrated their operations involving many aspects of the post farm gate operations. Value chain management is one of these. Some identified issues relates to supply chain bottlenecks resulting in farmers experiencing gluts of commodities, processors not being able to procure sufficient raw materials for their plants, retailers not getting sufficient products to meet the demand of consumers, and exporters are unable to meet foreign consumer requirements. Lack of innovation that affects the entire chain, an example being the introduction of plastic crates for a fruit processor involves a vast number of actors in the chain to coordinate their efforts.

25.1 INTRODUCTION

With the natures gift, consciously or unconsciously human select the best among the lot based on sensual judgment. Warnings about the dangers of the excessive use of the chemicals for the human health and biodiversity have been well reported over the years. The world health organization estimates the occurrence of some more than 25 million cases of excessive chemical use slow poisoning globally each year (Anon, 2010). In developing countries, sulphur and chlorine based formulations are often used for post-harvest treatments of horticultural produce. Recently, some bio-based and other safe post-harvest treatment materials have been formulated for loss reduction and shelf-life extension of fresh fruits. In this article, the recent and safe materials/agents for postharvest treatments are discussed.

25.2 MATERIALS FOR POST–HARVEST TREATMENTS

25.2.1 Polyamines

Polyamines (PAs) are low molecular weight small aliphatic amines that are ubiquitous in living organisms and have been implicated in a wide range of biological processes, including plant growth, development and response to stress (Smith, 1985). In plants, they have been implicated in a wide range of biological processes, including growth, development and abiotic stress responses. The most common polyamines are Putrescine (PUT), Spermidine (SPD) and Spermine (SPM) found in every plant cell in titers ranging from approximately micromolar to millimolar, together with the enzymes regulating their metabolism and depend greatly on environmental conditions, especially stress.

26.1 INTRODUCTION

India is the second largest producer of fruits and vegetables and ranks next to Brazil and China, respectively. With the commensurate total production of 63.5 and 87.2 million tonnes of fruits and vegetables, the country shares about 11 per cent of total production under fruits and 13 per cent of total production under vegetables, respectively (Anon., 2008) in global scenario. Horticultural produce undergoes spoilage at the time of harvesting, handling, storage, marketing and processing resulting in huge wastage. Efficient management of this waste can help preserving essential nutrients of our food and feeds and bringing down the production cost of processed product, besides minimizing pollution hazards and purifying the environmental condition. Recycling of horticultural waste is one of the most important aspects of utilizing it in a number of new ways to yield new products and meeting the requirements of essential products required to mankind.

In advance countries like USA, Australia, Brazil and Israel, more than 50 per cent of fruits and vegetables productions are processed into different products, whereas, in India it is less than 2.0 per cent of total production. Generally, post harvest losses in fruits and vegetables range between 25-30 per cent of total production, valued at more than 57,000 crores annually due to lack of availability of appropriate post harvest infrastructure (Guleria and Verma, 2008). Horticultural crops are grown all over the country incurring wastes everywhere. There are different stages of waste from farm to fork.

27.1 INTRODUCTION

In India, the horticulture sector contributes around 29 per cent of the GDP and 37 per cent of the total exports of agricultural commodities from about 13.08% of area. India has been placed as the second largest producer of fruits and vegetables; largest producer and consumer of cashew nut, tea, spices; third largest producer of coconut; fourth largest producer and consumer of rubber and sixth largest producer of coffee in the world. Several new programmes area in operation and significant developments in area expansion, production, value-addition and exports have taken place. Today, as a result of better synergy between research agencies, technological and policy initiatives by the governmental agencies, proactive participation of private players and higher degree of diversification to horticulture, this sector has emerged as a sustainable and viable proposition for even the small and marginal farmers including different stakeholders in the commodity chain. In spite of the remarkable progress made in the horticulture Sector in India, there is lot of scope in improvement in safety and quality aspects of horticultural produce.

The concept of biosafety encompasses a range of measures, policies and procedures for minimizing potential risks likely to appear to the environment and human health. Such safeguards must be put in place now. Biosafety is currently being promoted in a variety of ways by industry, governments and civil society. Quality and safety become prime concern because most of the horticultural produce are consumed daily in fresh, cooked and processed form and contribute major share in our daily diet. To ensure biosafety and quality of horticultural produce we need to ensure: a)Supply of quality inputs, b)Adoption of good cultural practices, c) Handling and processing of horticultural produce in scientific /hygienic manner, d)Packing, storage, transportation and delivery etc. in such a way that it reaches at consumers’ table without deteriorating the quality.

To ensure such aspects various preventive and certification measures have been initiated by government and certification agencies all over the globe including India , such as prevention of Food Adulteration Act 1954, Agricultural Produce Marketing Act, 1937, Food Safety Standards Association of India (FSSAI), Food Safety System Certification (FSSC:2200), International Food Certification (IFC), Food Chain Traceability, Hazard Analysis and Critical Control Point (HACCP), Food Product Orders (FPO), etc. The major emphasis under these certifications/regulations is to ensure quality and safety of the produce and minimize the risks by reducing the biological, chemical, physical hazards like microorganism contamination, level of heavy metal/chemicals/ drugs beyond the critical limits, residual effects of toxic substances etc. Brief of a few certification/regulations are listed below.

28.1 INTRODUCTION

Precision Farming has assumed great significance in the country for making the use of available resources more judiciously and efficiently. It is farm management strategy which utilizes precise information to increase profit and to reduce enviornmental impact. It takes into account in field variability in soil fertility and crop conditions. In nutshell, it may be defined as management of input variables such as application rates, cultivars selections, tillage practices, irrigation scheduling, optimization of soil and plant nutrient through nutrient management practices and management of pest and diseases by reducing the quantities of pesticides. Development of new technologies has become integral part of precision farming.

Precision farming was widely accepted firstly as a management practice in corn belt of mid west United States of America which helped in increasing the yield and significant reduction in production costs. Besides, crops like wheat and soybean have also been included in its purview. In south east parts of U.S.A., research is currently on in the crops of citrus, cotton, groundnut, vegetables and even livestock. Precision farming management practices have also integrated controlling and monitoring of field information using geographical information system (GIS), Global Positioning System (GPS), sensors, Variable Rate Technology (VRT) and yield monitoring. These components are highly sophisticated. GIS software stores data pertaining to soil type, nutrient levels etc in layers and assign that information to the particular field location. It can also be used to analyze characteristics between layers to develop application maps or other management options. Global Positioning System is a referencing device capable of identifying sites within a field. Global positioning system (GPS) helps in storing information regarding field location in terms of latitude and longitude. Maps showing variability of nutrient levels soil types, topography, pest incidence and yield can be created by virtue of it. It is a set of 24 satellites in high altitude orbit above the earth for pin pointing objects on the surface of the earth. These satellites continuously transmit radio signals which are picked up and deciphered by special receivers. A GPS receiver requires at least four satellites to determine its position on earth. Receivers are mounted on tractors/top of cab or on some high point to get a clear view of the spy. Crop stress, soil properties, pest incidence etc. are determined by the help of sensors through traveling over the field by tractors or combine. These can be used for measurement of soil conductivity, fertility status, weeds etc. Another type of sensor viz Remote sensors (aerial/ satellite) can provide instead maps of field conditions. Computer control device and associated hardware are part of Variable Rate Technology (VRT) for application of fertilizers, pesticides etc on the basis of field characteristics of the specific location. In precision farming, information is needed about mean characteristics of small, relatively homogenous management zones. It is data acquisition of the farms to find the soil, vegetation and other parameters which are amenable to remote sensing. Remote sensing techniques are helpful in providing continuous acquired data of agricultural crops. Remote sensors image vegetation growing on different soil types with different water availability. The following applications can be made by relief sensors:

29.1 INTRODUCTION

Some historians believe that it was women who first domesticated crop plants and thereby initiated the art and science of farming. While men went out hunting in search of food, women started collecting seeds from the native flora and began cultivating those of interest from the point of view of food, feed, fodder, fibre and fuel. This view is strengthened by the fact that women have been traditionally seed selectors. Even today this tradition has continued in many parts of the developing world. Women have played and continue to play a pivotal role in the conservation of basic life support system such as land, water, flora and fauna. They have protected the health of the soil through organic recycling and promoted crop security through the maintenance of varietal diversity and genetic resistance. In many hill and remote areas of developing countries such as Himalyan region, agriculture is largely in hands of women. Men tend to go to towns and cities in search of salaried jobs for fulfilment of family income. Therefore, without total intellectual and physical participation of women, it will not be possible to popularize alternative systems of land management for shifting cultivation, arrest gene and soil erosion, and promote the care of the soil and the health of economic plants and farm animals. Women also tend to look at problems in their totality from the sowing of the crop to its ultimate utilization either as food, feed or raw material for industry. Since they are usually involved in of marketing, they generally possess a clear understanding of market preferences and prejudices. Therefore, for an economically and ecologically sustainable agriculture the involvement of women farmers and farm women (agriculture farmers with and without assets) in the process of modernization of farming practices and village industries is absolutely essential. Horticulture is a major part of Indian agriculture. Although belated, their importance has now been recognized in India not only to provide the much needed balanced nutrition and gainful occupation to our populace but also to develop viable internal and export trade. Fruits like banana and vegetables like potato being energy rich are considered prominent food crops e.g. banana can produce as high as 37 million calories per hectare. Unfortunately the component of fruits and vegetables in Indian diet is hardly six per cent which should be raised at least five times so that the per capita per day consumption mathches the recommended dose of 85g. fruits, 75 – 125g. leafy vegetables 85g. other vegetable and 85g. roots and tubers. To achieve this present production of fruits and vegetables would need to be pushed up considerably by increasing the production levels and the area both.

Precision farming is also known as precision agriculture. A farmer is not only expected to produce more for the increasing population and his family but save and protect the fragile environment while practicing it. Advanced technologies with appropriate and exact inputs such as precision farming can take care better of environment. Precision farming is right farming operations at right time leading to maximize profit. Every farming activity performed with precision by doing the right thing, in the right place, in the right way, at the right time and with right technology leading to maximize profit is known as precision farming. It is an efficient, eco-friendly and accurate management of agriculture inputs such as water, seed, fertilizers, pesticides and harvesting tools and machinery to maximize profit and reduce waste. The basic concept of precision farming is to match agricultural inputs and operations as per crop (variety/hybrid/cultivar) and agroclimatic conditions with accuracy to their better use efficiency. Perfection (nothing requisite is wanting) in farming is the key to precision farming.

Precision farming is based on global positioning system (GPS). The unique character of GPS is precision in time and space. Its use is spreading to all farm operations. Precision farming is an integrated information and production based farming system that is designed to increase long term, site specific and whole farm production efficiency, productivity and profitability while minimizing, waste and unintended impacts on the environment. This concept of precision agriculture is based on observing, measuring and responding to inter and intra field variability in crops.

Farm management strategy is the key to precision agriculture that uses integrated smart technologies such as sensors, GIS, GPS, satellite radars, drones, IoT (Internet of things) and data analytics to develop informed crop production and management decisions. The field variations are precisely measured with the help of technologies to optimize applications of inputs such as manures, fertilizers, pesticides, bio-agents and water use to increase crop yield at minimum cost. The aim of precision farming is to increase productivity, decrease production costs and minimize the environmental impact of farming.

It is a common knowledge that most of the farmers apply irrigation water until all the points in the field are fully wetted and covered with a thin sheet of water. Studies have indicated that a significant (20-25%) amount of irrigation water is lost during its application at the farm due to poor farm designing and unevenness of the fields. This problem is more pronounced in the case of rice fields. Unevenness of fields leads to inefficient use of irrigation water and also delays tillage and crop establishment options. Fields that are not levelled have uneven crop stands, increased weed burdens and uneven maturing of crops. All these factors tend to contribute to reduced yield and produce quality which reduce the potential farm income. Effective land levelling is meant to optimize wateruse efficiency, improve crop establishment, reduce the irrigation time and effort required to manage crop.

Reasonably levelled agriculture fields has advantage over uneven and undulating crop fields as unevenness of the soil surface has a significant impact on the seed germination, crop stand and its yield. Traditionally land levelling was being done throughout India by bullock drawn plough or tractors and applying different devices for levelling the field by visual assessment e.g. on small plots with hoes, or with draft animals and equipment such as ploughs and bars or scrapers or grading. Equipment such as grading blades and hydraulically operated levellers mounted on wheels are used with tractors. More advanced and sophisticated levelling equipment is operated with a laser emitter, a laser sensor or receiver, and a scraper pulled by a tractor. After the desired level or slope of the field and/or the difference of the high and low spots have been surveyed, the emitter is set to send a rotating laser beam creating a plane of laser light above the field surface. The laser light is used as the levelling reference. It directs the hydraulic system of the moving tractor and scraper, and thereby controls the levelling. Hence, laser levelling or laser land levelling is levelling the crop field within certain degree of desired slope using a guided laser beam throughout the field.

Sowing of Seed: It is a process of planting seeds of crops in well prepared or no till field or nursery beds/pots for raising crops in following methods:

Methods of Sowing: The sowing method is determined by the crop to be sown and resources on the disposal of farmer. There are 6 sowing methods which differ in their merits, demerits and adoption. Those are:

1.Broad casting

2.Broad or Line sowing

3.Dibbling

4.Transplanting

5.Planting

6.Putting seeds behind the plough.

Seedling:A seedling is a very young plant that grows from a seed. When the moisture, light, and temperature conditions are correct, the seedling’s development begins with seed germination and the formation of three main parts:

1.Radicle - Embryonic root

2.Hypocotyl - Embryonic shoot

3.Cotyledons - Seed leaves.

In vegetables and annual ornamental crops where generally seed size is small they are germinated in nursery beds or in plug trays indoor (greenhouse) or outdoor(field), hardened before transplanting.

Sapling: A sapling is a young tree, say more than 1 year and less than 3 years’ old. In the life cycle of trees, a seedling converts into a sapling as the next stage of development. It is nearly one-meter tall and generally remains to be known as a sampling until its stem reaches 7 centimetre in diameter. The time period of this stage depends upon the particular species of a tree. In vegetable and annual ornamental crops seedlings generally are one month to 40 days old. Older than this, seedlings do not give better yields on transplanting. Very young seedlings exhibit larger mortality on transplanting.

Transplanting: Transplanting or replanting is the technique of moving a plant by uplifting from one location to another. From nursery beds seedlings or saplings are shifted and planted either in the field or greenhouses for commercial growing. Seedlings are uprooted if grown in soil medium. They are transplanted with growing medium. Uprooted seedlings take time to establish at a new place and face transplanting shock- time taken by roots to establish contact with the soil or growing medium.

In soil culture, also known as in-ground culture, crops are raised on level ground as well as in raised beds. Soil culture is more often used in growing vegetables (e.g., tomatoes, lettuce, cucumbers, and peppers) rather than ornamental crops such as herbs, roses, freesia, and foliage plants as well as popular with smaller commercial and organic growers. The soil should be well drained, fertile, have a medium to light texture and be high in organic matter. The soil in a greenhouse should be worked as deeply as possible to break any existing hardpans or those that may have developed because of repeated traffic over the area. Fumigation or pasteurization of the soil is a must before each crop or at least once a year. This will help to destroy disease, nematodes and weeds. If soil is steamed, hold it at 180 degrees F (82°C) for 4 hours. Production techniques used in soil culture are similar to intensive crop production methods used in the field. Although soil is readily available at most places where a greenhouse is located most commercial growers, no longer rely on soil culture in the greenhouse as they did ealier. Some of the reasons include insect and disease pressures and costly fumigation.

Crops are grown in soil. There are different types of soil. The soil type helps farmers decide what crops will grow best because some crops do better with particular types of soil. Testing the soil helps determine what nutrients are available or unavailable for growing certain crops. Farmers usually have local agricultural experts test the soil on their land for information on how to proceed in growing crops. The best soil has a balance of nutrients, such as potassium, magnesium, and others. Certain crops may need more of one nutrient, so farmers put back those ingredients into the soil for better crops.

Six different types of soil are listed below along with the crops which do well in these soils.

1.Loam: This type of soil helps grow the best possible crops because it provides the necessary elements for plant growth and development. Loamy sand contains mostly sand plus clay and silt. Such soils are good for root vegetables, such as carrots, radish, turnip, beets, leafy vegetables, potatoes and tomatoes.

2.Clay: Cabbage and broccoli grow well in clay soil, but it is not good for root vegetables because of its dense texture which does not allow free flow of water.

3.Sand: Root vegetables, such as turnips, parsnips, and carrots, grow well in sandy soil.

4.Silt: Silty soil is fertile and offers nutrients for plant development. Lettuce, cabbage, carrots, turnips, and many other vegetables flourish in silt. Strawberries, raspberries, blackberries do well.

5.Peat: Peaty soil provides plant growth when mixed with rich organic matter, lime, and compost that reduces its acidity. Legumes, root crops, cabbage, and spinach are easily grown in soil that’s well-drained.

6.Chalk: Sweet corn, beets, spinach, and cabbage are among the vegetables that benefit from chalkier soil. It is recommended that farmers use fertilizers and balance the pH levels to deal with the alkaline that can sometimes stunt growth.

Soil map is a map showing diversity of soil types and its properties such as pH, texture, organic matter and depth of horizons in the area of interest obtained as the end of soil survey. Generally, soil maps are used to simply identify soils and their properties, but are sometimes required for more specific purposes, such as the suitability of soils for a particular crop, suitability for irrigation, erosion risk and many other specific needs or environmental threats.

Soils fulfil many functions important for agriculture, forestry and the management of soil resources and natural hazards. The functionality of soils depends on their properties; hence, accurate and spatially highly resolved maps of basic soil properties such as texture, organic carbon content and pH for specific soil depth are needed for the sustainable management of soils. The surface soil organic carbon (SOC) concentration is a useful soil property to map soils, interpret soil properties, and guide fertilizer and agricultural chemical applications.

Traditionally farmers apply fertilizers, chemicals and other crop production inputs to optimize the production of the field as a whole. This results in application of over application of inputs and low inputs in certain locations of the field because of variation in field characteristics including soil organic carbon, soil texture, soil nutrients, field topography, and other properties. In addition, uniform applications may increase the chances of pollution of the environment due to excess application in some field area. Precision farming technology has been shown to optimize application rates if the variation of field characteristics can be used to guide the application rate of crop-production inputs. The organic carbon concentrations of surface soil have been used to spatially vary the application rate of some crop-production inputs. The surface soil organic carbon concentration affects the activity of many herbicides, influences plant-available nitrogen and also affects the soil’s ability to adsorb plant nutrients. Knowing its concentration may therefore be useful, especially if its spatial distribution could be determined accurately and for low cost.

In crop production mostly basic inputs are seeds or seedlings/planting material, irrigation water, fertilizers, weedicides and pesticides. Site specific input application means providing plant input requirement at right time, in right amount and at right place. Site specific is a term that refers to treating the smallest possible area as a single unit. A site is simply the smallest unit the farmer can manage with the tools available. The treatment of each site is specific to the needs of each site as determined by soil test data and crop scouting reports. There are technology tools for using site-specific management more effectively. In precision agriculture site specific application tools and technologies are as under

In crop production mostly basic inputs are seeds or seedlings/planting material, irrigation water, fertilizers, weedicides and pesticides. Site specific input application means providing plant input requirement at right time, in right amount and at right place. Site specific is a term that refers to treating the smallest possible area as a single unit. A site is simply the smallest unit the farmer can manage with the tools available. The treatment of each site is specific to the needs of each site as determined by soil test data and crop scouting reports. There are technology tools for using site-specific management more effectively. In precision agriculture site specific application tools and technologies are as under:

A. Precision irrigation

The prevalent flood irrigation in crops would be the thing of past because of limited water resources, waste of water in leaching and evaporation and cumbersome management resulting in considerable loss of water. The micro irrigation (sprinkler and drip- irrigation) are preferred depending on the field topography. Undulated fields are better irrigated by sprinkler and laser levelled field by drip irrigation. There are precise tools to deliver only required amount of water at different stages of growth of crops with the help of sensors. Irrigation water volume release is mechanised and automated. Efforts of using microirrigation methods such as sprinkler and drip irrigation have been made in last three decades in many parts of the world. There is no ideal irrigation method available which may be suitable for all weather conditions, soil structure and variety of crops cultures.

Precision irrigation is worldwide accepted concept in irrigation. Precision irrigation involves the accurate and precise application of water to meet the specific requirements of individual plants or management units and minimize adverse environmental impact. Commonly accepted definition of precision irrigation is sustainable management of water resources which involves application of water to the crop at the right time, right amount, right place and right manner thereby helping to manage the field variability of water in turn increasing the crop productivity and water use efficiency along with reduction in energy cost on irrigation. It utilizes a systems approach to achieve ’differential irrigation’ treatment of field variation (spatial and temporal) as opposed to the ’uniform irrigation’ treatment that underlies traditional management systems. Precise and regulated application of irrigation water and plant nutrients at low pressure and frequent intervals through drippers/emitters directly into the root zone of plant with the help of close network of pipes is known as drip irrigation system.

Sensing of heterogeneities in the field is the prerequisite for timely and spatially adjusted insect pests and disease management. Recent developments in sensor technologies have led to a broadening of their capacity to detect pests and thereby improve application in crop protection practice. These sensors can be space-borne (satellite), air-borne (airplane, unmanned aerial vehicle) or groundbased (handheld, vehicle-mounted) and provide spatial information that has added value management. Insects are usually unevenly distributed throughout an area in nature. Despite this knowledge, analytical methods and technology have limited insect pest management to uniform management decisions in the field. The methods and technology to map and analyse insect spatial distribution have been developed to a level where the uneven nature of insect populations can be considered for application of insect-pest management practices. Site-specific pest management utilizes spatial information about pest distribution to apply control method only where pest density is economically high within a field. This results saving in pesticide and labour cost. In conventional farming pesticides are applied uniformly to the field resulting in heavy use of pesticide and labour beside polluting the environment. Site-specific application of pesticides in precision farming helps to overcome this problem

Near-range and remote sensing techniques have demonstrated a high potential in detecting diseases and in monitoring crop stands for sub-areas with infected plants. The occurrence of plant diseases depends on specific environmental and epidemiological factors; diseases, therefore, often have a patchy distribution in the field. The use of non-invasive optical sensors for the detection, identification and quantification of plant diseases on different scales is made of in precision farming. Most promising sensor types are thermography, chlorophyll fluorescence and hyperspectral sensors. For the detection and monitoring of plant disease, imaging systems are preferable to non-imaging systems. To utilise the full potential of these highly sophisticated, innovative technologies and high dimensional, complex data for precision crop protection, a multi-disciplinary approach—including plant pathology, engineering, and informatics—is required.

Yield mapping or yield monitoring is a technique in agriculture of using GPS data to analyse variables such as crop yield and moisture content in a given field. This data produces a yield map that can be used to compare yield distribution within the field from year to year. This allows farmers to determine areas of the field that, for example, may need to be more heavily irrigated or are not yielding any crop at all. It also allows farmers to show the effects of a change in field-management techniques, to develop nutrient strategies for their fields, and as a record of crop yield.

Yield is ultimate indicator of variation of different agronomic parameters in different parts within the field. So mapping of yield and interpretation and correlation of that map with the spatial and temporal variability of different agronomic parameters helps in development of next season’s crop management strategy. Yield monitors measure the volume or mass flow rate to generate time periodic record of quantity of harvested crop for that period. Time periodic yield data is then synchronized with location address obtained from on-board GPS system to create most common colour coded thematic map. Yield mapping can be carried out easily in mechanized crops. By using either loading cells that weighed the crop passing on a conveying belt or an array of sonic beam mounted over the grape discharge chute to estimate the volume, and the tonnage, of fruit harvested. Tree crops seem to have more stable yields. In handpicked fruits yield mapping is more difficult. Yield maps are one of the most valuable sources of spatial data for precision agriculture. In developing these maps, it is essential to remove the data points that do not accurately represent the yield at a corresponding location. Map averaging or smoothing is usually done to aid data interpretation. A long yield history is essential to avoid drawing conclusions that are affected by the weather or other unpredictable factors during a particular year. Processed yield maps can be used to investigate factors affecting the yield or to prescribe variable rate applications of agricultural inputs according to spatially variable yield goals (yield potential).

Precision farming involves the collection of data by observation and measurement, and the subsequent response. Sensing is key to the collection of data; whether this is remote from space by satellites, by aircraft or drones, or by proximal sensors used on the ground, mounted on vehicles or otherwise. Responses are increasingly automated and data are often integrated into wholefarm management systems. Early commercial applications were directed towards improving crop nutrition, however, utilising precision technologies to control weeds, pests and diseases is now a reality.

Precision crop protection requires detailed data on the occurrence and distribution of problems at the earliest possible stage of detection. An early detection is the key for successful management of pests in precision farming. Some of the key aspects are:

Identification: Identifications of crops, targets and beneficial; temporal and spatial distribution: presence of the target before, during and after the crop growth period;

Sampling techniques: statistically valid sampling regimes must be used to permit an accurate view of any problem

Thresholds: under particular circumstances, the point at which action to ensure levels of infestation or damage are kept to those deemed to be acceptable;

Prediction: the speed and pattern of development of a problem must be capable of being modelled, e.g. spread and severity of insect pests and fungal diseases; weed emergence according to species, dormancy and environmental conditions.

Site-specific weed control technologies practiced in precision farming are defined as machinery or equipment embedded with technologies that detect weeds growing in a crop and take action to maximise the chances of successfully controlling them taking into account predefined factors such as economics.Some of the commercial hardware and software developed for precision agriculture practices comprise tools for weed mapping and control software that adapts spraying to local weed occurrence. However, few farmers have adopted sitespecific weed management, although several studies have shown that weed occurrence and density varies significantly within a farm or a field. Site-specific weed control techniques have gained interest in the precision farming community over the years. Managing weeds on a subfield level requires measuring the varying density of weeds within a field. Decision models aid in the selection and adjustment of the treatments, depending on the weed infestation. The weed control can be done either with herbicides or mechanically. A site-specific herbicide application technology can save large amounts of herbicides. Mechanical weed control techniques adapting to the weed situation in the field are applicable to a wide spectrum of crops.

A system for the discrimination of different weed species and crops from images is done which generates weed maps automatically. Models for the yield effect of weeds are developed and applied in on-farm-research experimental setups. Economic weed thresholds are derived and used for an herbicide application with a patch sprayer.Herbicide use has not eliminated weed problems in agriculture and the need for manual weed removal is still an issue within specialty crop systems, particularly during the first several weeks of crop emergence when competition for resources is greatest.

Precision agriculture is a powerful technology with potentially important applications to weed management. However, growers should remember good agronomic practices, including preventing weed infestations, managing herbicides wisely to prevent resistance, and minimizing environmental impact associated with weed management. Weeds, and methods used to control weeds, can have negative economic and environmental impacts. With precision agriculture, growers can take advantage of the patchy nature of weeds by targeting management efforts only where they are needed instead of wasting expensive and potentially hazardous inputs where weeds are not present. Weeds are patchy because weed spread, survival, and reproduction are variable within a field and over time. Weed patches stay in about the same place from year to year, even though weed density within a patch may vary

Precision agriculture is yet to be popularized for taking its enormous advantages. In laser land levelling and micro irrigation/ fertigation it must have made its prominence but others it is with research institutes where research is focussed on the spatial variability of production environments, development of efficient and suitable data management systems, efficiency of various types of image analyses and optical sensing, efficiency of sensors and related technologies, designs of precision agriculture equipment, optimal inputs and service uses, and their spatial allocations, potentials of unmanned aerial vehicles (UAVs), nanotechnologies and several others.The adoptions of precision-agriculture technologies have, so far, mostly been limited to parts of developed countries. Major contributions to the profitability of precision agriculture is reduced costs of plant protection inputs and higher output revenues.

Plants require proper environment for its growth and development. If environment is not suitable crop would not do well. To ensure proper environment to commercial crops for their better growth and development covered structures are used which provide microclimate appropriate for their growth and development. Growing of crops under such protective structures, also known as greenhouses, is termed as greenhouse technology. The structures harness solar radiation for photosynthesis in plants or can be provided with artificial lights (LEDs) for the purpose. The technology embraces many aspects of farming such as modelling of structures, agronomic practices for the production of the crop and the commercial viability of the venture. The technology ensures crop production in a cover more or less independent of natural prevailing environment. The covering or cladding permits desirable aspect of sun and air and help in modifying crop production environment inside. The modification of environment is aimed of creating micro-climate inside the structure/greenhouse most appropriate for the growth and development of the crop.

Hence greenhouse can be defined as a framed or inflated structure with claddings like glass polyethylene sheets, poly carbonates, fibre reinforced plastics and others in which plants are grown by creating microclimate conducive to crop for its growth and development with or without automation and mechanization. The purpose of growing crops under greenhouse conditions is to extend their cropping season and to protect them from adverse environmental conditions, such as extreme temperatures, precipitation and pests. A large number of greenhouses/poly houses have come up in almost all states of India. Though in infancy but greenhouse cultivation particularly in horticulture crops and nursery production is visible.

Different types of greenhouses or protected structures are designed to meet the specific needs. They can be classified based on shape, utility, construction, cladding material, net houses and technology adopted.

A. Classification based on shape of greenhouse: Greenhouses can be classified based on their shape or style. For the purpose of classification, the uniqueness of the cross section of the greenhouses can be considered as a factor. As the longitudinal section tend to be approximately the same for all types, the longitudinal section of the greenhouse cannot be used for classification. The cross sections depict the width and height of the structure and the length is perpendicular to the plane of cross section. Also, the cross section provides information on the overall shape of the structural members, such as truss or hoop, which will be repeated on every day. The commonly followed types of greenhouse based on shape are lean-to, even span, uneven span, ridge and furrow, saw tooth and quonset.

Lean-to type greenhouse: A lean-to design is used when a greenhouse is placed against the side of an existing building. It is built against a building, using the existing structure for one or more of its sides. It is usually attached to a house, but may be attached to other buildings. The roof of the building is extended with appropriate greenhouse covering material and the area is properly enclosed. It is typically facing south side. The lean-to type greenhouse is limited to single or double-row plant benches with a total width of 7 to 12 feet. It can be as long as the building it is attached to. It should face the best direction for adequate sun exposure. The advantage of the lean-to type greenhouse is that, it usually is close to available electricity, water, and heat. It is a least expensive structure. This design makes the best use of sunlight and minimizes the requirement of roof supports. It has the following disadvantages:

Application of greenhouses in agriculture is mainly to modify microclimate for the production of crops with multiple objectives of raising crops in season offseason, round the year, early crops, late crops, breed crops, raise genetically engineered plants, seed production so and so forth. With hi-tech agriculture and modern techniques greenhouses are used for growing crops anywhere and everywhere, on soil under soil, water, under water and space. Greenhouses are mainly used for crop nursery production, crop production largely in vegetables, flowers and herbs. Among fruits mainly strawberry is grown under greehouses commercially. Other fruits can also be grown.

Besides crop production greenhouses are used for dehydration or drying of produce, seed production, for crop improvement using biotechnology and other sciences. Use of greenhouses in uncongenial environments for crop production is common in places like high altitudes, deserts, arctic climate and alike. One of the largest greenhouse complexes in the world is in Almería, Andalucía, Spain, where greenhouses cover almost 200 km2 (49,000 acres). One of the important use of greenhouses world over is raising tissue culture plants through a popularly known process hardening. For hardening of tissue culture plants different types of low and high technology greenhouses are must. Greenhouses in hot, dry climates used specifically to provide shade are sometimes called shade houses. Hydroponic crop production is generally done in greenhouses. Greenhouses are also used as retail market centres mainly for ornamental plants and seedlings and grafts of horticultural crops. Greenhouses are used for maintaining bee (honey bees and bumble bees) colonies as crop pollinators.

Many crops can be grown in greenhouse but the choice depends on number of factors.

1.Requirement of the farmer, what for she/he wants to grow the crop.

2.For personal use number of vegetable crops and herbs and fruits like strawberry and papaya can be grown.

3.In case of commercial crops, the market must be ascertained before the choice of the crop.

4.Greenhouse must be equipped to create micro-climate for the crop of choice.

5.The choice of crop is a crucial factor for the economic feasibility and success of a commercial greenhouse operation. The revenue of cultivated crop makes the venture to progress.

6.Crop varieties, suitable for greenhouse cultivation should differentiate themselves from open-field varieties to fetch better price on quality.

The productivity of a crop is result of genetic make-up (heredity) and environment (climate) and their interaction. The components of crop environment or climate or microclimate are light, temperature, air compositions and the nature growing medium or soil. In open fields, only manipulation of nature of the soil or root medium by tillage, irrigation and fertilizer application is possible. Under greenhouse structure control of any one or more of the components of the micro climate is manipulated.

Light

The visible light of the solar radiation is a source of energy for plants. Light energy, carbon dioxide (Co2) and water all enter in to the process of photosynthesis through which carbohydrates are formed. The production of carbohydrates from carbon dioxide and water in the presence of chlorophyll, using light energy is responsible for plant growth and reproduction. The rate of photosynthesis is governed by available fertilizer elements, water, carbon dioxide, light and temperature. The photosynthesis reaction can be represented as follows

Soil is the main growing medium. Natural as well as synthetic substitutes to soils are cropping up. Under greenhouse cultivation growing medium is generally top soil as used in open field/traditional farming. The practices of soil preparation for planting crops are more or less same as under open field. Generally, crops are planted on raise beds. As under open conventional farming soil preparation are made as per the crops or their varieties/hybrids to be grown. To enrich the soil with nutrients soil is tested for its physical and chemical properties and amended accordingly keeping in view the crop requirement. The soil composition is checked with each crop cycle and amended as per requirement of next crop. To avoid the harmful microbes and insects build up in the soil it is advisable to solarize or fumigate the greenhouse soil each year during hottest month of the year. Soil solarisation is an environment friendly soil pathogen management method and practiced widely in north India.

Soil Solarisation

Soil solarisation is an environment friendly method of using solar thermal power for controlling pests such as soil borne plant pathogens including fungi, bacteria, nematodes, and insect and mite pests along with weed seeds and seedlings in the moist soil by mulching the soil usually with a transparent polyethylene cover, to trap solar energy in greenhouses. It may also be described as a method of decontaminating soil or soil disinfestation using sunlight or solar thermal power. This energy/temperature causes desirable physical, chemical, and biological changes in the soil.

Planning

A greenhouse, is basically the purpose of providing and maintaining a growing environment that will result in optimum production at maximum yield. The agriculture in the controlled environment is possible in all the regions irrespective of climate and weather. It is an enclosing structure for growing plants, greenhouse must admit the visible light portion of solar radiation for the plant photosynthesis and, therefore, must be transparent. At the same time, to protect the plants, a greenhouse must be ventilated or cooled during the day because of the heat load from the radiation. The structure must also be heated or insulated during cold nights. A greenhouse acts as a barrier between the plant production areas and the external or the general environment.

Site selection and orientation

A greenhouse is designed to withstand local wind, snow and crop loads for a specific cropping activity. In this way, the structure becomes location and crop specific. The building site should be as level as possible to reduce the cost of grading, and the site should be well aerated and should receive good solar radiation. Provision of a drainage system is always possible. It is also advisable to select a site with a natural windbreak. In regions where snow is expected, trees should be 30.5 m away in order to keep drifts back from the greenhouses. To prevent shadows on the crop, trees located on the east, south, or west sides should be at a distance of 2.5 times their height.

Greenhouses should provide a controlled environment for plant production with sufficient sunlight, temperature and humidity. Greenhouses need exposure to maximum light, particularly in the morning hours. Consider the location of existing trees and buildings when choosing your greenhouse site. Water, fuel and electricity make environmental controls possible that are essential for favourable results. For this reason, use reliable heating, cooling and ventilation.

The greenhouse temperature requirements depend upon which plants are to be grown. Most plants require day temperatures of 70 to 80 degrees F, with night temperatures somewhat lower. Relative humidity may also require some control, depending on the plants cultured. Some plants grow best in cool greenhouses with night temperatures of 50 degrees F after they are transplanted from the seeding tray. These plants include azalea, daisy, carnation, aster, beet, calendula, camellia, carrot, cineraria, cyclamen, cymbidium orchid, lettuce, pansy, parsley, primrose, radish, snapdragon, sweet pea and many bedding plants. Some plants grow best in warm greenhouses with night temperatures of 65 degrees F. These plants include rose, tomato, poinsettia, lily, hyacinth, cattleya orchid, gloxinia, geranium, gardenia, daffodil, chrysanthemum, coleus, Christmas cactus, calla, caladium, begonia, African violet, amaryllis and tulip. Tropical plants usually grow best in high humidity with night temperatures of 70 degrees F.

The variety of greenhouses and greenhouse material, equipment and accessories are so many. However, there are certain basic materials that essential in almost all types of green houses. These are

Structural framing materials

Such materialsinclude low maintenance non-heat conducting timber; strong and durable galvanized steel; or light, low-maintenance and sturdy aluminium alloys. Though plastic pipe frames are usable, they are not very strong to withstand snow load or strong wind sheering forces. What one should choose as the framing material would be determined by the material one wishes to use as glazing, his budget and the permanence of the structure one desires. Aluminium is a popular material for greenhouse framework because it is relatively lightweight, rustproof, affordable and easy to assemble. The downside is that it is not a good insulating material and in very cold weather, heat loss from the metal frame could inflate your heating bill. Also, you would need to look for sturdy frames if your greenhouse is located in an area that experiences high winds. Condensation could also occur on an aluminium frame. Wooden structural frameworks for garden greenhouses are also a popular choice for its aesthetic value, natural feel and the ’warmth’ it exudes. It is an easy material to work with especially if you are not using a greenhouse kit for building. Some greenhouse owners would settle for nothing else as they believe it is the only material that complements the natural beauty of plants inside the greenhouse! Wood is a good insulating material so it will not allow heat loss in cold weather. Reinforced wood has superior strength and has an excellent load bearing capacity. Being a natural material, it has the potential to develop mildew or disease and offer a haven to tiny pests. So, when you choose wood to build the framework of your greenhouse, be sure that you pick a high quality hardy wood such as redwood, cypress or cedar. Also, treat wood with non-hazardous chemicals so that your plants are not adversely affected. The preservatives used for wooden greenhouse frames should be pressure treated, salt type or copper naphthenate. Copper naphthenate is a general use preservative used for pressure treating utility poles and timber. It is known to be very effective in preventing mould, mildew and dry rot. It works very well against wood-damaging fungi and insect pests. Pentachlorophenol is a restricted use wood preservative and is toxic to plants and humans. It is not available to the general public and poles or timber treated with it are not suitable for use in a greenhouse. PVC pipe can also be used as support for small greenhouses that are to be covered with polyethylene, but PVC requires additional support to withstand strong winds. Being flexible, PVC can be used particularly well in hoop houses. Though it has the advantage of offering insulation and, if UV treated, are long-lasting, they are not good at bearing the load of hanging baskets and shelving to any appreciable degree. PVC that is treated to be resistant to ultraviolet radiation is also known as UPVC.

There are different types of greenhouses, the low cost and high cost or low technology or high technology greenhouses. The cost of greenhouse and expenditure on crop production under these greenhouses would vary according to technology to be used and the crop is to be produced. The cost would vary from place to place with location of greenhouse. For each type of greenhouse its cost would vary according to geo-climate, the production practices and input expenditure/availability. The cost of construction of greenhouse in 2019 hence varies from Rupees 500 to 6000 per square meter.

The modern or climate controlled greenhouse requires massive inputs of energy and cost of claddings to grow crops out of season making them high cost structures. However, growing of certain horticulture crops and their nurseries out of season is happening in a sustainable way, using the heat from the sun and soil too. These are called passive solar greenhouses designed to retain as much warmth as possible. This concept has revolutionized vegetable production in Ladakh, high altitudes and other parts of the country in winter months.

The solar greenhouse is especially successful in China and are contributing mainly in vegetable production. Solar passive greenhouses are designed in different shape size using different local and other materials keeping in view the local climate and terrain. The poly houses mentioned earlier such as, low cost polyhoses, Ladakhi poly house, solar trench, polyench are passive solar green houses. Being the opposite of the climate controlled greenhouse, the passive solar greenhouse is heated all-year round with solar energy alone, even when the outdoor temperature drops below freezing point. The indoor temperature of the structure can be higher than the outdoor temperature. The temperature can be around 25°C (45°F).

Such greenhouses have been experimented by Defence Research and Development Organization through its establishment FRL (Field Research Laboratory) now DIHAR (Defence Institute of High Altitude Research), Leh/ Ladakh since 1962 during November to the end of March, the period during which the outside temperature drops there below freezing. The average temperature in the coldest month is between -15°C and -18°C. Over the several decades of research different and effective designs of such greenhouses have been standardized which are suitable to produce fresh vegetables like most of the leafy vegetables, tomato, cole crops and potato at sub zero temperature.

There are several systems for greenhouse heating based on heat source and purpose or crops to be produced in greenhouse.

Electric heaters

Unit space heaters, either floor mounted or supported, are normally dependent on electricity supply supported by stand-by generators. Abroad they are fuelled with natural or bottled gas or fuel oil and use fans for heat distribution. This system requires a relatively moderate capital investment, is easy to install, and provides for easy expansion of facilities. If unit air heaters are used, they should be spaced and directed to blanket the entire area with heated air.

Hot Water Systems

Hot water systems utilize metal pipes that can be perimeter, under benches, or overhead fan forced unit heaters can be used. This system requires a boiler, valves, and other necessary controls. Hot water system is simpler to install and normally requires less maintenance than a steam system. Hot water systems are mainly used in smaller greenhouse.

About 80% of the world population live in developing countries and are dependent on agriculture. Agricultural products, just after harvesting, are dried to the safe moisture level. Open solar drying for drying agricultural products is being practiced since ages throughout the world. Due to its several drawbacks as danger of (dust, rain, ultra-violet rays, birds, animals etc.), advance technique, i.e. greenhouse drying, is being adopted for drying crops to reduce the drying time and increase the quality of the food products.

Drying involves a heat and mass transfer phenomenon in which heat energy supplied to the product surface is utilized in two ways: (i) to increase the product surface temperature in the form of sensible heat and (ii) to vaporize the moisture present in product through the provision of the latent heat of vaporization. The removal of moisture from the interior of the product takes place due to induced vapour pressure difference between the product and surrounding medium. The moisture from the interior diffuses to the product surface to replenish the evaporated surrounding moisture.

The working principle of greenhouse drying is in which the product is placed in trays receiving the solar radiations through the plastic cover and moisture is removed by natural convection or forced convection.

Greenhouse drying are being adopted to reduce the losses and to increase the quality of the dried products. Solar energy is the most promising power source of energy for drying of agricultural products. Most of the farmers adopt open sun drying because it is abundant and inexpensive. But the open sun dried products are also subjected to remarkable losses due to environment. Losses of fruits and vegetables are estimated to be 30%-40% during drying under open sunlight. The post-harvest losses can be reduced by adopting advanced means of drying, i.e. greenhouse drying. The greenhouse dryer can be operated in natural and forced mode as required. Studies reveal that the greenhouse dried products are of superior quality and better colour retention as compared to open sun drying.