eChapters

INTRODUCTION

Potatois theworld’s most importantnon-grain foodcommoditythatranks fourth as main food crop in the world after rice,wheat and maize. The crop is grown inmorethan 100 countries, mainly in Asia (195.67 million tons)and Europe (121.76 million tons)(yieldin 2017 as per FAOSTAT, 2019). Because of its efficiency in producing high dry matter, energyand edibleprotein per unit area per unit time, it holds promise for food security in the scenario of ever growing world population. The full potential of this crop however, can onlybe realized if diseases and pests are kept under control, especially in asubtropical country like India, wherethe weather is highly conducive for a number of pathogens.

A number of soiland tuber borne diseases are known to affectthe potato crop causing heavy yield losses. These diseases not only reduce quality and market value of the producebut also spread to new un-infested fields through infected seed potato tubers. Diseasessuch as black scurf, common scab and powdery scab disfigure potato tubers and reduce their market value whereas dry rot, charcoal rot and softrot spoilthe harvested produce during transitand storage. Potatowart is a serious disease which once established is difficult to eradicate and thus require quarantine measures. Bacterial wilt or brown rot of potato is another serious disease which is likely to threaten potato cultivation with the rise in globaltemperature and requires immediate attention.

Potato is becoming a more and more important foodstuff in the world and therefore, its cultivation is expanding fast especially in developing countries. This intensivecultivation, in fact, has led to the emergence of diseases in certain areas where they were of less importance in the past. For instance common scab, known to be a minor disease about2-3 decades ago, is now emerging as serious problem in many potato growing areasof the country including Indo Gangetic plains. Similarly brown rot/bacterial wilt which was endemic in mid hills and plateau region, has now become a limiting factor for potato cultivation in many areasin Madhya Pradesh, West Bengal, north eastern region and in Kumoan hills of Uttrakhand. Sclerotium wilt on the other hand has shown upward trend in plateau region especially in Karnataka. This is because the dynamics of pathogens keeps on changing over time and space and also with the changing farming practicesof a region. Many such new diseases are likely to emerge in a big way in future also, hence warrants regular and careful monitoring. In the following pages, the majorsoiland tuberbornediseases are discussed with special reference to India.

INTRODUCTION

Potato (Solanum tuberosum L.) is afflicted by many kinds of viruses and their various strains belonging to different taxonomic groups (Table 1) throughout the world resultingin declinein yieldand tuber quality. Exact estimation of yield and economic losses caused by potato viruses depends on a number of factors mainly strain of the virus, variety, seasonand growingconditions etc. Generally crop losses ranges between 5 to15 per cent if all plants are secondarily infected with PVX and PVS; 15-30 per cent for 100 per cent secondary infection of PVYnand 40-70 per cent due to PLRV. Besides, in Europe and North America Potato spindle tuber viroid (PSTVd) is wellknown to reduce yieldssignificantly (16-64 per cent) dependingon the viroid strain/potato varietyand warmweather (Singh, 1988). Thesevere strains of Potato virus Y (PVY)and Potato leafroll virus (PLRV) have the potential to reduce yield up to 80 per cent, while mild viruses like Potato virus X (PVX), Potato virus S (PVS)and Potato virus M (PVM) can cause up to 30 per cent yield loss in infected plants. Atospovirus Groundnut bud necrosis virus (GBNV) causing severe stem/leaf necrosis disease in plains/plateaux of central/western India heavily infects the early crop of potato. Similarly, a whitefly transmitted begomovirus Tomato leaf curl New Delhi virus-potato (ToLCNDV) known to cause apical leafcurl disease in India, has become a serious problem in North Indian plains.

The viruses can be mechanically transmitted with plant sap, by contact and with seeds. Infectedtubers, whitefly and aphid vectors are importantfactors for the transmission of the virusesin nature. Potatoviruses are transmitted by aphids in two ways. The viruses are either non-persistent (stylet-borne) or persistent and circulative (they are ingested and persist in the aphid throughout its life cycle). The most common persistent and circulative virus affecting potatoes in India is PLRV. Common non-persistent or stylet-borne viruses are PVY, PVA, PVS and PVM. Control of circulative viruses by insecticides is highly effective, which is not the ease with stylet borneviruses. Sustainable potato production is possible only if the virus incidenceis kept under check especially in sub tropics where the weather is highlyconducive both for vectors and the common viruses. In thischapterthe major viruses and viroidof potato including symptomatology, diagnostics and their management have been discussed.

INTRODUCTION

Insect pests cause variable and complex problems for potato farmers. Insect pests account for 16% of the crop losses of potato worldwide, and reductions in tuber yield and quality can be between 30% and 70% for various insect pests. India has a greatdiversity of insect pests that attack potato. Thesepests can damage potato plants by feeding on leaves, reducing the photosynthetic area and efficiencybyattacking stems, weakeningplants and inhibitingnutrient transport, and by attacking the potato tubers destined for consumption orfor use as seed. In India, approximately 60 billion rupees (US$1.2 billion)worth of potato tubersare lost annually due to pest damage, which accountsfor 10–20% of total production (Chandel et al., 2013). The potato pests are grouped into soil pests, foliage feeders, sap feeders, and storage pests. Inseed production, aphids and whiteflies are of greatest concern. In ware production, the key pests may be insects which attack tubers, such as tubermoth, whitegrubs, and cutworms. In some situations, foliage feeders suchas noctuid moths and coccinellidbeetles are also important.The Potato cyst nematode (PCN) (Globodera spp.) and root knot nematodes (RKN) (Meloidogyne spp.) are amongst the most economicallyimportant nematode pests of potato. Cyst nematodeshave amazing adaptation for long term survival in the soil, even in the absence of a suitable host whichmakesthemchallenging to the farmers, scientists and policy makers. They are subjected to stringent quarantine and/or regulatory procedures, wherever they occur and presents a serious threat to domestic and international commerce in potatoes. RKNs are prevalent all over the world and can cause significantcrop loss in both warmand cool climatic conditions, depending on their species. In this chapter, the current information on biology, ecology and management of the major potato pests is discussed in the Indiancontext.

INTRODUCTION

India is the second largest producer of potato in the world contributing about 12.52%of production from 11.29 % area under potato with an average yield of 22.31 t/ha. Potato is grown in almost allthe states in India under diverse agroclimatic conditions. About 90% of the total potato area is located in the subtropical plains, 6% in the hills and 4% in the plateau region of the peninsular India. Indo-Gangetic plains account for about 76% of the potato area and about 87% of the potato production in the country. Availabilityof assured qualityseed is the most important production constraint in all the potato growing regions of the country.

Seed is the basic vital input in agriculture and its timely availability in adequate quantity as per demand decides the strength growth of agricultural economy in the country. Seed has played a very important role in India’s green revolution and shallcontinue to be the importantcomponent in the days to come. There is a saying “as you sow, so shall you reap”, which traditionally relates to the quality of seed determining the production, has been the wisdom of our forefathers. The traditional farmers’ practices are to save their own seeds generally selected from healthy plants from fields which are freefrom diseases pests, harvest them separately, clean, cure and then store in containers and inspect regularly for any kind of damage; or they get quality seed from other seed producing farmers onbarter basis, indicating thereby the importance of seed in their production system.

INTRODUCTION

Potato production in India has shown a steady increase in the past, presently making the country second largest potato producer in the world. As per the latest available data, during 2018-19, approximately 52.5 million metric tons of potatoes have been produced (NHB, 2019). Increase in production, often resulting in gluts at harvest, has led to several post-harvest problems like storage and proper utilization of the produce. About 90% of the potato crop in the countryis harvested during January-February in the Indo-Gangetic plains comprising the states of Punjab, Haryana, UP, Bihar, West Bengal, MP and Gujarat where the harvest is followed by rising temperatures of hot and dry summer, and further by warm and humid rainy season. Since potato tubers contain about 80% water, under such circumstances, a semi-perishable commodity like potato, cannot be stored for more than 3-4 months without refrigeration because of very high losses due to shrinkage, sprouting and attack by microorganisms.

Therefore, potatoes are mostly stored in refrigerated cold stores maintained between 2-4^oC and 90-95% relative humidity (RH). Low temperature storage has advantages of natural control of sprout growth, low evaporative losses and minimum risk of diseases and pests. These conditions are ideal for storage of seed potato but these cause cold-induced sweetening leading to excessive accumulation of sugars in most of the potato cultivars making them unfit for processing due to browning in chips. Also, such tubers are less preferred for consumption because of sweet taste. Hence, potatoes meant for processing are either stored under non-refrigerated conditions for short term or stored at 10-12^oC with the use of some sprout suppressant like CIPC (isopropyl N-(3chlorophenyl) carbamate) to minimize the accumulation of reducing sugars. The chips produced from such tubers are light in colour.

Potato processing on the other hand is essential to sustain the increasing potato production in the country and to provide proper remuneration to the cultivators. Potatoes can be processed into a variety of products. Potato chips, French fries and dehydrated chips are the most popular processed potato products in the organized and unorganized sectors. The present chapter deals with postharvest management of potatoes in terms of dormancy and sprouting issues and storage technologies for seed, table and processing potatoes. Besides, areas suitable for growing processing potatoes in the country, potato processing scenario in the organized and unorganized sectors are also discussed.

INTRODUCTION

Potato plays a vital rolein foodsecurityworldwide. It is the third most important food crop, afterrice and wheat. It is a nutrient-rich crop which provides more calories,vitamins and nutrients per unit area than any otherstaple crops. FAO declared potato as the crop to address future global food security and poverty alleviation during2008. In Indian agriculture, potatoplays a very important role as it alone contributes about 21 percent of the total vegetable area and 26 percent of total vegetable production of India (DAC&FW, 2017a). As per FAOSTAT data for the year 2017,India with48.6 million t is ranked second in potato productionin the world, onlybehind Chinawith 99.2 million t (Figure 1).

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.

The following various types of irrigation methods and their systems are used in crop production in greenhouses and plant nurseries.

1.Hand Watering

2.Perimeter Watering System

3.Tube Watering System

4.Drip Irrigation System

5.Overhead Spray System

6.Ebb and Flow System.

Drainage is the natural or artificial removal of excess water from a surface or sub-surface from an area or field or soil or greenhouse. The internal drainage of most agricultural soils in greenhouse is good enough to prevent severe waterlogging. Water logging creates anaerobic conditions that harm root growth in absence of oxygen. Soils need artificial drainage to improve production or to manage water supplies in certain conditions. Though the roots need moisture but they need oxygen too and poor drainage is g result in roots rotting and death of plants.

The irrigation water inside the greenhouse may accumulate and cause anaerobic condition. Similarly plants in pots should not accumulate water. Water should not stand in pots and beds for longer period. If it stays longer drainage is poor and needs to be corrected. It is better to have good drainage system in greenhouses or protected structures.

Besides irrigation rains water seeps in the greenhouse. The drainage system prevents running or its accumulation in low lying portion of the greenhouse. Drainage system in greenhouses is a must for avoiding damage to the crops.

Flooding

Flooding affects both above and below ground ecosystem processes in greenhouses. Below-ground changes may be less obvious, they are as important as the above-ground changes. Soil microorganisms are sensitive to disturbance, and shifts in soil microbial community structure are expected when anaerobic conditions develop from flooding. The useful aerobic microbes are destroyed by flooding. It takes time to built-up their population in the soil to benefit plants. Due to anaerobic condition created by flooding in greenhouse plant roots in soil are not able to breath, function and hence wilting of plants occurs. Flood irrigation in excess create flood like condition in greenhouses at time. Excess water in soils is a major factor affecting plant survival and functioning. In saturated soils, the supply of atmospheric oxygen into the soil is curtailed and various facultative and obligate anaerobic microorganisms use oxidized compounds as electron acceptors for respiration, thus converting them to reduced forms. The reduction and the associated processes influence plant survival, growth and functioning in wetlands. Flood irrigation should always be just wet the soil not flood inviting stagnation of water.

A chain of reactions is initiated upon soil flooding leading to reduced soil redox potential conditions. These reactions include physical, chemical and biological processes that have significant implications on plants growth. Physical processes include restriction of atmospheric gas diffusion in the soil leading to depletion of soil oxygen and accumulation of carbon dioxide. Shortly after flooding, the limited supply of oxygen in soil pore spaces is depleted rapidly by roots, microorganisms, and soil reductants. This process leads to oxygen depletion and reduction in soil oxidation reduction potential followed by a chain of soil chemical changes. The processes that follow include denitrification, reduction of iron, manganese and sulphate, and changing soil pH

Pasteurization: The heat treatment given to soil to free it of harmful microorganisms or pathogens and pests is called pasteurization. It kills weed seeds also.

Pasteurization of greenhouse plant growing media

Greenhouse growing medium may contain harmful pests such as disease causing organisms, nematodes, insects and weed seeds. It is advisable to decontaminate it by heat treatment or by treating with volatile permissible chemicals.

Soilless media or culture

Gravel culture is a general term which applies to the growing of plants without soil in an inert medium into which nutrient solutions are usually pumped automatically at regular intervals. Haydite (shale and clay fused at high temperatures), soft- or hard-coal cinders, limestone chips, calcareous gravel, silica gravel, crushed granite and other inert and slowly decomposing materials are included in the term “gravel”. The more important greenhouse flowering crops include roses, carnations, chrysanthemums, gardenias, snapdragons, lilies, asters, pansies, annual chrysanthemums, dahlias, bachelor buttons and others.

Media ingredients and Mix

Commercially available materials like peat, sphagnum moss, vermiculite, perlite and locally available materials like sand, red soil, common manure/ compost and rice husk can be used in different proportions to grow greenhouse crops. These ingredients should be of high quality to prepare a good mix. They should be free from undesirable toxic elements like nickel, chromium, cadmium, lead etc. Most common medium other than soil used in India in greenhouses is coco peat. In other countries these are Rockwool and Peat-vermiculite.

Nutrient film technique popularly known as NFT is one of the methods of soilless farming or hydroponics where in plants have their roots in a shallow stream of recirculating water containing all the nutrients required for plant growth dissolved without any solid growing medium. The lower portion of roots remain submerged in flowing nutrient medium in a water tight gully having enough air for the roots. The nutrient film technique was developed during the late 1960s by Dr Allan Cooper at the Glasshouse Crop Research Institute, England. The method is already used in commercial horticulture in many countries including India. NFT is potential for other crops such as animal fodder and even energy-source plants for fuel production.

NFT related technologies

Hydroponics : Cultivation of plants in nutrient solutions is known as hydroponic cutlivation. This ia gerally done under protected structures and in containers arranged horizontally or vrtically (vertical garden). Use of nutrient film or fertilizers is made to feed the plants. Hydroponics can be practiced following nutrient film technique method, trough method, deep water floating method and coco peat bag culture.

The popularity of greenhouse-grown produce continues to rise as it provides a variety of produce during the “off” season. Greenhouses are good for healthy plant nursery production and other a number of crops for profit. Though the greenhouse farming in India like in other countries is progressing but there are certain problems and constraints as stated below.

1.Greenhouse production generally is highly technical and requires constant and continuous attention during cropping period. Relevant information about the crop environmental requirement such as right temperature, humidity etc is essential.

2.Knowledge about the right type of inputs for greenhouse production is a must which is not easily available.

3.Greenhouses cultivation increases the land, water and fertilizer productivity along with reduction in pesticide use. But such interventions are associated with very high initial cost. Although, it is linked with several Government Schemes in India and have 50-90% of subsidies depending on intervention, status / socio-economic condition and policy of State and Central Government.

4.Uninterrupted and regular power supply is required for operating cooling and heating system of the controlled environment greenhouses which necessitate a back-up power pack which is also expensive and underutilized.

Greenhouse technology development has made good progress in India during the last two decades, and steps necessary for promoting greenhouse cultivation of flower and vegetable crops have been started. Energy-efficient greenhouse cultivation continues to be an area of active research and development, and this is sought to be achieved through precision equipment and protocols. While the gap between the demand and supply of most horticultural crops remains wide and the country plans to double the production of horticultural crops by 2012, the protected cultivation technology holds the key to meet the targets. It clearly emerges that greenhouse technology has multipurpose application for sustainable development of a hilly zone. During harsh winter which otherwise threatens the survival of human beings in these remote hilly areas, popularization and further improvements in greenhouse management could provide a sign of relief in solitude of white snow cover.

1.1 INTRODUCTION

The share of agriculture in GDP is sharp declining. Its share which was 55.1 per cent in 1950-51 came down to 21.6 per cent in 2003-04 and it further reduced down standing barely at 14.6 per cent in 2009-10. Horticulture acconts for 29 per cent share in gross GDP obtained from agriculture sector from about 13.08 per cent area put forth under horticultural plantations (Anon., 2010). To achieve the targetted growth rate of 4 per cent in agriculture, horticulture has to grow at the accelerated growth rate above 7 per cent. As a result of R&D initiatives made, there has been considerable increase in horticultural produce which is acclaimed as golden revoution. Horticulture sector has emerged as the frontier area in dealing with the situation of livelihood security and the employment generation. However, looking to the pressure arising from rising population and erratic climatic variation, more attention is required towards the development of technology driven horticulture. Precision farming is being viewed as a promise in this regard.

Precision farming is the process by which exact or accurate results of farming can be obtained. It is a management strategy that relies upon detailed, site specific information to precisely manage production inputs.

Maximisation of quality yield by managing site variable specific management practices is the basic of precision farming. More emphasis needs to be given to make the farming sustainable. In order to make precision farming a reality the following area needs due consideration.

2.1 INTRODUCTION

With increasing population, urbanization and continuous depletion of natural resources, there has to be a paradigm shift in farmer’s perception from production to productivity and to profitability. In the present scenario, the major challenges arising are shrinking land and depleting water and other related resources in agriculture. There is need for promoting farmer friendly location specific production system management technologies in a concerted manner to achieve a vertical growth in horticulture production duly ensuring quality of produce and better remuneration per unit of area with judicious use of natural resources. In this endeavour, precision farming aims to have efficient utilization of resources per unit of time and area for achieving targeted production of horticultural produce. With the revolution in information technology, now it has become possible to focus on the positioning of agricultural tools with high degree of accuracy and sophistication for maximizing returns. The combination of information technology and use of hi-tech equipments made it possible for the introduction of precision farming. It is a comprehensive system designed to optimize agriculture production through the application of crop information, advanced technology and management practices. With recent advances in geographic information systems, it has become possible to focus on site specific crop production technologies so as to harness the potential of horticulture through innovative technologies in a sustainable manner.

3.1 INTRODUCTION

Today’s technological advancement has reached a level where a farmer can have access to information and tools to manage mechanized field operations. They can now measure, evaluate and deal variability within field (e.g. soil fertility, water availability and yield) that was known to exist previously but was not manageable, to his advantage. The ability to handle the variation in productivity in the field and maximize financial return, reduce waste and minimize impact on environment has always been objective of an enterprising farmer in horticultural sector, especially those who advocate sound horticultural practices. Since precision farming proposes to prescribe strategic farm management decision in the field operations to help to serve this purpose through mechanization, sensing and communication technology, automate data collection, documentation and utilization of this information. Such an approach in horticultural production management gives rise to what is now termed as precision horticulture, soil specific crop management (SSCM), spatially variable crop production (SVCP), smart farming (SF) etc.

4.1 INTRODUCTION

Ever since the man appeared on the earth, he has been harnessing the natural resources to meet his basic requirements. Reference to soil, water and air as basic resources, their management and means to keep them pure are mentioned in the Vedas, Upanishads and in ancient Hindu literature. Agriculture began sometime during 10000 BC and during 1930 AD use of chemical came into vogue (Sarswat et al., 2003). The phenomenal increase in population of both man and animal in the last century and fast growing industrialization and urbanization in last few decades have overstrained the natural resource base, which are getting degraded much faster than ever before. Thus, the attention of whole world is focused on how to increase production to feed the burgeoning population and the question uppermost in every ones mind is “how can we produce enough food without damage to the natural resource base, in a sustainable manner?” Precision farming is a promise in this regard. It appears to reduce risk of crop failure (De Boer, 1997).

5.1 INTRODUCTION

Drought and rampant poverty, the double plague of arid region, present a scenario of misery and insecurity across the region where agriculture is the main livelihood and chief source for subsistence of the rural people. The conditions of low and erratic rainfall, extreme temperature conditions, high evapo-transpiration, scarce water resources, infertile and saline soils with ill-defined profile development threaten sustainable agriculture. Sustainable productivity is difficult to achieve by monoculture of either seasonal or forage crops. Thus cropping system approach for agricultural production is of far greater significance in these regions. Traditionally efforts have been made by the native people, obviously to achieve sustainable production ensuring ecological stability, to grow several species together, e.g. pearl millet, moth bean, cluster bean and gram between the natural stands of khejri (Prosopis cineraria), bordi (Zizyphus rotundifolia), lasoda (Cordia myxa), pilu (Salvadora oleoides), and ker (Capparis decidua). The perennial species also provide fodder for sheep and goats during scarcity periods.

Fruit based cropping system is now considered to be the most ideal strategy to provide food, nutrition and income security to the people (Chundawat, 1993, Chadha, 2002, Awasthi and Pareek, 2008). Integration of annual crops with fruit trees yields multiple outputs that ensure production and income generation (Randhawa, 1990 and Osman, 2003) in a sustainable manner. Natural resources (land, solar radiation, water, soil etc.) as well as socio-economic inputs (labour, credit, power, and market infrastructure) are efficiently utilized. Crop productivity under tree canopy is enhanced due to improved soil fertility (Young, 1989) and ameliorative influence of shade by reducing understorey temperature and evapotranspiration (Bunderson et al., 1990). Incorporation of fruit trees into the cropping system is more remunerative. It increases the resilience of the system over time. It enables to i) maximize system productivity on annual basis, ii) utilize resources with high efficiency through due consideration of various interactions and direct, residual and cumulative effects occurring in soil-plant-atmosphere continuum, iii) intensify input use vis-à-vis quality of environment, and iv) impart sustainability of farm resources and environment in long term perspective. The type of horticulture based cropping system in arid region has been discussed in this paper considering these issues.

6.1 INTRODUCTION

Presently, pressure on productive land is greater than ever before and will be further more in years ahead. Per capita arable land is projected to decline from about 0.23 ha in 2000 to about 0.15 ha by 2050 (Lal, 1991). The global demand for food is projected to increase by 1.5 to 2 times due to ever increasing population and also due to demand for richer diets. On the other hand, volatility in the cost of agricultural inputs and the income generated from farm products leads to instability in the farm economy. Moreover, in conventional system, agriculture is practised for uniform application of fertilizer, herbicide, insecticides, fungicides, and irrigation, without considering spatial variability. In some cases, there is excessive use of nitrogenous fertilizer and pesticides, owing to air and water pollution but there are certain cases, where farmers hardly use any chemicals. Hence, to alleviate the ill effects of over and under usage of inputs, the scenario calls for the introduction of modern technologies to improve crop yield, provide information to enable better in-field management decisions, reduce chemical and fertilizer costs through efficient application, permit more accurate farm records, increase profit margin and reduce pollution.

Precision agriculture is a production system that promotes variable management practices within a field, according to site conditions. This system is based on new tools and sources of information provided by modern technologies. These include the global positioning system (GPS), geographic information systems (GIS), yield monitoring devices, soil, plant and pest sensors, remote sensing, and variable-rate technologies for applicators of inputs. Precision farming is concerned with the management of variability in the dimensions of both space and time. Aspects of precision farming, therefore, encompass a broad array of topics, including variability of soil resource base, weather, plant types, crop diversity, machinery performance and most of the physical, chemical and biological inputs used in production of a crop. These are closely linked to the socio-economic aspects of production system. Success in precision framing is directly related to how well it can be applied to manage the space-time continuum in production system. Thus precision farming is technology enabled, information based, and decision focused. It is the integration of these technologies that has enabled farmers and their service providers to do things not previously possible, at level of detail never before obtainable, and, when done correctly, at level of quality never achieved before. In our country, vast data on various aspects like soil characteristics, climatic parameters, topographic features, crop requirement in terms of consumptive use and nutritional requirements have been generated and instruments needed for recording these parameters are also available. However, applications of precision farming as a package in the farmer’s field have received little attention, although some aspects of precision farming have been prasticed. This has been primarily due to lack of awareness about the potential for increasing productivity and improving the quality of produce with minimum use of inputs.

7.1 INTRODUCTION

Production of temperate-zone fruits in subtropics may seem fanciful to be initiated, but it is a practice that has existed in localized regions for generations. Seedling peaches are grown in Venezuela, Northern Thailand, and Southern Mexico. No one knows precisely when these species were introduced, but local selection has produced cultivars adapted to areas with little or no chilling temperatures. Rest either does not occur or is sufficiently shallow to be broken by stress induced by defoliation or drought. Commercial cultivations of temperate-zone fruits are well-established in subtropical areas, where winter temperatures allow partial breaking of the rest period. In areas of Northern Mexico, Southern Africa, and Israel, for example, chemical treatments are regularly applied to supplement the effects of limited chilling. Because temperature declines with increasing elevations, many microclimates exist in the subtropics where temperate-zone fruits are not currently grown, but could be. Subtropical regions where temperate fruits are grown include the southern past of California (Mediterranean type), the low deserts of the Southwest USA (hot arid type), the Gulf Coast and most of Florida (humid type), the Southern Mediterranean and Northern Sahara, Northern India, Southeast China, the middle part of South America, and much of Australia. Similar potential climatic conditions are also available in subtropics of India.

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.