eChapters

Climate change and its variability imposed a great threat to agriculture production and ultimately on food security. Understanding of anomalies in climatic variables is essential to make agriculture sector resilient. Jharkhand state, geographically located at 220 28’ N – 250 30’ N latitude and 830 22’ – 870 40’ E longitude with an altitude up to 1142 m above msl and having humid to sub-humid tropical monsoon type of climate, has a number of agro-climatic/physiographic constraints. The state has 3 agroclimatic sub-zones viz; Central and North Eastern Plateau sub zone (zone IV), Western Plateau sub-zone (zone V) and South Eastern Plateau sub-zone (zone VI) falling under agroecological regions XI, XII and XIII. Zone IV is having 15 districts; Zone V has 6 and Zone VI have 3 districts. Agriculture in Jharkhand is very tedious due to topographical, physiographic and climatic constraints. Vagaries of climate put greatest limitation before the agricultural production system in the State.

Bihar’s economy is highly dominated by agriculture and allied sectors. Around 85 to 90 percent of the population still lives in rural areas, where agriculture along with animal husbandry, is the main source of their livelihood. In Bihar, the gross and net sown area is estimated at 8.26 and 5.64 million hectares, respectively. Nearly 60 per cent area under cultivation in the state is rainfed (Anon, 2008). The region comes under sub-humid subtropical monsoon climate. Most of the annual rainfall (almost 85 per cent) received from south-west monsoon, occurs during June to September (Sattar, 2010). There are three crop growing seasons in the state commonly known as kharif, rabi and zaid. The important kharif season crops, which are planted in May-June and harvested in September–October, are rice, maize, sesame, sorghum and bajra. Pigeon pea is an important long duration pulse crop sown during kharif season as sole crop or intercropped with maize. The important rabi crops which are sown in October–November and harvested in February–March are wheat, rabi maize, potato, chickpea, lentil, rapeseed, mustard, barley.

The State of Himachal Pradesh encompasses a geographical area of 55.7 lakh ha and is situated between 31°22’40" and 33°12’40"N latitude and 75°45’55" and 77°10’20"E longitude. The state is bordered by Jammu and Kashmir on the north, Punjab on the west, and Haryana on the south-west (Fig. 19.1). About 12 per cent of the state area is under agriculture which is mostly (80 per cent) rain fed. Wheat, maize, rice, and barley are the principal crops. In state, there are 12 districts, viz., Bilaspur, Chamba, Hamirpur, Kangra, Kinnaur, Kullu, Lahaul & Spiti, Mandi, Shimla, Solan, Sirmaur and Una. About 20 per cent of the area is under forest cover. It is rich in biodiversity of flora and fauna. Nearly 27 per cent of the area of the state is covered under permanent pastures. The state is endowed with a wide range of physiography/landform, climate, vegetation and geology which have influence on genesis of soils. The soils are mostly shallow, medium deep to deep, well/excessively drained, sandy, sandy-skeletal, loamy-skeletal, coarse-loamy and fine-loamy, calcareous as well as non-calcareous with low available water capacity. The State is the biggest montane ecosystem in India situated in northern part of the country. It is seventeenth largest state in terms of area and twentieth in population of which 65 per cent people are dependent on agriculture and 60 per cent of GDP comes from agriculture sector. Increasing temperature and reducing rainfall affecting the crop growth and crop production is a major issue everywhere in the world nowadays and this state has also not remained untouched by these prime issues of climate change. For sustainable development of agriculture in state, there was/is a need to identify and quantify climatic change where agriculture has a significant influence on both the economy and livelihood.

Agriculture is very intensely influenced by weather and climate. While farmers are often compliant in managing weather and annual variability, there is however a high degree of adaptation to the local climate. This may be in the form of conventional infrastructure, native agricultural practices or personal experience. Climate change an in this way be relied upon to affect the agriculture, possibly threatening established characteristics of farming systems and provide chances for improvements. The role of climate change in influencing human activities and the natural environment is all around acknowledged. This may go from an extreme event enduring just a couple of hours (i.e. hurricane, thunderstorm and showers) through to the multi-year dry spells (Maracchi et al., 2005). Increase in concentration of greenhouse gases in the atmosphere further contribute to climate change. This results in a strong impact on human activities and natural environments. Essential areas, for example agriculture and forestry, will be more susceptible than auxiliary and tertiary segments, for example manufacturing and retailing (Parry et al., 1998).

The Jammu and Kashmir State lies in the extreme North of the Himalayas and constitutes about 67.5 per cent of the North West Himalayan region. The State is predominantly a mountainous state with all the major Himalayan ranges and trans-Himalayas adequately represented. The State of Jammu and Kashmir located in the north Western corner of India, extends between 32o-17' and of 37o-50' North parallels of latitude and 73o-26' and 80o-30' East of meridians of longitudes and 81o East of Greenwich. The State on the basis of physiography may be divided into three main regions (i) outer Himalayas which comprise of Jammu province (ii) lesser Himalayas which comprises of Kashmir Valley and (iii) inner Himalayas which comprise of Ladakh province. Jammu, Kashmir and Ladakh regions have distinct agro climatic characteristics. Jammu region has two different climatic zones depending primarily on altitude. Lower hills & plains bear subtropical climate with hot dry summer lasting from April to July. The summer monsoon commences around first fortnight of July and fading away in early September.

Climate change is one of the most important global environmental challenges facing humanity and as per the instrumental records, the earth’s climate system has demonstrably changed on both global and regional scales since the preindustrial era. Further evidence shows that most of the warming (of 0.1°C per decade) observed over the last 50 years, is attributable to human activities. The levels of greenhouse gases namely carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) have increased markedly as a result of human activities. The CO₂ concentration in atmosphere is now more than 400 ppm and the decadal increase is from 0.86 ppm per year to 1.99 ppm per year (Table 16.1) which is the highest ever. The Intergovernmental Panel on Climate Change (IPCC, 2007) projects that the global mean temperature may increase between 1.4 and 5.8 oC by 2100. This warming of the earth-atmosphere system is expected to have severe impacts on the global hydrological system, ecosystems, sea level, crop production and related processes. Agriculture sector is the most vulnerable entity in light of the global warming and its impacts.

India, as a developing country has reasons to be concerned about the adverse impact of climate change on its economy. A large part of its population depends on climate sensitive sectors for livelihoods which makes it highly vulnerable to climate change. Climate change can have serious impact on its crops, forests, coastal regions, etc. which can in turn affect the achievement of its important national development goals. The issue of climate change cannot however be taken up without linking it to developmental needs such as poverty, health, energy access and education. Traditionally climate change experts have focused on mitigation measures, adaptation measures have also been acknowledged of late as effective and equitable means to deal with climate change impacts. Most of the mitigation measures are high in terms of technology and capital. Therefore, while developed economies choose to mitigate climate change by making heavy investments, developing economies choose to adapt (Monika and Hooda, 2018). There is increasing recognition that the world’s current progress on reducing greenhouse gas emissions is not occurring rapidly enough to avoid impacts from climate change in the coming century. Because of this, the world is “committed” to a certain level of global warming and therefore,

The Inter-governmental Panel on Climate Change  has confirmed that change in climate system is gradually leaving a strong impact. Observations undoubtedly show that there is increasein global temperatures, wide spread melting of snow and ice, and rising global mean sea level. Global climate has shown warming of 0.89 [0.69 to 1.08] °C over the period 1901–2012 which is mainly attributed to anthropogenic activities. Scientific findings indicate that warming is more pronounced than expected and the impact would be particularly severe in the tropical areas, which mainly consist of developing countries, including India (Shukla, 2016). Thus, climate change is a great challenge which is continuously being faced by the sustainable economic growth of the India. Climate sensitive sectors like agriculture, forestry, hydrology oriented sectors faces major threat due to projected changes in climate. India Meteorological Department (IMD) in 2012 reportedincreasing temperature trends during last 112 years and increase in heavy rainfall events and decrease in low and medium rainfall events over India.

In order to achieve maximum and sustainable crop production from available farm resources, it is essential to have proper knowledge of the agro-climatic resources of the location/region. Therefore, a thorough understanding of the climatic conditions would help in determining the suitable agricultural management practices for taking advantage of the favorable weather conditions and avoiding or minimizing risks due to adverse weather conditions. better planning of cropping pattern, developing irrigation and drainage plans for an area (Chaudhary et al. 2015). Hence, trends of temperature and rainfall are studied in this section with possible impact studies on rice production for Chhattisgarh state. Challenges of rainfed rice production can be understood through trend studies of key weather variables. Analysis of rainfall in the context of rainfed rice production in Chhattisgarh state has been carried out. Analysis has been done at Department of Agrometeorology under All India Co-ordinated Research Project (Raipur) to characterize the key weather parameters statistics.

Importance of rice in Konkan area is characterized by heavy rains of 100 mm per week or so over an extended period and contributes 42.9 % of total rice production in the Maharashtra State. Rice is the only suitable crop that can be grown under puddled soil conditions, i.e. with standing water over bunded fields. Tansplanting method of rice is commonly followed by most of the farmers in this region. Puddled rice is said to be of assistance in mitigating the effects of floods. The problem of weeds is minimal in puddled rice culture. Thus, rice serves as a livelihood crop for millions of small, and marginal farmers in Konkan who can afford only low-cost technologies. Even though the crop is robust and versatile, it has faced drawbacks in terms of low yield and reduction in acreage. In Konkan region of Maharshtra, there are two agro climatic zones viz., North Konkan coastal zone comprising three districts viz., Thane, Raigad and Greater Mumbai and South Konkan Coastal Zone comprising two districts viz., Ratnagiri and Sindhudurg. Ratnagiri district receives the highest rainfall of > 3500 mm while Thane district receives the lowest rainfall (2000-2500 mm) in this region. Sindhudurg and Raigad districts receives 3000-3500 and 2500-3000 mm rainfall, respectively.

Evidence is fast accumulating that the problem of climate change is of a scale not previously encountered by human societies. The scale and scope of climate change challenges to food and water security are unprecedented. World food supply is already facing significant pressures. Even without climate change, ensuring sufficient food for all in the 21st century would be difficult enough. Climate influences food security through many channels. Climate change will increase the severity and frequency of cyclones, flooding and drought. It will intensify rainfall variability, increasing water stress, weeds, pests, and erosion and reducing soil fertility. Above certain temperature ranges, crops develop more rapidly, resulting in lower overall grain production, even moderate increases in temperature can decrease yields in major food crops. Population growth, urbanisation, higher per capita calorie intake, and increasing consumption of meat combine to put more pressure on exiting water recourses.

The State of Andhra Pradesh in the present form came into being on June 2, 2014 as a result of the Andhra Pradesh Reorganization Act. The state has 13 districts out of which nine are along the coast of Bay of Bengal and four are land locked in the southern part. A part of Khammam district, which is now in the Telangana state, was also added to the East and West Godavari districts of the State of Andhra Pradesh. The existing data for these two districts do not include this part and this fact is to be borne in mind. The state has a geographical area of 1.602 lakh km2 with a population of 49.83 million. The state in the current form is more agrarian compared to the undivided state as about 62 per cent of population depends on agriculture as a source of livelihood. Yet, the contribution of agriculture to the state’s gross domestic product is only 17 per cent. Though the state is known as ‘rice bowl of India’, not all is well with agriculture in the state. Some parts, especially the coastal districts, are prone to incidence of cyclones and floods while some other districts, Rayalaseema districts, are chronically drought-prone. 

The extreme weather events of the present day and the expected future climate scenarios at global and regional scales have been attributed to the changes in the atmospheric chemical composition and the massive amounts of greenhouse gases (GHGs) emitted by humans since the industrial revolution, bringing about the global warming and resulting in Climate Change. Further, the natural disasters like flash floods are attributed to the highly conspicuous human interventions with nature – the earth and its atmosphere. The parody of the situation is that, while the GHGs sourcing countries are mainly the developed ones, the sink of the result are the agrarian-dominated and eco-sensitive economies of the tropics. Invariably, tropical regions are to be affected the most, because, on the one hand the general circulation of the atmosphere directly and naturally causes divergence of the polluted air from extra tropical regions towards tropics, while on the other, the industrialization within the tropical regions too would affect the local atmosphere. Karnataka State, being located well within the tropics, can be truly impacted by the climate change caused by anthropogenic sources and it is demarcated into 10 agroclimatic zones (Fig. 9.1) based on crops, soils and climate. Climate experts have warned that Karnataka is likely to be more vulnerable to climate change than other states in India.

The State of Karnataka is located between 11.50° to 18.50° N latitudes and 74.25° to 78.50° E longitudes and covers an area of 19.1 m ha which accounts for 5.8 percent of the total geographical area (TGA) of the country. Out of the total 19.1 m Ha in Karnataka the net cultivated area (2010-11) was 10.5 M Ha, net irrigated area 3.49 m Ha and net rainfed cultivated area 7.01 m ha. Karnataka has the largest area under rain-fed agriculture (Fig. 8.1). Nearly 55% of total food grain production and 74% of oilseeds production come from rainfed agriculture in Karnataka. Therefore rain-fed agriculture plays an important role in total food grain production in the state. Further the rain-fed agriculture has substantial untapped potential, which can be brought to use by increasing the crop yields in the dry land areas through the adoption of proper dry-land production technologies. The climate of the state is determined mainly by the geographical location with respect to the Sea, monsoon winds and physiography.

Tamil Nadu has unique physiography with western and eastern Ghats on the west and northwest, Bay of Bengal in the east and Indian Ocean to the south. Tamil Nadu has high dependence on natural resources and hence faces the threat of climate change and its impacts. Available evidence shows that there is high probability of increase in the frequency and intensity of climate related natural hazards (Stephen, 2012). Out of 13 million hectares of geographical area, about 7 million hectares of land is under cultivation. Of this 55 per cent is irrigated and rest is under rain fed / dry lands. In Tamil Nadu, ground water has been harnessed fully and dry land productivity is found oscillating with ruling variability in seasonal monsoon rain and hence agricultural productivity is always under stake.

The State of Kerala has witnessed an unprecedented and unusual flood which devastated the entire State during August 2018 after the notorious 1924 flood, popularly known as the flood of 1099. Heavy rainfall from 14 to18 August 2018 led to flash floods across the State. This was aggravated by the dam opening and subsequent water level in the downstream of the rivers. 33 dams were opened across the State. This has caused the river water to flow into the inland areas. Rivers overflowed and inundated the river side villages and towns. It was reported that the water levels at many places were of the order of 20 feet. Landslides were the major threat that claimed many human lives. A chain of mud slip/land slide events took place during the heavy rainfall period at the time of flood across the mid and high lands of the State, which are ecologically sensitive areas. Even before the heavy rainfall events started on 14th August, 2018 there were major rainfall events on August 8thand 9th. On 9thAugust 2018, Nilambur (Malappuram District) recorded extremely heavy rainfall of 400 mm which is a record rainfall in 24 hours as far as the State is concerned.

Climate risk management in the semi-arid tropics (SAT) is one of the major challenges to achieving food security and development in India and large parts of sub-Saharan Africa and also in the case of Australia. Climate-induced production risk associated with the current season-to-season variability of rainfall is a major barrier in making rainfed agriculture sustainable and viable farm business. Since season outcomes are uncertain, even with the best climate information, farmers have limited flexibility in applying management with confidence. In fact in risky environments, farmers most often respond by adapting a risk averse strategy and are reluctant to invest in even risk reducing measures (Leathers and Quiggin 1991). In the SAT agro-ecologies, there are a limited range of enterprise or crop options to consider which may be further restricted by cultural traditions, food preferences or market opportunities.While there are fundamental differences between large scale commercial farms in Australia compared to the predominantly smallholder resource poor farms found in India, when it comes to climate risk management in the SAT, there are many commonalities. The purpose of this paper is therefore to (i) establish a framework for managing climate variability and transforming farming systems to be more resilient and sustainable for future climates; and (ii) provide some case study examples from climate risk management in low rainfall cropping system in Australia and consider how they may be applied in smallholder systems of the SAT.

The Intergovernmental Panel on Climate Change (IPCC) in its fifth assessment report (AR5) stated that warming of the climate system is unequivocal and is more pronounced since the 1950s. The atmosphere and oceans warmed, the amounts of snow and ice have diminished, and rise in sea level is noticed. Each of the last three decades has been successively warmer at the earth’s surface than any preceding decade since 1850 and the globally averaged combined land and ocean surface temperature data show a warming of 0.85°C over the period 1880 to 2012. The recent years viz., 2015, 2016 and 2017 were the hottest years on record. The warming trend in India since 1961 has indicated an increase of 0.9°C, which is likely to impact many crops, negatively impacting food production. There are already evidences of negative impacts on yields of wheat and paddy in northern India due to increased temperature, water stress, and reduction in number of rainy days. Coastal agriculture has the onus of providing livelihood to nearly 20 % of Indian population. The water logging and coastal salinity are the major factors affecting the agricultural output from the regions.

Food security is one of the most important issues during this century under the projected climate change scenario. The world is facing severe food crisis due to weather vagaries as a part of global warming and climate change. Many countries are under severe food crisis during the crisis of weather abnormalities since 75 per cent of world’s population is dependent on agricultural activities for their livelihood. Therefore, there is an urgent need to produce more and more foodgrains at the global as well as national levels to meet the food requirement of growing population under the projected climate change scenario. There has been a major decline in world rice production since late 2007 due to various reasons including global warming and climate change in top rice producing countries. 

Natural disasters are of meteorological or hydrometeorological origin. Disasters such as earthquakes and tsunamis are occasional, but rainfall-related hazards, flood or drought, are very frequent and thus call for proper monitoring of large-scale rainfall variation, and better manage- ment and planning to combat the problem(s). Variation in rainfall is very large spatially and temporally compared to any other atmospheric parameter, such as pressure or temperature. The large temporal variability in the Indian rainfall has produced frequent flood/drought and periods of above/below normal rainfall for several centuries past. Areas of high rainfall and runoff are flooded in the summer monsoon season whereas others face water stress and drought conditions. The influence of global warming on rainfall variations over India is reported in numerous observational (Singh et al., 1991, 1992) and modelling studies (Lal, 1994). 

Climate Change has emerged as one of the most serious environmental concerns of recent times. The most imminent climatic change is increase in atmospheric temperature due to increased levels of greenhouse gases such as carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and hydrochlorofluoro carbons (HCFCs). Because of increasing concentrations of the greenhouse gases in atmosphere, there is much concern about future changes in the climate system viz., Atmosphere, Lithosphere, Biosphere, Hydrosphere and Cryosphere. Direct or indirect effects on the society linked sectors like water, forestry, agriculture, animal agriculture, fisheries, land and marine biodiversity and health due to climate change/variability are many-fold and economic impact of climate change is enormous. The recurrent drought and desertification threaten seriously the livelihood of over 1.2 billion people who depend on land for most of their needs.

In contrast to the earlier and existing non-sustainable land use practices, agro forestry presents a more dynamic, productive and sustainable solution to the increasing demand of food, fodder, timber and other agricultural and tree goods. According to the United Nations,the world population was more than 7 billion in 2011 which is expected to go up to 9.3 billion by the mid-century. Consequently food production needs to be increased by over 60% by the year 2050. Agroforestry, which is a multifunctional, ecologically based, natural resource management system can help in dealing with such environmental, economic or social issues.

Introduction

Agriculture expanded and forest dwindled. That eventually occurred with the expansion of civilization. Clearing of forests, granted in past, continued in modern times. Cutting of forests reached to such an alarming level that thinking of people turned back to create more forests. Sometimes over extraction of forest resources made forests unstable to yield perpetually according to necessity in future for which forests are turned unsupportive for livelihood and people tried for innovative means to enhance forest productivity in future (Nair 1993). Also with time agriculture faced the similar unfortunate condition towards intensive cultivation. So, peoples’ thinking turned back in agriculture how to make it stable and more supportive for livelihood year after year. Culturally human societies are connected both with agriculture and as well as forests from the time immemorial.

Introduction

Homegardens are traditional agricultural systems, particularly common in the tropics characterized by a high plant diversity (Kumar and Nair 2004, 2006; Scales and Marsden 2008; Galluzzi et al. 2010), maintain high level of productivity, stability, sustainability and equitability (Soemarwoto and Conway 1992), serve as a refuge for wildlife (Perfecto and Vandermeer 2008), contributing significantly to the household diet by producing a large variety of food commodities (Kumar and Nair 2004; Wiersum 2006; Pulido et al. 2008; Kortright and Wakefield 2011; Kumar 2017; Kumar and Tripathi 2017), nutritional supplies (Mendez et al. 2001; Perrault and Coomes 2008; Vlkova et al. 2010; Balooni et al. 2014), supplementary cash income for owner (Huai et al. 2011; Arifin et al. 2012; Yang et al. 2014) and important spaces for transmission of cultural heritage (Galluzzi et al. 2010). Many native or endangered species can be found in homegardens (Albuquerque et al. 2005; Akinnifesi et al. 2010; Milow et al. 2013), and they are niches for domesticating semi-wild species (Akinnifesi et al. 2010). Plants grown, intentionally or unintentionally, in homegardens are important for household subsistence and economy.

Introduction

Forest cover of India has been estimated to be 7,01,673 km2 (70.17 million ha) which is 21.34 per cent of the total geographical area of the country. The tree cover of the country is estimated to be 92,572 km2 which is 2.82 per cent of geographical area. The total forest and tree cover is 7,94,245 km2 which is 24.16 per cent of the total geographical area of the country. Out of this, 9.14per cent forest cover is in the form of open forests and another 1.26 per cent is scrub forests (FSI 2015). According to National Forest Policy 1988, one-third (33.33%) of the land area should be under the forest cover for sound ecological balance. It means that we have to bring another 11.66 % area under forest cover and at the same time improve quality of the degraded forests. However the horizontal expansion of land under tree cover is not possible. In order to increase the tree cover and fulfill the requirements of the people and industries,

Introduction

The literatures and researcher data showed that there is negative impacts of agricultural expansion, landscape modification and deforestation on biodiversity, ecosystem services, alteringthe species composition and their ecological functions (Tscharntke et al. 2005; Priess et al. 2007; Flynn et al. 2009; Senior et al. 2013; Deguines et al. 2014; Kumar 2016) which can lead to considerable changes in critical ecosystem processes. On the other hand, an increasingly industrialized global economy, rapid population growth, land degradation, land use pattern and role of various human activities have led to dramatically increased the pressure on the natural resources such as the available land for sustaining the livelihoods, and with over exploitation and extraction of the natural resources the ecosystems are becoming unsustainable and fragile since last century (Kumar 2017). Standardization of cultural practices is one of the primary objectives to make the system ecologically, sustainable and economically viable (Gill et al.2009).

Introduction

Agroforestry is a land-use management system where trees or shrubs are grown around or among crops or in pasture lands. It combines agricultural and forestry technologies to create more diverse, productive, profitable, healthy, and sustainable land use systems.
India has been at the forefront of agroforestry research ever since organized research in this area started worldwide about 25 years ago. Considering the country’s unique land use, demographic, political and socio-cultural characteristics as well as its strong contributions to agricultural and forestry research, India’s experience in agroforestry research has proved important to agroforestry development especially in developing countries.

Introduction

There is a growing interest in the role of different types of land use systems in stabilizing the atmospheric CO₂ concentration and reducing the CO₂ emissions or on increasing the carbon sink of forestry and agroforestry systems. Forestry has been recognized as a means to reduce CO₂ emissions as well as enhancing carbon sinks. There is considerable interest to increase the carbon storage capacity of terrestrial vegetation through land-use practices such as afforestation, reforestation, and natural regeneration of forests, silvicultural systems and agroforestry (Brown 1996; Canadell and Raupach 2008). Agroforestry systems are very important given the area currently under agriculture, the number of people who depend on land for their livelihoods, and the need for integrating food production with environmental services (Garrity 2004; Makundi and Sathaye 2004).

Introduction

Trees play an important role in ecosystem in all terrestrials and provide a range of products and services to rural and urban people (Gogoi 2015). As natural vegetation is cut for agriculture and other types of development, the benefits that trees provide are best sustained by integrating trees into agricultural system - a practice known as agroforestry. Agroforestry focuses on the wide range of trees grown on farms and other rural areas. Among these are fertilizer trees for land regeneration, soil health and food security; fruit trees for nutrition; fodder trees for livestock; timber and energy trees for shelter and fuel wood; medicinal trees to cure diseases and trees for minor products viz. gums, resins or latex products. Many of these trees are multipurpose, providing a range of benefits. Although effective and valuable tools have been introduced to evaluate the risk to construction in areas prone to geo-hydrological hazards, fewer steps have been made in the field of ordinary land use planning at different scales. 

Introduction

The world demand for wood is continuously increasing due to increase in population. The ever increasing population has led to depletion of existing timber reserves and the forestland base has been reduced by increased allocation of forest areas to urban, agricultural, recreational and other uses. The growing awareness towards development of plantations has generated a voluminous increase in the demand for quality planting material. Conventionally, propagation is achieved through sexual (seeds) or vegetative methods (rooting of cutting, grafting, layering, etc). Propagation through seeds is routinely used for production of planting material but it generates immense genetic variability which is not desirable while propagating perennial tree species. In order to propagate selected trees with desirable features vegetative propagation methods like rooting of cuttings, grafting, layering etc have been developed. These methods can produce genetically identical off springs thereby preserving the advantageous traits;

Introduction

Desertification is affecting the livelihoods of millions of people, mainly poor in the dry lands, which occupy nearly 41% of the Earth’s land area and are the residence of more than 2 billion people of the world. In India, the western part of Rajasthan is mostly affected by desertification process dominated by wind erosion. Kar et al. (2009) reported that 15.2 mha land in western Rajasthan is affected by wind erosion out of total 22.96 mha area under desertification. A brief account on issues and priorities related to wind erosion processes in Thar desert was reported in Santra et al. (2006). Plenty of incident solar energy in the region makes the desert surface very hot especially during summer months. Wind speed also remains very high in the region for most of the time in a year. Therefore, the loss of top fertile soils through wind erosion process is very active in the region. Eroded dust particles during severe wind erosion events commonly known as dust storms not only create the soils poor but also pose several environmental threats through generating aerosols in atmosphere. 

Introduction

The area under salt-affected soils in India is estimated to be 6.73 Mha spread over a number of states across the country. This 6.73 million ha are lying barren or produce very uneconomical yields of crops due to excessive accumulation of salts. These soils are agriculturally unproductive because of the high content of soluble salts which had harmful effects on plant growth due to moisture stress and toxicity/deficiency of some of the ions and the exchangeable sodium ions in clay complex lead to the unfavorable physical conditions of for the plant growth and water movement (Bhumla 1977). Saline and sodic soils have excess concentration of either soluble or exchangeable sodium, calcium and magnesium primarily in the form of chlorides and sulphates. Salt affected areas an expected to increase with spread of waterlogging and salinity due to increase in canal irrigation, and intensive exploitation of poor quality ground waters for agriculture in non canal commands. Certain states like Rajasthan and Haryana located in the western part of the country are endowed with 84 and 62% of poor quality ground waters, respectively. Continuous use of such waters for irrigation to agricultural crops is bound to increase the problem of salinity and sodicity in India (Yadav 1989; Minhas and Bajwa 2001). Introduction of irrigation without making proper provision for drainage is the major cause for the development of salinity in canal commands.It is severe on irrigated lands of the dry zone. It reduces crop yield and in severe cases causes complete abandonment of agriculture (Joshi and Dhir 1989; Joshi et al. 2000; Mahesh Kumar et al. 2016). The present paper deals with extent, causes, characteristics and management options of these soils for sustainability of agriculture in the area.

Introduction

A number of researchers have used morphological descriptors such as growth habit, leaf, shoot, flower, fruit morphology to classify and discriminate different varieties/cultivars and or detect inter and intra-specific variations in different tree species of economic importance (Saran et al. 2006; Holland et al. 2009). Such morphological descriptors are quite homogenous and often found insufficient to distinguish varieties within morphological groups. The choice of suitable cultivars is of paramount importance for its success. The lack of breakthrough has been due to under utilization of genetic variability for superior quality and high yield potential. Most of the fruit tree species demonstrates a rich genetic diversity mainly through natural cross pollination due to self incompatibility (Godara 1980). The elite plant types with desirable traits have been released as varieties, mass multiplied and propagated through standard vegetative multiplication. However, the authenticity of cultivar identification remains unclear (Devanshi et al. 2007).

Introduction

Rain fed agroecosystem occupies 68% of India’s cultivated area and supports 40% of the human beings and 65% of the livestock population. It produces 44% of food requirements, thus has and will continue to play a critical role in India’s agriculture (Singh et al. 2004). Besides their well established role in agriculture, livestock have crucial role in food security and as risk aversion mechanism for sustaining family, whenever there is crop failure. Indian hot arid zone which is about 12% of total geographical area of the landmass of 0.32 million km2 has maximum covering in western Rajasthan i.e. 61% of the total area whereas the other areas in arid region are available in the states of Gujarat, Punjab, Haryana, Andhra Pradesh and Karnataka accounting for 20, 5, 4, 7 and 3% of hot arid area whereas the cold arid area of 8.4 million ha lies in the state of Jammu & Kashmir covering the Leh and Ladakh region.

Introduction

Throughout the arid zones, there is no dearth of problems, but rapidly increasing desertification (some call it land degradation) is a problem of worldwide dimension. Water is a scare commodity in arid zones. Much of rainfall is lost by evapo-transpiration and as a result, ground water recharged only by seepage through soil profile. However, it is a common phenomenon in arid zones of the world that ground water is frequently used at the rate that exceeds recharge. The situation in arid tropics of India, which is spread over an area of 31.7 million ha, is no more different. Considering the role of agriculture in the social and economic progress of developing countries, the vulnerability of agricultural systems to the impacts of climate change has received considerable attention from the scientific community (Fischer et al. 2002; IISD 2003; Kurukulasuriya and Rosenthal 2003). Much of the available literature suggests that the overall impacts of climate change on agriculture especially in the tropics will be highly negative, although in a few areas there may be minor increases in crop yields in the short term (Maddison et al. 2007). Research on agroforestry as an adaptation to climate change and as a buffer against climate variability is in the process of evolving.

Introduction

Human civilization used to undergo several form of disasters throughout its life history. Most of such events are unpredictable, sudden and short in duration, and such events can easily classifiable as either natural (e.g. cyclones, earth quake, natural forest fires and tsunami) or manmade such as spread of toxic chemicals (e.g. Bhopal disaster 1984), nuclear explosions, civil war, diseases (Minamata, itaiitai, etc.). However, climate change is a real time prolonged disaster which is caused by both natural (caused by variation in solar irradiance, variations in orbital parameters of earth, volcanic activities, natural forest fire, methane release from thawing of permafrost from ocean floor, natural wetlands and cattle) and anthropogenic means (by greenhouse gases resulted from human activities-all kinds of combustion, industrial production of greenhouse gases and agricultural water lodging activities such as paddy cultivation and artificial wet lands, and deforestation).

Introduction

Two types of interactions, i.e. competitive and complementary, are found in ecosystems and agroecosystems (Callaway 1998), which shape community structure, plant diversity and system’s functions (Callaway 1995; Pugnaire et al. 1996; Bruno et al. 2003). Competitive interaction in ecosystems (Wedin and Tilman 1993) and agro-ecosystems (Pandey et al. 1999) is well documented. Mechanism of complementary interaction, however, is not much understood so far. Some studies (Bertness and Callaway 1994; Callaway 1998) argue that complementary interaction is facilitative, either facultative or obligatory, and occur generally in harsh physical environments. This suggests that habitat amelioration by neighbours is a common denominator of positive interactions (Bertness and Callaway 1994; Callaway and Walker 1997). Other studies report that complementary interaction is mutualistic (Boucher et al. 1982). Irrespective of whether facultative or mutualistic, it is now well established that complementary interaction is evolutionary (Bertness and Callaway 1994). But, it is still inconclusive how two species exist together in ecosystems and agroecosystems (Bertness and Callaway 1994).

Introduction

India has a long tradition of agroforestry which is widely practiced in all ecological and geographical regions of the country. Traditional agroforestry systems are broadly based on indigenous knowledge and the species are selected as a part of the cultural patterns of the community. The farmers and land owners in different parts of the country integrate a variety of woody perennials in the crop and livestock production systems depending upon the agro-climatic conditions and local requirements.

Introduction

Arid lands are among the world’s most fragile ecosystems, made more so by periodic droughts and increasing over exploitation of meagre resources. Arid and semi-arid lands cover around one-third of the world’s land area and are inhabited by about one billion people, a large proportion of whom are among the poorest in the world (Malagnoux et al. 2007). Arid environments are extremely diverse in terms of their land forms, soils, fauna, flora, water, and human activities. Aridity is usually expressed as ratio of mean annual precipitation (P) to the mean annual potential evapotranspiration (EPT) where potential evapotranspiration is calculated by method of Penman, taking into account atmospheric humidity, solar radiation, and wind speed. UNEP (1997) has recognized four main classes of aridity: hyper-arid (P/EPT < 0.03), arid (0.03 < P/EPT < 0.20), semi-arid (0.20 < P/EPT < 0.50), and dry sub-humid (0.50 < P/EPT < 0.65). Of the total land area of the world, the hyper-arid zone covers 4.2 %, the arid zone 14.6 %, and the semi-arid zone 12.2 % (FAO 1989). Therefore, almost one-third of the total area of the world is “arid land”. 

Introduction

Agriculture has always been vulnerable to fragile environmental conditions of dry areas, where droughts of varying amplitude and frequency influenced by insufficient and uncertain rainfall are common features. Recent anthropogenic activities have accelerated the rate of green house gas (GHGs) accumulation in atmosphere influencing atmospheric temperature and local patterns of temperature and precipitation, which ultimately affect agricultural production and food securities. About 35.5 percent of the total world’s population resides in dry areas, which is facing the problems of land degradation and food securities.

Introduction

Livestock sector plays an important role in the rural economy at national level and this sector is emerging as a driving force in agriculture by contributing towards the income and employment of rural households. Livestock contributed 16% to the income of small farm households that indicates importance of livestock sector as a whole. In 2010-11, livestock generated outputs worth Rs 2075 billion (at 2004-05 prices). Agriculture sector grew at low rate of 4.7% during 2013-14 and contributed 13.9% to National GDP (Economic Survey 2013-14). The livestock sector contributed over 4.1 per cent of the total GDP in 2012-13, that nearly accounts for 29.5% of the agricultural GDP (Economic Survey 2013-14) indicating a significant contribution of the livestock. Sheep and goats are an important livestock species for a large number of rural poor, especially socially backward, marginal and landless labourers in India. Sheep are mostly reared for wool and meat purpose. India ranks third in sheep population and account for nearly 6% of world sheep population, currently India has 65.06 million sheep as per Livestock census 2012.

Introduction

Arid regions of the world are diverse in terms of climate, soils, vegetation, animals and life style and activities of people. The binding feature of all arid regions in the world is aridity. Of the total area of arid zones of the world, Africa, accounts for 46.1 % followed by Asia (35.5 %). Majority of rest 19.4 % of arid zones are spread over in Australia, North America (Mexico and Southern part of USA), and South America. The Indian arid zone covers around 12 % of country’s geographical area occupying 31.8 million ha of land of which major part is in northwestern India (28.57 Mha) and some in southern India (3.13 Mha). It covers parts of Andhra Pradesh, Gujarat, Haryana, Karnataka, Maharashtra, Punjab and Rajasthan states of India (Table 1 and Fig. 1). The arid regions of Rajasthan, Gujarat, Punjab, and Haryana together constitute Great Indian Desert, better known as Thar. As arid western Rajasthan accounts for 61% of hot arid region of country, therefore it is considered principle hot arid region. Major part of it occurs between Aravalli ranges on the east and southeast and Thal desert of Pakistan (Thal desert is simply the western extension of Thar, only name has been changed) which is spread up to Suleman Kithara ranges in extreme west.

Introduction

Rainfall is the principal source of water in arid areas, which augments soil moisture, groundwater and surface flows. Agriculture and several of the other economic activities in arid areas depend on rain. This region is devoid of any well defined perennial river system. Under such circumstances every drop of water becomes very precious. Of the total water use about 85% of water is used for irrigation and remaining 15% is used for drinking, industrial and other purposes. About 65% of irrigation water and 30-40% of drinking water is subjected to serious losses. Hence, increasing water use efficiency coupled with increasing availability of water through rainwater harvesting and management is of prime importance for sustainable development of arid areas. Rainwater harvesting, its conservation and efficient utilization can solve problem of water scarcity to the greater extend. Rainwater harvesting in small ponds (nadis), underground tanks (tankas), Khadins (Low lying areas) etc. is an age-old tradition in arid zone of Rajasthan. These traditional rainwater harvesting structures vary in design, shape and size. These traditional methods have undergone several changes for being more economical and efficient. Central Arid Zone Research Institute (CAZRI), Jodhpur since its inception in year 1959 is continuously working for development and refinement of water efficient techniques for crop production, individuals and for the communities for development in hot arid zone of India.

Introduction

Agroforestry system (AFS) is a form of sustainable land use that combines trees, shrubs, crops and livestock so as to increase and diversify farm and forest production along with conserving natural resources. Microorganisms play a crucial role in improving nutrient availability to plants, thereby decreasing the dependence on chemical fertilizers and achieve sustainable agriculture through agroforestry (Araujo et al. 2012). Arbuscular mycorrhizal (AM) fungi, plant growth-promoting rhizobacteria (PGPR), and the association of rhizobia with leguminous plants are symbiotic associations of high economic importance for increasing agricultural production. Yadav et al. (2010) studied soil biological properties under different tree based traditional agroforestry systems in a semi-arid region of Rajasthan, India and concluded that biological properties can be optimized in the soil under AFS. Many authors have reported that soil microbial biomass and microbial diversity are greater in the AFS due to the ameliorative effects of trees and organic matter inputs and the differences in litter quality and quantity and root exudates (Mungai et al. 2005; Sørensen and Sessitsch, 2007). Also, the presence of a large and diverse soil microbial community is crucial to the productivity of any agroecosystem. Moreover, more than one plant species in AFS have been reported to have shown a larger diversity and/or abundance of mycorrhizal fungi than monocultures (Cardoso and Kuyper 2006) and more efficiency in biological fixation of the nitrogen, especially in tropical soils (Freitas et al. 2010). Also, soil microbial biomass has other important functions in the soil such as nutrient cycling and the degradation of pollutants (Watanabe and Hamamura 2003; Araújo and Monteiro 2006).

Introduction

Arid environs are delineated by extreme and harsh weather conditions due to excessive heat and inadequate, variable precipitation; however, contrasts in climate occur. These climatic disparities are the result of temperature variation, distribution and season of rainfall and the degree of aridity. Moreover, high evapo-transpiration, periodic droughts, low organic matter levels, different associations of vegetative cover and soil enhances the problems of these regions. In general, hot arid climates have excessive heat and strong prevailing winds, unhampered by obstacles on the ground and as result aeolian erosion is common with frequent seasonal drought occurrence (Sharma and Tewari 2005). These climatic limitations make very difficult place for the inhabitants to attain their livelihood. People of these areas have spent their life within these constraints for centuries. They have faced serious challenges due to lack of sufficient resources and very low productivity which has added to the vulnerability of the region. 

Effect on SOC and N losses through runoff and soil erosion

With increase in population, agriculture is being extended to even marginal soils which were hitherto uncultivated. Such soils are more seriously prone to erosion losses (FAO 2008), mostly because of their topographical position. Overall, soil organic matter and nutrient rich surface soil erosion could become more serious threat in the wake of changing climate in future; therefore, it is necessary to find suitable remedy measures to sustainable food production while protecting the soil from erosion.

Introduction

The rate of increase in anthropogenic CO₂ concentration of the atmosphere is increasing at an alarming rate from 1.7 µmol mol-1 yr-1 in 2009 (Tans 2009) to 2.2 µmol mol-1 yr-1 in 2013 (WMO 2013). At this rate, its level in the atmosphere will reach around 450 µmol mol-1 by the turn of century from its current concentration of 400 µmol mol-1, leading to increased global warming and concomitant climate change. There is, thus, a very strong scientific interest in finding ways to slow or reverse this trend. Mitigation strategy of diverting CO₂ from atmosphere to soil by adopting appropriate agricultural practices such as conservation agriculture (CA) is a recognized such method (Lal 2008 a, b). Broadly, CA has three major components- reduced tillage, crop residue management, and intensive cropping. Conservation tillage practices which include reduced tillage (RT) and no-tillage (NT) have been amply demonstrated as the agricultural practices that are very helpful in this direction (West and Post 2002; Franzluebbers 2010).

Introduction

Tree growing in hot arid region is basically concerned with the management of trees for conservation and for limited production objectives like wood for fuel, poles and fencing material; leaves for livestock fodder; and pod/seeds for many types use in human diet. The role of trees to conserve the fragile ecosystems of hot arid regions has been well recognized (Mann and Muthana 1984). The trees also provided so many services to mankind, which make them an intricate part of man-livestock-agriculture continuum, the lifeline of hot arid regions (Saxena 1997). 

Introduction

The green revolution in mid-sixties stirred by research based new technological developments involving new materials, models and ways of organizing farm inputs (water, fertilizer, chemical etc) and government’s policies transformed the agriculture dramatically. The outcome chewed a many fold increase in production and productivity viz. food grain production of 211 million tonnes (which was only 74.23 million tonnes in 1966-67) and food grain productivity of 1697 kg ha-1 (which was only 644 kg ha-1 in 1966-67). The country thus became self-sufficient in food production despite tremendous pressure to sustain 16% of world human population and 10% of cattle population with just 2.4% of total land.

Introduction

India is the seventh-largest country in the world, with a total area of 3,287,263 square kilometres, roughly 2.5 percent of global landmass but is home to 17.9 percent of global human population and 1/5 of the livestock. Most of this increase in human population has occurred in second half of 20th century. Similarly, India has the highest number of cattle (210.2 m), buffaloes (111.3 m) and goats (150.4 m) in the world. It ranks second in sheep (74 m), fifth in chickens (866 m) and sixth in ducks (26 m). The increased population and associated increased demand of resources has led to significant impact on land use-land cover and has consequence in negatively impacting various ecosystem services i.e., hydrology, soil conservation, wildlife support, biodiversity and environmental protection, these agroforestry systems used to provide. Agroforestry has traditionally been a way of life and livelihood in India for centuries. Now it is a modern science inviting deliberate management of trees on farms and surrounding landscape (Bargali et al. 2009;