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Sustainable development and efficient management of water is an increasingly complex challenge in India. Increasing population, growing urbanization and rapid industrialization combined with the need for raising agricultural production generates competing claims for water. Ground water has an important role in meeting the water requirements of agriculture, industrial and domestic sectors in India. About 85 percent of India’s rural domestic water requirements, 50 percent of its urban water requirements and more than 50 percent of its irrigation requirements are being met from ground water resources. Ground water is annually replenishable resource but its availability is non-uniform in space and time. Technically, the dynamic ground water refers to the quantity of ground water available in the zone of water level fluctuation, which is replenished annually. Hence, the sustainable development of ground water resources warrants precise quantitative assessment based on reasonably valid scientific principles. National Water Policy, 2012 has laid emphasis on periodic assessment of ground water resources on scientific basis. The trends in water availability due to various factors including climate change must also be assessed and accounted for during water resources planning. To meet the increasing demands of water, it advocates direct use of rainfall, desalination and avoidance of inadvertent evapo-transpiration for augmenting utilizable water resources. The National Water Policy, 2012 also states that safe water for drinking and sanitation should be considered as pre-emptive needs followed by high priority allocation for other domestic needs (including needs of animals), achieving food security, supporting sustenance agriculture and minimum eco-system needs. Available water, after meeting the above needs should be allocated in a manner to promote its conservation and efficient use.

Dry areas specially arid and semiarid regions are characterized by harsh climatic condition with limited natural resources like fresh water and vegetation. Soil which is most important component for agricultural production is also problematic in this region due to high salt content. Further, these regions face dual water problems: very low rainfall and poor quality of available water. Most of the available groundwater in these areas has high salt content, which further enhance salt content in soil after irrigation with this water. Salinity of soil is one of the most severe abiotic factors limiting agricultural production in arid and semiarid regions of the world. Term ‘salt-affected soil’ refer to soils in which salts interfere with normal plant growth, and is broadly divided into saline, saline- sodic and sodic soil, depending on amounts of salt, type of salts, amount of sodium present and soil alkalinity. Excessive soluble salts in the saline soil limit the ability of plant roots to absorb soil water even under wet soil conditions, while high sodium content in sodic soil reduce the availability of Ca, Mg, other micronutrients and finally deteriorate physical condition of soil. Poor physical structure of soil results in difficult to till, poor seed germination due to soil crusting and restricted plant root growth. Due to the poor physical structure, sodic soils are also susceptible to wind and water erosion compared to saline soils. All these negative impact of salt accumulation on the soil finally affect growth and yield of the crops. As per estimates of ICAR-Central Soil Salinity Research Institute (CSSRI), Karnal, crop production loss to country due to sodicity is around 11.18 million tonnes while due to salinity is around 5.66 million tonnes. Furthermore, the area under this category is rising due to secondary salinization caused by faulty management of irrigation water, seepage loss, impeded drainage, rapid rise of water table causing water-logging. Certainly, these soils and saline water threaten the livelihood security of farming community. The area under cultivation is decreasing due to diversion of agricultural land in to other uses to meet needs of rising population and as such, agriculture has to make best use of poor quality land and water resources to meet the food demand. Therefore, management of salt affected soil become necessary for ameliorating negative impact and enhancing agricultural production in these regions. Each type of salt-affected soil has different characteristics and thus required different strategies for management.

Global warming and climate change are becoming major challenges in the front of global community to deal with. Climate change is no more a myth but it is reality. The IPCC, 5^th assessment report clearly stated that “evidence of climate- change impacts is strongest and most comprehensive for natural systems”. Natural and human systems of almost all continents in the world have been affected by climate change in recent decades (IPCC, 2014). Agriculture is essential for sustainability of human life on earth but change in climate is threatening its sustainability. In recent decades all aspects of food security has been potentially affected by climate change, including food access, utilization, and price stability. It has been projected that in absence of adaptation measure, increases in local temperature by 2°C or more above late-20^th-century levels will negatively impact production of the major crops in tropical and temperate regions.

Agriculture is one of the major economic activities responsible for food security and livelihood for millions of people. Success, production and productivity of agricultural crops are highly dependent on climate, soil and water. Thus climate change will have adverse effect on agricultural crops. High atmospheric temperature, unpredicted erratic rainfall, rapid soil degradation and evolution of new insect and pests due to climate change will offer new challenge to sustain agriculture. Many part of the world and India is already experiencing impact of climate change on agricultural crops (like early maturity, geographical shift and occurrence of new pests) and these impacts are predicted to increase rapidly in future. The increasing concern about adverse impact of climate change on food security has led to extensive research and documentation of impact of climate change on field crops like rice, wheat and maize. While the clear and holistic idea about impact of climate change on horticultural crops like vegetables and fruits are not well documented especially in developing countries like India.

Biodiversity is a matter of concern to everyone as most of the economic sectors depends on it e.g. agriculture depends on it for wild genetic resources and biological control, human health depends on nature for many pharmaceuticals, industry requires raw materials which come from the nature, tourism increasingly base its attraction on natural amenities linked to biodiversity, water resources require intact vegetation to protect watershed and prevent siltation, disaster prevention needs natural vegetation to help people to respond to drought and the lists goes on and on (Mc Neely, 2004). Each of these sectors needs to be reminded of its reliance on biodiversity and provided with opportunity to invest in insuring the continued survival of the biological basis of their prosperity. Thus biodiversity has emerged as an integral aspect of human life and hence undoubtedly one of the keystone of sustainable development. Biodiversity in arid lands are under severe threats due to habitat destruction (Manuder and Clubbe, 2002), invasion of species (O’Kennen et al., 1999) dilution of customary conservation practices, climate change (Given, 1994; WCMC, 1992), increasing human population, unsustainable exploitation of natural resources, grazing pressure etc.

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.

The hot arid area is characterized by frequent droughts of 47% of frequency in the last century of moderate to severe nature. Due to higher occurrence frequency of droughts in this region of state, the livestock assumes great importance as a drought management measure as agriculture is at the mercy of rainfall pattern which is very uncertain in amount as well as distribution coupled with poor soil condition, higher evapotranspiration and higher wind velocity causing the soil erosion.

For arid region of Rajasthanthe general climatic conditions, topographical features and biotic factors do not encourage agricultural operations in the absence of extractive industry the peasantry has to fall upon animal husbandry as their main occupation. Rearing some of the finest breed of cattle, camel, sheep and goats known for their endurance making much use of the meagre feed resources which are grasses ,herbs, shrubs, tree leaves and cultivated feed and fodder crops. Livestock farming has some in built superiority over crop farming as far as growth; stability and resource conservation are concerned. On an average, the region experiences 3 years of drought in every 10 years. The natural forces constituting the soil-climatic complex, which conspire to reduce the crop productivity and cause instability in agricultural production, have much less impact on livestock farming. This is due to differences in the nutritive value of natural vegetation, which mainly sustains livestock.

Rainfed farming has a distinct place in Indian Agriculture, occupying 67% of the cultivated area, contributing 44% of the food grains and supporting 40% of the human and 65% of the livestock population. It is characterized by resource poor farmers, poor infrastructure and low investment in technology inputs (Singh, 1999). The land use in rainfed areas is quite diverse with a variety of crops, cropping systems, agroforestry and livestock farming. The productivity levels have remained low over the years and the share of rainfed crops in the total food grain production has been declining. The rainfed ecosystem suffers from the problems of (i) frequent droughts due to high variability in the quantum and distribution of rainfall, (ii) poor soil health due to continued degradation and inadequate replenishment of nutrient exhaustion, (iii) low animal productivity due to an acute scarcity of fodder and (iv) low risk bearing capacity of farmers due to poor socio-economic base, credit availability and infrastructure.

Of the total land area of the world, arid zones account for 18.8%. 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 worlds 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.

Agriculture is the human enterprise that is most vulnerable to climate change. Tropical agriculture including agriculture in arid tropics, particularly subsistence agriculture is vulnerable, as farmers do not have adequate resources to adapt to climate change. Land-use options that increase livelihood security and reduce vulnerability to climate and environmental change are necessary. Rural folk in arid western Rajasthan, the principal hot arid region of the country have been practising arable cropping in association with these scattered trees on crop fields since time immemorial. This combined protective-productive system of integration of trees into farming system rooted in the principles of ecology, productivity, economics and sustainability, is generally referred as agroforestry. In fragile ecosystems of hot arid regions of India

India is a huge importer of crude oil and spends about Rs. 1,200 billion of foreign exchange every year to meet 75% of its oil needs (Anand, 2006). This has affected its balance of payment adversely, especially after the unprecedented rise incrude oil prices. Being an agricultural country endowed with varied climates, nutrient-rich soil and ability to grow many different crops, India offers a great promise as a producer of surplus raw material for biodiesel and bioethanol production. India’s biofuel production currently accounts for only 1 percent of global production (Shinoj et al., 2012). Although all oils can be used, edible oils as a source for biodiesel production have to be ruled out because they are required for cooking and food purposes. Therefore, non-edible oils are the premier raw material for biodiesel production in India. Seeds rich in these oils are mostly produced by perennial species. Hence these trees are referred to as tree-borne oilseed species (TBOS) and they produce TBOs (Aurora and Kumar, 2015). TBOs are cultivated/grown in the country under different agro-climatic conditions in a scattered form in forest and non-forest areas as well as in waste land/deserts/hilly areas. The country has enormous potential of oilseeds of tree origin like mahua (Madhuca indica),neem (Azadirachta indica), simarouba (Simarouba glauca), karanja (Pongamia pinnata), ratanjyot (Jatropha curcas), jojoba (Simmondsia chinesis), cheura (Diploknema butyracea), kokum (Garcinia indica),wild apricot (Prunus armeniaca), wild walnut (Aleurites molucana), kusum (Schleichera oleosa), tung (Vernicia fordii), etc. The best characteristic is that it can be grown and established in the wasteland and have varied agro-climatic conditions. (Aurora and Kumar, 2015)

Distribution

Several countries grow henna on a commercial scale for its dye-bearing leaves, notably India, Egypt, Iran, Niger, Sudan and Pakistan. In India, it was once grown extensively in Punjab and Gujarat. However, gradually the major cultivation has shifted to the arid fringes of Rajasthan, with Pali district having the maximum area under henna. It is taken as an annual Ratoon crop under rainfed conditions. Presently over 39,000 ha of henna plantations in the district with nearly 70 per cent occurring in the Sojat area produce around 20,000 t dry leaves worth Rs. 40 crores. Besides this, leaf cuttings are also collected from existing farms and field boundary plantations in Gujarat and Madhya Pradesh. In Uttar Pradesh henna is grown for its scented flowers used in the essence industry. Kannauj, Lucknow, and Varanasi in Uttar Pradesh are reputed centres for the commercial extraction of mehndi oil from flowers and its use in traditional essence. Since henna is grown as a dryland crop under limited moisture conditions greater use of available moisture by the plants is possible.

Henna or Mehandi (Lawsonia inermis L.) a perennial shrub belongs to family Lythraceae. It is commonly cultivated as a commercial dye crop possess natural dyeing properties and are used for hair dyeing and for staining of palm, feet and other body parts since times immemorial. The plant finds their importance due to presence of orange red dye in its leaves and essential oil in its flower. Oil extracted from leaves and flower called ‘Otto of henna’ which is utilized as perfume (Jaimini et al., 2005). It can grow well in harsh climate of arid and semiarid regions. In India, over 90 percent of the henna production comes from Sojat region of Pali district of Rajasthan and Sojat is only center for its processing and trading in India. In India it occupies about 40,000 ha area out of which 35,000 ha alone is in Pali district (Sojat and adjoining tehsils).

Geographical distribution

It occurs naturally in North Africa mainly in countries of Algeria, Cyprus, Egypt, Eritrea, Ethiopia, Indonesia, Iraq, Iran, Jordan, Kenya, Kuwait, Lebanon, Libya, Malaysia, Morocco, Oman, Philippines, Qatar, Saudi Arabia, Syrian Arab Republic, Tanzania, Tunisia, Turkey, Sahara and Yemen. It is naturally occurring in many of these countries along the water courses and semi-arid regions where it can with stand dryness as well as drought. It has been introduced into countries like Australia, Benin, Burkina Faso, Cameroon, Central Africa, Chad, Congo, China, Gabon, Gambia, Ghana, Guinea, India, Liberia, Mali, Mauritania, Niger, Nigeria, Pakistan, Senegal, Sierra Leone, Spain, Sudan, Togo and Zanzibar (Suresh Kumar et al., 2005).

The arid zone eco-system of Rajasthan is very fragile and is prone to serious imbalance even with the slightest disturbance due to mismanagement of resources. Among the eastern margin of the mean annual rainfall is 500 mm, while in the western most part it is 100 mm. The rainfall is monsoon driven. It comes between June and September (in 9-21 short spells). Large coefficient of variation (40-60%) and erratic distribution during the monsoon are characteristics features of the rainfall, leading often to prolong drought and failure of rainfed crops (More and Samadia, 2007). Temperature as low as 4.4° C, and as high as 50° C has been recorded in Western Rajasthan. Farming system and cropping system approach for sustainable use of farm resources and reduced risks have been successfully demonstrated in perennial horticulture. There is great pressure of livestock on available feed and fodder, as land available for fodder production has been decreasing. The requirement of dry and green fodder by 2025 would be 1170 mt and 650 mt while supply is expected around 411.3 mt and 488 mt deficit will be 64.87 % green fodder and 24.92 % dry fodder (Table 1).

Since time immemorial India has been leader in respect to spice, area, production and consumption. India is known as ‘Land of spices. Out of 109 spices listed by the ISO, India produce as many as 63 owing to its varied agroclimatic regions. Almost all the state and union territory of the country grow one or the other spices. Spices are the sources of livelihood and employment for large number of people in the country. Seed spices are annual herbs, whose dried seeds or fruit are used as spices. Spices are the nature’s gift to mankind and since antiquity, spices have been considered indispensable in the culinary art, as they are used to flavour foods and beverages The important seed spices are coriander, cumin, fennel, fenugreek. ajwain, dill,, celery, anise, nigella and caraway. The other seed spices s are poppy seed, rai, yellow mustard, white mustard, parsley and sesame. In India, Rajasthan and Gujarat has emerged as “Seed spice bowl” and together contributes more than 80 percent of total seed spices.

Burgeoning population exerts pressure on limited precious natural resources for enhancing production of food, fodder and fuel. In order to meet out increasing demand for food, fruit, vegetables, oilseeds, fodder and timber wood for burgeoning population, it is necessary to utilize each unit of natural rsesource very efficiently. The productivity of the precious natural resources is to be enhanced per unit time per unit area by agronomic ally managing stresses soil and land ecosystem to harvest more benefit. The cropping system as well as intercropping system practised by using different trees, fruits, vegetables, crops are the very efficient enterprises for realising higher productivity of natural resources available with in specified ecosystem.

The arid zone of India covers about 12% of the country’s geographical area and occupies over 31.7 mha of hot desert and about 7 m ha under cold desert. The arid regions of Rajasthan, Gujarat, Punjab and Haryana together constitute the Great Indian Desert known as Thar Desert that accounts for 89.6% of hot arid regions of India. In Gujarat, 6.22 m ha area is under arid zone which constitute 19.6% of the arid area of country (Fig 1). In Gujarat, eight districts fall under arid zone, namely, Kachchh (100% of district area), Jamnagar (80%), Surendranagar (29%), Junagadh (20%), Banaskantha (18%), Mehsana (7%), Ahmedabad (6%) and Rajkot 6%).

India has witnessed tremendous increase in the production of horticultural crops especially fruits since independence. Due to specialized scientific interventions and application of latest research tools, the country is now among the top fruit producing countries of the world ranking second next only to China. However, the productivity has still remained low as against area under the fruit cultivation. Several neglecting issues related to the production technology have remained unattended so far. The old and senile orchards are now reverting towards a declining trend of production because of plant age factor, non-compatible varieties and poor canopy management (Baba et al., 2011).

In the recent past declining productivity of old and dense orchards existing in abundance has become a matter of serious concern for the orchardists, traders as well as scientists. In India 30-35 per cent area under fruit crops is occupied by old, dense and diseased orchards. For overcoming the problem of unproductive and uneconomic orchards existing in abundance, large scale uprooting and replacement with new plantations (rehabilitation) will be a long term and expensive strategy. Therefore research efforts were initiated to standardize a technology for restoring the production potential of existing plantations by a technique called Rejuvenation. The term ‘Rejuvenation’ means renewal or making new or young again. As applied to the orchard tree it would mean restoring the productive capacity of the fruit trees. The meaning of ‘Rejuvenation’ according to Chamber’s dictionary is ‘to recover youth character or to grow again’. Obviously, this would apply to those plants which have attained a stage where they are no more profitable from the grower’s point of view.

With the culmination of green revolution, the yield in agriculture is almost static with the use of even great deal of inputs and resources with appearing decadence in nature. The agriculture, if continuous on with same trend, will no longer productive and sustainable. Heterogenity being vested with best survival and sustenance, attempt is underway towards crop diversification deploying remunerative crops and techniques so as to keep pace with rising demand of mankind. Added to this, dwindling land : man ratio (0.13 ha during 1990s), harvesting more return from a unit area of land, disguised unemployment, improper availability of fruits and vegetables (40 g and 120 g respectively as against 120 g and 280 g for fruits and vegetables, respectively), generating employment (143 man-days/ha in cereals, 860 man-days/ha in fruit production and 1000-2500 man-days/ha in cultural intensive fruit crops), are major concerns for high density planting (HDP). It is a holistic production system which helps in promoting and preserving dynamic agro-ecosystem. HDP is also an aid to biodiversity, biological cycles and organic farming. As an alternative to raise production and productivity especially to compete global trade, HDP is worth adoption.

India is a natural reservoir of the several fruit species. The several less known fruit species, which have the potential for commercial exploitation, are yet to be utilized to their potential. An attention to the less known fruit would play a significant role in increasing the income, providing employment opportunities, uplifting of the poor, small and marginal farmers and the development of value added products. These fruits are well known for their medicinal and nutritive value. There is a great need to develop and popularize not only for their domestic market but also for their export. Some of the less known fruits are described here with respect to their cultivation technology.

Vegetables are short duration crops and provide more returns per unit area and time besides, they play a major role in balancing human diet, thus, helping in alleviating hunger and malnutrition (Annon., 2009). In the previous few years, India has attained quantum jump in vegetable production and present estimated vegetable production is around 162.9 mt in an area of about 9.4 mha (NHB, 2014), and holds second position at global level. But this level of vegetable production is insufficient to meet the recommended daily intake (~300 g per capita per day) for a huge population of the country. This is mainly due to lower average productivity (17.5 t/ha) of the nation. There are several crop diminishing factors such as soil borne- and foliar- diseases, insect-pests and nematodes as biotic factors, and soil or water salinity, alkalinity, metal toxicity and heat and moisture stress as abiotic factors, which greatly affect vegetable crops yield in almost all growing areas, especially in fragile arid and semi arid regions.

Vegetables are of short duration, have higher productivity and give more return per unit area, besides giving nutritious food to human being and can be fitted in different farming systems. They also play a major role in balancing human diet, thereby helping in alleviating hunger, poverty and malnutrition. Because of the public awareness for the significance of vegetable consumption, the demand of vegetables in the global market has increased immensely. Thus, vegetable farming is becoming profitable venture globally, opening avenues of self employment and revenue generation (Anon., 2009). At global level, India holds second position, next only to China in vegetables production with a share of about 14%. The present annual vegetables production of country is about 175 million tons from an area about 10.3 million ha with a productivity of 17.1 t/ha. India grows largest number of vegetables in the world, as having a spectrum of wide range of agro-climatic situations, ranging from dry temperate to humid tropics between the altitudes from sea level to snow line.

The Indian hot arid region is one of the most important arid ecosystems of the world in terms of biodiversity it possesses. This arid region spreads over 31.7 mha, occupies major part of north western India including Rajasthan, Gujarat, Punjab and Haryana, which together contribute 73% of arid region. High temperature, wind velocity, low humidity, low and erratic rainfall and high potential evapotranspiration are important characteristics of this region which narrowed down the choice for vegetables, besides permit their low productivity.

Rajasthan has geographical area of 3.42 lakh sq. km has attained the status of being the largest state of India. The state represents 10.4% land surface area with 5.5% population of India, 66% is dependent on agricultural for their livelihood. The state is divided into 33, districts, which are further subdivided into 338 Tehsils and 295 Panchayat Samitis. The total cultivable area is around 220.00 lakh ha. The average rainfall of the State is 575 mm, out of which about 532 mm precipitation occurs in the rainy season i.e. June to September. The average rainfall of eastern Rajasthan is about 704 mm and that of western Rajasthan is about 310 mm which reflects a vast variation. Rivers in Rajasthan are non-perennial except for Chambal and Mahi rivers. The State is presently divided into 33 administrative districts and has 10 agro-climatic zones. Agriculture in Rajasthan is primarily rain fed covering country’s 13.27 per cent of available land. Groundwater is getting depleted as well as polluted. In general, every third year is a drought year. Despite these, the State has made significant achievements since independence and has attained self-sufficiency in food- grains. Rajasthan is located in the north-western part of the subcontinent. It is bounded on the west and north-west by Pakistan, on the north and north-east by the states of Haryana, Punjab, and Uttar Pradesh, on the east; in the south- east by the states of Uttar Pradesh and Madhya Pradesh, and on the south- west by the state of Gujarat. The Tropic of Cancer passes through its southern tip in the Banswara district. In the west, Rajasthan is relatively dry and infertile: this area includes some of the Thar Desert, also known as the Great Indian Desert. In the south-western part of the state, land is wetter, hilly, and more fertile.

The hot arid regions of India are spread over 32 million hectares in the states of Rajasthan (61%), Gujarat (20%), Punjab (5%), Haryana (4%), Karnataka (3%) and Andhra Pradesh (7%). The arid regions of western Rajasthan experience an annual rain fall between 100-500 mm with a coefficient of variations varying from 40-70 per cent. Low and erratic rainfall coupled with extreme temperature results in complete or partial crop failure, considerably affects the agricultural economy of the region. High wind velocity causes wind erosion and shifting of sand dunes covers the fertile agricultural land and canals (Rao and Singh,1998). The rise in temperature begins from March onward and attains its peak in May as high as 46°C. The transpiration is low during winters but during summer in months (May & June), it reaches up to 16 mm per day. The annual estimated potential evapotranspiration values ranges from 1600 mm in eastern part and 1800 mm in western part of the region.

In the arid regions of Rajasthan, Haryana, Punjab and eastern part of arid Gujarat the soils have developed from alluvial and aeolian parent materials. In context to the type of soils light brown sandy soils with dune dominance is 30.6 per cent and associated others 34 per cent area, light brown soils 1.7 per cent, Grey brown soils 13.6 per cent hard pan in 5.9 per cent and seirozems in 1.7 per cent area (Dhir, 1977). Kolarker et al. (1989) reported that in 12 district of Rajasthan sandy soils dominated in 14.3 million ha. These soils are poor in fertility very low organic carbon (0.03-0.1%), light in texture called desert soils (north western) in the order of aridisols. It has undulated topography with the dominance of sand dunes inter-dunal plains. About 80 per cent area falls under rain fed cropping and moth bean, cluster bean, pearl millet, and sesame are the main crops grown during kharif season after the onset of monsoon. Under the vagaries of monsoon and recurrent drought the rain fed cropping becomes a gamble, which creates severe food and fodder scarcity in the region.