Preface Rainfed agriculture is practiced in most of the arid and semiarid areas of India. About 67 % of arable land in India (143.2 m ha) is rainfed. In terms of production rainfed agriculture accounts for production of more than 40 per cent of total food grains, nearly 75 per cent of oilseeds, 90 per cent of pulses and 70 per cent of cotton. Most of the rainfed lands are typified by highly fragile natural resource base; the rainfall is low; soils are often coarse textured, sandy, inherently low in fertility, organic matter and water holding capacity; and are easily susceptible to wind and water erosion. Deterioration of natural resources is the main issue threatening sustainable development of rainfed agriculture, more so in the Third World Countries. India will have to produce 300 million tonnes of food grains to feed 1.5 billion populations (approx.) in the coming years. This target cannot be realized from irrigated areas alone as we have irrigation potential for 178 million hectares only. Therefore, we will have to evolve an appropriate technology for dry land farming. On the other hand, we can say that second ‘Green Revolution’ in Indian agriculture can be in rainfed/dryland agriculture. In semester system of education the students are quite dynamic for which the students are to be helped for changeover. We can identify their difficulties for comprehensation of language, nonavailability of text books for their semester system. The need for comprehensive information on rainfed farming relevant to undergraduate and postgraduate students of agriculture has been felt for quite sometime. We hope this book will prove a fillip. The present book suite to the need of students. The chapters of the book have been selected and arranged in such a manner as to lead the students through the entire gamut of rainfed agriculture supported by suitable examples and diagrams.

Importance of Rainfed Farming In India, rain dependent areas are vast and they have a great contribution to make in agricultural production, with just 1/40th of the world land. India supports over half of its buffaloes and over one seventh of its cattle and goats that also share land utilization with humans and add to the national wealth. The second largest number (after Africa) of drought victims of the world live in India, out of 143 m ha cultivated land about 43 m ha are under irrigation and the rest of the area (about 70%) is rainfed but all is not too dry. About 90% of it located in the north-west part, out of which 60% is located in Rajasthan and sustains a human population of 20 million and a total livestock population of 23 million. The dry land areas contribute about 42% of food grains, almost all the coarse grains and about 75% of pulses and oil seeds of the total production of the country. About 2/3 of rice and rapeseed mustard and 1/3 of wheat are grown in rainfed areas. A large portion of industrially important crops such as cotton, groundnut and castor are cultivated under dry land conditions and has a great contribution to make to the production of food, fibre, fuel and furniture timber etc. Dry land agriculture may be classified into three groups on the basis of annual rainfall. a) Dry farming : Cultivation of crops in areas where annual rainfall is less then 750 mm and crop failures due to prolonged dry spells during crop period are most common. Dry farming is practiced in arid regions with the help of moisture conservation practices. Alternate land use system is suggested in this region. b) Dryland farming: Cultivation of crops in areas where annual rainfall is more than 750 mm but less than 1150 mm is called dryland farming. Dry spells may occur, but crop failures are less frequent. Higher evapotranspiration (ET) than the total precipitation is the main reason for moisture deficit in these areas. The soil and moisture conservation measures are the key for dryland farming practice in semi-arid regions. Drainage facility may be required especially in black soils.

The conservation of soil and water is very essential for sustainable production, environment preservation and balanced ecosystem. Fifty percent of total geographical area (329 m ha) of our country needs soil and water conservation measures. About 5334 million tonnes of soil is lost annually along with 10 million tonnes of fertilizer and other essential nutrients and organic carbon. Loss of nutrients is almost equal to their total production in India. In India about 70% of the cultivated area falls under the category of dryland conservation measures for soil and water and efficient utilization of these resources is needed in these areas. The fact that rainfed agriculture supports 44% of India’s human population and contributes 90 percent of coarse cereals and pulses, 80 percent of oil seeds and 65 percent of cotton and growing realization that further gains in productivity of crops and live stock will emanate from rainfed regions, leave no room for complacency in this regard. In these areas, rainfall frequently occurs with high intensity that produces higher runoff due to non adoption of soil and water conservation (SWC) measures and poor permeability of the soil. As a result crop grown during rainy season often suffer from moisture stress due to inadequate moisture storage in the soil profile. Secondly soil erosion problems such as sheet, rill and even gully erosion are common in the region. It has been reported that the black soils of peninsular region of India, under cultivated fallow gives runoff of about 23.4 percent of rainfall and results in a soil loss of 8.94 t ha-1 at 1.0 percent slope (Verma et al., 1990). They further reported that the rate of siltation reduced by 83 percent within a span of five years due to adoption of agronomic measure of SWC. These studies clearly showed that soil erosion and runoff are the major factors causing land degradation in the region that needs appropriate SWC measures so that crop productivity could be maintained.

Soil and moisture conservation measures are a prerequisite for ensuring a good crop stand, growth and development of crop, and higher crop yields. These measures depend mainly on the land (topography and slope), soil type, rainfall pattern, and nature of the crop. The various management practices are: Tillage Off-season tillage is necessary to get a weed free seedbed having good tilth and better moisture conservation. Pre-monsoon showers should be utilized for deep ploughing (where necessary) and blade harrowing. This will enable sowing of large areas in limited time- a necessary in dryland areas. Higher yield advantage with deep ploughing (22 cm) has been obtained in case of sorghum, pearl millet, maize, and rice. In case of rice, use of mould board plough to a depth of 30 cm every year increased the rice yield at Ranchi. For small seed crops like finger millet, soil compaction below the seeding zone is absolutely necessary for getting good crop stand establishment and higher yields. Tillage requirement for pulse crops (cowpea, mungbean, black gram) varies with the type of soil on which they are grown. For loamy sand or sandy loam soils, one or two cross cultivation using a sweep harrow, will be enough to provide a good tilth.

Natural resources conservation and their management hold key to sustainable agriculture and livestock production. It is all the more crucial for countries with predominant agrarian economies where development of sustainable agriculture is essential for overall growth, redressal of poverty and security. Conservation of both soil and rain water as very crucial and basic resources have been practiced since ancient times in India. However, there has been renewed emphasis on conservation and efficient utilization of these resources in the recent past. The fact that 70% of the arable area of India is rainfed with precarious supply of water and that rainfed agriculture supports 44% of India’s human population and contributes 90 per cent of coarse cereals and pulses, 80 per cent of oilseeds and 65 per cent of cotton and growing realization that further gains in productivity of crops and livestock will emanate from rainfed regions, leave no room for complacency in this regard. Year after year, the fate of a vast majority of Indian farmers hangs in balance, as success with rainfed agriculture continues to be a gamble. It is evident that crop yields in semi-arid areas depended more on rainfall distribution than on total rainfall and lack of serious efforts to create the water supply for crops through scientific management of rainwater is a factor favoring this avoidable uncertainty. In rainfed agriculture no other input can perhaps enhance the yield without effectively tackling of the rainfall aberration related sub-optimal moisture availability. Therefore a prerequisite for substantial improvement in the agriculture production in the semi-arid region is to manage runoff water and to use it either at the time of moisture stress even during the monsoon or in next season. It has been reported that only one supplementary irrigation at proper stage can double of rabi crops. But supplemental water is a developed resource and is more expensive than the natural resources. Hence, it is all the more necessary to use this water judiciously and efficiently. Standardization of techniques by which as much of precipitation as possible can be conserved for crop use, either directly in the soil profile through infiltration or through runoff collection and recycling is an area of priority in research.

Intercropping is growing two or more crops simultaneously on the same piece of land with a definite row pattern. The crops may or may not be sown or harvested at one time. Advantages of intercropping Intercropping provides yield advantages as compared to sole cropping. These are not by means of costly input but by the simple expedient of growing crops together. 1.It provides greater surety and stability of higher yield over different seasons. 2.It economizes the space and time of cultivating two or more component crops of comparable agronomic practices grown separately. 3.It helps to restore soil fertility when legumes are included as component crop. 4.It utilizes a greater total volume of both below and above ground environment. 5.It helps to avoid intra-crop competition and thus a higher number of crop plants can be grown per unit area. 6.It helps in better use of growth resources. 7.It also helps in better control of weeds pests and diseases. 8.It also controls erosion through providing continuous leaf cover over the ground surface. 9.It is the small farmers of limited means who is most likely to benefit.

Watershed management Watershed is defined as a geohydrological unit draining to a common point by a system of drains. All lands on earth are part of one watershed or other. Watershed is thus the land and water area, which contributes runoff to a common point. A watershed is an area of land and water bounded by a drainage divide within which the surface runoff collects and flows out of the watershed through a single outlet into a lager river or lake.

Low rainfall or failure of monsoon rains is a recurring feature in India. This has been responsible for drought and famines. The word drought, generally, denotes scarcity of water in a region. Though, aridity and drought are due to insufficient water, aridity is a permanent climatic feature and is the culmination of a number of long term process. However, drought is a temporary condition that occurs for a short period due to deficient precipitation for vegetation, river flow, water supply and human consumption. Drought is due to anomaly in atmospheric circulation.

Land capability classification Introduction: The United States Department of Agriculture (USDA) land classification system is interpretative, using the USDA soil survey map as a basis and classifying the individual soil map units in groups that have similar management requirements. At the highest of categorization, eight soil classes are distinguished, namely, arable lands (I to IV) and non arable lands (V to VIII). Origin of land capability classification (1933) : The Georgia Piedmont Land Capability Classification (LCC): First U.S. effort to systematically determine the best use of lands by classifying and mapping erosion rates and potential in relation to both physical characteristics and agricultural capacity. Definition: Land capability classification is a system of grouping soils primarily on the basis of their capability to produce common cultivated crops and pasture plants without deteriorating environment over a long period of time. Classes: Land capability classification is subdivided into capability class and capability subclass nationally. Some states also use a capability unit. The capability classification provides three major categories of soil groupings: (1) Capability unit, (2) capability subclass, and (3) capability class.

Tillage The mechanical manipulation of soil with tools and implements for obtaining conditions ideal for seed germination, seedling establishment and growth of crops is known as tillage. Tillage may be described as the practice of modifying the state of the soil in order to provide conditions favourable to crop growth.

Definition Soil erosion is the process of detachment of soil particles from the top soil and transportation of the detached soil particles by wind and / or water. The agents causing erosion are wind and water. The detaching agents are falling raindrop, channel flow and wind. The transporting agents are flowing water, rain splash and wind. Erosion is the process by which soil and rock are removed from the Earth’s surface by exogenic processes such as wind or water flow, and then transported and deposited in other locations. While erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. Excessive erosion causes problems such as desertification, decreases in agricultural productivity due to land degradation, sedimentation of waterways, and ecological collapse due to loss of the nutrient rich upper soil layers. Water and wind erosion are now the two primary causes of land degradation; combined, they are responsible for 84% of degraded acreage, making excessive erosion one of the most significant global environmental problems. Industrial agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of denuded soils.

Drainage - definition Agricultural drainage is the artificial removal and safe disposal of excess water either from the land surface or soil profile, more specifically, the removal and safe disposal of excess gravitational water from the crop root zone to create favourable conditions for crop growth to enhance agricultural production. Benefits of drainage a)It provides better soil environment for plant growth by creating favourable soil aeration conditions. b)It improves the soil structure and in turn increases the soil infiltration. c)High infiltration capacity reduces soil erosion. d)It hastens the warming of the soils and maintains desirable soil temperature, which accelerates plant growth and bacterial activity. e)It promotes increased leaching of salts and prevents accumulation of salts in the crop root zone. f)In well drained soils, less time and less labour are required for tillage operations.

Both dryland crops and irrigated crops experience an assortment of ecological or environmental stresses which include abiotic viz., drought, water logging, salinity, extremes of temperature, changes in atmospheric gases and biotic viz., insects, birds, other pests, weeds, pathogens. Dryland crops are more vulnerable to stress in the present context of changing climatic scenarios. The ability to tolerate or adapt effectively by challenging these stresses is a very complicated phenomenon would be due to various plant interactions occurred in the specific environment. Both biotic and abiotic stresses occur at various stages of plant growth and development and frequently more than one stress concomitantly affects the crop. It is difficult to distinguish effects of these stress factors on the performance of crop plants with respect to yield and quality of harvested products. This is of special significance of maximizing productivity of dryland crops in changing climate scenarios, with complex consequences for ecologically and environmentally sound Indian agriculture. In order to successfully meet this challenge, one should understand the various aspects of stresses in view of the current development and to promote a competitive dryland production system.

In dryland areas, moisture conservation accounts prime most important concept for maximizing productivity of dryland crops. Varied topographic and agro- climatic conditions ranging from arid to semi-arid climates with high evaporation because of varied temperature regimes permit the cultivation of drought resistance crops. Reducing the cost of cultivation without compromising the socio-economic status of farmers is prime importance. Conservation of moisture by reducing the weed menace is great task performed by the dryland farmers. Under such situations, effective utilization of dryland tools and implements used are of a primitive nature throughout the dryland farmers for higher factor productivity. Traditional farm tools and implements for self-sustenance have been adapted through experience over generations to meet emerging socio- economic and farming challenges. Relatively small yields consequently larger areas must be farmed for a given return and the successful exploration of dryfarming requires the adoption of methods. The methods which enable farmers to do the maximum effective work with the smallest expenditure of energy. The type of soils and topographic conditions largely influence the type, size and shape of particular tillage tools/ implements among the dryland farmers. The following is a list of local tools/ implements found in the various dryland regions.

Understanding the principles involved in plant growth and development is prime important for managing agronomic practices for higher productivity of dryland crops sustainably. Systematic study of plant growth based on the variability and interpreting plant development based on biometric methods is called as growth analysis. Plant data in turn biometric data is collected from the field and analysed over the period to know the growth condition of the plants. Based on biometric data, agronomic practices like application of fertilizers, irrigation and weed management practices were employed. Several growth indices are devised for identifying environmental or genetic factors as sources of variation in plants. Both whole plant and their component organs (leaf) are basis for calculating growth indices. The most common parameters used in growth analysis are leaf area index, crop growth rate, relative growth rate, net assimilation rate and leaf area duration.

For the preparation of this book, the authors have drawn heavily from the following sources. Aamodt,O.S and Johnston W.A. 1936. Can.J.Res.14: 122-152. Adams, J. E. 1962. Agron. J. 54: 257-261. Barrs, H.D. and Weatherley, P.E. 1962. Australian Journal of Biological Sciences, 15:413-428. Blackman, V.H. 1919. Annals of Botany, 33:353-360. Chen, D; Sarid, A. and Katchalski, E.1968.Proc. Nat.Acad.Sci;US. 61: 1378-83. De, G.C. 1989. Fundamentals of Agronomy. Oxford and 1 BH pulishing Co. Pvt. Ltd. New Delhi. El Sharkawy, M. Loomsi, R.S. and Williams, W.A. 1968. J. Applied Ecol.5:241-51.

Exercise No. 1. Rainfall analysis and interpretation Procedure: Collect the rainfall data from the Department of Agrometeorology and interprete it zonewise and district wise for various districts of Haryana. Correlate it with last year’s rainfall.