SIMULATION OF SUSTAINABLE PRODUCTIVITY OF CROPLANDS IN IRRIGATED COMMANDS

Abstract

India would need to produce 227 million tonnes (against the present production of about 180 million tonnes) of food to meet the per capita requirements of 225 kgs (i.e. about one-fourth of a tonne) per year for an estimated population of 1231 million in the year, 2030. This realization to the scientists and planners had led the development of high yielding varieties of crops, increased production of chemical fertilizers and improved irrigation facility. All these measures so far have collectively contributed towards increasing agricultural production in the country. While maximising the net benefit from the crops in the command area it is imperative to make balanced use of fertilizers. Faulty use may affect the soil fertility adversely and cause soil sickness thereby reducing the productivity of land. In order to obtain sustained production of the crops, a suitable fertility level of the soil need to be maintained. Fertility level of a soil is a measure of available nutrient status (N, P and K and other micro nutrients) in the soil. Sustained productivity of the crops depends on judicious use of fertilizers and different crop activities. Sankhyan and Sirohi (1971)(85) reported the possibility of increasing net return from the crops by increasing the use of fertilizers, water etc. in Haryana. Mishra and Kapoor (1992)(72) observed a difference in the sustainability concept of developed and developing countries. The developed countries are mainly concerned with maintenance of environmental quality and ecological balance whereas developing countries aim at increasing productivity along with proper care of environment and ecology. Goswami (1992)(41) emphasised the need of maintaining soil health as an essential in pre-requisite for sustained agricultural productivity. Biswas (1993)<IJ) studied the impact of excessive use of nitrate fertilizers and pesticides and concluded that the excessive use of fertilizers not only pollute the ground water but also affect the quality and quantity of the crop produced. FAO (1989) defines sustainable agricultural development as the management and conservation of natural resource base and the orientation of technological and institutional change in such amanner as to ensure attainment and continued satisfaction of human needs for the present and future generations. Such sustainable development in the agriculture, forestry and fisheries sectors may conserve land, water, plant and animal genetic resources. This is environmentally sound, technically appropriate, economically viable and socially acceptable. Rajamane (1986), however, reports^ that in developing countries like India there is a continuous decline in productivity of land with the increase in the fertilizers use under intensive cropping system. The World Commission on Environment and Development (1994) has characterised the sustainable development on the following lines : (a) This should not damage or destroy the basic life support system of our planet i.e. the earth, air, water, soil and biological systems. (b) The development should be economically viable to provide continuous flow of goods and services derived from the earth's natural resources. Therefore, this study was planned to know the production response of crops to different inputs viz. net sown area, net irrigated area, fertilizer's use, pesticide's use, weather conditions and water balance as well as to obtain the optimum crop plan for sustainable productivity. Chapter III describes Paithan left bank canal (P.L.B.C.) command of the Jayakwadi project which has been selected for this study. This area receives water delivery through acanal with the capacity of 100.8 cumecs. ' IV The length of the canal is 208 kms. and divided into eleven reaches keeping in view the topographic features of the area. The cultivable command of P.L.B.C. is 1,42,000 ha. Chapter IV describes resources of the study area such as human labour (4450761 Nos.), bullock labour (3694258 Nos.) fertilizers (5000 M.T.), pesticides (250.60 M.T.) surface water (45783.49 ha.m.), ground water (189275.28ha.m.), Rain (650 mm), seeds (4400 t.t.) etc. as per 1981 estimates. Water quality of the area is good for irrigation. The command falls in the agroclimatic condition of semi-arid tropic. Chapter V describes the theory of crop production function,technical consideration and relationship.lt also describes the technique of regression analysis and different tests to be carried out for testing the adequacy of mathematical model. Linear and power production response functions were developed for India and the study area are also discussed in this chapter. For the estimates,, of both study area and also India, variables taken were net sown area, net irrigated area, fertilizers and pesticides consumption as well as the weather condition and annual rainfall (mm). For the study area fertility equations were developed taking variables i.e. initial fertility level of N, P, and K ; final fertility level of N, P, and K and rainfall during the season. R2 values were recorded higher for power production function over linear function. Therefore, power functions were adopted for making yield projections. Tests and results concerning production sustainability of the cropping pattern at 100 % cropping intensity have been discussed in chapter VII. Optimium cropping pattern at 72.85, 81.37, 90.52, 99.82 and 100 percent cropping intensity was determined and the net benefit corresponding to these levels of intensity was as Rs. (million) 570, 660, 750, 780 and 913 v respectively using the proposed method. The existing cropping intensity is 83.25% that records a net benefit of only Rs. 480 (million). It was estimated that the area would have a population of 0.686 mby 2030. The demand of foodgrains, edible oil and sugar in the area would be 0.155 m.t. 0.017 m.t. and 0.123 m.t. respectively. Against this need the proposed cropping pattern with 100% cropping intensity will be able to produce 0.187 m.t. foodgrains, 0.0183 m.t. oilseed, and 0.47 m.t. sugarcane. Chapter VIII describes the summary of all the chapters and conclusions drawn from the study undertaken.lt also gives the scope for further study. vi