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Assessing Agricultural Sustainability in Watersheds in India using Geomatics

Dr. Kausalya Ramachandran
ICAR National Fellow,
Project Staff, CRIDA, Santoshnagar
Hyderabad – 500059, India
kausalya@crida.ernet.in

Dr. K.L.Sharma
ICAR National Fellow,
Project Staff, CRIDA, Santoshnagar
Hyderabad – 500059, India

T. Srinivas, M. Shankar Rao, M. Gayatri & V. Bhaskar

Abstract
In India watershed-based development has been the strategy for growth and sustainability of agriculture in the vast semi-arid and dry sub-humid regions popularly called rain-fed regions. Watershed Development Projects have been undertaken to enhance agricultural production, conserve natural resources base and ensure rural livelihood since 1980s. Initially soil and water conservation was the primary objective of the program which attracted large public investments in the last 25 years. Subsequently, egalitarian principles of equity and enhancing rural livelihood were given prominence; more recently the principle of sustainable development with emphasis on tenets of development economics like cost of degradation of fragile land and economic ecology like valuation of ecological services have gained emphasis. Large investments have been assigned for watershed based development in the National Five-Year Plans since 1990s and more investments have been earmarked till 2025.

The rain-fed regions of India span across several agro-climatic and ecological regions which warrant location-specific approaches to watershed development and management. Besides this three major ministries of the Govt. of India, development agencies and NGOs are involved in implementation of the projects. As a result, notwithstanding, the common guidelines for implementation, the projects have yielded little by way of lopsided development and impact assessment has been rendered impractical. In view of the huge investments already made and the necessity for effective implementation of watershed development projects in rain-fed areas of India, the tools of Geomatics were employed to evaluate the impact of various aspects of the program on agricultural sustainability, natural resource base and rural livelihood in selected villages. The present paper elucidates the multi-disciplinary approach of using satellite data, GPS and GIS along with conventional methods of field survey, transect walk, PRA, soil sampling and physico-chemical analysis and socio-economic survey for evaluation and monitoring these developmental activities for initiating corrective measures in order to increase their efficiency.

Introduction
Rain-fed agro-ecological regions (AER) which encompass the semi-arid tropics (SAT) and hot dry and moist sub-humid regions of India, extends over 76.74 M ha out of the total geog. area of 90.4 M ha in the states of Andhra Pradesh (AP), Maharashtra (MAHA), Karnataka (KAR) and Tamilnadu (TN) in Peninsular India. Watershed-based development has been an important component in the schemes for economic planning for development for ensuring agricultural productivity, natural resources management and enhancing rural livelihood. Over 71 million persons depend on agriculture and allied activities in these states alone according to 2001 Census of India (GoI,2001). Annual rainfall in this vast region ranges from 400 mm in the arid belt of Rayalseema in southern Andhra Pradesh to over 800 mm in the rest of the region which occur in 52 - 55 rainy days. Over 50 % of this rainfall which occurs in summer is associated with thunderstorm activity which lasts for a few hours. Considering such a rainfall pattern, rain - water harvesting, storing and prudent use for agriculture and other allied activities is of utmost importance.

Watershed Development Program was initiated in 1980s to address these limitations of the rain-fed agro-climatic and ecological niches of India (MoRD 1994; Hanumantha Rao 2000; Planning Commission, 2002, 2005). The emphasis and approach of the projects vary in consonance the ecological nuances of the regions. In scanty rainfall regions like in case of Maharastra uplands where annual rainfall is 500 mm, increasing irrigation potential by water harvesting and recharge of groundwater is given precedence. In case of Telengana region where annual rainfall is 800 mm and the terrain is gently undulating, water harvesting and surface storage in soil profile and farm ponds in preferred for enhancing productivity of rain-fed crops. In case of arid regions of Rayalseema where rainfall is scanty, water harvesting in field tanks for irrigation during crop stress, are preferred modes. The soil and water conservation structures (S&WC) viz., check-dam, stone weirs, contour bund, live bunds, vegetative cover, key-line plantation, grass way etc. are planned to provide impediments to overland runoff which induce soil erosion and deplete nutrients from agricultural fields. The structures are laid to guide runoff to designated farm ponds and tanks for water harvesting on surface besides impounding water for facilitating deep percolation for groundwater recharge. Also, soil degradation is a matter of grave concern in India which threatens agriculture. In Peninsular India over 47.3 M ha area have poor degraded soils (Saxena et al., 1999) of which 0.15 M ha have been categorized as wasteland (NRSA, 2000). More recently, the frequency of abnormal trends in climate like late onset of monsoon, early withdrawal, long inter-seasonal breaks, shift in peak rainfall period, cloud-burst, thunder storms, etc., are increasing leading to drought or flood occurrences. Thus, watershed development program (WSP) is undeniably, the most comprehensive program for achieving agricultural and ecological sustainability in the rain-fed regions of India.

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