Concept Of Watershed Management
Out of the 20.1 million hectares of cultivable land in the state about 17.5 million hectares are under rained agriculture. At presents nearly 13 percent of the cultivated area is irrigated. After harvesting all the available water resources at the most 30 per cent of the cultivated area can be brought under irrigation. Thus, 70 per cent area would remain as rained in the state. The crop production under rained agriculture is most unstable due to inadequate, uncertain and ill – distributed rainfall. Besides. Non adoption of improved agricultural practices in rained agriculture has further deteriorated the socio – economic status of the farmers.
The major food grain requirement of the state is net from the rained areas which contain mostly all grains pulses and oilseeds while in many areas heavy soils are utilized only for rabi cropping. Crop production under rained agriculture is mostly subsistence oriented producing food grains for home consumption including cash crops and fodder for livestock. The cropping patterns vary according to soils, climate, and farmer preference and to a limited extent market demands. Sorghum, cotton, pearl millet, groundnut, pigeon pea, green gram, black gram, sunflower, wheat, gram and safflower are among the important crops grown in rained agriculture. However, the productivity of the crops is extremely low due to improper crop management practices including land management treatments adopted in rained agriculture.
Most of the community lands and privately owned marginal lands which are unsuitable for arable farming remain uncultivated and serve as grazing grounds for village livestock and source of fuel supply. The Government lands are normally located at higher elevations and are badly eroded and deprived off any vegetation. The communal grazing lands are also severely denuded and eroded leaving thin vegetative cover. As a result, these areas serve as an origin of erosion.
It is estimated that out of 30.6 million hectares of the geographical area of the state, nearly 13.8 million hectares suffers from moderate to heavy soil erosion. The detailed crosion studies made in Solapur district indicated that the percentage of deep soils (depth > 45 cm) came down from 46 to 29 in a period of 75 years indicating the severity of erosion hazard. From the studies, it is observed that the soil loss was in the range of 60 to 90 tonnes / ha per annum. With this rate is estimated that 20 cm of fertile soil may be lost within a pan of 24 years. However, under natural conditions of weathering process the process the formatting of 1 cm top soil layer will require more than 100 years.
Agricultural development of such rained areas has remained neglected compared to irrigated agriculture. The integrated development efforts in these areas initiated in most parts in the country under the name. "Water shed Development in Rainfed Areas" since 1984 – 85.
Definition of watershed:
i) Watershed is an area above a given drainage point on a stream that contributes water to the flow at that point.
ii) Watershed is a natural unit draining runoff water to common point of outlet.
iii) The watershed is geohydrological unit or a piece of land that drains at common point. Catchments basin or drainage basin are synonymous of watershed.