International Journal of Innovative Research and Development

Abstract

An accurate assessment of agricultural blue and green water use is a key to estimate agricultural water demand and to understand human’s interference with the ecosystems. Ground water is the primary source for irrigation in Upper Manair catchment, Andhra Pradesh. Due to continuous over-pumping, groundwater resources have been greatly depleted. It is extremely important for a sustainable agricultural water management to explicitly estimate the groundwater consumption for agriculture. Crop water requirements (CWR) of various crops in a catchment are computed using CROPWAT software. The seasonal ETc values for rabi crops were 430 mm, 365 mm and 222.5 mm for paddy, sunflower and maize, respectively, and for kharif crops were 525 mm, 261 mm, 1041 mm and 535 mm for paddy, maize, sugar cane and cotton respectively. However, the amount of ground water applied (MCM) for rice (Kharif), cotton, sugarcane, sunflower, double crop rice and double crop maize are 340.11, 57.94, 114.29, 18.0, 186.75 and 175.43 respectively. The total amount of ground water applied for different agricultural crops is 421.92 MCM more than the required amount of water which leads to depletion of ground water. Hence, immediate measures are required to reduce the blue and green water loss by developing efficient irrigation practices for sustainable ground water resources. 

Full Text

Abstract

Water use in agriculture is highest among other water users and economically far less efficient.  The production per unit water consumed, the water productivity, must be increased to increase its economical efficiency. Knowledge about water resources availability and crop water productivity with high spatial and temporal resolution is necessary for water productivity improvement analyses. Therefore, the study has been taken up to characterize the hydrologic processes of the Upper Manair catchment and assess crop water productivity using Soil and Water assessment tool (SWAT) to evolve irrigation management plans to sustain the use of groundwater resources for irrigation. The biological and economical yield of different field crops, viz. Rice, Maize, Cotton, Sugarcane and sunflower were predicted successfully. Water productivity for Rice, Maize, Cotton, Sugarcane and sunflower were estimated at 0.61, 1.27, 0.41, 8.04 and 1.05 kg /m³, respectively, which were significantly lower than the potential. SWAT model predicts crop yield, biomass and water productivity temporally and spatially which will help to finalize the management practices to sustain ground water resources. In addition to adopting water saving technologies, reliable quality and hours of supply of power is extremely important for achieving higher water productivity in ground water irrigation.

Full Text

Abstract

Land use plays an important role in controlling hydrologic response of catchment, particularly in terms of the nature and magnitude of surface water and ground water interactions and surface water availability. The change in land use controls the water yield of surface streams and groundwater aquifers and thus the amount of water available in a watershed. Hence, the hydrological model SWAT has been applied to upper Manair catchment, Andhra Pradesh, India to determine the impact of land management practices and change in land use on water yield for sustainable use. The model was run for a period of 21 years, i.e.1992 to 2012. It was calibrated against observed reservoir volumes using Nash Sutcliffe criteria (0.85). To obtain sustainability of ground water resources in the watershed, it was tried to simulate the water balance components by reducing the area under paddy cultivation through three alternate cropping scenarios. The evaluation of three scenarios clearly demonstrated the impact of conversion of paddy (water intensive crop) on the hydrology of watershed. The base flow was reduced from 31.42mm to 6.21mm. The lateral flow through soil has decreased to 3.05mm from 3.92mm. The deep aquifer recharge has been reduced to 356.79mm from 464.51mm. Actual ET has been increased to 592.8 from 545.1mm due to more vegetation. It can be concluded that converting paddy area to dry land crops will enhance availability of surface water resources and decrease ground water resources.

Full Text