Agricultural Engineer

Drawdown and recuperation pattern of wells are much dependent on the aquifer parameters. Analysis of drawdown and recuperation pattern of wells is necessary for the determination of various aquifer parameters. The levels at which water stands in a well before pumping is called static water level. When a well is being pumped, the water level in the well lowers. In general case initial contribution of water from the well mostly comes from the well storage. It is only after sometime that the aquifer starts contributing to pumpage. The time gap between the onset of pumping and the beginning of an appreciable flow of water from the aquifer to the well depends mainly on the transmissivity of the aquifer. The linear relationship between drawdown and time implies that the water is pumped mostly from storage. Thus time drawdown curves were initially linear, but later with the beginning of the contribution from the aquifer; they gradually become non-linear.

Efficient utilization of available water resources requires appropriate management strategies considering the changing environmental conditions. The present study used a widely adopted crop water requirement estimation model-CROPWAT 8.0 for estimation and scheduling of irrigation requirement for onion crop grown under Vertisol in the Rabi season in the semi-arid region of Raichur district. The soil moisture at the root zone was not allowed to fall below 50% depletion. The irrigation events brought the soil moisture back to the field capacity level. The total water requirement for the 1st and 2nd seasons was 428.77 mm and 399.98 mm respectively at 90% irrigation efficiency. CROPWAT based two days irrigation scheduling scenario was found to be appropriate to maintain optimal soil moisture range within the crop root zone at different crop stages.