Feasibility studies on raingun method of irrigation system in groundnut

Abstract

A field study was conducted on groundnut by using different irrigation techniques, such as raingun, check basin and sprinkler irrigation systems. In our country, raingun method of irrigation is becoming more popular for sugarcane due to convince in shifting. Sufficient information such as coefficient of discharge, percentage of overlapped diameter for uniformity, etc. is not available for designing the raingun system. A medium volume raingun model was operated at different operating pressures of 2.0, 2.5 and 3.0 kg.cm-2 with 14mm diameter nozzle. The discharge was found increasing with increase in pressure head for raingun of nozzle size 14mm was 3 kg.cm-2. It was observed that increase in pressure increased the discharge of medium volume raingun irrigation system. The minimum discharge was observed at 2 kg.cm–2 as 10.30 m3.h–1 for 14mm diameter nozzle. The maximum discharged was observed at 3 kg.cm-2 as 12.13 m3.h–1 for 14mm diameter nozzle. The coefficient of uniformity of the raingun was determined at different operating pressure. The high coefficient of uniformity was found at 3 kg.cm-2 operating pressure and low uniformity of coefficient was found at 2 kg.cm-2 operating pressure. The water application rates of the raingun under various pressures were determined. The maximum application rate of 10.86 mm.h–1 was found at 2 kg.cm-2 and the minimum application rate of 9.32 mm.h-1 was found at 3 kg.cm-2. The water use efficiency was maximum in case of raingun method of irrigation as compared to check basin and sprinkler irrigation system. Use of raingun sprinkler irrigation during early crop season helped in saving water when the soil infiltration rate was very high and need of water in the root zone was less. Using raingun method of irrigation system, 0.79 kg.m-3 higher water use efficiency was achieved as compared to check basin and sprinkler irrigation system. Benefit cost ratio of the raingun method of irrigation was found as 1.05, which indicated that the raingun method of irrigation was economically feasible.