Application rate of sprinkler as influenced by nozzle size, operating pressure and nozzle elevation.

摘要

Sprinkler irrigation is an advance method of irrigation in which water is sprayed into the air and allowed to fall on the ground surface somewhat resembling rainfall. During the field operation of sprinkler irrigation system, sprinkler is associated with some problems like fixation of nozzle size, nozzle elevation and operating pressure to suit the demand of water requirement of crop and other for high water discharge at controlled water application rate and better performance of sprinkler for high yield of crop. The water application rate by sprinklers is limited by the infiltration capacity of the soil. Application with the higher rates, than infiltration capacity of the soil results in run-off, with accompanying poor distribution of water, loss of water and soil erosion. Normally, sprinkler irrigation systems are designed such that no runoff occurs. Thus, the rate at which a sprinkler is designed to apply water is less the infiltration capacity of the soil that is the maximum rate at which water can enter the soil at a given time. It is only possible by careful selection of nozzle sizes, operating pressure, nozzle elevation and sprinkler spacing, the amount of water required to refill the crop root zone can be applied nearly uniformly at the rate to suit the infiltration rate of the soil, thereby obtaining efficient irrigation. To obtain a proper solution for above problem, a field test was conducted to study and find out the effect of nozzle size, operating pressure and nozzle elevation on application rate. Application rate from nozzle of sprinkler head was measured with the help of catch can. Application rate was determined at three operating pressures i.e. 2.5, 2.0 and 1.5 kg/cm2 with three nozzle elevations 150, 110 and 75 cm for 5.6, 4.7 and 3.1 mm nozzle size. It was analyzed from field study that application rate was increased with an increase in nozzle size & operating pressure but decreased with an increase in nozzle elevation.