Water temperature and system pressure effect on drip lateral properties

Abstract

A study was conducted at the department of Agricultural Structure and Irrigation, Harran University, Sanliurfa, Turkey, to determine the effect of increased irrigation water temperature at various irrigation system pressures on emitter flow rate, lateral elongation, and Standard Flow Rate Index for six different brands of drip laterals. Test materials consisted of seven pressure and seven non-pressure compensating irrigation laterals from different manufacturers. Tests results showed that (a) tensile resistance stress tests indicated that 25% elongation levels were reached at about 40 kg of load. On average, pressure compensating laterals reached 25% elongation at 38 kg, while non-pressure compensating laterals reached 25% elongation at 32-kg load. There was no clear indication of the tested brands’ lateral wall thickness on the measurement, (b) pressure-regulated drip emitters had no or limited flow rate change due to increased irrigation water temperature, whereas non-pressure compensating emitters had significantly (P < 0.05) increased flow rates, and (c) finally, increased irrigation water temperature resulted in decreased flow rate variations that had a positive effect on standard deviation. Standard uniformity values improved with decreased flow rate variations in drip emitter flow rates.