CORN GROWTH AND YIELD AS AFFECTED BY DRIP IRRIGATION UNIFORMITY AND APPLICATION AMOUNT IN NORTH CHINA PLAIN

摘要

The uniformity coefficient is an important parameter for designing the drip irrigationrnsystems, but the influence of irrigation uniformity on crop growth is still unclear. Fieldrnexperiments were conducted in two growing seasons of spring corn (Zea mays L.) inrnthe north China plain to evaluate the influence of drip irrigation uniformity andrnapplication amount on corn growth and yield. Three Christiansen uniformityrncoefficients (CU) of 0.66, 0.81, and 0.99 and three levels of water application at 50%,rn75%, and 100% of the irrigation requirement were used. During both growing seasons,rncrop parameters including plant height, leaf area index (LAI), chlorophyll meter readingrn(SPAD reading) and dry biomass above ground were regularly measured, and thernyield was recorded on harvest. The results showed that drip irrigation uniformity andrnapplication amount had insignificant influence on the mean of plant height, LAI, SPADrnreading and dry biomass in both years (α =0.05). The uniformity coefficients of therncrop parameters increased with spring corn growing, and their final value were largerrnthan 0.90. The uniformity coefficients for yield along a dripline were larger than 0.93 forrnthe three CU treatments tested. The drip irrigation uniformity, application amount andrnthe interaction between the two factors had insignificant influence on the mean and thernuniformity of yield (α =0.05). These results demonstrated that the drip uniformityrncoefficient had less important effect on the spring corn growth and yield. It suggestedrnthat the current design standard of drip irrigation uniformity coefficient (CU≥0.80) couldrnbe fairly lowered in the semi-humid regions, such as in the north China plain, to reducernthe initial and operation costs of drip irrigation systems.