Irrigation treatments for corn with limited water supply in the Loess Plateau, China

摘要

The lack of available growing-season water in the middle reaches of the Yellow River watershed has caused the development of deficit irrigation in the Loess Plateau of China. This research was conducted to evaluate the effect of different irrigationfrequencies and timings on water use and com yield and to determine optimum water management practices with limited water supply. Irrigation treatments were zero (I0), one (II), two (I2), three (I3), and four (I4) irrigations per growing season with each irrigation consisting of a 87.5 mm depth of water. For treatment I1, the irrigation water was applied at tasselling, whereas I2 consisted of I1 plus an irrigation during the vegetative stage. Treatment I3 consisted of I2 plus an irrigation at silking,while for I4 an additional irrigation was provided at the grain filling stage, irrigation quantities ranged from deficit to excess irrigation. The study was conducted at the Changwu Agriecological Station of the Loess Plateau from 1991 to 1995 on a moderately permeable silty clay loam soil. A single irrigation increased yield by an average of 20 percent. On average, two, three and four irrigations increased yields by an additional 16.9, 6.7, and 4.3 percent, respectively. There were no significant differences in corn grain yield and water use efficiency (WUE) among treatments I2, I3, and I4, but I1 yield was significantly lower. We concluded that substantial water savings can be achieved by applying two irrigations, one at tasselling and one during thevegetative stage. This should increase yield significantly compared to the no irrigation treatment, without significantly reducing yield compared to four irrigations per growing season.