Trials were conducted to examine the effects and ec onomic feasibility of
supplemental drip irrigation on
watermelon production in g ravel and plastic mulched fields in the Loess Plateau of northwest China in 20 01. The trial comprised four levels of supplemental drip irrigation: 0
mm, 22 5 mm, 45 0 mm and 67 5 mm. The treatments were laid out in two complete randomiz ed blocks with 4 replications. The precipitation during the experiment, which co vered the watermelon growing period was 125 8 mm. The results indicated that so il water content increased with increasing irrigation amounts. Soil water conten t was the greatest for the 67 5 mm irrigation treatments (D 3), 2 2% higher t han non irrigated treatments (D 0). Soil water content fluctuated greatly at t he soil depth intervals of 0～40
cm and 40～80 cm, and was relatively stable in the 80～120 cm layer Supplemental irrigation increased watermelon
yield and wa ter use
efficiency (WUE) in the gravel and plastic mulched fields. The 45 0 m m and 67 5 mm irrigations increased yields by 36 3% and 45 7% respectively. T he 67 5 mm drip irrigation had the highest water use efficiency (WUE) of 2 6 7 kg/m 3 , which was 17 0% higher than the non irrigated treatments. Ir rigation amount also influenced soluble carbohydrate content of watermelon. Ther e were small differences in soluble carbohydrate content for irrigation less tha n 45 0 mm, however, the soluble carbohydrate content decreased by more than 0 44% for 67 5 mm irrigation. The net economic income was estimated to be highest (43,677 yuan/hm\+2) for the 67 5 mm supplemental irrigation treatment followed by 45 0 mm supplemental irrigation (41,360 yuan/hm\+2) treatment. The highest net profit per m 3 of water was 18 48 yuan(RMB) for the 67 5 mm supplemental irrigation treatment. The study demonstrated that supplemental drip irrigation h as a positive role in increasing the productivity of watermelon in gravel and sa nd mulched fields in the Loess Plateau of northwest China.
More abstracts about the Effect of supplemental irrigation with harvested rainwater on w atermelon (Citrullus lanatus) produc