Performance of drip irrigation and nitrogen fertilizer in irrigation water saving and nitrogen use efficiency for waxy maize (<i>Zea mays</i> L.) and cucumber (<i>Cucumis sativus</i> L.) under solar greenhouse

Abstract

Abstract An experimental study was conducted to determine the optimum water amounts, irrigation water use efficiencies ( IWUE ) and irrigation water saving for waxy maize and cucumber, and the optimum nitrogen (N) quantity and nitrogen use efficiency ( NUE ) for maize under fertigation. The different irrigation treatments were estimated using the CROPWAT model based on the Penman–Monteith method, and the different N fertigation rates were determined based on the locally recommended dose. The results showed that the vegetative growth, yield and quality traits of maize and cucumber were significantly affected by different irrigation water amounts and N fertigation rates. The water application depths of 50% and 100% of the crop evapotranspiration inside the greenhouse ( ET c,in ) for maize and cucumber were found to be the optimum amounts that resulted in the highest yield of 26.8 t ha −1 for maize and 37.8 t ha −1 for cucumber. The 50% and 100% ET c,in for maize and cucumber resulted in water saving of 102.9 mm and 29.0 mm, respectively. The fertigation quantity of 125% N dose was the optimum N level that obtained highest maize yield of 26.2 t ha −1 , and the NUE was 7.198 t ha −1 kg −1 . The vegetative growth and fruit quality reached the best at irrigation depth of 50% ET c,in and N dose of 125% for maize, and irrigation depth of 100% ET c,in for cucumber. The IWUE varied from 0.102 to 0.209 t ha −1 mm −1 for maize and 0.152–0.340 t ha −1 mm −1 for cucumber. Furthermore, the IWUE and NUE increased with the decreasing irrigation water amount and the N application dose. Findings from this research may provide technical guidance for reducing irrigation water use in agriculture in order to solve the water scarcity problem. There is water saving potential observed in this study.