Drip irrigation and fertilization improve yield, uptake of nitrogen, and water-nitrogen use efficiency in cucumbers grown in substrate bags

This study was conducted to identify ideal irrigation and fertigation levels for maximum yields and profitability of cucumber grown in a substrate-bag cultivation system. The experiment was laid out in randomized complete-block design, with combinations of four drip irrigation rates (75, 100, 125, or 150% of crop evapotranspiration (ETc)) and three fertilization (F) levels (60, 100, or 125% of one dose of Yamazaki nutrient solution formula). The 'irrigation level x fertilization level' interaction significantly affected cucumber yield and nitrogen accumulation. The treatment combination of 125% ETc and 100% F promoted yield relatively best. Plants were grown in the 125% ETc and 125% F treatment combination accumulated the most nitrogen. The greatest nitrogen use efficiency (NUE) was observed in the 100% ETc plus 60% F treatment combination. Water use efficiency (WUE) decreased with increasing irrigation rate, and considering just one fertilization level. Through the multivariate regression analysis and the spatial analysis methods to evaluate yield, WUE, and NUE, we conclude that the combination of 13.54-23.78 g/plant and 37.71-52.59 L/plant were the best strategy of fertigation and irrigation for the production of drip-irrigated cultivated cucumber grown in substrate bags in spring.