Cucumber production and the economic revenues under various nitrogen applications in an unheated solar greenhouse on the North China Plain

Abstract The over‐application of cucumber ( Cucumis sativus L.) with nitrogen (N) fertilizers grown in greenhouses can produce adverse environmental consequences. In this study, a five‐season experiment was conducted from 2014 to 2018 to determine the influence of N rate on N use and economic returns. The experiment contained traditional N application under furrow irrigation (CK) and three N rates with drip irrigation, they are 100, 75, and 50% N applied in the check, referring to T100, T75, and T50, respectively. However, the irrigation rates in drip irrigation were approximately 40% lower than the check. The N losses from gas emission and leaching nitrate accounted for approximately 70% of the applied N when the traditional N rate was applied (CK and T100); however, the loss reduced to 12% in the T50 treatment. The highest cucumber production was found in the T100 treatment, which was 6.1 and 9.4% higher than the T75 and T50 treatments, respectively. The highest net revenue was found in the T100 treatment, followed by the CK (–5.8%), T75 (–7.6%), and T50 (–9.4%) treatments. The highest N productivity and economically applied N productivity were found in the T50 treatment, which were approximately 60% higher than those in the T100 and CK treatments. Fully considering the economic benefit, N productivity and environmental protection, the local N application for cucumber cultivation in greenhouses on the North China Plain (NCP) can be reduced by 50% with drip irrigation system.