Nitrogen leaching and grey water footprint affected by nitrogen fertilization rate in maize production: a case study of Southwest China
Zhi Yao, Wushuai Zhang, Yuanxue Chen, Wei Zhang, Dunyi Liu, Xiaopeng Gao, Xinping Chen
Abstract
Abstract BACKGROUND Effective nitrogen (N) management measures are required to control environmental problems caused by N fertilizer use in intensive maize production systems. Soil N losses associated with high precipitation and over‐fertilization in maize production can cause substantial environmental problems, whereas there is a lack of quantitative data and effective study countermeasures. A 2‐year field study was conducted in the subtropical maize production system in Southwest China to quantify N leaching under varying N application rates of 0, 90, 180, 270 and 360 kg N ha −1 yr −1 . RESULTS The results indicated that N leaching accounted for 16–38% of N fertilizer input. For farmer practice treatment (360 kg N ha −1 yr −1 ), N leaching loss was high at 110 kg N ha −1 yr −1 and accounted for 31% of the N applied. As an indicator of the ambient water quality pollution, the grey water footprint across all treatments ranged from 376 to 1092 m 3 Mg −1 , with an average of 695 m 3 Mg −1 . Reducing N rate to agronomically optimized treatment (180 kg N ha −1 yr −1 ) significantly decreased N leaching by 77%, and maintained high grain yield of 8.1 Mg ha −1 . The grey water footprint was reduced by 52–63% with N rates from 270 or 360 kg N ha −1 yr −1 to 180 kg N ha −1 yr −1 . CONCLUSION Nitrogen surplus (applied N rate minus N uptake by maize) resulted in higher soil residual nitrate concentration and consequently high N leaching. High precipitation and low soil pH were the main ecological factors leading to high N leaching. © 2021 Society of Chemical Industry.