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Nitrogen rate is more important than irrigation rate in mitigating nitrogen leaching in flood-irrigated maize: A 6-year lysimeter experiment
Geoderma ( IF 5.6 ) Pub Date : 2024-06-12 , DOI: 10.1016/j.geoderma.2024.116940 Liyao Hou , Xiaotong Liu , Jianhang Luo , Ying Zhao , Xuejun Zhang , Qiuliang Lei , Hongbin Liu , Peng Zou , Zhanjun Liu
Geoderma ( IF 5.6 ) Pub Date : 2024-06-12 , DOI: 10.1016/j.geoderma.2024.116940 Liyao Hou , Xiaotong Liu , Jianhang Luo , Ying Zhao , Xuejun Zhang , Qiuliang Lei , Hongbin Liu , Peng Zou , Zhanjun Liu
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Excessive nitrogen (N) fertilization and irrigation prevail in irrigated agriculture worldwide. However, little information is available that systematically evaluates grain yield, plant N uptake, residual soil NO-N (RSN), and N leaching under different irrigation–N regimes in an irrigated maize production system. To address such agronomic and environmental issues, a 6-year in situ lysimeter field trial was conducted in the Hetao Irrigation District of China with five treatments: 1) conventional irrigation (3,900 m/ha) and local farmer fertilizer N rate (490 kg ha) (CON); 2) conventional irrigation and the recommended fertilizer N rate (420 kg ha) (RN); 3) deficit irrigation (2,730 m/ha) and the recommended fertilizer N rate (SRN); 4) deficit irrigation and the recommended fertilizer N rate (with ∼ 10 % organic fertilizer N substitution) (SMN); and 5) conventional irrigation and controlled-release N fertilizer (270 kg ha) (CRF). Maize yield was not significantly different across treatments in 2015–2020. Averaged across years, SMN, SRN, and CRF significantly increased plant N uptake compared with that in CON by 28.84 %, 19.15 %, and 17.53 %, respectively. Residual soil NO-N at 0–90 cm was ranked as SRN > CON ≈ SMN > RN > CRF, whereas cumulative N in leachate from 2015–2020 (N) in CON was 86.2 % to 187.1 % higher than that in other treatments. The N in SRN was equivalent to that in RN and SMN, but N in SMN decreased significantly compared with that in RN, indicating additive benefits of deficit irrigation and organic input on reducing N leaching. Structural equation modelling revealed that irrigation had greater effects on plant N uptake than those of fertilization, whereas N rate had a greater total effect on N leaching than that of irrigation. Overall, rampant excessive irrigation and N fertilization by farmers can be substantially reduced while maintaining grain yield and mitigating N leaching loss, with further benefits gained by applying controlled-release N fertilizer and manure in irrigated maize production.
更新日期:2024-06-12