Liu Ruliang, Wang Ying, Hong Yu, Wang Fang, Mao Xinping, Yi Jun
Institute of Agricultural Resources and Environment, Ningxia Academy of Agro-forestry Science, Yinchuan, China.
National Agricultural Environment Yinchuan Observation and Experiment Station, Ningxia Academy of Agro-forestry Science, Yinchuan, China.
Front Plant Sci. 2023 Jan 26;14:1033506. doi: 10.3389/fpls.2023.1033506. eCollection 2023.
Nitrogen loss from paddy fields contributes to most of the nitrogen pollution load in the Ningxia Yellow River irrigation area, threatening the water quality of the Yellow River. Consequently, optimizing the nitrogen management practices in this area is essential, which can maintain paddy grain productivity and reduce nitrogen loss simultaneously. Five treatments with different nitrogen application rates and nitrogen fertilizer types were set in this study, including conventional urea application with zero nitrogen application rate (CK, 0 kg hm), nitrogen expert-based fertilization application strategy (NE, 210 kg hm), optimized nitrogen fertilizer application strategy recommended by local government (OPT, 240 kg hm), and farmer's experience-based nitrogen fertilizer application strategy (FP, 300 kg hm), and controlled-release urea application (CRU, 180 kg hm). The data from one growth season field experiment in 2021 revealed the dynamics of nitrogen concentration, paddy yield and its nitrogen uptake characteristic, and nitrogen balance in the paddy field under different nitrogen application practices. Most nitrogen leaching was observed during the seedling and tillering stages in the form of nitrate nitrogen (NO N). Compared with the FP, the CRU and OPT significantly reduced the nitrogen concentrations of total nitrogen (TN), ammonium nitrogen (NH -N), and NO N in the surface and soil water and reduced the nitrogen leaching at 100 cm soil depth. Meanwhile, the paddy grain yield in CRU (7737 kg hm) and OPT (7379 kg hm) was not significantly decreased compared with FP (7918 kg hm), even though the nitrogen uptake by grain and straw was higher in FP (135 kg hm) than in other treatments (52.10~126.40 kg hm). However, the grain yield in NE (6972 kg hm) was decreased compared with the FP. The differences in grain yield among these treatments were mainly attributed to the ear number and grain number changes. Also, the highest nitrogen use efficiency (40.14%), apparent nitrogen efficiency (19.53 kg kg), and nitrogen partial productivity (43.98 kg kg) were identified in CRU than in other treatments. Considering increased grain yield and reducing nitrogen loss in the paddy field simultaneously, the treatments of CRU (i.e., 180 kg hm nitrogen application rate with controlled-release urea) and OPT (i.e., 240 kg hm nitrogen application rate with conventional urea) were recommended for nitrogen fertilizer application in the study area.
宁夏引黄灌区稻田的氮素流失是黄河氮污染负荷的主要来源，威胁着黄河水质。因此，优化该地区的氮素管理措施至关重要，既能维持水稻产量，又能减少氮素流失。本研究设置了五种不同施氮量和氮肥类型的处理，包括不施氮的常规尿素处理（CK，0 kg hm）、基于氮肥专家推荐的施肥策略（NE，210 kg hm）、当地政府推荐的优化氮肥施用策略（OPT，240 kg hm）、基于农民经验的氮肥施用策略（FP，300 kg hm）以及控释尿素处理（CRU，180 kg hm）。2021年一个生长季的田间试验数据揭示了不同施氮措施下稻田氮素浓度、水稻产量及其氮素吸收特性以及氮素平衡的动态变化。在苗期和分蘖期观察到的氮素淋失大多以硝态氮（NO₃-N）的形式存在。与FP处理相比，CRU和OPT处理显著降低了表层水和土壤水中总氮（TN）、铵态氮（NH₄-N）和NO₃-N的氮素浓度，并减少了100 cm土壤深度处的氮素淋失。同时，CRU处理（7737 kg hm）和OPT处理（7379 kg hm）的水稻产量与FP处理（7918 kg hm）相比没有显著下降，尽管FP处理中籽粒和秸秆的氮素吸收量（135 kg hm）高于其他处理（52.10~126.40 kg hm）。然而，NE处理（6972 kg hm）的籽粒产量低于FP处理。这些处理间籽粒产量的差异主要归因于穗数和粒数的变化。此外，CRU处理的氮素利用效率（40.14%）、表观氮素利用率（19.53 kg/kg）和氮素偏生产力（43.98 kg/kg）均高于其他处理。综合考虑提高水稻产量和减少稻田氮素流失，推荐在研究区域采用CRU处理（即施氮量为180 kg hm的控释尿素）和OPT处理（即施氮量为240 kg hm的常规尿素）进行氮肥施用。
