Luo Xiaosheng, Kou Changlin, Wang Qian
Henan Key Laboratory of Agricultural Eco-Environment, Institute of Plant Nutrition, Resources and Environmental Sciences, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China.
Key Laboratory for Agricultural Environment of Ministry of Agriculture and Rural Affairs, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Plants (Basel). 2022 Jul 28;11(15):1963. doi: 10.3390/plants11151963.
Agricultural nitrogen (N) non-point source pollution in the North China Plain is a major factor that affects water quality and human health. The characteristics of N leaching under different N application conditions should be further quantified accurately in winter wheat ( L.) and summer maize ( L.) rotation farmland in North China, and a basis for reducing the risk and evaluation of N leaching in this area. A three-year field experiment was conducted using an in situ leakage pond method at a typical farmland in Henan in 2017-2020. Crop yield, soil nitrate N residues, and N utilization were also studied during the study period. Five N fertilizer rates were established with 0 (CK), 285 (LN), 465 (MN), 510 (MNO), and 645 (HN) kg N ha for one rotation cycle. MNO was applied with chemical and organic fertilizers. The concentration of nitrate N in the soil leaching solution of CK, LN, MN, MNO, and HN was 0.81-, 1.49-, 3.65-, 5.55-, and 7.57-fold that of the World Health Organization's standard for underground drinking water. The exponential relationship between the N application rate and leaching was obtained when the annual N input exceeded 300 kg ha, and the N leaching rate increased greatly. The leaching rate of nitrate N in the total N was 50.6-82.4% under different treatments of N application. The combination of chemical and organic fertilizers treatment (MNO) reduced the amount of N that was leached in dry years. The nitrate leaching amount of summer maize accounts for 83.0%, 49.4%, and 72.0% of the total nitrate leaching amount of the whole rotation cycles in 2017-2020. LN and MN were recommended as the optimized N application here (285-465 kg N ha) with the two-season rotation grain yield of 17.2 ton ha (16.5-17.9 ton ha) and nitrate N leaching of 21.6 kg ha (12.6-30.5 kg ha).
华北平原的农业氮素面源污染是影响水质和人类健康的主要因素。华北冬小麦-夏玉米轮作农田不同施氮条件下的氮淋溶特征需进一步准确量化，为该地区降低氮淋溶风险及评估提供依据。2017—2020年在河南典型农田采用原位渗漏池法进行了为期三年的田间试验。研究期间还对作物产量、土壤硝态氮残留量及氮素利用情况进行了研究。设置了5个施氮量水平，一个轮作周期分别为0（CK）、285（LN）、465（MN）、510（MNO）和645（HN）kg N·ha，其中MNO处理采用化肥与有机肥配施。CK、LN、MN、MNO和HN处理土壤淋溶液中硝态氮浓度分别是世界卫生组织地下饮用水标准的0.81倍、1.49倍、3.65倍、5.55倍和7.57倍。当年施氮量超过300 kg·ha时，施氮量与淋溶量呈指数关系，氮淋溶率大幅增加。不同施氮处理下硝态氮淋溶量占总氮淋溶量的50.6%82.4%。化肥与有机肥配施处理（MNO）在干旱年份减少了氮素淋溶量。2017—2020年夏玉米硝态氮淋溶量占整个轮作周期总硝态氮淋溶量的83.0%、49.4%和72.0%。推荐在此处采用LN和MN作为优化施氮量（285465 kg N·ha），两季轮作粮食产量为17.2 t·ha（16.517.9 t·ha），硝态氮淋溶量为21.6 kg·ha（12.630.5 kg·ha）。
