[Current status of nitrogen and phosphorus losses and related factors in Chinese paddy fields: A review]

Ying Yong Sheng Tai Xue Bao. 2019 Oct;30(10):3292-3302. doi: 10.13287/j.1001-9332.201910.029.
[Article in Chinese]

Abstract

Rice is one of the main crops in China. Therefore, it is important to understand the current status and influencing factors of nitrogen and phosphorus losses from paddy fields in China, which would facilitate assessing the potential of chemical fertilizer reduction in different rice cultivating regions. We summarized the current knowledge on nitrogen and phosphorus losses from surface runoff in major rice cultivating areas in China, as well as their influencing factors, such as rainfall, planting pattern, cultivation techniques, fertilization management, water management strategies, etc. The total nitrogen (TN) and total phosphorus (TP) losses from runoff in six major rice cropping areas ranged from 5.09 to 21.32 and 0.70 to 3.22 kg·hm-2, respectively. The highest losses of TN and TP were the South China double rice cropping area. The TN runoff losses were the lowest in the North China single rice cropping area, while the lowest TP runoff losses occurred in plateau single and double rice cropping area of the Southwest China. The peaks of TN and TP in surface water of paddy fields were generally higher than those of the runoff water based on farmers' conventional fertilization in different rice cropping areas. The peak period of nitrogen and phosphorus losses was in a week after rice fertilization. There could be a potential of 20% reduction of nitrogen and phospho-rus for farmers' conventional fertilization compared with the optimized fertilization. Among all the factors, rainfall and fertilization management were the main ones affecting the runoff losses of nitrogen and phosphorus in paddy fields. Fertilization management and water management strategies were the mostly controllable, including reduction of fertilizers, application of new fertilizers, replacement of chemical fertilizers by organic fertilizers, water-saving irrigation, etc. Overall, the risk of nitrogen and phosphorus losses in paddy fields was more prominent in the Southern China than in any other areas of China. Rice cultivation should be carried out in a more resource-efficient way to reduce nutrient loss. Future research should focus on non-point source pollution monitoring of paddy fields, nitrogen and phosphorus losses risk assessment, nitrogen and phosphorus losses characteristics and mechanisms, and new technologies for reducing chemical fertilization inputs and environmental risks.

水稻是我国主要的粮食作物,分析现阶段我国稻田氮磷流失现状及影响因素,对明确不同区域水稻化肥减施潜力具有重要意义.本研究对我国主要稻区地表径流氮磷流失现状特征和降雨、种植模式、栽培技术、施肥管理、水分管理方式及其他影响因素进行了总结.六大稻区全氮(TN)、全磷(TP)径流损失量范围分别在5.09~21.32和0.70~3.22 kg·hm-2,均以华南双季稻区最高,TN径流损失量以华北单季稻区最低,TP径流损失量以西南高原单双季稻区最低.各稻区农户习惯施肥的水稻田田面水TN、TP峰值普遍高于径流水.水稻施肥后一周内为氮磷流失高峰期.与优化施肥相比,农户习惯施肥仍具有20%左右的氮磷减施潜力.各因素中,降雨和施肥管理是影响稻田径流氮磷流失的主要因素,而施肥管理和水分管理则最具可控性,具体调控措施包括化肥减量、施用新型肥料、有机肥代替化肥和节水灌溉等.整体上我国稻田氮磷流失风险在南方更突出.应以资源高效利用模式进行水稻种植以降低养分流失风险.未来研究应侧重稻田面源污染监测、氮磷流失风险评估、氮磷流失特征和机理、化肥减施增效新技术等方向.

Keywords: environmental benefit; influencing factor; nitrogen and phosphorus losses; optimized fertilization; rice.

MeSH terms

  • Agriculture
  • China
  • Environmental Monitoring
  • Fertilizers
  • Nitrogen
  • Oryza*
  • Phosphorus*

Substances

  • Fertilizers
  • Phosphorus
  • Nitrogen