不同水稻种植模式对氮磷流失特征的影响

Effects of rice cultivation patterns on nitrogen and phosphorus leaching and runoff losses

  • 摘要: 过量施用化肥造成的氮、磷流失已成为农业面源污染的主要污染源。为探究不同种植模式对氮、磷流失的影响, 采用大田试验, 研究比较了常规种植、绿色蛙稻和有机蛙稻3种水稻种植模式下稻田生态系统的田面水氮、磷浓度特征规律, 以及径流、渗漏的氮、磷流失特征和产量差异。结果表明, 3种水稻种植模式中, 田面水总氮(TN)平均浓度为: 常规种植>绿色蛙稻>有机蛙稻, 分别为18.87 mg L-1、8.98 mg L-1和8.20 mg L-1。与常规种植模式相比, 绿色蛙稻模式和有机蛙稻模式在整个水稻季中的TN总流失负荷分别减少15.27%和25.76%。径流流失负荷为: 绿色蛙稻>常规种植>有机蛙稻, 氮的主要形态为铵态氮(NH4+-N); 渗漏流失负荷为: 常规种植>绿色蛙稻>有机蛙稻, 氮的形态以硝态氮(NO3--N)为主。田面水总磷(TP)平均浓度为: 有机蛙稻>绿色蛙稻>常规种植, 分别为0.82 mg L-1、0.64 mg L-1 和0.37mg L-1。总磷(TP)总流失负荷为: 有机蛙稻>绿色蛙稻>常规种植, 总流失负荷占施磷量的比例为: 绿色蛙稻>常规种植>有机蛙稻, 并且以溶解性磷(DP)为主。3种模式下水稻产量为: 常规种植>有机蛙稻>绿色蛙稻, 与常规种植模式相比, 绿色蛙稻模式和有机蛙稻模式分别减产19.33%和8.51%。研究结果表明, 有机蛙稻和绿色蛙稻模式能够有效地控制水稻田中氮、磷流失, 但会造成水稻减产。由于有机蛙稻模式要求种、养条件更高, 因此有机蛙稻模式下的产品往往品质最好, 经济效益最高。

     

    Abstract: The loss of nitrogen and phosphorus due to excessive fertilizer application has become a major form in agricultural non-point pollution. In order to explore the impact of different planting patterns (conventional cultivation, green rice-frog ecosystem, organic rice-frog ecosystem) on nitrogen and phosphorus loss, a field experiment was conducted and the characteristics of nitrogen and phosphorus in surface water, runoff, leakage as well as rice yield differences analyzed in three paddy ecosystems. The results showed that among the paddy ecosystems, the order of average concentration of total nitrogen (TN) in surface water was: conventional cultivation (18.87 mg·L-1) > green rice-frog ecosystem (8.98 mg·L-1) > organic rice-frog ecosystem (8.20 mg·L-1). Compared with conventional cultivation, green rice-frog ecosystem and organic rice-frog ecosystem decreased TN loss during rice growth season by 15.27% and 25.76%, respectively. The TN runoff loss was in the following order: green rice-frog ecosystem > conventional cultivation > organic rice-frog ecosystem. NH4+-N was the main form of TN runoff. The order of TN leaching loss of was conventional cultivation > green rice-frog ecosystem > organic rice-frog ecosystem, with NO3--N as the main form of TN leaching. Also the ratio of total TN loss to nitrogen fertilizer use in the three treatments was in the range of 1.25%-2.38%, all less than 3%. Average total phosphorus (TP) concentration of surface water was in the following order: organic rice-frog ecosystem (0.82 mg·L-1) > green rice-frog ecosystem (0.64 mg·L-1) > conventional cultivation (0.37 mg·L-1). Total loss of TP was in the order of: organic rice-frog ecosystem > green rice-frog ecosystem > conventional cultivation. Then the order of proportion of total loss of phosphorous fertilizer was: green rice-frog ecosystem > conventionally cultivation treatment > organic rice-frog ecosystem, most of which was dissolved phosphorus. The order of rice yield under the three treatments was: conventional cultivation > organic rice-frog ecosystem > green rice-frog ecosystem. Compared with conventional cultivation, yield under green rice-frog ecosystem and organic rice-frog ecosystem decreased respectively by 19.33% and 8.15%. Research results showed that organic rice-frog ecosystem and green rice-frog ecosystem effectively controlled nitrogen and phosphorus loss in paddy fields although production decreased. Production quality and economic benefits of organic rice-frog ecosystem were better than those of green rice-frog ecosystem and conventional cultivation treatment. The requirements for organic rice-frog ecosystem were higher than those for green rice-frog ecosystem and conventional cultivation treatment.

     

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