减量施肥对湖垸旱地作物产量及氮磷径流损失的影响

Effect of reducing fertilizer application on crop yield and nitrogen and phosphorus loss in runoff from embankment upland in Dongting Lake Region

  • 摘要: 为探明洞庭湖区旱地生产中的氮磷盈余问题, 利用在该区域连续两年的玉米 油菜轮作田间小区试验, 研究了常规施肥玉米: 400 kg(N)·hm-2, 90 kg(P2O5)·hm-2, 135 kg(K2O)·hm-2; 油菜: 180 kg(N)·hm-2, 65 kg(P2O5)·hm-2, 60 kg(K2O)·hm-2、常规施肥减氮15%、减氮30%、缓控释肥减氮30%+减磷20%、常规施肥减磷20%共5个处理下, 玉米和油菜产量、氮磷肥利用率、氮磷径流损失量以及土壤氮磷养分的变化。结果表明, 在研究区域现有施肥水平下(常规施肥), 减量施肥对玉米和油菜产量没有显著影响; 缓控释肥减氮30%+减磷20%处理下玉米和油菜对氮磷养分的利用率显著提高, 其中氮素利用率较常规施肥处理两年平均提高7.96%和4.89%、磷素利用率提高2.02%和2.56%; 同时, 减量施肥各处理下氮磷径流损失量与常规处理比较, 分别减少3.54%~29.36%和7.14%~35.71%; 试验期内, 减量施肥下土壤全量氮磷及硝态氮含量与常规施肥处理无显著差异。根据本研究结果, 各施肥处理中, 以缓控释肥减氮30%+减磷20%处理效果更佳。研究结果可以为该地区旱地作物合理施肥、区域农业面源污染防控和洞庭湖区水环境保护提供参考依据。

     

    Abstract: A continuous 2-year maize/rape rotation experiment was conducted to study the effects of five fertilization treatments on crop yield, fertilizer use efficiency, runoff-driven N and P loss and soil N, P contents. The study also explored excess N and P in the embankment upland of Dongting Lake Region (DLR). The five treatments were conventional fertilization, 85% conventional N application, 70% conventional N application, 70% conventional N application of slow-controlled release N fertilizer plus 80% conventional P application, and 80% conventional P application. The conventional applications of N, P2O5 and K2O for maize field were 400 kg·hm-2, 90 kg·hm-2 and 135 kg·hm-2, respectively. Those for rape field were 180 kg·hm-2, 65 kg·hm-2 and 60 kg·hm-2, respectively. The results suggested that compared with conventional fertilization, reduced fertilizer application had no obvious effect on maize and rape yield. 70% conventional N application of slow-controlled release N fertilization plus 80% conventional P fertilization significantly improved N and P fertilizer use efficiencies of maize and rape. N fertilizer use efficiencies of maize and rape during the 2-year cultivation period averagely increased by 7.96% and 4.89%, respectively. Also P fertilizer use efficiencies averagely increased by 2.02% and 2.56%, respectively. Reduced fertilizer application decreased N and P loss via runoff by about 3.54%~29.36% and 7.14%~35.71%, respectively. Compared with conventional fertilization, total soil N, P and nitrate nitrogen contents under reduced fertilizer application were insignificantly different. Reduced slow-controlled release fertilizer application had the best performance among all the treatments. The results provided useful references for reasonable fertilization, prevention/control of regional agricultural non-point source pollution and protection of the water environments of DLR.

     

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