不同施肥对双季稻田径流氮磷流失特征的影响

通过定位试验,研究了不施氮肥(WN)、单施化肥(HF)、猪粪替代20%氮肥(ZF)、沼渣沼液替代20%氮肥(ZYF)、堆肥替代20%氮肥(DF)、早稻绿肥、晚稻稻草代替20%氮肥(LDF)6种不同施肥处理下双季稻径流氮磷含量和累积流失负荷的影响。结果表明,水稻基肥和追肥后,径流水中全氮、硝态氮、铵态氮、全磷和水溶性磷含量逐渐下降。HF处理双季稻季径流水中全氮、铵态氮、硝态氮平均含量最高,分别为5.91,3.65,0.82mg/L。相比HF处理,有机物料替代20%氮肥处理能够降低径流水中全氮、铵态氮、硝态氮的平均含量,其中以DF处理下降幅度最大,分别下降1.18,0.71,0.14mg/L;除DF处理外,有机物料替代20%氮肥能够增加径流水中全磷和水溶性磷的平均含量。相比HF处理,有机物料替代20%氮肥能够减少氮素径流流失负荷,以DF处理总氮、铵态氮和硝态氮累积流失负荷最小,分别为10.25,6.17,1.71kg/hm2;DF处理磷素流失负荷与单施化肥处理持平。综上,DF处理能够降低径流水中氮磷流失负荷,对于保护环境和控制面源污染具有重要意义。

Effects of Fertilizer Applications on Runoff Nitrogen and Phosphorus Loss in Double Cropping Paddy Field

In order to provide scientific basis for rational fertilization, a field experiment was conducted to evaluate the effects of different fertilization methods on runoff nitrogen (N) and phosphorus (P) loss in double cropping paddy field. Six treatments were designed: without N (WN), chemical fertilizer (HF), pig manure alternative 20% N fertilizer (ZF), biogas slurry and biogas residue alternative 20% N fertilizer (ZYF), compost alternative 20% N fertilizer (DF), and green manure in early rice and straw in late rice alternative 20% N fertilizer (LDF). The results showed that total N, NO3-, NH4+, total P and water soluble P in runoff water were decreased after base fertilizer and topdressing application. In double cropping rice field, total N, NH4+and NO3- contents in runoff water under HF reached 5.91 mg/L, 3.65 mg/L and 0.82 mg/L respectively, which were higher than other treatments. Compared with HF, total N, NH4+and NO3- contents in runoff water were significantly decreased when chemical fertilizers were partially replaced with organic materials, and the reduction of DF reached up to 1.18 mg/L, 0.71 mg/L and 0.14 mg/L respectively. Moreover, the treatments with organic materials alternative 20% N fertilizer significantly increased total P and soluble P content in the runoff water with the exception of DF. Compared to HF, other organic-inorganic fertilizers treatments decreased runoff N loss. In addition, total N, NH4+and NO3- loss of DF treatment was 10.25 kg/hm2, 6.17 kg/hm2 and 1.71 kg/hm2 respectively, which were nearly equal to those of HF. In conclusion, DF could significantly decreased runoff N and P loss, and was of great importance in protecting environment and controlling non-point pollution.