小麦/玉米套作条件下氮、磷配施的肥料效应研究

针对内蒙古河套灌区农业面源污染的现状,本研究以内蒙古河套灌区常规作物小麦和玉米为供试材料,采取"3414"部分实施方案,对氮、磷肥的施用效应及养分交互作用进行了研究,探讨进一步削减当地农业生产过程中的肥料用量的施肥技术。结果表明:小麦/玉米套作条件下,作物产量与氮、磷肥施用量之间满足二次型回归模型,氮肥、磷肥及氮磷交互效应对产量产生显著影响,氮磷交互作用氮磷。在施肥水平较低时,氮、磷肥表现出较好的协同促进作用,在达到产量的极限值后,则表现为无效及拮抗作用;中氮中磷处理能够较好地满足作物生长发育过程中对氮和磷的需求,提高作物对氮、磷的利用率。但随着施肥量的进一步增加,作物植株吸肥量也随之增加,施肥效益降低,肥料利用率持续下降。通过对氮、磷单因素及二因素肥料效应的分析,对施肥水平做进一步优化,得出小麦最佳施氮量为167.67~196.61 kg·hm-2,最佳施磷量为130.43~186.64 kg·hm-2;玉米最佳施氮量为222.10~299.14 kg·hm-2,最佳施磷量为156.14~188.00 kg·hm-2。这将为进一步削减氮、磷配施量,改善当地土壤养分平衡,减轻农业面源污染提供一定的指导作用。

Effect of combined nitrogen and phosphorus fertilizer application of wheat-maize intercropping system

Agricultural non-point source pollution in Hetao Irrigation Area of Inner Mongolia has been the main source of pollution in the Yellow River. There was the need to reduce the use of fertilizer in the croplands of the Yellow River Basin. This study explored the application effects of nitrogen (N) and phosphorus (P) fertilizers of wheat-maize intercropping, the conventional cropping systems in the Hetao Irrigation Area of Inner Mongolia. The results showed that under wheat and maize intercropping, the relationship between yield and nitrogen/phosphorus fertilization rate was best explained by quadratic regression model. Nitrogen, phosphorus and nitrogen plus phosphorus interactions had a significant effect on wheat-maize yield. The order of significance of the effect was N+P > N > P. With low fertilization, the synergistic enhancement effect of nitrogen and phosphorus fertilizers on yield was high. Beyond the threshold value, nitrogen and phosphorus fertilizer antagonistic limited wheat-maize yield. N₂P₂ (180 kg·hm^-2 N and 157.50 kg·hm^-2 P₂O₅ for wheat, 270 kg·hm^-2 N and 180 kg·hm^-2 P₂O₅ for maize) treatment satisfied the demands for crop growth and development in wheat-maize intercropping and there was fully efficacy in fertilizer use. With further increase in fertilizer, however, nitrogen uptake by crops increasingly limited fertilizer use efficiency and fertilizer utilization by crops continuously declined. Based on the of single- and double-factor effect analysis of nitrogen and phosphorus fertilizer, the best nitrogen application rate for wheat was 167.67 196.61 kg·hm^-2 and the best phosphorus application rate for wheat was 130.43 186.64 kg·hm^-2. Also the best nitrogen application for maize was 222.10 299.14 kg·hm^-2 and the best phosphorus application for maize was 156.14 188.00 kg·hm^-2. This finding was useful for reducing the application of nitrogen and phosphorus fertilizers and improving soil nutrient balance in the Yellow River Basin. It also provided a useful guidance on the mode of reducing agricultural non-point source pollution in the Yellow River Basin.