施用氮肥对太行山前平原区作物产量和土壤硝态氮残留量的影响

Effect of Nitrogen Application Rate on Crop Yield and the Soil Nitrate Nitrogen Content in Taihang Piedmont Area

为解决氮肥施用过量引起地下水硝酸盐含量超标问题,通过连续10年的氮肥定位试验,研究太行山前平原区不同氮肥用量对小麦-玉米轮作体系中0-200 cm剖面土壤硝态氮残留量和作物产量的影响,结果表明,2004-2014年间小麦、玉米平均产量与氮肥用量间呈显著的二次抛物线关系,施氮量为246 kg/hm^2时小麦获最高产量6 555kg/hm^2。施氮量为159 kg/hm^2时玉米获最高产量8 860 kg/hm^2。氮肥用量与0-100,100-200 cm剖面土壤硝态氮残留量分别符合显著的线性相关。连续10年施用氮肥量最高的处理（小麦-玉米轮作周年施氮量为575 kg/hm^2）0-100,100-200 cm土壤硝态氮残留量分别达到449.05,580.63 kg/hm^2。小麦、玉米最高产量时（周年施氮量为405 kg/hm^2）,0-100,100-200 cm剖面土壤硝态氮残留量分别为320.79,408.43 kg/hm^2。每个轮作周年减少氮肥用量30%-44%,连续10年后0-100,100-200 cm剖面土壤硝态氮残留量分别降低28.56%-42.34%和29.66%-44.64%。综合考虑作物产量和地下水硝酸盐污染风险,提出太行山前平原中等肥力水平的地块,小麦-玉米轮作周年氮肥用量应控制在400 kg/hm^2以下。适宜的氮肥用量既可保证作物产量又能明显降低土壤硝态氮的残留。

To solve the problem of nitrate nitrogen content in groundwater exceeding standard caused by excessive fertilization. The field experiment was carried out to study the effects of nitrogen application rate on 0-200 cm soil nitrate nitrogen residual and yield of wheat and maize in Taihang piedmont area for 10 years. The results showed that the significant quadratic parabola correlation were found between average yield of wheat-corn and nitrogen fertilizer application rate. The amount of nitrogen fertilizer application should be 246 kg / ha to guarantee the highest yield of winter wheat for 6 555 kg / ha. The amount of nitrogen fertilizer application should be 159 kg / ha to guarantee the highest yield of summer maize for 8 860 kg / ha. A significant linear correlation were found between 0-100,100-200 cm soil nitrate accumulation and nitrogen fertilizer. The treatment of N 575 kg / ha for wheat-corn rotation anniversary,0-100,100-200 cm soil nitrate residual reached 449. 05 kg / ha and 580. 63 kg / ha for 10 years of nitrogen fertilizer application. When the highest yield of wheat and corn（ annual nitrogen rate was 405 kg / ha）,0-100,100-200 cm soil nitrate accumulation was 320. 79 kg / ha and 408. 43 kg / ha,respectively. Nitrogen fertilizer application reduced 30%-44% for each wheat-corn rotation period,0-100,100-200 cm soil nitrate residual decreased by28. 56%-42. 34% and 29. 66%-44. 64% after planting wheat and maize for 10 consecutive years. Considering thenitrogen leaching risk and crop yield,it is advisable to suggest that the N application rate should be controlled within 400 kg / ha for wheat and corn in Taihang piedmont area. Appropriate nitrogen fertilizer amount can ensure crop yield and significantly reduce soil nitrate residual.