秸秆还田条件下氮肥运筹对作物产量和氮肥利用效率的影响

研究秸秆直接还田条件下,水旱轮作区水稻和旱作区小麦的适宜氮肥施用量和氮肥运筹的组合,为秸秆还田后氮肥的合理施用提供依据。2014~2017年度在安徽省肥东县和太和县布置田间试验,比较不同施氮处理对作物产量和氮肥利用效率的影响。结果表明,与当地推荐氮肥用量和习惯运筹方式处理相比,在水稻和小麦上增加氮肥用量作物产量均未有显著提升;降低氮肥用量则显著降低了水稻产量,降幅在6.51%~10.25%间;降低氮肥用量时氮肥前移处理小麦产量并未下降。在水稻和小麦上推荐氮肥用量时氮肥前移处理(N210 M7/2/1和N240 M8/2)均获得了较高产量,分别为10066和7583 kg/hm^2,与最高产量处理差异均不显著。氮肥农学利用率和偏生产力整体上随着氮肥用量的增加而降低;同一氮肥用量下,利用效率则表现为氮肥前移>习惯基追比>一次性基施。在推荐氮肥用量和高氮条件下,推荐氮肥用量时氮肥前移处理的农学利用率和偏生产力均处于最高水平,高氮各处理氮肥利用效率均较低。秸秆还田条件下,提高氮肥用量并不能显著提高水稻或小麦产量;推荐施氮量下氮肥前移在水稻和小麦上均获得较高的产量和氮肥利用效率,是目前推荐施氮量下的较优运筹方式。

Effects of nitrogen fertilization managements on crops yield and nitrogen nutrient use efficiency under straw returning

In order to provide a scientific basis for rational application of nitrogen fertilizer after straw returning,the suitable combination of nitrogen fertilizer application and management in rice of paddy-upland rotation field and wheat of dry farming region under the condition of straw directly returning to field was studied.Two field experiments were conducted to compare the effects of different nitrogen treatments on crop yield and nitrogen use efficiency in Feidong and Taihe county in Anhui province during 2014~2017.The results showed that compared with the local recommended nitrogen fertilizer dosage and the conventional operation method,the crop yield did not increase significantly when increasing nitrogen fertilizer on rice and wheat,but the decrease of nitrogen fertilizer application significantly decreased the rice yield by 6.51%~10.25%,and the wheat yield did not decrease when the reduced nitrogen fertilizer was applied earlier.When the recommended nitrogen fertilizer application rate was applied on rice and wheat,the nitrogen fertilizer topdressing earlier treatments(N210 M7/2/1,and N240 M8/2)obtained higher yield,which was10066 and 7583 kg/hm2,respectively,and there was no significant difference compared with the highest yield treatment.The agronomic utilization rate and partial productivity of nitrogen fertilizer decreased with the increase of the amount of nitrogen fertilizer.The nitrogen use efficiency among the treatments showed that nitrogen fertilizer topdressing earlier>farmer practice for nitrogen fertilizer application>one-time base application of nitrogen fertilizer under the same amount of nitrogen fertilizer.Under the condition of recommended nitrogen fertilizer and high nitrogen,the agronomical utilization rate and partial productivity of nitrogen fertilizer topdressing earlier treatment were the highest,and the nitrogen use efficiency of high nitrogen treatment was lower.Under straw-return conditions,the yield of the rice or wheat did not increase obviously by increasing amount of nitrogen fertilizer.And the high yield and the utilization efficiency of the nitrogen fertilizer for both rice and wheat were obtained under the recommending nitrogen application level of the nitrogen fertilizer topdressing earlier treatment,which was the best operation method of recommended nitrogen fertilizer application and management at present.