Supplemental Nitrogen Fertilizer to Soybeans : IV. Influences of soil conditions on the yield response to supplemental nitrogen

[摘要] The influence of soil conditions on increase of nitrogen assimilation and yield as a result of supplemental nitrogen fertilizer application at flowering were examined with soybean (Glycine max L. Merr.). Non-nodulating line (T 201) was used as a reference to estimate the uptake amount of soil-N and fertilizer-N and the amount of fixed-N in the testing cultivars. The yield increase by the supplemental-N was depressed when the soil fertility of nitrogen increased by applying manure. Further, the effect of supplemental-N decreased progressively as the amount of N released from the soil increasrd. However, in a frame experiment of different soils, the amount of absorbed soil-N, fixed-N and total assimilated-N by soybean plants until flowering under no supplemental-N condition was not negatively correlated writh the effect of supplemental-N on yield. But the increase of total assimilated-N from flowering to early pod-filling stage by applying the supplemental-N positively correlated with its effect on grain field. In grey lowland soil, the effect of supplemental-N on the total assimilated-N was high due to the low N-fixing activity under no supplemental-N conditions in the silty clay loam, and also to the significant uptake rate of supplemental-N in a frame of the loam. The loam of andosol was inferior to any of the grey lowland soil because of serious inhibition of N-fixing ability by supplemental-N, which appeared to be based on low concentration of Truog-phosphate in this soil.

[学科分类] 农业科学（综合）

[关键词] Glycine max;Nitrogen fertilizer;増収;Nitrogen fixation;大豆;Soil;窒素肥料;Soybean;追肥;Top dressing;土壌;Yield Increase