用15N研究吉林黑土春玉米对氮肥的吸收利用

用1 5N示踪技术在吉林省中部黑土地区进行田间微区试验 ,研究不同氮肥追施深度与次数对氮肥利用率的影响。结果表明 ,两次深追肥处理 ( 1 0～ 1 5cm)比当地传统的垄上一次浅追肥处理 ,肥料氮的利用率从 2 4 5 %提高到 39 0 % ,氮肥深施并增加追肥次数能有效地提高利用率 ;肥料氮的总损失为 1 6%～ 2 7% ,土壤残留率为 34%～ 5 4 % ;吸收的标记肥料氮中有 1 /2是在 8月 1日以后籽粒形成期被玉米吸收利用的 ;氮肥损失的 70 %～ 90 %是在追肥以后 35天期间发生的 ;施肥的激发效应较弱

APPLICATION AND RECOVERY OF 15N-FERTILIZER FOR SPRING MAIZE IN BLACK SOIL OF JILIN

In central Jilin a ¹⁵N micro-plot experiment was conducted in a piece of farmland of black soil to study ef ect of the depth and frequency of N application on utilization rate of N fertilizer.Results show that the treatment of sidedressing twice at a depth of 10~15cm increased the rate from 24.5% in the CK,the traditional once for all shallow sidedressing on the ridge,to 39.0%,clearly indicating that deep and split application of N fert ilizer improves utilization rate.The total fertilizer N loss was 16%~27%;N residual in the soil 34%~54%;about half of the ¹⁵N labeled fertilizer was taken up by maize during the grain-forming period after Aug.1;70%~90% of the loss occurred within the 35 days after the N fertilizer was sidedressed;and crop response to the application was not significant.