应用~(15)N示踪研究砂姜黑土冬小麦尿素施用方式和氮素利用率

应用1 5N示踪技术研究砂姜黑土冬小麦尿素施用方式和氮素利用率 ,结果表明 :尿素不同施用方式对冬小麦产量影响不显著 ;产量高低与每桶总粒数成正相关 (r=0 .98 )。土壤—小麦系统中化肥氮约有 1/2被植株吸收 ,以处理③的氮素利用率最高。剩余 1/2的化肥氮属于土壤残留和损失 ,处理⑤损失最少 ,残留量最多 ;处理②、③残留量最少 ,损失最多。植株吸收的化肥氮中籽粒约占 72 .0 % ,茎叶、根系、麦糠合计占 2 8.0 %。 76.5 %～ 94.2 %的残留氮集中在 0～ 2 0cm土层中。综合分析 ,冬小麦以处理⑤ (2 /3的氮肥作底肥 ,4/15的氮肥作冬前追肥 ,1/5的氮肥于扬花期喷施 )施肥效果最好。

Study on 15N Trace in the Rational Urea Application Technique for Winter Wheat in Sandy and Black Soil

Based on the study on 15N trace technique to rational urea application time and utilization ratio of nitrogen in winter wheat, the effect of different urea application time on the yield of winter wheat was not significant. There were the positive correlations between total grain amount per spike and the yield, its correlation co-efficiency was 0.98 **.In the system of soil and winter wheat the half of nitrogenous fertilizer was absorbed by the plant, the utilization ratio of nitrogen was high under the treatment.The other nitrogenous fertilizer belonged to soil remained and nitrogen loss. Nitrogen loss was little and soil remained under the treatment of applying 2/3 nitrogen to the subsoil, topdressing 4/15 and spray 1/15;soil remain was little and nitrogen loss under the treatment of applying all nitrogen to the subsoil or applying 2/3 nitrogen to the subsoil and harrow 1/3. In the nitrogen fertilizer absorbed by the plant the grain accounts for 72.0% and all the stem, root and wheat straw account for 28.0%.76.5%～94.2% percent of nitrogen remained was collected in the surface soil(0～20?cm).To sum up,the effect on fertilizer application was best under the treatment of apply 2/3 nitrogen to the subsoil,top apply 4/15 and spray 1/15 in winter wheat.