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对氮肥和稻草氮的利用率进行了3年6季同位素15N田间定位研究。结果表明,首季单季水稻对氮肥的利用率为37.02%,050cm土壤中15N的残留率为25.81%。经过连续3年6季的种植,作物肥料N的累计回收率分别为40.15(秸杆还田)41.63%(秸杆不还田),050cm土壤中15N的残留率仍达到23.62(秸杆不还田)28.33%(秸杆还田)。在不施氮肥条件下,小麦对稻草氮的吸收率为4.46%,第二季单季稻对稻草氮的吸收率为4.78%。5季作物累计吸收稻草氮11.76%,而土壤残留率为70.37%。
Three years of 6-year isotopic 15N field mapping of nitrogen and rice straw nitrogen utilization rates were conducted. The results showed that the single season rice utilization in the first season was 37.02% for nitrogenous fertilizer and 25.81% for 15N in 050cm soil. After six years of continuous planting in three years, the cumulative recoveries of crop fertilizer N were 40.15 (straw returning) and 41.63% (returning no straw), while the residual rate of 15N in 050cm soil still reached 23.62 Field) 28.33% (straw returning). Under the condition of no nitrogen fertilizer, the absorption rate of wheat nitrogen to straw was 4.46%, and the absorption rate of nitrogen to straw rice in the second season was 4.78%. The 5 seasons crops accumulatively absorbed 11.76% of straw nitrogen, while the soil residual rate was 70.37%.