应用^(15)N示踪研究麦秸还田中氮的去向

STUDIES ON THE FATE OF NITROGEN IN WHEAT STUBBLE APPLIED ON SOIL SURFACE AND INCORPO RATED WITH SOIL

应用^(15)N示踪技术研究了麦秸铺施和混施方式下,秸秆中氮在土壤中的去向。试验结果表明:1.麦秸铺盖土表还田的,夏谷地上部分和籽粒部分对秸秆氮的利用率分别为28.3%和15.2%,而麦秸与土壤混合施用还田的,其对秸秆氮的利用率则分别为20.6%和12.0%。前者明显优于后者。2.夏谷生长87天后,麦秸铺施还田的,秸秆氮有28.3%进入夏谷株体中;16.5%进入土壤腐殖质;0.5%和3.1%分别进入渗漏水和以气态等形式逸失;残留于土壤中的秸秆氮(包括夏谷根系)约有51.6%。而麦秸混施还田的,秸秆氮进入夏谷株体、土壤腐殖质、渗漏水和以气态逸失的量分别占施入秸秆氮总量的20.5%,14.8%,0.2%和11.5%,残留于土壤中的约占总量的53.0%。

The fate of nitrogen in wheat stubble incorporated with soil or mulched on soil surface was studied by ^(15)N tracer technique. Pot experiment in which millet was sown and harvested after 87 days was conducted at cinnamon soil Beijing Drab Soil. The results arc as follows: 1. The applied nitrogen recovery in straw and grain of millet was 28.3% and 15.2% respectively under wheat stubble mulch as compared to that of 20.6% and 12.0% by incorporation with soil. 2. After 87 days of millet grown, 28.3% of the N of wheat stubble applied on soil surface was in millet plant, 16.5% in humus, 8.5% leached off by percolating water, 3.1% lost by volatilization and about 51.6% remained in soil, whil 20.0% of that incorporated with soils was in millet plant, 14.8% in humus, 0.2% leached off, 11.5% lost by volatilization and 53.1% remained in soil.