应用~(15)N对提高氮肥利用率与土壤氮值的研究

试验指出春小麦一生吸收土壤氮占78％左右,吸收肥料氮占25％左右。产量与植物吸收土壤氮成正相关,而与吸收肥料氮无明显相关。从氮肥平衡来看,尿素、硫铵在黑土和白浆土中被作物吸收平均占48％,土壤残留18％,未回收(损失)33％。加沸石按肥料重1:10显著地提高土壤残氮量。残留的氮绝大部分在0—15厘米的土层里,下层很少,30厘米以下没有氮肥下渗损失。黑土比白浆土肥力高。黑土的AN值为450,平均产量为6400公斤/公顷,白浆土为260,平均产量为4900公斤/公顷。

USING ~(15)N AS TRACER FOR STUDYING THE RATE OF UTILIZATION OF NITROGENOUS FERTILIZER AND SOIL NITROGEN

It was shown in our experiment that about 78％ of soil N and. 25% of fertilizer N was absorbed in the life of spring .wheat. The grain yield was positively correlated with the amount of soil N absorbed by the plant, but not significantly correlated with the absorption of fertilizer N. So far as fertilizer N balance is considered, on an average, 48% of urea and ammonium sulfata was absorbed by the plant in both black and ochric soils, 18% remained in the soil and 33% was lost. When zeolite was added to the fertilizer with a ratio of 1: 10, the amount of N remained in the soil can be significantly increased. Most of the N in the soil distributed in the 0—15cm layer, only a few were found beneath. And no N fertilizes can reach to the soil under 30cm. Fertility of black soil was higher than that of ochric soil. An value of black soil was 450, it yielded 6400kg/ha. An value of ochric soil was 260 and its yield averaged 4900kg/ha.