水稻对有机、无机态肥料氮和土壤氮的吸收利用探讨

为了研究我国有机、无机肥配合施用的供肥特点,培土效果和增产作用,我们从1978年春以来,以¹⁵N示踪法进行有机、无机态肥料氮转化问题研究,在江苏四种代表性士壤上,即太湖地区黄泥土(代号A),丘陵地区板浆白土(代号B),苏北里下河地区鸭屎土(代号C),淮北地区花碱土(代号D)上进行。以¹⁵N标记的怪麻和硫酸按分别作有机和无机态氮源,全部作基肥,供试作物为水稻南粳34号,盆淋试验重复三次,另在板浆白土上增加重复次数,以分期测定土壤、植株中氮素动态。详细的试验材料及方法已另文登载^1]。试验中的不同肥料处理列于表1。

DISCUSSION ON THE ABSORPTION AND UTILIZATION OF ORGANIC AND INORGANIC FERTILIZER NITROGEN AND SOIL NITROGEN BY RICE

1. Negative correlation was found between the total N absorbed by rice and F/T (The ratio of fertilizer N absorbed by rice to total N absorbed by rice) in four paddy soils of Jiangsu Province. It means that the more the N uptake by rice, the less the proportion of fertilizer N in the total N uptake. 2. Regular distribution of three levels of rice yield was found in the figure on which the. total N uptake by rice was plott ed against F/T. It was shbwed that the high yield of rice was mainly dependent on soil nitrogen. 3. Isotopic study showed that contrary to the inorganic fertilizer N, the recovery of organic fertilizer N in grain was higher than that in straw. 4. It was found that the duration of nitrogen supply from inorganic fertilizer could be lasted when it was mixed with organic matter. In present experiment, the N supply status of inorganic fertilizer nitrogen seemed to be similar to that of organic fertilizer nitrogen. 5. The fate of inorganic and organic fertilizer nitrogen applied in rice-soil system has been determined respectively after harvest.