无氮肥投入条件下黑麦生长过程中土壤酸解氮的消长动态

Rising and falling trend of acid hydrolzable-N during the course of rye grouth without N fertilizer application

取沙、壤、粘 3种质地的潮土 ,采用盆栽试验 ,应用Bremmner法测定黑麦不同生育时期土壤酸解氮及各组分氮含量。结果表明 ,3种质地的土壤氮素主要以酸解氮为主 ,占土壤全氮的 70 %以上 ,在酸解氮中 ,氨基酸氮和酸解未知态氮为主要成分 ,其次为氨态氮 ,最低为氨基糖态氮。黑麦生长过程中 ,在无氮肥投入条件下 ,酸解氮及各组分氮处在动态变化中 ,而且变化趋势相似 ,3种质地的氨基酸氮和酸解未知态氮相对变化率较氨态氮和氨基糖态氮大 ,说明质地不能改变酸解氮及各组分氮的变化趋势 ,但可以改变其变化程度 ;同样水平的全氮量 ,而质地不同的土壤供应速效氮的能力是沙土 >壤土 >粘土 ,但在无氮肥投入情况下 。

The content of acid hgdrolysable-N was determined during the different growing period of rye with Bremmner method in pot experiment, with three texture soils: sand soil, loam soil and clay soil. It was showed that in the three kind soils acid hydrolysable N was the main form of nitrogen, amounting to 70 percent of the total N. The results also indicated that amino acid N and unidentified N were the main compositions of hydrolyzable acid N, the second was ammoniacal N and the last was amino sugar N. The percentage of all forms of N in total N was high in clay soil, moderate in loam soil and low in sand soil. During the course of rye growth, acid hydrolysable-N and other forms of N were in kinesis variation, moreover, the tendency of the change was similar. In the three soils, the relative variation rate of amino acid N and unidentified N was higher than that of amino sugar N and ammoniacal N, which indicated that the soil texture couldn't change the variation tendency of all forms of N, but could change the variation degree. For the different texture soils, though having the same content of N, the ability of providing rapidly available N was not the same: the highest was sand soil, loam soil was moderate and clay soil was the lowest. Under the condition of no nitrogen fertilizer used, the quantity and the quality of N in soils would decline.