不同种植年限苜蓿地亚硝化菌、反硝化菌和固氮菌的垂直分布

Vertical Distribution of Nitrifying Bacteria,Denitrifying Bacteria,Nitrogen-Fixing Bacteria of Alfalfa in Different Planting Years

本文对西辽河平原不同种植年限苜蓿地亚硝酸细菌、反硝化细菌、固氮菌的垂直分布规律进行研究,结果表明,苜蓿地的亚硝酸细菌数量5月份比4月份减少4个数量级,固氮菌的数量在2个不同种植年限苜蓿地无明显差异,反硝化细菌在2年生苜蓿地中多于5年生苜蓿地,2年生苜蓿地的亚硝酸细菌多于5年生苜蓿地。试验期间土壤中反硝化细菌最多,固氮菌次之,亚硝酸细菌最少。

This study deals with the vertical distribution of nitrifying bacteria, denitrifying bacteria and nitro- gen- fixing bacteria in the alfalfa crops of different ages in Xiliaohe Plain. The results showed that alfalfa crops in April had more nitrifying bacteria （ about 104 ） than that in May. The amount of nitrogen - fixing bacteria did not have obvious difference between the 2 - year - old and 5 - year - old alfalfa crops. However, the 2 - year - old alfalfa crops had higher amount of denitrifying bacteria than that of the 5 - year - old alfalfa crops. During the studying period, the amount of soil denitrifying bacteria was most abundant, followed by the nitrogen -fixing bacteria, with the nitrifying bacteria the least in alfalfa crops.