摘要:
本研究以根瘤菌为材料,采用“土壤载菌量”概念来探讨土壤中微生物数量变化的规律及其生态学和农学意义。“土壤载菌量”是指单位土壤所能容纳的最高菌数值,其单位用“细胞数/克干土”表示。本文报道了根瘤菌在砂土和重壤土两种土壤中的数量变化规律,以此为根据讨论了影响根瘤菌应用效果的接种量问题。研究表明,一定条件下,土壤有确定的载菌量。自然状态下,起始菌量对砂土载菌量有明显影响,不论有无植物生长,土壤的起始菌量高,其载菌量也高;在起始菌量相差104倍和2×106倍的处理中,各自的菌数起落幅度只有几十倍。但土壤经灭菌处理后再接种根瘤菌,起始菌量则对土壤载菌量影响不明显了,起始菌量相差10万倍和100万倍的4个处理中,土壤载菌量基本接近,这就是说,在土壤中没有其他微生物的情况下,起始菌量低,根瘤菌能猛烈增长;砂土和重壤土的载菌量也比较接近。
Abstract:
Rhizobium was used in the study with the term of "bacterium capacity" of soil to describe the quantitative changes of viable rhizobia in soil and to discuss its ecological and agtronomic significances. The term meant the highest population per unit soil and was. expressed in cell numbers/g dry soil generally. The rule of quantitative changes of viable Rhizobium in sandy soil and heavy loam. Inoculum density of Rhizobium influence the effect an application were also discussed.The results showed that there was a definite rhzobium capacity in both surveyed heavy loam and sandy soil under certain conditions. The effect of rhizobial cell number at the beginning of experiment on the rhizobium capacity was signigicant in natural soil. It was found that the higher the starting cell number, the higher the rhizobium capacity, whetherthere was legume growth or not. In treatments with different initial number of 104 or 2 x106, the number of rhizobia differed only times of tens each.When soil sample was first sterilized then rhizobia was added in, initial cell number had little effect on rhizobium capacity. In the four treatments in which the starting cell number differing in 105 or 106 times, the rhizobium capacities were similar. That meant that in the soil with low starting cell number rhizobia grew abundantly. The rhizobium capacities of heavy loam and sandy sosul were close.
点击查看大图
下载:
