杨树不同栽培模式生长量、土壤微生物及酶活性的研究

The poplar increment with different cultivation models and the microbiota and enzyme activity were studied based on 7-years' continuous observation at two stages (1992～1995 and 1996～2000). The poplar stand located in Minquan County of Henan Province with an area of 3.12 hectares. The results showed that the annual average increment in the second stage of all models was higher compared with that in the first stage in height and diameter breast-high (DBH) . The model A and B of the second stage were the best with an increase of 135%, 175% and 214%, 250% higher than that of the first stage, while the control was only 122% and 130%. The amount of three soil microbiota in the second stage was higher than that in the first stage. The bacterium was the most among the three microbiota, and the fungus was the least. All the enzyme activities of five models in the second stage were higher than that in the first stage (except D, E of catalase). The increase ranges from 3% to 161%. In model A and B, the phosphates and urease increased by 135%, 89% and 161%, 105% respectively.