Northeastern Leymus Chinensis Steppe Plant Communities In Enzyme Activity

This paper dealt with the soil enzymes of three main plant communities (Leymus chinensis community, Puccinellia tenuiflora community, Puccinellia tenuiflora community) in the Leymus chinensis grassland in northeast China .The activities of soil catalase, urease, invertase and polyphenol oxidase were determined in three soil depth (0-10cm,10-20cm,20-30cm). We studied the seasonal dynamics, the rule of variation with soil depth and the distribution regularity of the four soil activities. The correlation between the activity of soil enzymes and environmental factors were analyzed in different soil layers.The results show as follow: the seasonal dynamics of the activities of soil catalase, urease, invertase in three communities all appeared single-peak curves and had obvious regularities, which could be described by mathematics models. And the peak values of the three different enzymes appeared in July or August, the minimize values appeared in September or October, while the peak values of soil polyphenol oxidase appeared in September or October. The activities of soil catalase, urease. invertase were decreased gradually with depth of soil layer, while the activities of soil polyphenol were decreased rapidly in 10-20cm soil layer, and increase again in 20-30cm soil layer.The correlation between the activity of soil enzyme and environmental factors were analyzed in different soil layers. The results show that the activities of soil invertase and soil urease were closely correlated with soil fertility; the correlation between the soil catalase activity and the aboveground vegetation was very significant; the correlation between the soil polyphenol oxidase activity and the environmental factors were not significant. In the invert reaction of soil organic matter, the three enzymes promoted specially and affected each other greatly; while the correlation between the soil catalase activity and the other three soil enzymes were not significant.