Abstract:

To investigate the effects of continuous cropping of crayfish and rice on functional diversity of soil microorganisms, some rice paddy fields and ponds with continuous cropping of crayfish and rice were selected as research objects, Biolog-ECO method was used to detect the utilizing capacity of 31 carbon sources by microorganism in soils. The metabolic activity and the difference of metabolic diversity of microorganism were studied in the rice paddy fields with continuous cropping of crayfish and rice and rice paddy field. The influencing factors were analyzed. The results showed that the contents of nitrogen, phosphorus, potassium and organic matter, and the microbial metabolic activities in fields with continuous cropping of crayfish and rice were all lower than that in rice paddy fields (P<0.05). The metabolic diversities of soil microorganisms in fields with continuous cropping of crayfish and rice and rice paddy fields were significantly different (P<0.05, and the results of redundancy analysis showed that and the difference was positively correlated with the content of organic matter in soil (R²=0.814, P =0.001). To sum up, the continuous cropping of crayfish and rice can influence the functional diversity of soil microorganisms significantly, and the reduction of fertilizer uses, especially the reductions of organic matter, is the important cause.

Key words: continuous culturing of crayfish and rice, microbial metabolic activities, Biolog-ECO, metabolic diversity, organic matter