Jun Yan;Xiaowen Han;Chunxiang Xu;Xinchun Lu;Wenfeng Chen;En Tao Wang;Wenxiu Zou;Zhiming Zhan

Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081 (China;State Key Laboratory of Agrobiotechnology, College of Biological Sciences and Rhizobia Research Center, China Agricultural University, Beijing 100193 (China);Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081 (China);Department of Microbiology, National College of Life Sciences, National Institute of Technology, México 11340 (México)

rom;chinese;mollisols;diversity;soybean;rhizobial diversit

Rhizobial diversity is affected by interactions between soil features, fertilization strategy, and cropping system. However, interactions among the rhizobial community, chemical-organic manure fertilization, and plant production have not been well documented in Mollisols from long-term experiments. Aimed at maintaining and recovering the productivity of Chinese Mollisols, a long-term fertilization experiment had been carried out for 29 years under a wheat-maize-soybean rotation system, involving the application of recycled organic manure (ROM), chemical fertilizers (N, P, and/or K), or ROM plus N, P, and/or K. In the present study, the effects of different treatments were evaluated by determining soil physicochemical features, soybean production, and soybean rhizobial diversity. The results showed that application of ROM plus NPK maintained or increased soil fertility, which was accompanied by higher production and higher diversity of rhizobia, as compared with the other treatments. The negative association of Bradyrhizobium japonicum with N fertilizer, positive association of B. diazoefficiens with soil pH, and alleviation of N-inhibition on the diversity of Bradyrhizobium by the addition of ROM were recorded as new findings. Therefore, application of ROM or ROM plus NPK could be a feasible strategy for maintaining and recovering the fertility of Chinese Mollisols, whereas rhizobial diversity could be an indicator of soil fertility.