Effects of the Winter Crop On the Spore Density of Arbuscular Mycorrhizal Fungi and the Growth of Succeeding Soybean.

In this research, the effects of the introduce of winter crops on the arbuscular mycorrhizal fungi (AMF) spore density, succeeding soybean AMF colonization rate, growth and yield. From autumn to spring, the wheat (Wheat plot) or rapeseed (Rapeseed plot) were grown in experiment field in each year. And Fallow plot (no crops from autumn to spring) was prepared. From spring, soybean plants were grown in all plots. The field experiments were performed from 2007 to 2010, three years. In this period, phosphorus fertilizer did not applicant in all plots. The AMF spore density in soil of Rapeseed plot and Fallow plot decreased after cultivation winter crops in each year. This tendency was remarkable in third year. On the other hand, the AMF spore density in soil of wheat plot increased after the cultivation of wheat. And the AMF colonization rate of succeeding soybean in wheat plot was higher than those in rapeseed plot and fallow plot. The difference of succeeding soybean growth and yield of each plot. The growth of succeeding soybean in each plot did not cleared in each plot in the first and second year, but, in the third year, that was cleared in each plot. For example, the soybean phosphorous absorption, growth, and yield of wheat plot was better than that of other plots in third year.