Abstract
The effect of the cropping system on arbuscular mycorrhizal fungi, growth and yield of succeeding corn or soybean were studied over the rainy season on Andosol field in Ibaraki, Japan, since a high soil moisture status has been suggested to improve the efficiency of arbuscular mycorrhizal infection. Corn and soybean were grown in plots of seven cropping histories. All the previous crops except for the crops of the genus Brassica were mycorrhizal in cropping system. Grain yield of soybean and ear yield of corn following soybean and sweet potato were much higher than following a crop of the genus Brassica and fallow. In particular, continuous cultivation of crops of the genus Brassica depressed the yield of the succeeding crop. The previous crop clearly influenced the spore population and arbuscular mycorrhizal formation in corn root. It was thus concluded that both the population and colonization of arbuscular mycorrhizal fungi after cropping of the genus Brassica and fallow were less than after cultivating soybean and sweet potato. Consequently, our results indicate that the cropping system affected the growth and yield of the succeeding crop through symbiotic association with arbuscular mycorrhizal fungi on Andosol in the central region of Japan.
