Rice (Oryza sativa L.) is the world’s most important crop and a primary food for half of the world’s population [16].
Soybean (Glycine max L.) is the world's foremost provider of protein and oil, which could form symbiosis with rhizobia to form nodule and thus fix atmospheric N [17].
In this study,pot experiments on rice-soybean rotation were conducted for two years (2009 and 2010) using newly cultivated acid soils at the Ningxi experimental site of South China Agricultural University in Guangdong Province.