Application of organic manures can help in forming soil aggregates and improving their stability. Li et al. (1999) showed that application of green manure could increase the content of >0.25-mm water-stable aggregates. Jiang et al. (2010) found that application of green manure could help transform smaller water-stable aggregates into larger ones, and increased the content of those >0.25 mm. Long-term winter planting of green manure, especially of Chinese milk vetch (Astragalus sinicus L.), can increase the content of 0.25-5-mm water-stable aggregates in soil (Yang et al. 2012). Chen et al. (2009) showed that long-term application of Chinese milk vetch green manure increased the content of >2-mm but decreased that of 1-mm aggregates. Application of inorganic fertilizer and organic manure both have a large impact on the distribution of organic C and nitrogen (N) in soil aggre-
gates; and the larger the aggregates, the more organic C and N will be contained.