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By analyzing the different crop interplanting test in chestnut forests, the results show that soil nitrate nitrogen, ammonium nitrogen and available phosphorus fell in October when intercropped plants, this may be related to the growth of chestnut trees absorb nutrients and microorganisms in the soil. The results of this study show that interplanting different plants had an impact on soil microbial biomass carbon and microbial biomass phosphorus. Microbial biomass carbon turnover rate in the order: ryegrass> clean tillage> natural grass> Alfalfa> flat Agropyron> soybean; turnover rates of soil microbial biomass phosphorus in the order: clean tillage> Alfalfa> ryegrass natural grass> soy> flat crested wheatgrass.

Tillage greatly influences the aggregation and stability of soil aggregates. This study investigated the effects of conservation tillage on soil aggregate characteristics. During a four-year study period (2001-2005), soils were sampled from no-tillage (NT), rotary tillage (RT), and conventional tillage (moldboard tillage, CT) plots at the Luancheng Agriculture and Ecology Experimental Station in Hebei Province, China, and the amount, size distribution, and fractal dimension of the aggregates were examined by dry and wet sieving methods. The results indicated that NT significantly increased the topsoil (0-5 cm) bulk density (BD), while RT maintained a lower BD as CT. Dry sieving results showed that NT had higher macro-aggregate content ( R 0.25 ), and a larger mean weight diameter ( MWD ) and geometric mean diameter ( GMD ) than other treatments in the 0-10 cm layer, while RT showed no difference from CT. In wet sieving, results showed that most of the aggregates were unstable, and the MWD and GMD of water-table aggregates showed the trend of NT > RT > CT. At 0-5 cm layer, the fractal dimension ( D ) of water-stable aggregates under NT was lower than it was under RT and CT. At 5-10 cm, RT yielded the highest D , and showed stability. After four years, NT increased the aggregation and the stability of soil aggregates; while due to intense disturbance, the aggregation and stability of the upper layer (0-10 cm) under RT and CT decreased.