Effects of crop type on soil microbial properties in the cropland of the Jianghan plain of China

Soil microbial properties are varied by growing different crops, ultimately reflecting the growth and reproduction of crops. In this study, two types of oilseed rape (Brassica napus L. ZS11 and ZY821) and wheat (Triticum aestivum L. ZM9023) were planted in the Jianghan plain of China. Rhizosphere soil samples were collected three months after sowing. Soil physicochemical properties, enzyme activities and microbial diversity were determined. The results showed that soil available phosphorus significantly increased from 25.57 mg/kg (ZM9023) to 33.20 mg/kg (ZS11) and 35.72 mg/kg (ZY821), respectively. Invertase activity of ZS821 (0.86 mg glucose/g) was significantly lower than in ZS11 (1.04 mg glucose/g). Acid phosphatase activity under planting rapes was significantly higher than that under wheat. Urease activities significantly increased from 40.88 mg NH4+-N/g soil/24 h (NFP) to 49.04 mg NH4+-N/g soil/24 h (FNP) and 51.28 mg NH4+-N/g soil/24 h (ZM9023), 51.60 mg NH4+-N/g soil/24 h (ZY821) and 52.28 mg NH4+-N/g soil/24 h (ZS11), respectively. The ACE (abundance based coverage estimator) and Chao1 indexes of bacteria of ZS11 were lower than ZY821, which were similar to ZM9023. Fertilization increased soil bacterial ACE and Chao1 indexes. However, ACE and Chao1, Shannon and Simpson indexes of soil fungi for ZS11 were significantly higher than in ZY821, which were similar to ZM9023 (except for the Shannon index).