Cover cropping with white clover and ratten grass impacts soil microbial and nematode communities

Objectives Cover crop species affect soil microbial and nematode community in orchard soils. We compared the effect of white clover ( Trifolium repens ) and rattan grass ( Vulpia myuros ) to provide theoretical basis for ecological orchard management.

Methods A field experiment was conducted in a kiwifruit orchard in Shiyan of Hubei Province. The tested kiwifruit was Actinidia deliciosa, which was planted in 2015. Clean tillage was used as control (CK). The soil microbial and nematode community, as well as the physical and chemical properties were analyzed.

Results Compared with clean tillage, white clover significantly increased soil moisture and NO₃^–-N, total N, soil organic C contents and decreased C/N ratio, improved the total microbial biomass, bacterial biomass; whereas rattan grass only increased soil moisture. Both white clover and rattan grass covers significantly increased the Shannon-Wiener diversity index and Simpson dominance index of microbial community, but not F/B and G+/G– ratio. The number of total nematodes, fungivores and plant parasites in soils were in order of white clover > rattan grass > clean tillage treatment, and the difference between white clover and clean tillage treatment was all significant. Redundancy analysis indicated that soil moisture, total N and organic carbon were the main factors affecting soil microbial and nematode communities.

Conclusions White clover and rattan grass covering is efficient in keeping soil moisture, nutrient content and microbial community diversity. Different from covering rattan grass, covering white clover could significantly increase soil carbon, nitrogen content, increase the soil microbial biomass and nematode number and richness of its communities. So covering white clover is more efficient for keeping healthy and fertile orchard soil than rattan grass.