Rhizobox was employed to stimulate the sod culture orchard, with Citrus sinensis and Stylosanthes gracilis as plant material. The effects of grass mowing, arbuscular mycorrhizal inoculation and P application on minimizing the competition between fruit tree and grass were investigated. Results indicated that 3 practices alleviated the inhibiting effect of grass on citrus at different magnitude, leading to increased plant height, leaf number and dry matter. Grass mowing took the greatest effect among 3 practices, resulting in a sharply decreased (R/S,) which implied a mediated nutrient competition following inhibition of root growth by grass mowing.