Abstract: To investigate the influences of mowing on the fruit tree growth and nutrient competition in a sod culture system, and to elucidate the corresponding mechanisms, Citrus sinensis and Stylosanthes gracilis were grown in rhizoboxes as tested plants. The results showed that mowing significantly alleviated the grass competition for phosphorus , and promoted the citrus plant growth , in a low P soil . Mechanism analysis indicated that mowing
strongly inhibited the grass root growth , significantly decreased the total root length, and also changed the root system distribution, which resulted in a significant decrease in plant P content and P uptake. For citrus plants,the total root length and apparent P uptake rate of root were increased , P content and P uptake were significantly enhanced, to a comparable level with fertilized plants. It is suggested that mowing changed the competition status between fruit tree and grass through the influence on root system, and the root distribution pattern may play a important role in the nutrient competition.

Key words: Citrus, Sod culture, Mowing, Nutrient competition, Phosphorus