THE ECO-ENVIRONMENT OF A YOUNG LITCHI ORCHARD INTERPLANTED WITH FORAGE GRASS IN SOUTH CHINA

Six kinds of grasses including Stylosanthes humilis, Desmodium heterocarpum, Desmodium intortum, Trifolium repens, Melinis minutiflora and Paspalum notature were grown in a young litchi orchard on the slopes of latored (hapludox) soils in south China, and their effects studied. Inter-row forage grass increased land coverage and soil water capacity, and decreased water and soil losses. Water and soil conservation increased by 50 to 60% compared with bare lands. Forage grass also improved the fertility and texture of the soil, and hence productivity. Organic matters, total N, total K, rapidly available N, rapidly available K and CEC were also higher. The soil texture changed from sandy loam to light loam after 3 years. The biomass of six kinds of grasses was higher and exceeded 10 t ha^-1 annually, and litchi trees grew vigorously. The establishment of a forage grass interplanting system enhanced the biodiversity in the orchard, which helped control diseases and pests, and suppressed weeds. However, the grass competed for soil nutrients, water and light. Forage grass in young litchi orchard is a sustainable land-use system. Further studies on suitable forage grass and their management are still required.