Grassland development in tropical and subtropical southern China

Abstract

China’s 79 million ha of tropical and subtropical grasslands represent a significant national forage resource with a potential for further development for sustainable livestock production. The species rich original forest vegetation has been converted through natural and human activities to secondary forest, grassland and agricultural land. The grasslands which include savannah, shrubland, coppice forest and arable land sown with exotic legumes and grasses are expected to become China’s third largest livestock production zone. Despite degradation the grasslands retain a high level of biodiversity which has been preserved in germplasm depositories with on-going collection expeditions throughout south China. Productivity of natural grasses is moderate (<5 t DM/ha) but can be increased significantly by augmenting with Stylosanthes and other introduced legumes adapted to the infertile or acidic soils and seasonal rainfall. Stylosanthes species which is used for grazing, green chop or leaf-meal production, as well as a cover crop in orchards, plantations and forest are successful because they are simple to establish and deliver immediate profits to farmers through improved livestock production or sale of forage for leaf meal manufacture. On-going plant breeding programs are delivering new higher yielding legume and grass cultivars with disease resistance and acid soil tolerance. They are expanding selection priorities to address environmental concerns (e.g. soil acidifying legumes) and to meet the needs of new integrated production systems. Introduced legumes and grasses have provided benefits to the environment through improved soil fertility, reduced soil erosion, increased infiltration rates and reduced weed invasion. Experts believe that the southern tropical and subtropical grasslands still have the capacity to safely increase production and contribute significantly to the improvement of the regional ecosystem. However, this can only be achieved if current programs on germplasm preservation, breeding new cultivars and developing management systems for integrated production systems need to be balanced with work precision livestock management and promotion of monitoring individual animal performance to achieve improved livestock production efficiency.