Nutrient Management Strategies for Forage in Yunnan

The expansion of forage grass cultivation and animal husbandry is one of the most important measures towards improving human nutrition in Yunnan. Balanced plant nutrition plays a key role in the production of both high quality forage grass as well as meat and dairy products. This project was initiated in 2004 with research aimed at determining (i) the yield-limiting nutrients for soils in Xiaoshao and Xundian counties, two of the major forage production centers in Yunnan, and (ii) nutrient management strategies for profitable forage grass production. The dominant nutrient deficiencies were nitrogen (N), phosphorus (P), and potassium (K). Yields of both ryegrass and white clover significantly increased with applied P and K. The objective in 2005 was to further verify the nutrient-limiting factors and fertilizer recommendations while demonstrating and extending the technology throughout the region.

In 2005, ryegrass yields once again increased with applied K. The study was expanded to paddy lands with higher fertility than the uplands used in 2004. In summer, ryegrass is harvested every 10 days and yields hover around 10 t/ha for each harvest. In the winter and spring, grass is cut every two months and yields reach 30 t/ha for each harvest. Average yield improvements at the three sites due to balanced fertilization (BF) were: (i) 202% with 120-90-90 kg N-P₂O₅-K₂O/ha compared to farmers' practice (FP) of 36-96-0 kg/ha; (ii) 180% with 90-60-90 kg/ha compared to FP of 48-192-0 kg/ha; and (iii) 180% with 135-105-90 kg/ha compared to FP of 150-60-0 kg/ha. Field demonstrations also showed farmers using BF could produce 2.5 to 3.0 times more than is achievable through traditional methods.

Most farmers and local leaders are now well exposed to BF technology. There are 33,000 ha of ryegrass planted in Yunnan and improved practices have the capability to increase ryegrass yields by 5.9 million metric tonnes (Mt) while supporting an additional 825,000 head of beef cattle, or 24.75 million rabbits, or 270,000 t of fish annually. Improved ryegrass production alone is estimated to increase K consumption by nearly 3,000 t K₂O per year. Yunnan-NMS-02