Effect of Improved Fertilization on potato Yields in Tibet


09 Jan 2009

2008 Annual Interpretive Summary

Effect of Improved Fertilization on Potato Yields in Tibet, 2008

The experiment was initiated in 2007 in a river valley in the Shannan region, the main potato production base in Tibet. The project was aimed at determining the optimal rates of N, P, and K fertilizers for potato and provide scientific fertilizer recommendations for the region. Treatments include an optimal treatment (OPT) using 105-75-120 kg N-P2O5-K2O/ha, three nutrient omission treatments, and an unfertilized check. The project was continued in 2008 to validate the preliminary results obtained.

Due to more favorable weather in 2008, potato yields were about 7 to 9% higher than those in 2007. Fertilizer response trends remained constant as N was most limiting, followed by K, and then P. Compared to the OPT treatment, yield was reduced by 29.9 t/ha (43%) when N was omitted from application. Omission of K or P both led to 11% reductions in yield. The better weather conditions in 2008 generally narrowed the differences between the OPT and nutrient omission treatments indicating better nutrient uptake by potato under more favorable conditions.

Based on 2 years of research, the current fertilizer recommendations from the local government of 150-75-0 kg/ha over emphasize N and ignore the potential benefits from applying K. A reduction in N rate and inclusion of K can boost potato yields, creating real incentives for local leaders to disseminate the information on a wider scale, and for local potato farmers to adopt balanced fertilization. Tibet-07