Effect of Balanced Fertilization on Reviving Degraded Grasslands in Tibet

IPNI-2003-CHN-XZ9

12 Jan 2005

2004 Annual Interpretive Summary

Effect of Balanced Fertilization on Reviving Degraded Grasslands in Tibet, 2004

This project seeks to revitalize the degraded grassland areas of Tibet through balanced fertilization, and thus protect the still undamaged grassland reserves. Soil nutrient deficiencies, fertilizer recommendations, placement methods, and timing were investigated in 2003. The objective in 2004 was to examine the residual effect of fertilizers applied to established grass stands and to determine a rational fertilization frequency.

In 2003, the optimal treatment of 210-60-135 kg N-P2O5-K2O/ha produced a grass yield of 500 kg/ha, or 2.6 times the prevailing practice... represented by an unfertilized check. In 2004, the yield produced by the residual effects of this treatment remained the highest at 950 kg/ha... nearly double the amount produced in 2003 and 8.6 times the yield produced by the check. The presence of residual nutrients allowed for greater proliferation of the crop root systems, and thus plants could more thoroughly explore the soil for both nutrition and water. The effect of residual nitrogen (N) was most pronounced, followed by potassium (K). There was little effect for residual phosphorus (P) in these sites. Balanced fertilization has proved to be a most promising method for rapid revitalization of degraded grasslands and maintenance of established grass stands in Tibet. Evidence concerning residual fertility indicates that the proper frequency for fertilizer application could extend over 2 to 3 years, or longer, but this needs to be confirmed with further study. Tibet-NMS02