Abstract:
Being one of the first works on rhizobial nitrogen fixation on the Qinghai-Tibet plateau, this work by has employed a variety of methods (wild legume transect sampling, vetch fertilization and inoculation experiments, numerical taxonomy of rhizobia) to explore the feasability of inoculation techniques its high-alpine grasslands. A huge diversity of legumes has been found, and it has been shown that wild grassland astragali and Onobrychis are nodulated by a wide rhizobial cluster in the Rhizobium-huakuii group, which seems to confirm observations in Canada in Russia. In Xiaman soil there are already sufficient rhizobia for the nodulation of vetch (whose growth showed P- and not N-limited), the situation however appears to be different for Sinorhizobium-nodulated plants which offer some potential for improvement. Legumes performed best on dunes. It is concluded that leguminous efficiency mainly depends on soil texture and available soil temperature. However, on the plateau, the semihumid Xiaman area might be relatively unideal for fast improvement for climatic as well as agrosocial reasons.