Abstract: For accurate and fast monitoring of the aboveground biomass and botanical composition of the alpine meadow, we examined the Australian dryweight rank (DWR or BOTANAL) method for use in the alpine pasture of Tianzhu County, Gansu Province. We compared the results from the DWR method with that from the traditional quadrat sampling (QS) in short, medium and tall pastures and analyzed their accuracy and efficiency. The results showed that there was no significant difference in biomass production and botanical composition between the DWR and QS (P>0.05). There were significant positive relationships in biomass production between the DWR and QS (P<0.01) with the correlation coefficient (r) being 0.919, 0.982 and 0.859 for the short, medium and tall pastures, respectively. The species recorded by the DWR and QS were
identical and there were significant relationships in the botanical composition of the major species between the DWR and QS (P<0.01) with r being 0.961, 0.975 and 0.972 for the short, medium and tall pastures, respectively. In terms of measurement efficiency, the number of observers and time required for the DWR method were 1/4 and 1/9 of that required by the QS, respectively, for the same amount of data collection. These demonstrated that the DWR method is an accurate technique to monitor aboveground biomass and botanical composition in the alpine meadow and could dramatically save time and improve work efficiency in these harsh environments.

Key words: phosphorus, organic carbon, pollution evaluation, nitrogen, Haihe River Basin., sediment