[Effects of grassland management on soil nutrients and their spatial distribution on the Qinghai-Tibetan Plateau, China].

After grasslands were contracted to individual households on the Qinghai-Tibetan Pla-teau, two grassland management patterns were formed, i.e., the single-household management pattern (SMP) and the multi-household management pattern (MMP). The soil nutrients and their spatial distributions under those two patterns were compared in the Nagchu Prefecture of Tibet. The results showed that the soil organic carbon, total nitrogen, and total phosphorus under the MMP (84.31, 6.87 and 0.59 g·kg-1 ) were all significantly higher than those under the SMP (73.57, 6.07 and 0.54 g·kg-1 ). On the vertical dimension, the variation coefficient of soil total phosphorous between 0-15 cm layer and 15-30 cm layer under SMP had no significant difference, while that of soil pH, soil organic carbon and total nitrogen in 15-30 cm layer were all higher than 0-15 cm layer under both patterns. On the horizontal dimension, the variation coefficients of soil organic carbon and total nitrogen under SMP were significantly higher than those under MMP, with the estimated values for the former being 25.7% and 23.5%, and for the latter being 19.3% and 18.6%, respectively. Compared with the MMP, the uneven distribution of nutrients could easily lead to soil nutrient loss under the SMP.