关键词: 土壤容重, 土壤孔隙度, 土壤贮水量, 秸秆还田, 土壤养分, 氮肥, 玉米产量

Abstract: Soil heterogeneity is one of the major factors that influence vegetation heterogeneity and habitat selection of soil fauna and rodents. Rational soil sample size and distribution is very important for reflecting the useful information of soil. In this study, we investigated soil compaction, soil bulk density, and soil moisture in alpine meadow of the eastern Qilian Mountain, by setting up 121 sampling points within a 110 m × 110 m plot. We compared the results of different sampling sizes (3-36 sampling points) and three sampling methods (random sampling, grid sampling, and diagonal sampling) with entire sampling method (121 sampling points). We found that: (1) The standard errors of sampling decreased with increasing the sampling sizes using different sampling methods. (2) Among the three sampling methods, the random sampling method was the best one. Sampling size of >18 points could meet accuracy requirement under 90% and 95% confidence level. We suggest that the sampling effects should be considered according to the study purpose and grassland type.

Key words: soil bulk density, straw returning, soil nutrient, nitrogen fertilizer, soil porosity, soil water storage, maize yield