The inverse texture effect of soil on vegetation in temperate grasslands of China: Benchmarking soil texture effect

The inverse texture effect of soil on vegetation has been reported in a few arid regions, but no information is available on the vast Chinese temperate grassland. In addition, no consistent criteria and approaches have been used to classify soil texture groups, determine the precipitation threshold (P?) below which the inverse texture effect occurs, and quantify the effect size (Z), which has limited the generalization of the rules of the soil texture effect in different ecosystems. We analyzed the soil texture effect on vegetation using the remotely sensed vegetation data (MODIS/NDVI) and the Chinese soil profile texture data at 6851 sites in temperate grasslands of China. We found, first, a strong inverse texture effect, i.e., a higher NDVI on coarse- (>50 % sand) than finetextured soil in low precipitation areas, and P? was variable with annual precipitation and averaged 260 mm in the region. Second, we proposed a novel method to use the loam soil as a benchmark against which to quantify the effect of various textured soils, and determine P? as the point on precipitation gradient where the soil texture effect shift from positive to negative or vice versa. As such, P? decreased with soil coarseness, and increased with precipitation; and the texture effect decreased from positive to negative for sandy soils, whereas it increased from negative to positive for silt or clay soils, on the gradient of precipitation increase. Our results provide new insights into the relations of vegetation pattern and dynamics with precipitation and soil texture, and a method for quantifying and comparing soil texture effect across ecosystem types.

Automated summary

This study analyzed the effect of soil texture on vegetation in the temperate grasslands of China. The results showed a strong inverse texture effect, with higher vegetation index on coarse-textured soil in low precipitation areas. The study also proposed a novel method to quantify the effect of different textured soils using loam soil as a benchmark and determine the precipitation threshold for the texture effect. These findings provide new insights into the relationship between precipitation, soil texture, and vegetation pattern and dynamics.