3.1 Effects of grassland conversion on soil physicochemical
properties
Grassland cultivation significantly decreased SOC, STN, soil moisture and
pH, but did not change the C:N ratio (Figure 1, Table S1). We also
observed significant decreases in SOC, STN and STP concentrations at
increasing soil depths in grassland across all three sites (Table S1).
However, the SOC, STN and STP concentrations in cropland did not differ
significantly among different soil layers (Table S1). Moreover, we found
significant decreases in >1mm soil aggregation and
increases in <1mm soil aggregations (Figure S2) in the
cropland sites compared with the reference grasslands. Furthermore,
grassland conversion to cropland significantly declined the soil
NH4+-N concentration, but increased
the NO3--N concentration (Figure S3).