The influences of long-term residue and fertiliser management on soil organic carbon (SOC) and related physical properties were investigated in a wheat (Triticum aestivum L.)–corn (Zea mays L.) double-cropping system in the North China Plain. The experiment was initiated in 1981, including 4 treatments: control (no fertiliser); mineral N and P fertilisers; low residue rate plus N and P fertilisers; and high residue rate plus N and P fertilisers. In June 2006, soil samples were taken from the 0–0.05, 0.05–0.10, and 0.10–0.20 m layers to determinate bulk density (ρb), water-stable aggregates, bulk SOC, and aggregate-associated C concentrations. Soil water retention curves and saturated hydraulic conductivity (Ks) were measured using samples collected from the 0–0.05 and 0.05–0.10 m layers. The results indicated that residue incorporation significantly increased (i.e. improved) bulk SOC and aggregate-associated C concentration, aggregation, Ks, soil matrix and structural porosities, and water retention capacity. The improvements in soil physical properties by mineral N and P fertilisers alone were limited.
Residue input significantly (P < 0.05) increased the value of S, an index of soil physical quality. A high correlation existed between S and SOC concentration, and the key soil physical parameters, suggesting that S was an effective parameter for evaluation of soil physical quality. Our study concluded that a combination of residue with mineral N and P fertilisers improved SOC concentration, and consequent soil physical quality under the wheat–corn double cropping system.
Spatiotemporal differences in the arbuscular mycorrhizal fungi communities in soil and roots in response to long-term organic compost inputs in an intensive agricultural cropping system on the North China Plain