Soil quality, elemental stoichiometry and crop yield under partial substitution of chemical fertilizers with organic inputs in Vertisols: a six-site field study

Summary

This three-year, six-site field experiment in the North China Plain evaluated partial substitution of chemical fertilizers with pig manure in wheat–maize systems grown on Vertisols. Replacing 30% of nitrogen input with organic manure significantly reduced soil bulk density (1.3–17.1%), increased organic carbon (0.77–22.5%), improved nutrient availability (2.1–23.7%), and elevated the Soil Quality Index (31.5–335.6%), resulting in substantial yield gains (1.3–251.3%). Structural equation modelling demonstrated that yield responses were primarily mediated through improvements in soil quality, nutrient availability, and optimised elemental stoichiometry.

Regional applicability

This study was conducted in China's North China Plain on Vertisols, a soil type also found in parts of the United Kingdom, particularly in regions with heavy clay-rich substrates. Whilst the specific cropping system (intensive wheat–maize rotation) and pig manure availability differ from typical UK farming contexts, the underlying principles of partial organic amendment substitution and soil quality improvement may be transferable to UK Vertisol-dominant areas, though site-specific validation and consideration of UK regulatory frameworks around manure application would be necessary.

Key measures

Soil bulk density, soil organic carbon content, total and available nitrogen/phosphorus/potassium, C:N/C:P/N:P ratios, Soil Quality Index, wheat and maize yields, yield stability

Outcomes reported

The study measured soil physical properties (bulk density, organic carbon), nutrient availability, elemental stoichiometry (C:N, C:P, N:P ratios), soil quality indices, and crop yields in wheat and maize systems. It assessed how partial substitution of chemical fertilizers with pig manure at 15% and 30% rates affected these parameters over three years across six field sites.

Topic tags