Responses of carbon, nitrogen and phosphorus to two consecutive drying–rewetting cycles in soils

Summary

This controlled laboratory study quantifies how successive drying–rewetting cycles—a realistic field disturbance—alter pools and transformations of carbon, nitrogen and phosphorus in soil, and associated gaseous losses. The work provides mechanistic evidence for nutrient mineralisation and microbial community responses to soil moisture fluctuations, with implications for understanding field-scale nutrient availability and greenhouse gas dynamics under variable rainfall or irrigation regimes.

UK applicability

The findings are applicable to United Kingdom agricultural soils, particularly in regions subject to variable summer rainfall or drought conditions. Understanding these short-term nutrient transformations during moisture cycling informs predictions of nitrogen availability and emissions risk under climate scenarios featuring more frequent wet–dry cycles.

Key measures

Microbial biomass carbon (via fumigation-extraction); mineral nitrogen (NH₄⁺, NO₃⁻); extractable phosphorus; soil respiration (CO₂); nitrous oxide (N₂O) and methane (CH₄) emissions; gravimetric soil moisture

Outcomes reported

The study measured changes in soil microbial biomass carbon, extractable nitrogen and phosphorus pools, and greenhouse gas emissions (CO₂, N₂O, CH₄) across two consecutive 7-day drying periods followed by rewetting to 60% water-holding capacity, compared to continuously moist controls.

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