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

Summary

This 14-day soil incubation study examined how two consecutive drying–rewetting cycles affect the availability and cycling of carbon, nitrogen, and phosphorus alongside changes in microbial biomass and trace gas emissions. Drying periods followed by rewetting to 60% water-holding capacity induced significant mobilisation of nitrogen and phosphorus pools, with particularly pronounced CO₂ release upon the first rewetting event (55.4 µg C g⁻¹ d⁻¹). The findings suggest that future climate patterns characterised by altered precipitation and soil moisture variability may substantially impact soil nutrient dynamics and microbial functioning.

UK applicability

The results are relevant to UK soil management and climate adaptation, as seasonal drying–rewetting cycles are common in British agricultural soils and may intensify with changing precipitation patterns. The study's combined measurement of C, N, and P cycling provides a foundation for understanding how UK soils may respond to projected climatic variability, informing future soil management and nutrient stewardship practices.

Key measures

Extractable ammonium; total oxidised nitrogen; bicarbonate-extractable phosphorus; microbial biomass carbon (MBC) and phosphorus (MBP); CO₂ flux (µg C g⁻¹ d⁻¹); N₂O emissions; soil water holding capacity

Outcomes reported

The study measured short-term responses of carbon, nitrogen, and phosphorus concentrations, microbial biomass, and greenhouse gas emissions in soil subjected to two successive drying–rewetting cycles over 14 days. It quantified extractable ammonium, oxidised nitrogen, bicarbonate-extractable phosphorus, CO₂ and N₂O fluxes, and microbial biomass carbon and phosphorus under contrasting moisture regimes.

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