Infiltration and soil water storage under winter cover cropping in california’s sacramento valley

Summary

This field study from California's Sacramento Valley examined whether winter cover cropping improves rainfall infiltration and soil water storage compared to fallow management across two winters (1998–2000). Cover-cropped plots consistently showed lower runoff and higher post-rainfall soil water content than fallow fields, with hydrologic modelling suggesting that cover cropping reduces surface hydraulic conductivity decline over successive rainfall events. The findings suggest cover cropping can enhance water availability for subsequent crops in regions with concentrated winter precipitation, potentially reducing irrigation demand.

Regional applicability

This study was conducted in the United States (California's Sacramento Valley) and therefore has limited direct applicability to United Kingdom farming systems, which operate under different climatic and hydrological regimes with more distributed rainfall and different seasonal water balances. However, the principles of cover crop-mediated soil structure improvement and infiltration enhancement may be transferable to UK winter cereal or arable rotations, particularly where soil compaction or surface sealing is a concern, though UK growers would need locally-adapted trials given the wetter climate and shorter growing season.

Key measures

Cumulative event runoff from infiltration test areas, soil water content at 0-1.05 m depth, surface hydraulic conductivity, daily water budget components (runoff, infiltration, evaporation, evapotranspiration, soil water storage)

Outcomes reported

The study measured rainfall infiltration, runoff, soil water content, and hydraulic conductivity under winter cover crop versus fallow treatments across three 4-year rotation farming systems. Winter cover cropping reduced cumulative runoff and increased soil water storage in the root zone compared to fallow management.

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