Soil water repellency (SWR) is an intrinsic and dynamic soil property that can influence soil hydrology and crop production. Although several land use systems have been shown to induce water repellency in soil, the specific effects of no-till cropping on SWR are poorly understood. This article reviews the impacts of no-till on SWR and identifies research needs. No-till cropping generally induces 1.5 to 40 times more SWR than conventional tillage, depending on soil type. This may result from near-surface accumulation of hydrophobic organic C compounds derived from crop residues, microbial activity and reduced soil disturbance. While large SWR may have adverse impacts on soil hydrology and crop production, the level of SWR under no-till relative to conventional tillage may contribute to aggregate stabilization and intra-aggregate C sequestration. More research is needed to discern the extent and relevance of no-till induced SWR. This includes: (1) further assessment of SWR under different tillage systems across a wide range of soil textures and climates, (2) comparison of the various methods for measuring SWR over a range of water contents, (3) inclusion of SWR in routine soil analysis and its use as a parameter to evaluate management impacts, (4) assessment of the temporal and spatial changes in SWR under field conditions, (5) further assessment of the impacts of the small differences in SWR between no-till and conventionally tilled soils on crop production, soil hydrology and soil C sequestration, and (6) development of models to predict SWR for different tillage systems and soils.
