Adaptive multi-paddock grazing improves water infiltration in Canadian grassland soils

The maintenance of hydrologic function on grazing lands is an important management objective to sustain forage production during low moisture supply, safeguard other ecosystem goods and services and build resilience to a warming climate. Hydrologic function can be influenced by grazing patterns, as represented by variation in the timing, intensity and frequency of livestock use. While rotational, adaptive grazing (a short-duration, multi-paddock grazing system that emphasises plant recovery between grazing events) is growing in popularity and has the potential to influence grassland hydrological processes such as water infiltration, few studies have comprehensively examined infiltration in relation to on-ranch grazing practices. We examined water infiltration in grasslands on 52 ranches (set up as matched pairs) to examine whether adaptive grazing alters water infiltration in the Great Plains of western Canada, as compared to conventional grazing management employed on neighbouring ranches. We also used producer survey information to test for the influence of ongoing nuanced grazing practices on water infiltration rates, over and above the biophysical effects of soil texture, soil bulk density and plant litter, as well as cultivation history and climate. Overall, adaptive grazing, and specifically the use of higher rest-to-grazing ratios early in the growing season (prior to August 1), led to increased water infiltration in grassland soils. Water infiltration was positively associated with increased litter mass under adaptive grazing, whereas higher bulk density (and sandier) soils were associated with decreased infiltration rates. This study highlights the potential of specialised rotational grazing systems using cattle to improve soil hydrologic function in grazed grasslands.