Recent mechanical cultivation of lawns enhances lime application efficacy

While the relationship between soil acidity and thatch accumulation in maintained lawns has been reported, interacting effects of cultivation and surface lime applications on soil acidity have not. The experimental objective was to determine how antecedent mechanical cultivation of mature turfgrasses interacts with surface application of liming agents to neutralize soil acidity within the upper and lower depth segments of a hectare furrow slice (2.24 × 10⁶ kg soil). Various liming agents were applied to three lawn systems, each afflicted with soil acidity and thatch accumulations, at rates from 0 to 200% of soil test lime recommendations (LR). In Experiment 1, resulting active acidity (pHw) was measured in the 0 to 5 (thatch excluded) and 5 to 10 cm soil depths over 23 mo. In Experiments 2 and 3, described lime applications followed mechanical cultivation treatments; core aeration, vertical mowing, or none. Resulting pHw and exchangeable acidity (pH_KCl) were measured in 0 to 6 (thatch excluded) and 6 to 12 cm soil depths after 1 or 2 yr. Application of the prescribed LR (100%) to uncultivated surfaces did not increase 5 to 10 or 6 to 12 cm pHw levels above unlimed plot levels. One or 2 yr following either lime application rate, statistically higher pH_KCl values corresponded to either cultivation treatment in the 6 to 12 cm soil depth. Mechanical cultivation, conducted before surface application of the LR, accelerated the rate of acid neutralization throughout the 0 to 12 cm soil depths of mature lawn systems.