White Clover Growth and Morphology under Contrasting Cutting Regimes

Abstract

Climatic conditions contribute to reduced white clover (Trifolium repens L.) productivity and plant survival in the southeastern USA, particularly during the summer. Our objective was to determine the influence of cutting height and frequency on yield and plant morphological traits associated with survival of white clover under humid‐subtropic conditions. Regal (large‐leaf), Louisiana S‐1 (medium‐largeleaf),and Grasslands Huia (medium‐small‐leaf) white clover were sown on a Catalpa silty clay (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) and were cut every 7, 28, and 49 d at a 2.5‐ and 10‐cm stubble height from March to November. Forage yield was measured at each harvest. Stolon growth and branching (growing point density; GPD) and post‐harvest leaf area index (LAD were measured in May, August, and November. Dry matter (DM) yield measured by season (spring, summer, and autumn) increased as leaf size increased and cutting height decreased. The effect of cutting height on stolon DM was opposite that of its effect on DM yield. After the spring, stolon DM of all cultivars was reduced by harvesting at 2.5‐ vs. 10.0‐cm stubble, regardless of cutting interval. Within a cutting height, increasing the harvest interval from 7 or 28 to 49 d generally resulted in greater stolon DM accumulation by autumn. During much of the growing season, there was a positive association between stolon GPD and post‐harvest LAI. Our results suggest that close defoliation of white clover (2.5‐cm stubble) during the summer and autumn detrimental to plant survival, particularly when combined with a short (7‐d) defoliation interval.