Influence of Autumn Management on Orchardgrass-White Clover Swards
- David P. Belesky and
- James M. Fedders
The influence of autumn management on the productivity, morphology, and botanical composition of an orchardgrass (Dactylis glomerata L.) and white clover (Trifolium repens L.) sward was investigated over 3 yr. Stockpiled (nongrazed) canopies were clipped at fixed intervals throughout autumn from exclosures established in each of nine paddocks to determine growth rates and productivity of standing herbage. Pastures were grazed by weaned lambs (Ovis aries) beginning in August in each of 3 yr. Grazing animals were removed from three replicate paddocks after 30 (early closed), 60, or 90 d (late closed). Paddocks were sampled at 2-wk intervals to determine herbage mass, botanical composition, and total nonstructural carbohydrate concentrations of grasses and legumes. Early-closed paddocks continued to accumulate herbage during autumn, resulting in greater senescence over winter than in lateclosed paddocks. Herbage mass in spring was not affected by autumn management. Late-closed paddocks had significantly more clover than did early-closed paddocks in spring. Early-closed paddocks were comprised of grass plants that had relatively few and large tillers and by white clover plants that had fewer growing points than those in lateclosed paddocks. In comparison, late-closed paddocks had grass plants comprised of many small tillers and white clover plants with about twice as many growing points. Stolon mass was greater, but total nonstructural carbohydrate concentrations were less during autumn in late- than in early-closed paddocks. The decrease in clover mass over the course of the experiment coincided with a decrease in total herbage mass. A delicate balance between growing points and carbohydrates may be involved in clover presence in mixed swards.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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