Nitrogen Partitioning in Arrowleaf, Crimson, Rose, and Subterranean Clovers without and with Defoliation
- G.W. Evers * and
- M.J. Parsons
Cool-season annual clovers are used in the southeastern United States as a N source but there is limited information on the N concentration and distribution in the clover plant during the growing season. The objective of the study was to document N concentration and accumulation in shoots and roots of ‘Yuchi’ arrowleaf (Trifolium vesiculosum Savi), ‘Tibbee’ crimson (T. incarnatum L.), ‘Mt. Barker’ subterranean (T. subterraneum L.), and ‘Overton R-18’ rose (T. hirtum All.) clovers for three growing seasons when uncut, and after cutting once, or cutting twice. When uncut, shoot N concentration decreased throughout the growing season with plant maturity from about 35 to 40 g kg−1 in autumn to 10 to 15 g kg−1 at maturity in late spring. Shoot N concentration after cutting once or twice was greater than in the uncut treatment on the same sampling date. Root N concentrations were about one-half that of the shoot N concentration and declined slowly during the growing season regardless of cutting treatment. When uncut, average maximum shoot N accumulations were 382 kg ha−1 for arrowleaf, 227 kg ha−1 for crimson, 203 kg ha−1 for subterranean, and 226 kg ha−1 for rose clovers. Cutting once or twice reduced maximum shoot N accumulations of all clovers except subterranean clover. Root N accumulations increased during the growing season when uncut, were not affected after cutting once but decreased after a second cutting. The optimum species as a N source would be crimson clover through April and arrowleaf clover in May and June.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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