Plant Responses to Stocking Rate in a Subtropical Grass‐Legume Pasture

Abstract

Abstract‘Florida’ carpon desmodium [Desmodium heterocarpon (L.) DC] is a persistent legume under grazing but is often difficult to establish. Aeschynomene (Aeschynomene americana L.) and, especially, phasey bean [Macroptilium lathyroides (L.) Urb.] establish more reliably. Overseeding a mixture of these legumes in bahiagrass (Paspalum notatum Flugge) pastures could provide the quality forage and N input of legumes initially from the rapidly establishing species and for extended periods from the persistent carpon desmodium. The objective of this study was to evaluate the potential of such mixtures. Effects of stocking rate and grazing season on botanical composition, herbage availability, and herbage nutritive value were evaluated on a Pomona fine sand (sandy, siliceous, hyperthermic Ultic Haplaquod). Following overseeding of legumes in March 1987, pastures were grazed at three stocking rates in summer 1987 and in spring and summer 1988. Carpon desmodium increased from less than 1% at the start of grazing in 1987 to over 7% of the live herbage in 1988. Combined percentage of aeschynomene plus phasey bean decreased during 1987 from more than 4 to 1.6%. Carpon desmodium percentage was highest (P < 0.10) at the intermediate stocking rate, while percentage of other legumes was not affected by stocking rate. Herbage mass decreased linearly with increases in stocking rate in both summer grazing seasons. Leaf/stem ratio and nutritive value of legume leaf and stem were not affected by stocking rate but decreased with time during each grazing season. The short‐lived legumes, aeschynomene and phasey bean, provided high quality forage during the establishment period of carpon desmodium but contributed negligibly during the second year.