Limpograss and hymenachne grown on flatwoods range pond margins.

Abstract

Limpograss (Hemarthria altissima [Poir] Stapf and C.E. Hubb) and hymenachne (Hymenachne amplexicaulis [Rudge] Nees) may reduce weight loss of cows grazing Florida range from September to March. These grasses were grown on maidencane (Panicum hemitomon Schult) pond margins and were evaluated as stockpiled forage (ungrazed 6-10 months) at 2 locations over 4 years. Floralta limpograss received 0 or 3,000 kg dolomite ha (2 whole plots) and N-P-K fertilizer (5 subplots): 50-25-50, 50-25-0, 50-0-50, 50-0-0, 0-0-0 kg/ha. Hymenachne was grown without dolomite, N, P, or K. Hymenachne failed to establish at Ona in central Florida, but persisted for 1 year at Immokalee near the Everglades where dry matter production in October to January was 1,540, 2,160, and 2,910 kg/ha at 35, 70, and 105 days after N fertilization, respectively. Crude protein (56 g/kg) was highest at 70 days and IVOMD (47.4%) was highest at 105 days. Limpograss established without dolomite, N, P, or K fertilization, and forage available for winter grazing often exceeded 7,000 kg/ha. Application of 50 kg N/ha to stockpiled limpograss increased yield (compared to no N) in 1 of 4 years at Ona and in both years at Immokalee. Applying N to stockpiled limpograss always increased crude protein and IVOMD above that of grass receiving no N, but increases were slight (10 g crude protein/kg). Crude protein seldom exceeded 50 g/kg with 50 kg N/ha applied in late August at Ona or in October at Immokalee. In vitro organic matter digestion often exceeded 45%, which could help limit weight loss of cows grazing range in winter. Neither grass was observed to be invasive, as growth was confined to plots after 5 and 8 years at Immokalee and Ona, respectively.