Influence of management on production, development, and protein utilization of warm-season grasses

A 3-year study in the Nebraska Sandhills on a Valentine fine sand (mixed, mesic Typic Ustipsamments) measured the effects of defoliation on dry matter yield and bud and tiller development of sand bluestem (Andropogon gerardii var. paucipilus (Nash) Fern.), prairie sandreed (Calamovilfa longifolia (Hook.) Scribn.), and little bluestem (Schizachyrium scoparium (Michx.) Nash). Defoliation (7 cm) treatments were: 1 defoliation (10 June, 10 July, or 10 Aug), 2 defoliations (10 June and 10 Aug), and 3 defoliations (10 June, 10 July, and 10 Aug). Control plants were defoliated only in October. Treatments were initiated annually and for a 3-year period (1986 to 1988). Switchgrass (Panicum virgatum L.) and smooth brome (Bromus inermis Leyss.) from near Mead, Nebraska and sand bluestem, prairie sandreed, and smooth brome from the Gudmundsen Sandhills Laboratory near Whitman, Nebraska were collected to measure rumen protein degradation (12 h in situ technique). Following 1 year of defoliation highest production and development of sand bluestem and prairie sandreed occurred with multiple defoliations. After 3 years, a single June or July defoliation of sand bluestem optimized production and development while a 2 defoliation scheme was optimum for prairie sandreed. After 3 years of defoliation, the control was highest in total yield and buds and tillers. The optimum defoliation scheme considering production and development was a single July defoliation. Rumen escape protein, averaged over harvest dates of switchgrass (51%), was higher than smooth brome (19%) from near Mead, NE. Prairie sandreed (57%) had higher values than sand bluestem (51%) and switchgrass (40%) from the Nebraska Sandhills. Concentration of escape protein averaged over harvest dates and species (smooth brome, switchgrass) was higher in leaves than stems (50 and 19 mg protein/g DM, respectively)

Extension Through Partnerships: Research and Education Center Teams with County Extension to Deliver Programs.

Budget reductions have severely affected resources available to deliver agriculture and natural resource Extension programs in Florida. University of Florida/Institute of Food and Agricultural Sciences delivers Extension programming through a unique partnership between research and education centers and county Extension. Science-based information is shared between the research and education center and county Extension who have similar clientele or stakeholders and organizational missions. Extension agents disseminate cutting-edge research information generated by specialists at the center, and the specialists use county agent input to identify local and regional research problems

Defoliation Effects on Production and Morphological Development of Little Bluestem

Response of key warm-season grasses to time, frequency, and duration of defoliation is needed to develop grazing systems for the Nebraska Sandhills. A 3- year (1986 to 1988) study was conducted on a Valentine fine sand (mixed, mesic Typic Ustipsamments) at the Gudmundsen Sandhills Laboratory near Whitman, Nebraska, to determine the effect of defoliation on little bluestem [Schizachyrium scoparium (Michx.) Nash]. Treatments were: 1 defoliation (to 7 cm) on 10 June, 10 July, or 10 Aug.; 2 defoliations on 10 June and 10 Aug.; and 3 defoliations on 10 June, 10 July, and 10 Aug. Control plants were harvested only at the end of the growing season (October). All plots receiving summer defoliation were harvested in October to obtain aftermath yield. Treatments were initiated in 1986, 1987, and 1988 and the effects of 1, 2, and 3 years of defoliation on dry matter (DM) yield, bud and tiller numbers, and tiller weight were measured. Experimental design was a split block with 4 plants as replications. In the first year of treatment annual DM yield from control plants was 2 times greater than that from all defoliated plants, but bud and tiller numbers were similar. In the second year of treatment, all treatments reduced annual DM yield and morphological development below that of the control if precipitation was subnormal, but not if precipitation was above normal. In the third year of defoliation, with above-normal precipitation, single June or July defoliations produced DM yields and morphological development similar to that of the control, but single August or multiple defoliations generally reduced yield and development. Little bluestem may not persist if exposed to multiple, close defolitions during the growing season

Defoliation Effects on Yield and Bud and Tiller Numbers of Two Sandhills Grasses

Intensive grazing strategies for the Nebraska Sandhills must be based on time and frequency of defoliation of key warm-season grasses. A 3-year field study was conducted in the Nebraska Sand-hills to determine the effects of defoliation on yield and bud and tiller number of sand bluestem [Andropogon gerardii var. paucipilus (Nash) Fern.] and prairie sandreed [Calamovilfa longifolia (Hook.) Scribn.]. Defoliation (7 cm) treatments imposed on a 1.5 X 1-m plot were: a single defoliation on 10 June, 10 July, or 10 August; 2 successive defoliations on 10 June and 10 August; or 3 successive defoliations on 10 June, 10 July, and 10 August. All plots were harvested in October to obtain aftermath yield. Control plots were harvested only at the end of the growing season (October). Defoliation treatments were initiated in 1986, 1987, and 1988 on different plots and the effect of year of initiation as well as the effect of 3 successive years of repeated treatment (1986 plots) was evaluated. Annual dry matter (DM) yield, and bud and tiller numbers were measured. Following the initial year of treatment multiple defoliations increased yield of both grasses while bud and tiller numbers were similar to those of the control plants. After 3 years of repeated treatment, annual DM yield of sand bluestem for all defoliation treatments was lower than the control. A single defoliation of sand bluestem in August or a June-July-August defoliation reduced bud number compared to other treatments and the control. A June-August defoliation of prairie sandreed over a 1 year period increase annual DM yield compared to all treatments and the control although defoliation treatments reduced bud number. The optimum time and frequency of defoliation for annual DM yield and bud and tiller number was 8 single June or July defoliation for sand bluestem and a June-August defoliation for prairie sandreed