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Grass production was monitored based on seasonal harvests under various canopy covers of h&ache on a Coastal Prairie blackland range site during 1978 and 1979. Grass production (Y) was not decreased in 1978, compared to that on essentially brushfree areas, until huisache canopy cover (X) exceeded 30% based on the reiationship, Y = 2,346 -I-20X -0.62X*. Texas wintergrass standing crop apparently increased as huisache canopy cover increased to 25% and its growth during winter partly compensated for standing crop losses of warm season species during the winter. In 1979, the contribution of the cool-season species was masked by greater production of warm-season species. Consequently, grass production decreased with increasing huisache canopy cover according to the relationship, Y = 4,047 -14.9X -0.29X2. Based on the functional relationship Y = a -blX-bzX*, coefficients of determinations (P) ranged from 0.50 to 0.96 when estimates of annual production of grasses or production for the growing season only were regressed against huisache canopy cover.

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Crude protein content of herbage produced by buffelgrass, blue panicgrass, and Bell rbodesgnss was improved with nitrogen and phosphorus fertilization and clipping every 4 or 8 weeks, compared to harvests only at the end of the growing season. Within a fertiliution level, the (I-week clipping frequency generally increased dry matter production of the grasses over the 4-w-k clipping frequency or the end-of-season single harvest. Kkberg bluestem herbage generally contained less protein at all pbenological stages than that of buffelgrass, blue panicgrass, or Bell rbodesgnss, and dry matter production was not increased by fertiliution. Crude protein content of Kleberg bluestem herbage was only slightly increased with the highest level of fertilization, regardless of clipping frequency.

Production of native grasses following aerial application of 1.12 kg/ha of 2.4.5-T ((2,4,5-trichlorophenoxy)acetic acid), 2,4,5-T + dicamba (3,6-dichloro-o-anisic acid), or 2,4,5-T + picloram (4-amino-3,5,6-trichloropicolinic acid) (1:) to a south Texas mixed-brush (Prosopis-Acacia) community was significantly increased by all herbicide treatments the year of application, by the herbicide combinations during the second year, but only by 2,4,5-T + picloram the third year after treatment. Moisture-use efficiency based on kg/ha native grass produced/cm precipitation was greastest where the herbicide combinations were applied. Defoliation of woody plants in years of above-average rainfall resulted in favorable grass production responses regardless of herbicide(s). However, range improvement over the 3-yr of study was dependent on maintenance of herbicide effectiveness, especially control of underbrush which resulted only where 2,4,5-T + picloram were applied. Consumption of native grass was a direct function of availability in response to brush control as augmented by rainfall. Forb production was reduced by all herbicides the year of treatment and by 2,4,5-T + picloram the year following application, but was not reduced by any treatment during the third growing season.