• Cane Bluestems: Forage Yield, Forage Quality, and Water-Use Efficiency

      Koshi, P. T.; Eck, H. V.; Stubbendieck, J.; McCully, W. G. (Society for Range Management, 1977-05-01)
      Three collections of cane bluestem (Bothriochloa barbinodis Herter) were evaluated under three water and three harvest regimes. Dry matter yields, under natural rainfall and irrigation, averaged 3.8 and 8.7 metric tons/ha, respectively. Productivity of the three collections ranked G-866 > G-820 > PMT-333 under natural rainfall, but with irrigation, the ranking was G-820 > G-866 > PMT-333. One and two harvests per season resulted in near-equal yields, but three harvests decreased yields. Cane-bluestem forage contained about 10% protein and 0.22% phosphorus (P) in mid-June. In November, previously unclipped forage contained 4.4% protein and 0.12% P, while that clipped twice contained 7.3% protein and 0.18% P. Yield and quality of cane bluestem compared favorably with that of switchgrass (Panicum virgatum L.) grown in a similar study. Maximum production was obtained with about 77 cm of water use (rainfall + irrigation + soil water).
    • Forage Potential of Irrigated Blue Grama with Nitrogen Fertilization

      Lehman, O. R.; Bond, J. J.; Eck, H. V. (Society for Range Management, 1968-03-01)
      In 1959, ammonium nitrate was surface applied to blue grama at rates of 0, 200, 400, and 800 lb N/acre. Initial plant response to fertilizer N was measured in 1959, and residual response in 1960 and 1961. High moisture levels were maintained by irrigation. Each increment of applied N increased forage yields and yield trends indicate that with adequate water and N blue grama will produce at least 7,500 lb/acre/year of oven-dry forage. Recovery of added N was very low, ranging from 28 to 34% for the 200- and 800-lb rates, respectively. Total water use was similar for all treatments, but pounds of forage produced per inch of water used increased with each increment of N. The results indicate blue grama is a relatively inefficient user of moisture and N when compared with sudan grass, bermuda grass, and some other introduced grasses. However, further studies are needed to determine if blue grama can be managed to use fertilizer and water more efficiently.
    • Grass Species Adaptability in the Southern High Plains—A 36-Year Assessment

      Eck, H. V.; Sims, P. L. (Society for Range Management, 1984-05-01)
      A 36-yr old species adaptation test was evaluated and the relative quality of some persisting native and introduced grass species was determined. The site was Conlen loam on the Rita Blanca National Grassland in Dallam County, Texas. Of the 25 species planted, only yellow bluestem (Bothriochloa ischaemum),1 Caucasian bluestem (Bothriochloa caucasica), and galleta (Hilaria jamesii) tended to dominate the plots on which they were originally planted. Yellow and Caucasian bluestem had spread into plots planted to other grasses but galleta had spread very little. Yellow bluestem was as high or higher in protein, mineral content, and digestibility (IVDMD) than the other grasses analyzed [Caucasian bluestem, galleta, sideoats grama (Bouteloua curtipendula), blue grama (Bouteloua gracilis), and western wheatgrass (Agropyron smithii)]. The contents of Caucasian bluestem and galleta were not significantly different from those of yellow bluestem, except that galleta was lower in IVDMD, especially when mature. These 3 grasses merit consideration in range seeding programs on Conlen and similar soils in the Southern High Plains.
    • Nutrient and Sediment Discharge from Southern Plains Grasslands

      Smith, S. J.; Menzel, R. J.; Rhoades, E. D.; Williams, J. R.; Eck, H. V. (Society for Range Management, 1983-07-01)
      Amounts of nitrogen, phosphorus, and sediment were measured in runoff from grassland watersheds in the Blackland Prairies, High Plains, Reddish Prairies, and Rolling Red Plains land resource areas of Oklahoma and Texas. Periods of study were 3 to 5 years and included treatments involving fertilization, cultivation, and burning. Overall nutrient concentrations generally ranged from 2 to 10 mg/l for nitrogen and 0.3 to 2 mg/l for phosphorus. In most cases, less than half the nutrients existed as soluble forms in the runoff water. Typically, annual sediment losses were less than 0.5 metric tons/ha. Corresponding losses for nitrogen and phosphorus were less than 5 and 2 kg/ha, respectively. In the case of nitrate, more was received in precipitation than was lost in runoff. Total nitrogen and phosphorus losses were strongly correlated with sediment losses. Preliminary results using predictive techniques to estimate nutrient and sediment discharge from the watersheds were encouraging. With proper management, the likelihood of any adverse environmental effects due to nutrient and sediment discharge from Southern Plains grasslands appears slight.
    • Response of Shortgrass Plains Vegetation to Clipping, Precipitation, and Soil Water

      Eck, H. V.; McCully, W. G.; Stubbendieck, J. (Society for Range Management, 1975-05-01)
      Clipping shortgrass range in Texas at 2-week intervals gave 94% more forage yield than fall harvest. Clipping treatments had little effect on ground cover and plant composition. Yield was shown to be a function of current season precipitation, while plant composition and ground cover were more closely related to previous season precipitation. In the one of seven seasons when stored soil water was available at the beginning of the growing season (4.91 inches of plant-available water), it was depleted by June 15.
    • Switchgrasses: Forage Yield, Forage Quality and Water-use Efficiency

      Koshi, P. T.; Stubbendieck, J.; Eck, H. V.; McCully, W. G. (Society for Range Management, 1982-09-01)
      The purpose of the study was to evaluate 3 strains of switchgrass (Panicum virgatum L.) under 3 water and 3 harvest regimes. Dry matter yields, under natural rainfall and full irrigation, averaged 2.0 and 6.7 metric tons/ha, respectively. Productivity of the 3 strains ranked G 300>HV-341>Blackwell. Yields of HV-341 and Blackwell were similar under 1, 2, or 3 harvests per year but those of G-300 were reduced by 2 or 3 harvests. Switchgrass forage contained about 10.8% crude protein (CP) and 0.23% P in late June. In November, previously unclipped forage contained 4.3% CP and 0.12% P, while that clipped twice contained 5.5% CP and 0.15% P. Maximum production was obtained with 116.5 cm of water use but maximum water use efficiency was obtained with about 85.5 cm of water use (rainfall + irrigation + soil water). The switchgrasses are adapted for use both without irrigation and when varying amounts of irrigation water are available. G-300 yielded more and produced earlier and later than the other two strains thus it may be the best choice for use for range improvement or for irrigated pastures. However, it requires careful management because it is more susceptible to overuse than the other two strains.