• The Effect of Nitrogen, Phosphorus and Potassium Fertilization on Chemical Content of Sheep Diets

      Doyle, J. J. (Society for Range Management, 1979-03-01)
      Sixteen mixed breed sheep, 1-2 years old and fitted with esophageal fistulas, were allotted at random to four range pastures in southeastern South Dakota. Two of the pastures (4.9 and 5.3 ha) were treated with 67.2 kg of N, 33.6 kg of P, and 89.7 of K/ha, whereas the other two pastures (6.9 and 7.3 ha) received no fertilizer treatment. Esophageal extruded samples were collected at two time periods (June-July and August) from all animals in the four pastures. Ash, N, cellulose and energy content were determined on all extruded samples. Fertilizer treatment had no significant effect on the nutritive content of the diet selected by the sheep. However, time of collection had significant effects on the protein and energy content of the diet selected. A significant fertilizer-collection period interaction was observed for percentage of ash.
    • The effects of grazing intensity on annual vegetation

      Pitt, M. D.; Heady, H. F. (Society for Range Management, 1979-03-01)
      Pastures grazed by sheep at moderate and 1 1/2-, 2-, and 2 1/2- times the moderate stocking rate from 1969-1973 were analyzed for relative changes in cover, herbage productivity, and botanical composition. All four pastures were less productive in 1973 than in 1969, but exhibited similar trends in cover and botanical composition regardless of grazing intensity. Only grazing at 2 1/2 times the moderate stocking rate produced a residual decline in productivity following 1 year of rest from the grazing treatment. However, this decline in productivity was managerially negligible compared to other stocking rates, and would probably disappear within 2-3 years in response to the overriding influence of annual weather, especially precipitation, patterns.
    • The Effects of Nitrogen Fertilization on Water Use by Crested Wheatgrass

      Williams, R. J.; Broersma, K.; Van Ryswyk, A. L. (Society for Range Management, 1979-03-01)
      The application of N fertilizer to crested wheatgrass on a dry rangeland site increased yields substantially. In the early part of the growing season when moisture was not limiting, soil moisture was withdrawn from the fertilized site at a higher rate than from the unfertilized plots. At later periods in the growing season the soil water potential curves paralleled each other with the fertilized crop growing under conditions of lower soil water potential. The decreased soil water potential was confirmed when the actual evapotranspiration, as measured by the energy balance method, was examined. The data indicate that for a period following rapid growth in the spring, the evapotranspiration of the fertilized block was less than that of the unfertilized. The soil water potential data indicate that seasonal evapotranspiration was slightly higher on the fertilized plot than on the unfertilized. The water use efficiency, in terms of biomass produced per unit of water used, was much greater for fertilized crested wheatgrass and resulted in increased yields.
    • Variability in Predicting Edible Browse from Crown Volume

      Bryant, F. C.; Kothmann, M. M. (Society for Range Management, 1979-03-01)
      Biomass estimates were made with regression techniques using crown volume and weight relationships. The log-log function yielded the highest coefficient of determination for Vasey shin oak, plateau oak, Texas persimmon, and honey mesquite. A quadratic function was best for wollybucket bumelia, littleleaf sumac, agarito, and pricklyash. Sugar hackberry showed equally high coefficients with either the linear or quadratic. Coefficients of determination for catclaw acacia, elbowbush, and skunkbush sumac generally were low regardless of the type of regression equation used. When sampled at various periods over the year, predictive accuracy declined for Vasey shin oak and plateau oak through fall and winter but rose again in spring and early summer. For both species, the log-log function was best from late summer to winter but during spring and early summer the quadratic function was best.
    • Vegetation of the Willa Cather Memorial Prairie

      Nicholson, R. A.; Marcotte, M. G. (Society for Range Management, 1979-03-01)
      The purpose of this study was to analyze the interrelationships of the Willa Cather Memorial Prairie in terms of the characterizing species and types of vegetation. At each of 100 sample stand locations data were obtained on the 244-ha prairie in Webster County, Nebraska, to estimate percent basal cover and percent species composition. Estimates were analyzed quantitatively with the aid of vegetation ordination techniques, from which 15 vegetation types were discerned. Of the 15 types, two accounted for over 40% of the stands: a Kentucky bluegrass (Poa pratensis)-buffalograss (Buchloe dactyloides)-blue grama (Bouteloua gracilis)-type and a Kentucky bluegrass-sideoats grama (Bouteloua curtipendula)-big bluestem (Andropogon gerardi) type. Two secondary types accounted for another 16% of the stands, while the remaining 44% of the stands were fairly evenly dispersed within nine other types. Uplands were predominately Kentucky bluegrass, buffalograss, blue grama, and Japanese brome. Sideoats grama, little bluestem (Andropogon scoparius), and Kentucky bluegrass dominated hillside stands. Most abundant in lowlands were Kentucky bluegrass, sideoats grama, Japanese brome, and big bluestem. Due to the abundance of Kentucky bluegrass, late spring burning was prescribed to improve the condition and productivity of the prairie.