• Carbohydrate Reserves of Intermediate Wheatgrass after Clipping and Etiolation Treatments

      Ogden, P. R.; Loomis, W. E. (Society for Range Management, 1972-01-01)
      The total water-soluble carbohydrate (TWSC) fraction of intermediate wheatgrass stem bases and roots is depleted with etiolation and is a good measure of the reserve energy of this species. When the TWSC fraction was depleted to about 1% dry weight, vigor of the grass was too poor to recover from a clipping treatment. Root weight was also reduced with etiolation. Late September to early November was a period of active herbage and root growth for intermediate wheatgrass. Growth during this fall period enabled grasses which had been clipped three times at 6-week intervals during the summer to recover to very nearly the level of TWSC and root weight as the check plants.
    • Effects of Soils on Forage Utilization in the Desert Grassland

      Vandermark, J. L.; Schmutz, E. M.; Ogden, P. R. (Society for Range Management, 1971-11-01)
      This study was made in southeastern Arizona to determine some of the factors affecting utilization by cattle of two key species on three desert grassland soils. Results showed that macronutrient content of the soil and the plants, and corresponding utilization of blue grama (Bouteloua gracilis) and curlymesquite (Hilaria belangeri), were always significantly greater on the Pima bottomland soil than on the two upland soils, but they were not always significantly different between the two upland soils. No consistent relationships were found between forage utilization and micronutrient, sugar or starch content in the plants./El estudio se llevó a cabo en una zona desértica en el Estado de Arizona, E.U.A. Hubo una correlación significativa entre el consumo de forraje y los contenidos de nitrógeno, fósforo y potasio. No hubo una correlación entre el consumo y los contenidos de azúcar, almidón, micronutrientes ni humedad. El consumo fué mucho más significativo en cuanto al forraje en los valles con suelos profundos que en los suelos de las dos mesetas.
    • Estimating Botanical Composition of Forage Samples from Fistulated Steers by a Microscope Point Method

      Galt, H. D.; Ogden, P. R.; Ehrenreich, J. H.; Theurer, B.; Martin, S. C. (Society for Range Management, 1968-11-01)
      A microscope point method was used to develop weight prediction equations for plant species in masticated forage samples of known species weights collected at the end of two successive growing seasons. A high correlation was found in regressions of percent weight on percent points for all the masticated plant species. Two observers were consistent in their ability to estimate similar amounts of plant species in a given species mixture. With 400 microscope points, the average weight of a species was estimated within 5% of the mean at a 90% level of probability when the species constituted 30 to 60% of the sample weight.
    • Response of Four Perennial Southwestern Grasses to Shade

      Tiedemann, A. R.; Klemmedson, J. O.; Ogden, P. R. (Society for Range Management, 1971-11-01)
      A nursery plot study was conducted to determine if the observed relative abundance of Arizona cottontop, bush muhly, and plains bristlegrass under mesquite trees on native range was related to the ability of these grasses to adapt to shade. Plants of these species plus black grama which grows in open areas were subjected to shading only and shading after defoliation treatments using five levels of shade from 0 to 80%. Evaluation of morphological, physiological, and yield responses showed that all plants made their best growth in full sunlight; but Arizona cottontop, bush muhly, and plains bristlegrass displayed greater ability than black grama to adapt to shade.
    • Response of Lehmann Lovegrass to Time of Fertilizer Application

      Billy, B.; Stroehlein, J. L.; Ogden, P. R. (Society for Range Management, 1973-05-01)
      On a desert grassland site in southern Arizona, production of Lehmann lovegrass (Eragrostis lehmanniana) was significantly increased by applications of 30-10-0 fertilizer as late as July 22. Seed yields were least with later dates of fertilization. Nitrogen and phosphorus contents of the plants were increased within 1 week after application; thereafter they generally declined. Nitrate-nitrogen and available phosphate in the surface 4 inches of soil increased immediately after fertilization, and the nitrate-nitrogen then decreased rapidly. Plots fertilized at later dates generally reached their peak yield and higher nitrogen and phosphorus contents later and remained greener into the fall months than those fertilized at the beginning of the rainy season. Herbage growth of forbs the following spring was greater on fertilized plots than on control plots, but data were very variable and not significant. No residual response of Lehmann lovegrass was found the second summer growing season after fertilization, probably a result of the dry summer.
    • Time of Fertilizer Application on Desert Grasslands

      Stroehlein, J. L.; Ogden, P. R.; Billy, B. (Society for Range Management, 1968-03-01)
      In most fertilization studies on desert grasslands, little attention has been paid to soil moisture conditions at the time of application. Results have been highly variable and fertilization has not been accepted as an economical management practice. These studies were designed to determine if the time of application could be adjusted to soil moisture conditions in order to insure maximum response to fertilization. In general, fertilization of desert grasslands after the start of the summer rainy season gave best results in three of four sites studied. Applying fertilizer after soil moisture is present helps prevent fertilizer losses during a dry season. Maximum response to the fertilizer is assured because application is just prior to the time of the greatest demand for nutrients.
    • Vegetative Response Following Pinyon-Juniper Control in Arizona

      O'Rourke, J. T.; Ogden, P. R. (Society for Range Management, 1969-11-01)
      Mean percentage calcium carbonate levels of near 13% in the surface foot of soil and low pinyon-juniper crown cover (13% and 26%) were associated with no increase in perennial grass herbage production four to five years after pinyon-juniper control in north-central Arizona. Both percentage calcium carbonate in the surface soil and percentage pinyon-juniper crown cover are expressions of the long-time moisture regime of a site and may be good indices for predicting potential understory response which might be expected from pinyon-juniper control.