• Energy Balance Relative to Percent Plant Cover in a Native Community

      Aase, J. K.; Wight, J. R. (Society for Range Management, 1970-07-01)
      Net radiation (Rn) and evapotranspiration (ET) were poorly correlated during both a "wet" and a "dry" period on native range near Sidney, Montana within each of five levels of vegetational cover. The ratio ET:Rn fluctuated greatly in all cases and was generally higher during the period of higher rainfall. During dry periods, substantial amounts of energy were dissipated as heat flux to the atmosphere. Maximum evaporation and/or transpiration from 0%, 25%, 50%, 75%, and 100% cover occurred for 12 days after rainfall and was, respectively, 0.7, 0.8, 1.1, 0.3, and 1.9 times the evaporation from a Class A evaporation pan. Total evapotranspiration for the season was 21% lower and dry matter production was 14% higher with 50% cover than with complete cover. Water use from 75% and 25% cover was similar to that from 50% cover, but forage yields were 5% and 14% less, respectively, than from complete cover.
    • Improvement of Panspot (Solonetzic) Range Sites by Contour Furrowing

      Soiseth, R. J.; Wight, J. R.; Aase, J. K. (Society for Range Management, 1974-03-01)
      We studied the effects of 3-, 7-, and 10-year-old contour furrowing on some physical and chemical soil properties of panspot range sites in southeastern Montana. Changes in soil bulk density, sodium-adsorption-ratio (SAR), and salinity (EC) on the contour-furrowed areas were generally small, but a definite ameliorating trend was established. Contour furrowing increased infiltration rates 0.25 to 3.11 cm/hr and increased forage yields 498 to 770 kg/ha. Reduced SAR and EC on contour furrowed areas were attributed to increased infiltration.
    • Prairie Sandreed (Calamovilfa longifolia): Water Infiltration and Use

      Aase, J. K.; Wight, J. R. (Society for Range Management, 1973-05-01)
      Prairie sandreed (Calamovilfa longifolia) near Sidney, Mont., grows on rangeland in colonies ranging from 1 to 8 m in diameter. There were small differences in soil texture between prairie sandreed colonies and surrounding vegetation. Increased plant growth and residue accounted for higher water infiltration rates within the prairie sandreed colonies than on surrounding vegetation. Prairie sandreed used slightly more water, but the water-use efficiency was nearly twice that of the surrounding vegetation.
    • Radiometric Reflectance Measurements of Northern Great Plains Rangeland and Crested Wheatgrass Pastures

      Aase, J. K.; Frank, A. B.; Lorenz, R. J. (Society for Range Management, 1987-07-01)
      Calculated reflectance factors and vegetation indices derived from radiometric reflectance measurements were used in regression analyses to test for a single relationship between canopy reflectance characteristics and measured vegetation parameters from 1 moderately grazed and 1 heavily grazed native rangeland pastures and 1 crested wheatgrass [Agropyron desertorum (Fisch. ex Link) J.A. Schultes] pasture. The study was located on a Williams loam (fine-loamy mixed, Typic Argiboroll) near Mandan, North Dakota. Reflectance measurements were made near solar noon once a week during the 1983 and 1984 growing seasons. There was a statistically significant relationship (r=0.76**) between leaf area index and dry green matter among pastures and years. However, each pasture exhibited a unique relationship (statistically significant) between vegetation indices developed from the reflectance measurements and leaf area index or dry green matter. Based on the techniques and wavebands used in this study, over a given geographic region and with pasture management practices known, it may be possible to remotely estimate green dry matter.