Now showing items 1-18 of 18

• #### A Portable Burner for Evaluating Effects of Fire on Plants

A portable propane plant burner was constructed for use in evaluating the effects of fire on individual plants. The plant burner is inexpensive to build and allows application of specific time-temperature heat treatments. Moreover, careful calibration of the plant burner allows simulation of a variety of burn treatments.
• #### Cattle Activities and Preferences Following Strip Application of Herbicide

Santa Gertrudis cattle activities were dominated by grazing, standing and ruminating. Only minor differences occurred between winter and summer activities. Summer morning temperatures were negatively related to percentage of herd grazing, indicating a decrease in grazing as temperature increased. However, summer daytime vapor pressure deficit (VPD) showed a better correlation with grazing habits. As VPD increased the number of cattle grazing decreased; conversely, as VPD decreased cattle grazing increased. Cattle indicated a strong grazing preference for untreated vegetation, even though herbage production was substantially higher in the herbicide treated strips.
• #### Protection of Instrument Wires in the Field

Electrical wires used with field instruments are frequently damaged by adverse environmental conditions and animal activities. Such damage can be minimized by enclosing the wires in a housing made of polyvinyl chloride water pipe as described in this paper.
• #### Structural Changes in Chamise (Adenostoma fasciculatum) along a Fire-induced Age Gradient

Chamise (Adenostoma fasciculatum) undergoes major structural changes in above-ground biomass along a gradient of increasing stand age since fire. Shrub growth in volume and biomass is rapid through 16 years but levels off in older stands. In this early phase of linear biomass increase, net above-ground productivity has a mean of 430 g yr-1 for each shrub, or 60 g m-2 yr-1 over the period of 2-16 years stand age. Individual shrubs at 37 years in Sequoia in the southern Sierra Nevada have more than twice the biomass and four times the annual above-ground productivity of chamise of similar age in the San Gabriel Mountains of Los Angeles County. Between 16 and 37 years, shrub senescence increases with no increase in above-ground biomass and a sharp reduction of available photosynthetic surface area. Total stand biomass continues increasing with stand age up to 37 years as shrub biomass increases, with a maximum at approximately 15,000 kg ha-1. Fine fuels less than 10 mm comprise more than 500 g m-2 in all chamise canopy ages, providing an important structural element of flammability.
• #### Variation in Winter Levels of Crude Protein among Artemisia tridentata Subspecies Grown in a Uniform Garden

We discovered that the midwinter crude protein content of Artemisia tridentata is under genetic control. Our study demonstrated that some accessions of A. tridentata, grown under uniform conditions, contained significantly higher levels of crude protein than others. Subspecies tridentata contained significantly higher levels of crude protein than subspecies vaseyana and wyomingensis. However, the accessions that contained the highest levels of crude protein have been reported to be least palatable to mule deer. A superior strain of A. tridentata can be developed by combining the high protein-yielding accessions with accessions that are higher in palatability. The new strain could supply more protein for mule deer on winter ranges.
• #### Yield and N Uptake by Seven Perennial Grass Species as Affected by High Rates of N Fertilizer

Seven species of grass were grown on plots to which N had been applied at progressively increasing rates (0 to 775 kg N/ha) to reach and exceed those required for maximum yields. Yield of hay and protein in all seven grasses increased with N fertilizer. Recoveries of N were only 12 to 31% when applied once, and 8 to 14% when applied every year. Because these recoveries are considered to be uneconomical, massive rates of N fertilizer are not recommended. Intermediate wheatgrass produced the most hay and protein. All seven grasses responded most to applied N in the first 2 years after application, regardless of age of stand.
• #### Effects of Agricultural Terraces on the Reestablishment of Bluestem Grasslands

The effects of agricultural terraces on the reestablishment of a bluestem grassland were evaluated 5 years after seeding. Terrace intervals (the slopes extending between terraces), terrace channels, terrace ridges, and terrace slopes (2 meters downslope from the terrace ridge) in both burned and unburned areas were evaluated. Canopy cover for all seeded native grasses averaged higher on terrace locations than on terrace intervals. Little bluestem (Andropogon scoparius) and Indiangrass (Sorghastrum nutans) were best established in terrace-channels, whereas sideoats grama (Bouteloua curtipendula) and blue grama (B. gracilis) were most abundant on terrace-ridges. Big bluestem (Andopogon gerardii) coverage was greatest on terrace-channels in burned and terrace-slopes in unburned areas. Canopy cover of nonseeded grasses and forbs averaged highest on terrace-ridges and terrace-slopes; forbs were markedly reduced as a consequence of burning but foxtail (Setaria spp.) increased. Total productivity was substantially greater on terrace locations (6,757 kg/ha) than on terrace intervals (3,620 kg/ha). Burning reduced total biomass the year of the burn with the reduction most pronounced in the terrace-channel where productivity was highest. This study indicates that terraces provide microhabitats which result in species distributions that differ markedly from those expected for native prairies. In addition, terrace conditions appear to slow the process of establishing a continuous stand of native perennial grasses. Thus, it appears to be advisable to remove terraces and redistribute terrace soil prior to reseeding with native grasses.
• #### Nematode Density and Biomass in an Annual Grassland Ecosystem

The nematode community structure was examined in grazed and ungrazed annual-plant rangeland on the US/IBP Grassland Biome San Joaquin Site located in the foothill-grasslands of central California. Nematode numbers and biomass were estimated from early growth to mature stages of the annual-plant vegetation. Nematode density was greater on the grazed area, predominately forbs, than on the ungrazed, mainly grass, area. A lower than normal precipitation appeared to be a limiting factor of nematode population density. The nematode trophic structure differed between the two sites, fungivores and microbivores predominating on the grazed and ungrazed sites, respectively. Indications are that the critical factors controlling nematode density and community structure on this annual grassland are not grazing but soil moisture and temperature.
• #### Performance Evaluation of Water Harvesting Catchments

The runoff efficiencies of 14 operational water harvesting catchments were estimated using a small portable sprinkler. The sprinkler method was verified using actual rainfall-runoff data from test plots of various water harvesting treatments at the Granite Reef Test Site. Sprinkler results showed that membrane-type treatments yielded 90-100% runoff. The runoff from properly installed wax-type treatments averaged over 80%. The sprinkler method permitted evaluation of catchment runoff efficiencies without resorting to the time and effort required for large field-instrumentation projects.
• #### Residual Effects of Phosphorus and High Rates of Nitrogen on Shortgrass Rangeland

Plots on shortgrass rangeland in southeastern Wyoming that received high rates of nitrogen applied once in 1970 or four times (1970 through 1973) were split, and phosphorus (P2O5) at 56 kg/ha was applied to half of each plot in the spring of 1975. Over a 3-year period (1975-77), average total herbage yields and yields of individual species were generally less for all treatments during the residual period (1975-77) than during the years of fertilization (1970 through 1973). Blue grama density decreased during the nitrogen fertilization period but increased during the 3 residual years, so that in 1977 density was almost the same as that in 1970. Western wheatgrass increased in all nitrogen treatments and generally remained high during the 1975-1977 period. During this residual period, previous nitrogen fertilization tended to increase the yield of western wheatgrass, forbs, and total herbage and decrease that of blue grama and dryland sedges. The application of phosphorus did not influence herbage yields or crude protein content of western wheatgrass or blue grama. Phosphorus also did not influence concentrations of calcium, magnesium and potassium in blue grama.
• #### Supplementary Feeding of Range Sheep

Droughts significantly reduce the production from range sheep and in severe cases affect survival. In order to avoid losses in times of feed shortage, pastoralists must either supplement sheep at pasture or implement total hand-feeding strategies. To employ either practice necessitates familiarity with the principles of supplementary feeding, many of which are summarized in this paper. In addition to discussing the nutrient requirements of grazing sheep, the expected responses to supplementary feeding for different classes of sheep and production activities are reviewed. The question of when to commence feeding is discussed and information is provided on the formulation of diets with respect to the physical form and the nutritive value of the ingredients. Finally, research highlighting the importance of feeding frequency is reviewed.
• #### Survival Patterns of Major Perennials in Salt Desert Shrub Communities of Southwestern Utah

Chart quadrat records periodically taken at the Desert Experimental Range in southwestern Utah over 34 years were examined for evidence of establishment and survival of eight major perennial plant species. A set of seedlings that became established in 1935-37 were followed until 1968-70. Relatively few individuals have died since the second year after establishment. There were few significant differences between the survival of plants in the grazed versus ungrazed plots.
• #### Impact of a White Grub (Phyllophaga crinita) on a Shortgrass Community and Evaluation of Selected Rehabilitation Practices

During the spring of 1973, white grubs, Phyllophaga crinita (Burm.), at a density of $46.3/{\rm m}^{2}$, reduced cover of perennial grasses by 88% in localized areas of a shortgrass community in Scurry County, Texas. Forbs and broom snakeweed were not affected. Chlordane applied to the soil surface at 3.36 kg/ha did not control white grubs. Chlordane, nitrogen fertilization (112 kg/ha of N), and a combination of the insecticide-fertilization treatments did not appreciably enhance rehabilitation of white grub-denuded rangeland. Seeding with introduced grasses was not successful because of inadequate precipitation, heavy grazing by lagomorphs on the small areas, and competitive effects of buffalograss. Forbs and broom snakeweed were not important in the early seral stages of secondary succession on the study site, but common broomweed and common sunflower were dominants on other denuded sites in the area. Most plant species had recovered by the end of the second growing season without fencing to control livestock grazing.
• #### Fairy Rings and Wildlife

Fairy rings 25×30 m in diam were observed on southwest-facing grasslands of the Rock Creek drainage of Montana at the 1,450-m elevation on May 20, 1970. Within the stimulated growth portion of the rings there was 5 to 9 times as much new grass growth in proportion to old standing litter than outside the rings. Protein, calcium, and phosphorus values were 3.7, 1.6, and 3.9 times higher, respectively, for the new forage on the rings than for the old forage elsewhere. Deer use of the ring area was more than twice as great as that away from the rings, according to fecal group counts.
• #### Diets of Sheep, Angora Goats, Spanish Goats and White-tailed Deer under Excellent Range Conditions

A study was initiated in August 1975 to illuminate the dietary interrelationships among four kinds of small ruminants on the Edwards Plateau of Texas. Sheep diets were dominated by grass followed by browse, goat diets were nearly equal in percent grass and browse, and deer spent most of their feeding time on browse followed by forbs. Livestock diets were not as high in forbs as expected, indicating that abundant grass due to excellent range condition may relieve livestock pressure on forbs, leaving more forbs for deer. Increased feeding time by deer on grass regrowth, after livestock were removed from the study area in July for a 4-month deferment, indicated that grazing systems were favorable to deer by providing regrowth forage. However, where livestock and deer graze in common, there are periods of competition even under excellent range conditions. These periods were fall and winter for browse, winter and early spring for forbs, and anytime immature grass was available. Relative to deer, sheep probably were most competitive for forbs and succulent grass, while goats, particularly the Spanish goats, were most competitive for browse. Similar annual trends for diets for all kinds of animals for all forage classes suggested competition was primarily for palatable green forage.
• #### Evaluation of Wire Fences for Coyote Control

Thirty-four electric and nonelectric wire fence configurations were evaluated for deterrent effect to coyotes (Canis latrans). Tests of fences were conducted using a conditioned test regime or live prey to elicit fence-crossing responses from 15 captive coyotes during 980 exposures to fences. Fence height and mesh size were important factors in controlling jumping over and crawling through, respectively. Overhangs and aprons were necessary to preclude climbing over and crawling under fences. Electric fences generally were not effective deterrents under test conditions. Construction of a fence necessary to deter all methods of crossing is described. Subsequent field tests have verified the suitability of such a fence to control losses of sheep to coyotes.
• #### Evaluation of Fall Burning on Bighorn Sheep Winter Range

Bighorn sheep and mule deer grazed bluebunch wheatgrass on areas on a Wyoming big sagebrush/bluebunch wheatgrass winter range significantly greater than adjacent unburned sites for 4 years after burning. Grass production decreased slightly the first year after burning but returned to preburn levels 2 years afterwards. Frequency of bluebunch wheatgrass in plots was reduced for 2 years following burning but returned to preburn levels by the third year. Big sagebrush seedlings were noted on burned sites 2 years after burning. Burning was considered to benefit bighorn more than mule deer because sagebrush, an important component of the mule deer diet, was effectively removed from the site for at least 4 years after burning.