Redberry juniper mortality was determined following spring broadcast burns in 1979 and 1980, and individual-plant burns with 3 heat treatments in 1981. Mortality varied from 1 to 100% and was related to bud zone location, plant size, site, and growing conditions. During years of above average precipitation, mortality averaged 70% for plants with the bud zone above the soil surface contrasted to 3% for plants with the bud zone partially below the soil surface. Plant size and site factors such as slope and soil surface stability appeared to affect the rate at which the bud zone was buried by soil, thus producing a fire resistant plant. Plant mortality was significantly increased across all size classes and sites when burns were conducted under hotter conditions and followed by a dry growing season.

A grazing trial comparing fertilized and unfertilized 3-pasture systems has shown that the addition of 56 kg nitrogen (N)/ha substantially improved forage and beef production. Forage production from the fertilized system was increased by 46% over the unfertilized system while per acre beef gains were increased 35%. Each 3-pasture system utilized crested wheatgrass for spring and early summer, native mixed grass prairie for mid and late summer and Russian wildrye for fall grazing. Comparison of Hereford and Angus-Hereford crossbreds indicated a slight gain advantage for the crossbred animals, although the increase was not statistically significant. The addition of the biuret supplement Kedlor was found to improve gains of steers grazing the native pastures in late summer but resulted in decreased gains on fall-grazed Russian wildrye pastures. Analysis of the forage samples showed that in all samples except one, the addition of N fertilizer increased the protein content.

A plant establishment study was conducted in the oil shale region of northeastern Utah where annual rainfall averages 200 mm. Treatments consisted of annual weed removal for 2 years, for 1 year, and no removal to test the impact of competition on survival of bareroot and container-grown transplants. Competition had a major negative effect on the survival and growth of fourwing saltbush (Atriplex canescens), winterfat (Ceratoides lanata), prostrate summer cypress (Kochia prostrata), and russian wildrye (Elymus junceus). At the end of 4 growing seasons only 21% of the plants survived under normal site competition compared to 84% survival with 2 years of weed removal. The area of plant canopy under the influence of full competition averaged 0.95 dm2 as compared with 4.03 dm2 where competition was absent for 2 years for the same period.

Sulfur deficiencies are widespread on the rangeland soils of California and the application of sulfur-bearing fertilizers has been widely recognized as a promising range improvement on these soils. Considerable work has been done on the management and ecological aspects of sulfur fertilization of California rangeland; however, little or no economic analysis of this improvement exists. Using existing data from subclover-grass pastures in northern California to derive aggregate production functions, optimal application rates of sulfur applied as elemental sulfur and gypsum were determined using standard marginal analysis. Both elemental sulfur and gypsum proved to be profitable means of increasing both winter and total yearly production when either harvested hay or grazed forage (AUM's) were considered as products. Using 1981 material costs and product prices applied to total yearly hay production, the optimum rate of sulfur applied as gypsum with 3 years residual was 251 kg/ha for an increased profit of $101/ha/yr over unfertilized pastures. The optimum rate of elemental sulfur was 147 kg/ha for a profit increases of $93/ha/yr. When total yearly grazed forage was considered the product, optimum application rates were 195 kg/ha of sulfur as gypsum and 126 kg/ha for elemental sulfur yielding profit increases of $46/ha/yr and $48/ha/yr, respectively. Optimal application rates and profits were lower for both hay production and grazed forage when winter production was optimized.

Because of the selective nature of grazing livestock, the use of whole plant samples to estimate the nutritional potential of forages may be misleading. During this 2-year study, the distribution of dry matter (DM), crude protein (CP) in vitro organic matter digestibility (IVOMD), and concentrations of P, K, Ca, Mg, Mn, Fe, Cu, and Zn were determined in the individual leaf blades, leaf sheaths, nodes plus internodes, and infloresences of creeping bluestem (Schizachyrium stoloniferum), lopsided indiangrass (Sorghastrum secundum), maidencane (Panicum hemitomon), and wiregrass (Aristida stricta) when they were in the anthesis stage of maturity. Most of the DM was in the nodes plus internodes (avg. 45%), while the leaf blades (avg. 18%) generally made up the smallest amount of the total plant DM. In a progression from the bottom to top of the plant the CP, IVOMD, and most of the mineral concentration of the different leaf blades, sheaths, and nodes plus internodes increased. Crude protein, IVOMD, and most of the minerals of the grasses were higher in leaf blades, followed by sheaths, and nodes plus internodes. When compared with other grasses, maidencane had a higher proportion of CP and minerals in the leaves and nodes plus internodes and a higher percentage of plant weight in these parts. Wiregrass was found to be similar to creeping bluestem and indiangrass in CP and most minerals, but IVOMD of wiregrass parts were lower. Dietary requirements for dry, pregnant cows for P, N, Mg, and Cu might not be met by any part of the 4 grasses, while apparently adequate levels of Fe, Mn, and Zn could be provided by each part. Leaf blades and infloresences had sufficient Ca concentrations for dry pregnant cows.

Dogs used to protect domestic sheep from predators are expected to be attentive to the animals they guard. However, 40% of the sheep producers cooperating in our experimental program to assess the potential of Old World dogs to deter predation in the United States have expressed dissatisfaction with their dog's attentiveness. In contrast, European shepherds appear satisfied with their dogs. In order to find the causes of this apparent difference, a series of measured observations was made in Italy, and data on 4 different strains of imported guarding dogs working in the U.S. were analyzed. The results indicate that the 4 strains are significantly different in attentiveness, although overall it was remarkably similar to the actual attentiveness of Italian dogs. The attentiveness of livestock guarding dogs can be maximized for U.S. sheep producers by (1) selecting strains for superior attentive behavior and (2) adjusting management systems slightly to take advantage of the dogs' capabilities.

Esophageal fistulation, stomach content analysis, fecal analysis, and forage utilization were compared as techniques for determining food habits of large herbivores. Each technique was evaluated based upon information collected using bi-fistulated (esophageal and rumen) sheep during 2 study phases. In the first study phase, microscope slide mounts were made of plant fragments collected from the esophagus, rumen, and feces of 10 confined sheep fed a hand-composited mixture of forage. Dietary composition as determined by each technique was compared to the original feed. Stomach content analysis and fecal analysis produced dietary estimates higher in grasses and lower in forbs than the known feed values. Esophageal fistulation results were not significantly different from the known feed values. In the second study phase, esophageal, rumen, and fecal collections were gathered from 16 sheep grazing a common plant community. Ocular estimates of forage utilization were made concurrently. All data were converted to percent composition on a dry weight basis for comparisons. Significant differences in percent diet composition among techniques occurred for 18 of the 31 plant species consumed. Diets determined by stomach content analysis and fecal analysis were significantly higher in grasses and lower in forbs than those determined by esophageal fistulation and ocular estimates of utilization.