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A study was conducted on pastures grazed by sheep in late winter at the Desert Experimental Range in southwest Utah. Estimates of plant cover and herbage production were obtained in 1977 and used to examine longterm trends in the vegetation. The nutritional value of the six most important species of the area was assessed by chemical analysis. In addition, a management strategy was developed for obtaining some utilization of the range during the spring and summer months without affecting the traditional winter use by sheep. Long-term records (since 1937) in cover suggest a modest increase in grasses and a decrease in shrub cover. But there are insufficient data to infer range condition and trend. Long-term herbage production data (since 1938) show a substantial increase in annual species over the last twenty years. The year-to-year variability is very high, apparently depending on the prevailing climate conditions. Grass production was less variable than shrub production. No significant difference (P<.05) in crude protein content was found between shrubs and grasses from April to September, which contrasts with the later decline in nutritive value of grasses during the winter. Phosphorus content was significantly higher in shrubs than in grasses, but the high lignin content of shrub forage made its digestibility significantly lower than for grasses. Based on the nutritional analysis of forage and long-term records of climate and plant production, a management strategy was devised to make more efficient use of the salt-desert shrub vegetation. Climatic conditions will favor good forage production about four years out of ten. Perennial grasses, annuals, and winterfat (Ceratoides lanata) showed better response to favorable climatic conditions than the other species. It is proposed in this study that, in these years of high production, the range could be used by cattle in the spring or summer, and thereby al low occasional resting of mountain summer pastures. Such opportunistic summer grazing on the desert should not be detrimental to winter sheep grazing, but the plan would need to be field-tested on an experimental or trial basis to evaluate ecological responses to increased livestock use.

Differentials between rancher costs of operating on private and public range were studied in an attempt to define market areas for livestock grazing in western United States. The problem of defining market areas is basically a problem of grouping differentials between rancher costs of grazing on private leased range and National Forests that are reasonably homogeneous and statistically testing differences among means of the different groups. Several methods were used to group forests with reasonably uniform differentials into market areas for cattle. A grouping of forests which have the same ave rage grazing fee does not, however, yield market areas which are statistically different from each other.

Orientador: Rogério Teixeira de Faria / Banca: Fernando Campos Mendonça / Banca: Antonio Sérgio Ferraudo / Banca: Gilmar Oliveira Santos / Banca: Abmael da Silva Cardoso / Resumo: Em manejo de pastejo intensivo de forragens tropicas dispendem-se níveis de trabalho e recursos elevados para se aumentar a produtividade por área e ou por animal. Dentre as estratégias de manejo, destaca-se a frequência de corte por altura do dossel, que estimula maior produção de folhas do que colmo e material morto para obtenção de maior produtividade e valor nutritivo da forragem. Outra estratégia é a adubação nitrogenada, que possibilita o crescimento vegetal mais rápido, além de forragem de melhor qualidade. As águas residuárias são promissoras para uso em pastagens, na forma de fertirrigação, pois pode suprir as necessidades hídrica e nutricional do cultivo em parte ou na sua totalidade. Devido às limitações climáticas ao longo do ano, a efetividade dessas estratégias pode ser comprometida, o que resulta a sazonalidade de produção. Há carência de estudos sobre a interação das estratégias de manejo de fertirrigação com água residuária e de colheita da forragem com diferentes alturas de corte para as forrageiras tropicais. Os objetivos deste trabalho foi determinar a produtividade e o valor nutritivo da forragem, e as características morfogênicas e estruturais de Urochloa brizantha, em função da fertirrigação com efluente de estação de tratamento de esgoto (EETE), complementada com ureia (U), associada à colheita com duas alturas de plantas, durante os períodos seco (PS) e chuvoso (PC). O experimento foi conduzido em Jaboticabal, SP (Latitude 21º15'S, Longitude 48º18'W),... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In tropical forages under intensive grazing management, high labor and resources are used to increase productivity per area and / or animal units. Among the management strategies, the frequency of harvesting by canopy height is advantageous because it stimulates more leaf production than stalk and dead material to obtain high productivity and forage nutritive value. Another strategy is nitrogen fertilization, which enables faster plant growth, in addition to better forage quality. Wastewater is promising for use in pasture in the form of fertigation, since it can meet the water and nutritional needs of the crop in part or in its entirety. Due to climatic limitations throughout the year, the effectiveness of these strategies can be compromised, resulting in seasonality of production. There is a lack of studies on the interaction of fertigation management strategies with wastewater and forage harvesting with different cutting heights for tropical forages. The objectives of this work were to determine the productivity and nutritive value of forage, and the morphogenic and structural characteristics of Urochloa brizantha, as a function of fertigation with treated sewage (TSW), complemented with urea (U), associated with harvest at two plant heights during the dry (DP) and rainy (RP) periods. The experiment was conducted in Jaboticabal, SP, Brazil (Latitude 21º15'S, Longitude 48º18'W), from february, 2015 to february, 2017. The management strategies for forage harvesting heights w... (Complete abstract click electronic access below) / Doutor

Grazing trials were conducted in west-central Utah in August and November, 1983. Sheep were stocked in 0.06 hectare paddocks containing a homogeneous stand of the shrub big sagebrush (Artemisia tridentata subsptridentata). Stocking rate was 1344 animal-unit-days per hectare. Close observation was made of plants and plant parts of the sagebrush that the sheep consumed or refused to consume. Similar samples were hand-harvested from browsed and rejected plants and plant parts. These samples were later analyzed in the laboratory for monoterpenoid content, crude protein levels and digestible organic matter. There was large variability of monoterpenoid concentrations from plant to plant ranging from 0.06% to 0.63% dry matter basis among the browsed plants and from 0.30% to 1.80% among the rejected . Sheep consumed those plants and plant parts that were relatively lower in monoterpenoid content. They did not select for the proximate constituents (crude protein and digestible organic matter) of the whole plant or plant parts. The rejected plants and plant parts were generally higher in bach monoterpenoids and proximate constituents than were the corresponding browsed plants and plant parts. Seasonal effects were important on the composition of entire diets selected by the free grazing sheep. From observation, sheep consumed more sagebrush in autumn than they did in summer. Samples collected from esophageally fistulated sheep showed crude protein content to be significantly (P = O.OS) higher in autumn than in summer. As sheep shifted the ir dietary select i on from annual grasses to big sagebrush , genera l ly upward trend in dietary crude protein was observed during both seasons . In vitro organic matter digestibilities (IVO MD ) were generally low due to the nature of plant parts consumed by the sheep, i.e., they consumed growth from the previous year. Feeding station intervals (FSI) , the time spent per feeding station, were measured . A feeding station is the amount of forage available to a grazing animal when its forefeet are stationary. As sheep shifted their dietary selection to sagebrush, FSI increased significantly. Apparently shrubs offered relatively larger amounts of forage to select from than herbaceous vegetation call ing for more time per feeding station.

Phragmites australis is a plant that is causing problems in wetlands by outcompeting native plants that provide food and shelter for millions of migratory birds. Currently, managers try to control Phragmites australis by spraying herbicide, burning, and mowing, but these methods are costly, time consuming, and have low levels of success. Adding grazing as a tool to control Phragmites australis provides a cheap and low labor alternative. However, there are many concerns regarding if grazing will cause nutrient loading in our wetlands that will decrease water quality and alter beneficial functions of wetlands. To better understand the effects of grazing in wetlands, we proposed a two-year study and received funding from many organizations including the Utah Department of Fire, Forestry, and State Lands, South Davis Sewer District, and the Utah Department of Environmental Quality and Water Quality. Also, the Utah Department of Natural Resources helped tremendously in allowing access to the sites, in the actual implementation of the project, coordinating with local ranchers who allowed for their cattle to be in the study, managed their cattle during the study, and assisted with fence installation, and many volunteers from Utah dedicated hunters helped with the fence installation. We collected water, manure, soil, and leaf samples over time to analyze nutrient changes and measured changes in the plants, water levels, soil cover, and litter cover over time. We then compiled and analyzed this information to better understand how grazing impacts our wetlands. As a result, we were able to make some recommendations for future research and how best to graze in wetlands with minimal impacts according to the information we found.

Dyers woad (Isatis tinctoria L.) is a noxious weed on northern Utah rangelands. Chemical and mechanical means of control are unsuitable for rangelands. A potential alternative, biological control, is difficult due to a lack of basic ecological information. To remedy this, some aspects of the population biology and autecolgy of dyers woad were studied. The feasibility of controlling dyers woad by early spring grazing was also investigated via clipping experiments. A population study followed the survivorship of experimentally established populations over two years. Fall germinating individuals (1984) overwintered as rosettes twice and all survivors reproduced successfully. Spring germinating individuals (1985) overwintered as rosettes only once and 87% seeded the subsequent spring. Thus, on a good condition {high seral) foothill rangeland, dyers woad behaved predominantly as a biennial. Peak mortality in both fall and spring populations coincided with summer drought. The population size of dyers woad was constricted at two stages: (i) germination and establishment, and (ii) young rosette. The risk of mortality mortality in young rosettes was 77%. Dyers woad should be targeted for biological control at this vulnerable stage of growth. The seed dispersal pattern of dyers woad was best described by a negative exponential model of the type logy= a+ bx; (r = .78, a= 1.92, and b = -0.02). Ninety-five percent of a11 fruits were deposited within 54cm of mother plants. The root system of dyers woad was predominantly a taproot with some lateral sin the upper 30cm of the soil. There was little difference between mapped taproot and total mapped root lengths of rosette and mature plants. Significant mortality and reduction in reproductive performance occurred only by clipping, on or after 23 May 1984, at 60% or 90% intensity. Clipping twice, at either intensity, before 23 May had no effect on dyers woad. Sheep utilization of dyers woad ceased after mid-May, and had no significant effect on its mortality, percent flowering, and fruit production. Sheep grazing on dyers woad did not occur when much impact on mortality or seed production could be expected. The stocking re qui red to restrict dyers woad will result in range deterioration. More host-specific biological control agents should be tried.

Rangelands in Jordan are deteriorated due to a combination of harsh environmental conditions and human misuse. Jordan is importing increasingly large quantities of meat and animal products to meet the demand from its growing population. Sheep are supplementaQ ly fed during the dry season and large quantities of grain supplements are imported every year. Significant success has been attained in the establishment of Atriplex nummularia lindl. (ATNU) in Jordan. There is, however, a general lack of adequate research to determine if ATNU is effectively utilized by local sheep, to what extent it is utilized and to what extent it tolerates grazing. The objectives of this research were to determine the effects of grazing ATNU at two intensities (moderate and heavy) on subsequent production of ATNU browse, and on sheep live weight. Results of this research showed that HNU shrubs are grazing tolerant, they are stimulated by grazing to produce more forage than the non-grazed shrubs. When heavily grazed in the fall, they showed greater compensatory growth than moderately grazed shrubs, but the moderately grazed shrubs gave sustained production better than those heavily grazed in both good and bad years. Sheep grazing ATNU shrubs with native forage (grasses and forbs) in the fall gained more weight at the moderately grazed treatments. The amount of sheep-live-weight gain was positively affected by the amount of food intake per sheep metabolic body weight and inversely affected by the percentage of ATNU browse in the diet. ATNU although less preferred by sheep than grasses and forbs, could probably be used up to 40% of the diet and still maintain sheep live weight. ATNU is a good source of forage especially during the dry season, it provides (with native grasses and forbs) a high-quality forage and may considerably reduce the amount of costly supplements imported to Jordan.

Contamination of freshwater systems by nutrients has been studied extensively in the eastern U.S. Little research on the fate of nutrients in grazing conditions has been done in the western U.S. Western agriculture is often irrigated and research addressing the potential for leaching under these conditions is warranted. This study used Management Intensive Grazing (MIG) and eight grass-legume mixtures to evaluate the management and forage choice in relation to nitrogen and phosphorus leaching to ground water. Soil water samples were taken weekly through the growing season from 2001 through 2003. Water samples were analyzed for nitrate, ammonia, and phosphate. Soils were described and a textural discontinuity was discovered in two of the six soil profiles described. Data were analyzed by treatment, grass, legume, and soils by treatment. Three-year nitrate-N means were found to be in a range of 4.50 to 48.10 and 2.11 to 49.5 mg NO3 - -N L-1, at 60 cm and 90 cm, respectively. The amount of leaching depended on the grass-legume mixture as well as the soil characteristics. Significant differences were found between grasses (P=0.0001) with tall fescue leaching the least and orchardgrass leaching the most. Differences in leaching under legumes were also found to be significant (P=0.001), with white clover always leaching more than birdsfoot trefoil when significant differences were observed. Ammonia leaching was nonsignificant at a studywide analysis. Phosphorus treatment concentrations ranged from 0.025 to 0.41 mg PO4- -P L-1 and were significantly different (P=0.001). A comparison by grass type indicated that perennial ryegrass leached significantly higher concentrations of P (P=0.01) at 60 cm than the other grasses, but found no difference at 90 cm. No significant differences were found between legumes at either depth. Leaching of P was less affected by the soil textural discontinuity than nitrogen leaching. Soil differences affect leaching in varying degrees. Nitrate was affected most strongly by soil differences. These differences were more strongly evident at 60 cm than 90 cm. Soils affected phosphorus leaching differently than nitrate, and were more strongly affected at 90 cm than at 60 cm. Ammonia was not affected by soil characteristics.

The objectives of this study were to 1) determine the effects of livestock grazing and periods of rest from grazing on infiltration and erosion rates of unchained woodland; chained, debris-in-place; and chained, debris-windrowed pinyon-juniper sites; and 2) utilize these measurements in developing guidelines for grazing management of pinyonjuniper rangelands that protect or improve the hydrologic condition of the watershed. The study was conducted on sandy loam soils in southeastern Utah during the summers of 1971 and 1972. Runoff and erosion were artificially induced from small plots by simulating rainfall with the Rocky Mountain infiltrometer. Infiltration rates, erosion rates, and selected vegetative and edaphic parameters were measured on each plot. Forage removal by clipping and soil compaction subtreatments were applied to randomly selected plots in an effort to simulate the forage removal and trampling activities of livestock. Analysis of variance techniques were used to determine the effect on infiltration and erosion rates of forage removal and soil compaction subtreatment, grazing and varying periods of rest from grazing, and chaining treatments with similar grazing histories. Multiple regression techniques were used to evaluate the influence of vegetative and edaphic factors on infiltration and erosion. Forage removal and soil compaction subtreatments had no consistent effect on infiltration rates. However, the clipping and compaction subtreatments were an instantaneous application of forage removal and soil pressure and thus may not adequately represent long term, accumulative conditions imposed by actual grazing. Areas rested from livestock grazing since 1967 had significantly higher infiltration rates than grazed areas on unchained woodland and chained, debris-in-place sites. Grazed plots consistently had the lowest infiltration rates although this lower rate was not significantly different from infiltration rates measured on areas protected from grazing since 1969 or 1971. Grazing did not consistently affect infiltration measured on chained, debris-windrowed sites. Infiltration rates increased on all three vegetative conditions as the period of rest from grazing increased. None of the 21 soil and vegetative variables included in this study were identified by multiple regression models as consistently explaining significant amounts of variation in infiltration rates. Results of this study indicate that the primary value of multiple regression models is not to predict changes that will occur in infiltration because one management alternative is selected over another, but to help explain significant differences measured between treatments. Erosion rates were not significantly affected by forage removal subtreatments, but a trend indicates that erosion increases on plots when above ground vegetation is removed by clipping. No consistent relationship between -erosion rates and soil compaction subtreatments was found. A trend toward increased erosion rates on grazed areas was found. No consistent relationship between erosion rates and the various periods of rest from grazing was recorded. Thus, any rest from grazing appears to reduce the erosion potential from pinyonjuniper sites. In summary, pinyon-juniper rangelands can be improved for livestock by chaining and seeding without causing a deterioration in watershed condition. However, to achieve these objectives, the sites to be treated must be carefully evaluated and the appropriate chaining, plant debris disposal, and seeding techniques identified. And following vegetative conversion, the areas must be properly grazed.