Shortgrass Rangeland Research Articles

Airborne environmental DNA metabarcoding detects more diversity, with less sampling effort, than a traditional plant community survey

BackgroundAirborne environmental DNA (eDNA) research is an emerging field that focuses on the detection of species from their genetic remnants in the air. The majority of studies into airborne eDNA of plants has until now either focused on single species detection, specifically only pollen, or human health impacts, with no previous studies surveying an entire plant community through metabarcoding. We therefore conducted an airborne eDNA metabarcoding survey and compared the results to a traditional plant community survey.ResultsOver the course of a year, we conducted two traditional transect-based visual plant surveys alongside an airborne eDNA sampling campaign on a short-grass rangeland. We found that airborne eDNA detected more species than the traditional surveying method, although the types of species detected varied based on the method used. Airborne eDNA detected more grasses and forbs with less showy flowers, while the traditional method detected fewer grasses but also detected rarer forbs with large showy flowers. Additionally, we found the airborne eDNA metabarcoding survey required less sampling effort in terms of the time needed to conduct a survey and was able to detect more invasive species than the traditional method.ConclusionsOverall, we have demonstrated that airborne eDNA can act as a sensitive and efficient plant community surveying method. Airborne eDNA surveillance has the potential to revolutionize the way plant communities are monitored in general, track changes in plant communities due to climate change and disturbances, and assist with the monitoring of invasive and endangered species.

Land use change and collaborative manureshed management in New Mexico.

Agricultural communities of New Mexico regularly redistribute manure nutrients from dairies to nearby croplands to fulfill agronomic nutrient needs and protect water quality. Yet competition for water resources can result in land use change that affects these cooperative manure transfers. Focusing on three clusters of New Mexico dairy farms and their surrounding lands (three manuresheds), we calculated the magnitude of land use changes in 2008-2019 and the balance between manure nutrient supply and crop demand in 2019 to assess how past change may predict future prospects for sustainable management. The overall magnitude of change was small, with each manureshed experiencing a different complement: an exchange of cropland and rangeland in the Roosevelt manureshed (7,975ha rangeland to cropland; 7,624ha cropland to rangeland), a 464-ha gain in cropland but a 1,187-ha loss of "spreadable" land (cropland, rangeland, fallow) to developed land in the Doña Ana manureshed, and relatively minor changes in the Chaves manureshed. Nutrient supply and demand were mainly in balance, but a surplus of manure phosphorus (P) in the Chaves manureshed and a thin margin of P assimilation by croplands in the Roosevelt manureshed point to the need for preserving existing croplands and understanding of effects of dairy manure on shortgrass rangeland. Our assessment suggests that an ideal scenario would entail manure being generated in landscapes with portfolios of productive lands that can sustainably use the manure nutrients to minimize environmental quality concerns and agronomic tradeoffs. Coordinated, participatory, and interdisciplinary research and planning are needed.

Potential Consequences of Repeated Severe Drought for Shortgrass Steppe Species

Future climate projections indicate temperatures in the shortgrass steppe region are likely to increase up to 3°C by midcentury, with a corresponding reduction in soil moisture even without precipitation deficit. Although periodic drought is a natural disturbance in shortgrass rangeland, negative effects on characteristic shortgrass species are possible as the frequency and severity of drought events increase in comparison with recent historic norms. As part of a study intended to detect vegetation changes at a shortgrass steppe site on Colorado’s eastern plains, frequency and canopy cover percentage were measured in 37 permanently marked plots over a period of 17 yr. The study period included the two lowest total annual precipitation yr (2002 and 2012) in the period of record for regional weather stations, exceeding even the driest years of the extended 1930s drought. Growing season mean temperatures during those drought years were 1°C and 1.6°C above the 1971−2000 average, respectively. Three of the six perennial grass species monitored showed a decline over the period of the study. Blue grama (Bouteloua gracilis), a dominant and important forage species in the shortgrass steppe, declined in both cover and frequency, while alkali sacaton (Sporobolus airoides), not an important forage species, slightly increased. In addition to changes in graminoid dominance, we observed an increase in cholla (Cylindropuntia imbricata) and a decrease in sandsage (Artemisia filifolia) densities between 1999 and 2015. Even if total productivity of the shortgrass steppe is maintained under warming and drying conditions, changes in species composition have implications for rangeland quality with regard to its use for livestock grazing and use by wildlife such as small mammals and songbirds.

Animal finishing-phase response to modified intensive-early stocking on shortgrass rangeland

ABSTRACT A comparison of animal performance and carcass traits was made from 2002 to 2008 following the finishing phase of a continuous season-long stocking (SLS) system and a modified intensive-early stocking system with late-season grazing (IES 1.6× + 1) on shortgrass native rangeland of western Kansas. The continuous season-long stocked system placed animals at a density of 1.37 ha per steer from May through October, or 2.63 animal unit months/ha, whereas the intensive-early stocked system with late-season grazing (3.33 animal unit months/ha) stocked pastures at 0.85 ha per steer from May through the middle of July, moved the heaviest animals mid-July to the feedlot, and then stocked pastures at 1.37 ha per steer until October. Animals moved from pasture to the feedlot in July and October from the modified IES 1.6× + 1 stocking system were approximately 27.3 kg per steer lighter than the continuous SLS animals entering the feedlot from pasture in October. This greater BW entering the feedlot carried over into greater HCW at the end of the feeding period for the continuous SLS animals. Average daily gain, total individual BW gain, and feed efficiency were similar among groups at the end of the feedlot finishing phase. Marbling score was greatest for the continuous SLS animals, but fat thickness over the 12th rib was similar among groups. Differences between groups during the feedlot finishing phase appeared to be related more to size of animals when removed from pasture and duration on pasture more than any other factors.

Spatial Redistribution of Nitrogen by Cattle in Semiarid Rangeland

Nitrogen (N) availability can strongly influence forage quality and the capacity for semiarid rangelands to respond to increasing atmospheric CO2. Although many pathways of nitrogen input and loss from rangelands have been carefully quantified, cattle-mediated N losses are often poorly understood. We used measurements of cattle N consumption rate, weight gains, and spatial distribution in shortgrass rangeland of northeastern Colorado to evaluate the influence of cattle on rangeland N balance. Specifically, we estimated annual rates of N loss via cattle weight gains and spatial redistribution of N into pasture corners and areas near water tanks, and used previous studies to calculate ammonia volatilization from urine patches. Using measurements of plant biomass and N content inside and outside grazing cages over 13yr, we estimate that cattle stocked at 0.65 animal unit months (AUM) · ha−1 consumed 3.34kg N · ha−1 · yr−1. Using an independent animal-based method, we estimate that cattle consumed 3.58kg N · ha−1 · yr−1 for the same stocking rate and years. A global positioning system tracking study revealed that cattle spent an average of 27% of their time in pasture corners or adjacent to water tanks, even though these areas represented only 2.5% of pasture area. Based on these measurements, we estimate that cattle stocked at 0.65 AUM · ha−1 during the summer can remove 0.60kg N · ha−1 in cattle biomass gain and spatially redistribute 0.73kg N · ha−1 to areas near corners and water tanks. An additional 0.17kg N · ha−1 can be lost as NH3 volatilization from urine patches. Cumulatively, these cattle-mediated pathways (1.50kg N · ha−1) may explain the imbalance between current estimates of atmospheric inputs and trace gas losses. While NOx emission remains the largest pathway of N loss, spatial N redistribution by cattle and N removed in cattle biomass are the second and third largest losses, respectively. Management of cattle-mediated N fluxes should be recognized as one means to influence long-term sustainability of semiarid rangelands.

Effects of a New Herbicide (Aminocyclopyrachlor) on Buffalograss and Forbs in Shortgrass Prairie

Herbicides used to control many forb species in pastures may injure desirable native grass species. Buffalograss, a major component of shortgrass rangeland, often is injured by some growth regulator herbicides, such as 2,4-D and dicamba. Aminocyclopyrachlor (formerly known as DPX-MAT28 and herein termed ACPCR), a new synthetic auxin herbicide chemistry for control of broadleaf weeds, was investigated for injury to buffalograss and control of forbs in shortgrass prairie at varying rates of application. In the season of application, ACPCR at rates of 140 g ai ha−1or less caused buffalograss injury that was either negligible or short-lived, and visual estimates of grass injury were 8% or less at the end of the growing season. At ACPCR rates of 280 g ha−1, more injury was evident at 3 wk after treatment (WAT) than at the end of the season if adequate precipitation was available for new leaf growth. When precipitation was lacking, evidence of injury persisted through to the end of the season when treated at the greatest rate of ACPCR. Buffalograss injury was mainly in the form of browned leaf tips, but total buffalograss dry matter yield was not different between any treatments in either year. The year after treatment, no buffalograss injury was evident from any of the herbicide rates. Final forb control was 97% or greater each year for ACPCR at the 140 and 280 g ha−1rates. In this experiment, rates as low as ACPCR at 140 g ha−1provided excellent forb control and maintained buffalograss productivity.

Animal and Vegetation Response to Modified Intensive–Early Stocking on Shortgrass Rangeland

Abstract A comparison of animal gains and vegetation trends was made from 2002–2008 between a continuous season-long stocking (SLS) system and a modified intensive–early stocking system (IES) with late-season grazing (IES 1.6× + 1; 1.6 times the number of animals of the SLS system from May 1 to July 15, and 1 times the number of animals of SLS from July 15 to October 1) on shortgrass native rangeland of western Kansas. The continuous season-long stocked system placed animals at a density of 1.37 ha · steer −1 from May through October, or 2.63 animal unit months (AUM) · ha −1 , whereas the intensive–early stocked system with late-season grazing (3.33 AUM · ha −1 ) stocked pastures at 0.85 ha · steer −1 from May through the middle of July, and then stocked pastures at 1.37 ha · steer −1 for the remainder of the grazing season by removing the heaviest animals mid-July each yr. Average daily gains (0.78 vs. 0.70 kg · d −1 , P = 0.039) and total animal gain (58 vs. 52 kg, P = 0.042) were different between the continuous season-long stocked and the intensive–early stocked animals during the first half of the grazing season. No difference was found between average daily gain (0.61 vs. 0.62 kg · d −1 , P = 0.726) and total animal gain (48 vs. 49 kg, P = 0.711) for the continuous season-long stocked and intensive–early stocked with late-season grazing animals during the last half of the season. Total individual animal gain (106 vs. 101 kg, P = 0.154) and average daily gain (0.70 vs. 0.66 kg · d −1 , P = 0.152) was not different between the continuous season-long stocked and the intensive–early stocked system animals that were on pasture the entire grazing season. Total beef gain on a land-area basis (96 vs. 77 kg · ha −1 , P = 0.008) was greater for the modified intensive–early stocked system with late-season grazing with greater animal densities. Changes in residual biomass and most key vegetation components at the end of the grazing season were not different between the two systems.

Steer Nutritional Response to Intensive-Early Stocking on Shortgrass Rangeland

Steer nutritional response to vegetation conditions created by 4 grazing treatments was evaluated during the final 2 years (1987-88) of a 9-year grazing trial. Treatments were season-long stocking (treatment 1) at a moderate stocking rate and intensive-early stocking at 3 stocking rates: equal to season-long stocking by using twice as many steers for the first half of the season-long stocking grazing season (double-stocked-intensive-early stocking, treatment 2), and 2 rates greater than season-long stocking made by stocking at 2.5 or 3 times the stocking density or season-long stocking (2.5X- and triple-stocked-intensive-early stocking, treatments 3 and 4). Each treatment was replicated twice in a randomized-complete block. Three esophageally fistulated steers were placed in each pasture to collect diet samples for nutritional analyses, including crude protein and cell wall constituents. Total feces were collected from 3 steers in each pasture to estimate fecal output and calculate forage intake. Diet digestibility was estimated using alkaline-peroxide lignin as an internal marker. Three or 4 sampling periods were conducted during each grazing season. Herbage availability and dietary crude protein were similar among treatments in 1987, but both declined as stocking density increased in 1988. Cell wall constituents generally increased as stocking density increased in 1987, but were similar among treatments in 1988. Digestibility and forage intake were unaffected by grazing treatments in both years. Steer average daily gain declined as stocking density increased in both years. Seasonal changes in diet quality and forage intake reflected the precipitation pattern with improved nutrition whenever precipitation caused growth of the warm-season shortgrasses. Nutrient intake was reduced by stocking rates greater than that employed under season-long stocking, but was generally similar between season-long stocking and double-stocked-intensive-early stocking. DOI:10.2458/azu_jrm_v55i3_olson

Steer nutritional response to intensive-early stocking on shortgrass rangeland

Steer nutritional response to vegetation conditions created by 4 grazing treatments was evaluated during the final 2 years (1987-88) of a 9-year grazing trial. Treatments were season-long stocking (treatment 1) at a moderate stocking rate and intensive-early stocking at 3 stocking rates: equal to season-long stocking by using twice as many steers for the first half of the season-long stocking grazing season (double-stocked-intensive-early stocking, treatment 2), and 2 rates greater than season-long stocking made by stocking at 2.5 or 3 times the stocking density or season-long stocking (2.5X- and triple-stocked-intensive-early stocking, treatments 3 and 4). Each treatment was replicated twice in a randomized-complete block. Three esophageally fistulated steers were placed in each pasture to collect diet samples for nutritional analyses, including crude protein and cell wall constituents. Total feces were collected from 3 steers in each pasture to estimate fecal output and calculate forage intake. Diet digestibility was estimated using alkaline-peroxide lignin as an internal marker. Three or 4 sampling periods were conducted during each grazing season. Herbage availability and dietary crude protein were similar among treatments in 1987, but both declined as stocking density increased in 1988. Cell wall constituents generally increased as stocking density increased in 1987, but were similar among treatments in 1988. Digestibility and forage intake were unaffected by grazing treatments in both years. Steer average daily gain declined as stocking density increased in both years. Seasonal changes in diet quality and forage intake reflected the precipitation pattern with improved nutrition whenever precipitation caused growth of the warm-season shortgrasses. Nutrient intake was reduced by stocking rates greater than that employed under season-long stocking, but was generally similar between season-long stocking and double-stocked-intensive-early stocking.

Grazing Intensities, Vegetation, and Heifer Gains: 55 Years on Shortgrass

Shortgrass rangeland, dominated by blue grama (Bouteloua gracilis [H.B.K.] Lag. ex Steud), was grazed at 3 intensities, equivalent to mean stocking rates of 16.7, 23.0, and 36.5 heifer-days ha-1, from 1939 through 1994. Few changes in plant communities had been documented by the early 1970's. In 1992-1994, frequency of occurrence, basal and foliar cover, and biomass at peak standing crop (PSC) were determined on the remaining pasture at each grazing intensity, and on 3 ungrazed exclosures. Blue grama and buffalograss (Buchloe dactyloides [Nutt.] Engelm.) increased, and western wheatgrass (Pascopyrum smithii [Rydb.] A. Love) and needle-and-thread (Stipa comata Trin. R biomass was 4 to 6 times as high in the exclosures as under any grazing intensity. Heifer gains declined linearly with increasing grazing pressure index. Optimum (most profitable) stocking rate was about 20% higher than that under the moderate grazing intensity, under which biomass production was maintained and shrub and pricklypear remained at low levels. Returns to land, labor, and management were only slightly higher under the optimum stocking rate than under the moderate grazing intensity. The moderate grazing intensity appears to be both profitable and sustainable.

Feeding by a Native Grasshopper Reduces Broom Snakeweed Density and Biomass

Broom snakeweed [Gutierrezia sarothrae (Pursh) Britton and Rusby] destruction by 1, 3, or 5 snakeweed grasshoppers [Hesperotettix viridis (Thomas)] per plant was quantified and compared with forage gain the year of and the year after herbivory. Grasshoppers were caged (6.25m2 cages) in 1991 and 1992 over dense stands of broom snakeweed growing in association with shortgrass rangeland near Corona and Folsom, New Mexico. A significant negative relationship between grasshopper feeding pressure in each cage and broom snakeweed biomass was found. The dry weight of broom snakeweed herbage removed per grasshopper per day was 45 mg at Folsom and 85 mg at Corona. Feeding by grasshoppers stocked at 5 per plant killed 91% of the broom snakeweed resulting in a 75% reduction in biomass. Mortality varied between sites and years; however, 3 grasshoppers per plant killed about 69% of the broom snakeweed and reduced biomass by 61%. One grasshopper per plant killed 53% of the broom snakeweed and reduced biomass an average of 39%. In 1991, removal of most broom snakeweed by the high density of grasshoppers increased standing crop of grasses 23% at the end of the treatment year and 44% one year after treatment compared with grasshopper-free cages at the 2 sites. Feeding by low and medium densities of grasshoppers did not increase grass biomass in most situations. The increase in grass biomass only after grasshoppers removed most of the broom snakeweed is similar to the response observed from other methods of broom snakeweed removal such as band thinning, chemical control, and burning. Preferred host plants such as broom or threadleaf snakeweed must be present for specialist snakeweed grasshoppers to occur. However, if snakeweed grasshoppers are present, care should be taken to ensure their survival.

Milk yield and composition in first-cross and backcross beef cows

Milk yield and composition from three distinct milkings (spring, August, and fall) were evaluated on first-cross and backcross cows maintained under two contrasting environments. The dam crosses at Brandon (semi-intensive cultivated pasture management) were HA, SN, CN, ACA, CCA, ASA, SSA, HCH, CCH, HSH, SSH, NCN, CCN, NSN, and SSN with H = Hereford, A = Angus, N = Shorthorn, C = Charolais, S = Simmental and a SSA cross was 3/4 Simmental-1/4 Angus. At Manyberries (semi-arid and short grass rangeland) the dam crosses were HA, SN, ASA, SSA, HSH SSH, NSN, and SSN. All cows were bred to Limousin bulls and milkings took place from 1981 to 1985, inclusive. Definitive differences among the backcrosses and between the backcrosses and the F1 crosses were not present. Possible genotupe × environment interactins were observed for milk yield and composition. Milk yield and composition were affected by age of cow and influenced cow and calf weight changes. Key words: Beef cattle, crossbreeding, backcrosses, milk yield, milk composition

Mechanical Renovation of Shortgrass Prairie for Increased Herbage Production

A study to determine the effects of single ripping, double ripping, and contour furrowing treatments was conducted on shortgrass rangeland in southeastern Wyoming from 1979-1982. The mechanical treatments changed species composition and increased total forage production over the control. Western wheatgrass (Agropyron smithii Rydb.) exhibited increased production on the treated areas compared to the control. Blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Griffiths] production was significantly lower on the double ripping (1981 and 1982) and the contour furrow (1981) treatments than on the control. Needle-and-thread (Stipa comata Trin. & Rupr.) exhibited an increasing trend on the single and double ripping treatment over the control treatment all 4 years. Forbs also showed his trend in 1979, 1980 and 1981 on all renovation treatments, however little difference in forb production was evident in 1982. Total production differences were the greatest in the first year of renovation (1979) and in 1980 when the annual precipitation was below the long-term average. Increased livestock carrying capacities would result in payback of the renovation costs in 4 years. Numerous mechanical treatments have been used on rangeland during the past 40 years to increase herbage production on some range sites. The most commonly used mechanical treatments in the Great Plains are pitting, furrowing, and ripping. Ripping and contour furrowing can increase productivity by disturbing the native sod and shifting the botanical composition to more productive cool-season species (Branson et al. 1966, Rauzi 1975). Success of the mechanical treatments has varied depending on the degree of surface modification. Barnes (1948) found that more than 1.5 m spacing of furrows for interseeding did not significantly improve forage production. However, Barnes (1952) and Rauzi (1968) noted that spacing furrows no more than 0.6 m apart and about 10 to 20 cm deep was the most effective and profitable furrowing treatment. Rauzi (1975) stated moldboard-plow, disc plow, and rotovator treatments increased western wheatgrass (Agropyron smithii Rydb.) by pruning and redistributing the western wheatgrass rhizomes. To be effective on shortgrass rangeland a treatment should increase water infiltration and storage and reduce competition from unwanted vegetation to allow more desirable cool-season species to become established. Branson et al. (1966) found that the 2 most effective mechanical treatments in increasing forage production and water storage were contour furrowing at intervals of 0.9 to 1.5 m and depths of 20 to 25 cm, and broadbase furrowing, which consisted of low dikes about 0.5 m in height. They concluded that effective mechanical treatments modify the soil surface, not the subsoil, to increase retention and storage of precipitation. Wight and Siddoway (1972) and Neff and Wight (1977) found surface modification affects the amount of water available to the plants by preventing runoff, trapping snow, and reducing the number of plants competing for water. The effectiveness of a Authors are agricultural research technican, soil scientist, soil scientist (retired), USDA-ARS, High Plains Grasslands Research Station, 8408 Hildreth Road, Cheyenne, Wyo. 82009, respectively; and area range conservationist, Soil Conservation Service, Torrington, Wyo. 82240. Acknowledgement is given to D. Heyne, district conservationist, Soil Conscrvation Service, Cheyenne, Wyo., for his assistance in obtaining landowner cooperation and development of the project. Manuscript accepted May 3, 1984. specific surface treatment was dependent on range site and vegetation characteristics. Mechanical disturbances of native sod have also resulted in the release of plant nutrients through soil weathering and decomposition of organic matter (Wight and White 1974). They found that western wheatgrass quickly reinvaded disturbed areas and significantly increased total forage production. Changes in species composition resulting from surface modification can be relatively permanent. Wight and Siddoway (1972) noted that abandoned cultivated fields of the Northern Plains became dominated by needle-andthread (Stipa comata Trin. & Rupr.) and western wheatgrass, resulting in higher production than the contiguous undisturbed range. Estimations of surface modification longevity range from 15 to 25 years. Rauzi (1974) estimated longevity of range pitting in southeastern Wyoming to be about 15 years, depending on range site, climate, and management. Fisser et al. (1974) stated production on contour furrows would probably remain higher than the untreated native rangeland for at least 20 years. Wight and White ( 1974) estimated longevity of lister furrows and pits to be 15 and 25 years, respectively. The purpose of this study was to determine the effects of contour furrowing and ripping of shortgrass rangeland on herbage yields, botanical composition, and livestock carrying capacity.

Residual Effects of Phosphorus and High Rates of Nitrogen on Shortgrass Rangeland

Residual Effects of Phosphorus and High Rates of Nitrogen on Shortgrass Rangeland

The Microhistological Technique: Testing Two Central Assumptions in South-Central New Mexico

Analysis of the botanical content of diets of livestock, big game, small mammals, and insects has become common in research. The better known dietary analyses utilize either stomach, fecal or esophageal fistula samples. The respective advantages and disadvantages of these procedures have been recognized, and the use of a particular procedure is dictated by the type of study, subject animal, available facilities, time, manpower, and information desired. Methods for quantifying the diet sample obtained by an analytical procedure have been generalized as visual appraisal, manual separation, microhistological techniques, and microscope point techniques (I’heurer et al. 1976). Of these general categories, visual appraisal and manual separation are limited by the ability of the researcher to quantify individual species in the sample diet. Hence, these methods may contain large inherent personal errors. The microscope point techniques require statistical regression procedures, determination of species weight/volume relationships, and overestimation correction tactors. The microhistological techniques have become the most favored method. Sparks and Malechek (1968) have outlined the basic procedure for this method. However, its accuracy in determining dry-weight composition of masticated forage samples was not examined. The objective of this study was to examine two central assumptions of the microhistological technique and determine if these assumptions were satisfied when determining dry-weight composition of masticated forage samples from blue grama (Bouteloua grucilis) foothill mngeland. These assumptions were that percent frequency can be used to estimate particle density and the percent of identifiable material is constant for each species. Methods Samples were collected from esophageal-fistulated steers grazing native shortgrass rangeland in south-central New Mexico. The study area was located on the Fort Stanton Experimental Ranch. The blue grama-dominated rangeland has been described by Allison et al. ( 1977). Dietary sampling was conducted during 1975 and 1976. Three periods representing three different plant growth stages+arly summer, late summer, and mid winter-were selected for study. Handling and slide preparation of sample material as well as calculations for frequency, particle density, relative density, and percent dry-weight followed the procedure outlined by Sparks and Malechek (1968). Five slides were prepared for each sample period, and 20 systematically located fields were sampled for particle frequency and density on each slide to give 100 fields for each period. Reference material for all species present was collected during late summer. Reference slides, drawings, and photographs were utilized in identifying species within sample diets. When a particle observed in a field could not be identified, the slide was moved so that identification was improved by observing the entire particle.

High Rates of Nitrogen Change Composition of Shortgrass Rangeland in Southeastern Wyoming

High Rates of Nitrogen Change Composition of Shortgrass Rangeland in Southeastern Wyoming

Forage Losses Caused by the Grasshopper Aulocara elliotti on Shortgrass Rangeland

Highlight: A field-cage study was conducted in 1973 and 1974 to determine the amount of forage (mainly grasses) destroyed by different population densities of the grasshopper Aulocara elliotti. The amount offorage consumed during the third instar and through the adult stage averaged 34.5 mg offorage per grasshopper per day. Thus, an estimated loss of 23.1 lb offorage per acre will resultfrom a density of one Aulocara/m2 if the grasshopper lives for 75 days (45 days as a nymph and 30 days as an adult). Based on total available forage (standing dead and new growth), a 63% forage loss was recorded in 1973 at one site and losses of 26% and 29% at two sites in 1974 resulting from about 20 grasshoppers/iM2. Severe grazing by grasshoppers also resulted in reduced production offorage during the subsequent (1974) season.

Equipment for Harvesting Shortgrass Rangeland Plots

Equipment for Harvesting Shortgrass Rangeland Plots

Influence of Climatic Conditions on Forage Production of Shortgrass Rangeland

This study was initiated to determine the influence of climatic factors upon range forage production, which in turn determines the production of livestock on the range. By determining the relationships that exist between certain climatic conditions and forage yield, it may be possible to make accurate forecasts on the productivity of the range. Such forecasting could aid in developing good management practices in relation to proper grazing of native rangelands.