• Comparing techniques for determining steer diets in northern Chihuahuan Desert

      Mofareh, M. M.; Beck, R. F.; Schneberger, A. G. (Society for Range Management, 1997-01-01)
      Diets determined by bite count and microhistological analysis of esophageal extrusa and feces were compared for steers grazing on grass-shrublands in the northern Chihuahuan Desert. The study was conducted on the Chihuahuan Desert Rangeland Research Center near Las Cruces, New Mexico. The purpose was to determine the similarity of 3 dietary techniques on arid, heterogeneous rangeland. It was proposed that the number of bites of each species eaten was directly proportional to the weight eaten as determined by the 2 microhistological techniques. Samples of diets were collected in 4 seasons from 2 steers grazing in a continuous yearlong pasture and in season-long rotation pastures. The 3 dietary techniques did not give similar (P<0.10) estimates of the diets eaten by the steers. Mean similarity indices were highest (77%) comparing diets from analysis of esophageal and fecal material. Lowest mean similarity indices (57%) were from comparing diets from bite count and fecal analysis. Much of the discrepancy between techniques was because of different size plants being eaten and heterogeneity of plant distribution. An importance ranking of dietary species using the 3 techniques showed that the top 3 species comprised over 68% of the total diets. Any of the 3 techniques can be used to determine the common species in the diets which may be all that is necessary for some management and analysis needs.
    • Comparison of techniques for determining the nutritional carrying capacity for white-tailed deer

      McCall, T. C.; Brown, R. D.; Bender, L. C. (Society for Range Management, 1997-01-01)
      Estimates of carrying capacity for herbivores are useful for determining the relative value of different ranges. We compared 6 estimates of nutritional carrying capacity for white-tailed deer (Odocoileus virginianus L.): digestible energy consumed by tame deer, and 5 methods using forage supplies of dry matter, digestible energy, digestible nitrogen, dry matter*digestible energy, and dry matter*digestible nitrogen in two 1-ha enclosures of different shrub plant communities in southern Texas. For the north enclosure, carrying capacity estimates (90% CI) were 3.65 (CI = 3.61-3.69), 4.5 (CI = 3.7-5.3), 9.4 (Cl = 73-11.5), 15.2 (CI = 11.6-18.8), 3.5 (CI = 2.7-4.3), and 3.5 (CI = 2.7-4.3) deer ha-1 58 days-1 for the digestible energy tame deer, dry matter, digestible energy, digestible nitrogen, dry matter*digestible energy, and dry matter*digestible nitrogen techniques, respectively. Corresponding estimates for the south enclosure were 2.6 (CI = 2.5-2.7), 3.5 (CI = 3.2-3.9), 6.8 (CI = 6.0-7.6), 10.1 (CI = 8.8-11.3), 2.1 (CI = 1.8-2.6), and 2.8 (CI = 2.4-3.1). Some methods for estimating carrying capacity provided different absolute estimates, but all produced similar relative estimates between enclosures. Similar relative results between enclosures suggests any of the methods can be used to determine the relative nutritional quality of plant communities. However, the dry matter-based technique was less expensive than the other techniques; therefore, there is no need to use more costly techniques for determining the relative stocking rates for white-tailed deer, unless forage quality differs greatly among plant communities.
    • Determination of animal behavior-environment relationships by Correspondence Analysis

      De Miguel, J. M.; Rodriguez, M. A.; Gomez-Sal, A. (Society for Range Management, 1997-01-01)
      The paper describes an analytical procedure to preliminarily investigate large scale animal-environment interactions. The method is based on Correspondence Analysis applied over a contingency table in which the columns are percentage categories of animal activities and the rows, states of environmental variables. Each cell entry in the table represents the number of times a row and a column have been recorded together. This means that investigation of animal-environment interactions does not require defining specific sampling stations, or subdividing the study area into environmental units; i.e. the method can be used in studies in which sampling consisted of following the animals and noting their activities and characteristics of the environment. The graphical display resulting from the analysis shows the main patterns of association between animal activities and environment, and its numerical output allows one to identify the variables that have played a major role in the display. Taking into account these variables and their associated animal activities, the method allows one to define archetypal habitat models for each animal activity. Correspondence Analysis of animal activities by environmental variable matrices may give insights about animal's perception of the environment. The use of the method is illustrated by analyzing habitat preferences of free-ranging cattle during 2 different seasons on an estate in Spain. Results indicate the validity of the method as a first global analysis of the relative importance of environmental variables for the distribution of the animal activities in the landscape.
    • Development and vigor of diploid and tetraploid Russian wildrye seedlings

      Berdahl, J. D.; Ries, R. E. (Society for Range Management, 1997-01-01)
      Poor seedling vigor limits the use of Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski] for complementary pasture. Tetraploid (2n=4x=28) plants of Russian wildrye have greater seedling vigor in greenhouse studies when compared to plants with the normal diploid chromosome complement (2n=2x=14). Objectives of this research were (i) to compare seedling emergence and development of diploid and tetraploid Russian wildrye in solid-seeded, single-row field plots and (ii) to document early seedling development and morphology in a controlled environment chamber. Seed mass averaged 2.70 mg seed(-1) for diploids and 4.66 mg seed(-1) for tetraploids. Initial seedling emergence averaged approximately 33% greater for tetraploids than diploids for both early and late field planting dates. Tiller number averaged only slightly, and generally not significantly, greater for diploids than tetraploids (maximum difference of 0.3 tillers plant(-1)) in solid-seeded rows in the field. Seedling height was consistently greater for tetraploids than diploids, a result of greater leaf length. Larger leaf size did not result in fewer leaves or in slower leaf development for tetraploids. Seedling emergence from a 63 mm depth in a controlled environment chamber averaged 46% for tetraploids and 10% for diploids at a 16/13 degrees C diurnal temperature regime and 11 and 6%, respectively, for tetraploids and diploids at a 23/18 degrees C temperature regime. Coleoptile length averaged 61 mm for tetraploids and 49 mm for diploids at the 16/13 degrees C temperature regime and 42 and 43 mm for tetraploids and diploids, respectively, at the 23/18 degrees C temperature regime. Tetraploid Russian wildrye provides a unique germplasm pool from which additional improvement in seedling vigor can be accomplished beyond the limits that are possible from continued selection in diploid germplasm.
    • Phosphorus supplementation of range cows in the Northern Great Plains

      Karn, J. F. (Society for Range Management, 1997-01-01)
      Low phosphorus (P) levels in Northern Great Plains rangeland forage combined with limited data on the P requirements of range cows (Bos taurus), precipitated 2 studies conducted to compare the performance of P supplemented and no P supplemented (control) beef cows. Phosphorus supplementation levels ranged from 4 to 8 g day-1 depending on estimated P needs at different times of the year. The 2 groups of cows previously had been involved in replacement heifer growing studies, with P treatments established 462 and 402 days, respectively, before initiation of these studies. Winter feed consisted of mixed hay, primarily smooth bromegrass (Bromus inermis Leyss.), with corn silage (Zea mays L.) fed only in 1982 and 1983 from calving to the time cows were turned on summer pasture. Summer pastures contained primarily western wheatgrass [Pascopyrum smithii (Rydb.) A. Love], needleandthread (Stipa comata Trin. and Rupr.), green needlegrass (S. viridula Trin.), blue grama [Bouteloua Gracilis (H.B.K.) Griffiths] and upland sedges (Carex spp.). The P status of cows used in these studies appeared to be estimated more reliably by forage P than by serum or fecal P. According to P levels in hay and pasture, the diets of control cows were below recommended P levels for about 9 months of the year. However, weight change differences between P supplemented and control cows during the first lactation and gestation periods were gradually lost by the end of the studies. Conception rates of control cows were slightly lower (P<0.08) in the first but not the second study. There were no differences in average calving date or calf birth weights, but P supplementationndid increase (P<0.01) calf weaning weights. Cow weight changes, calf weaning weight differences, forage and serum P data, and in the first study conception rate differences indicate that Northern Great Plains forages are marginal to deficient in P for optimal production of beef cows. The most consistent benefit from P supplementation was an increase in calf weaning weights. Data also indicate that energy supplementation for 30 days after calving may increase conception rates.
    • Seedlings dynamics of Festuca spp. in a grassland of Patagonia, Argentina, as affected by competition, microsites, and grazing

      Defossé, G. E.; Robberecht, R.; Bertiller, M. B. (Society for Range Management, 1997-01-01)
      The effects of competition, grazing, and microsites on seedling dynamics of Festuca spp. were investigated in a semiarid steppe of Patagonia, Argentina. In an exclosure and an adjacent grazed area, the level of root competition for seedlings was controlled through root exclusion tubes (0.1 m diameter, 0.4 m long) installed adjacent to 7 similarly-sized Festuca pallescens plants and in the interspace between F. pallescens plants. Seedling dynamics at the phenological stages of a) recently emerged and up to 4 leaves and b) 5 leaves and up to 1 tiller were followed inside the tube area (no competition) and in paired circles (competition) for approximately 3 growing seasons. Peak density of Festuca spp. seedlings occurred in fall and early spring, when water content in the first 0 to 5 cm of the soil was above 8%. Seedling densities of Festuca spp. at the 2 phenological stages were significantly reduced by grazing. At the phenological stage of 1 to 4 leaves, seedlings were not affected by root competition, although their densities were significantly higher for seedlings adjacent to F. pallescens plants than in the interspace between plants. This was due to higher soil water content in these areas throughout the season in the 0 to 5 cm of the soil. Seedling densities at the phenological stage of 5 leaves and up to 1 tiller were significantly higher when there was no competition from neighboring grass plants as compared to seedlings exposed to competition. In regard to microsite differences, seedling density was significantly greater in the interspaces than adjacent to mature plants. These results suggest that although higher seedling densities can be obtained by excluding the area from grazing, intraspecific competition for soil water during the summer drought period can act as a barrier for further Festuca spp. seedling establishment.
    • Preparing sagebrush seed for market: Effects of debearder processing

      Booth, D. T.; Bai, Y.; Roos, E. E. (Society for Range Management, 1997-01-01)
      Debearders are machines originally developed to remove grain from bearded (awned) seed heads of small grains. They are now used in many types of seed cleaning, including preparing sagebrush seed for market. Some people have suggested that debearders may decrease sagebrush seed quality. We tested this hypothesis by using a debearder to process seeds of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis) and measuring subsequent seed quality. Seed stalks were cut from 2 Wyoming locations, stored in an unheated warehouse, and then processed with a debearder for 2, 4, 6, 8, or 10 min. Seed germination and seedling vigor were tested at 2-month intervals up to 16.5 months after processing. Temperature and relative humidity inside the debearder increased linearly from 14.0 to 22.4 degrees C and from 59.0 to 81.2 % during the 10-min. processing time. However, the moisture content of seed materials did not change during this period. The number of undamaged seeds per gram of material did not change with processing and was similar between collections. Stem length decreased with processing duration while percent of seed with pericarp removed increased. Germination percentage, time to 50 % germination (T50) and seedling vigor were similar among treatments in both collections. Germination percentage increased in the first 4.5 months after processing and then remained at that level up to 16.5 months. Germination rate decreased (T50 increased), but seedling vigor did not change with storage time. We recommend that seed dealers continue to use properly adjusted debearders to process sagebrush seed.
    • Range or meadow regrowth and weaning effects on 2-year-old cows

      Lamb, J. B.; Adams, D. C.; Klopfenstein, T. J.; Stroup, W. W.; Lardy, G. P. (Society for Range Management, 1997-01-01)
      Eighty 2-year-old spring calving primiparous cows were assigned to 2 weaning and 2 grazing treatments (20 cows/treatment) from 7 September to 7 November in 1991, 1992, and 1993. Grazing treatments were native sandhills range or subirrigated meadow regrowth. Weaning treatments were weaning on 7 September or 7 November. Calves weaned on 7 September grazed subirrigated meadow regrowth after weaning. Crude protein of diets from esophageally fistulated cows averaged 7.6% on range and 12.3% on subirrigated meadow on an organic matter (OM) basis. In vitro organic matter digestibility was 55.1% on range and 61.1% on subirrigated meadow. No year X grazing treatment or weaning X grazing treatment interactions were detected (P > 0.10) for any traits measured. Forage organic matter consumed by cows differed between years: 7.7 kg day-1 in 1991 and 105 kg day-1 in 1992; but was similar (P>0.10) for all grazing and weaning treatments. Cows grazing meadow gained more body weight and body condition than cows grazing range. Dry cows gained more weight and body condition (P<0.01) than lactating cows. Lactating cows grazing meadow maintained body weight and body condition, while lactating cows grazing range lost body weight and body condition. Calves nursing cows on meadow gained 28.8 kg more (P<0.01) than calves nursing cows on range and 34.4 kg more than weaned calves grazing meadow. Body weight gains of weaned calves grazing meadow and calves nursing cows on range were similar (P>0.10). We concluded that dry cows and cows that grazed subirrigated meadow regrowth during September and October increased body condition score over lactating cows and cows grazing range, respectively. Calf body weight gains were greatest for nursing calves on subirrigated meadow, but grazing weaned calves on subirrigated meadow was an effective alternative for calf growth to calves nursing cows on range.
    • Recovery of leafy spurge seed from sheep

      Olson, B. E.; Wallander, R. T.; Kott, R. W. (Society for Range Management, 1997-01-01)
      Sheep are often used to graze North American rangelands infested with leafy spurge (Euphorbia esula L.), a long-lived perennial forb from Eurasia. Our objective was to determine if sheep grazing infested rangelands disperse leafy spurge seed by transport in their fleece or by depositing seeds in their feces. Twenty-four yearling Targhee ewes grazed a 2.4 ha native bunchgrass range site infested with leafy spurge from late-May through mid-August of 1993 and 1994. Six of the 24 ewes were shorn in October 1993. To recover leafy spurge seeds from those fleeces, we used a standard method to test wool for vegetable matter. On average, 38 seeds were recovered per fleece. During these summers, 6 small groups (n = 4 sheep per group) each grazed 3 separate paddocks. We estimated the density of leafy spurge seed before the groups were moved into 1 of 3 paddocks. After the sheep were moved into a paddock (day 0), we collected fresh feces from each group on or about day 4, 10, and 14. Feces were then washed over sieves to recover leafy spurge seeds. All seeds were tested for germinability and viability. The number of viable seeds excreted daily per ewe was estimated. In 1993, 1,796 +/- 405 (S.E.) leafy spurge seeds m-2 were produced in the field, whereas in 1994, 399 +/- 63 (S.E.) leafy spurge seeds m-2 were produced. The summer of 1994 was much drier than the summer of 1993. We estimated that 41 to 144 leafy spurge seeds were excreted daily per animal in mid-July 1993. Viability of seeds in the feces averaged 5%, whereas viability of seeds collected from seed stalks was 42%. We estimated that the ewes excreted from 2 to 41 leafy spurge seeds daily at the peak in mid-July 1994. Viability of seeds excreted during 1994 averaged 24%, whereas viability of seeds collected from seed stalks was 68%. Sheep can pick up leafy spurge seed in their fleece, and will consume and pass viable seed. However, viability of seed recovered from feces was highly variable and almost always lower than seed collected in the field. Despite reduced seed numbers and viability, sheep have the potential to spread leafy spurge and should be managed accordingly.
    • Nitrogen and biomass dynamics following brush control in the cross timbers

      Gay, D. L.; Engle, D. M.; Allen, E. R.; Stritzke, J. F. (Society for Range Management, 1997-01-01)
      Converting marginal hardwood forest to grassland has the potential of increasing economic output with livestock grazing. Nitrogen (N) management during conversion needs to be evaluated to minimize possible adverse effects on the environment. This study was conducted to determine temporal changes in quantities of N and biomass within ecosystem compartments after herbicide application in a mature post oak (Quercus stellata Wangenh.)-blackjack oak (Quercus marilandica Muenchh.) forest. The 4 treatments evaluated included; 1) no brush kill with no grass overseeding, 2) brush kill with no grass overseeding, 3) brush kill with cool-season grass overseeding, 'K-31' tall fescue (Festuca arundinacea Schreb.), and 4) brush kill with warm-season grass overseeding, 'Plains' Old World bluestem [Bothriochloa ischaemum var. ischaemum (L.) Keng.]. Excellent brush kill was accomplished with 2.2 kg a.i. ha(-l) tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2 yl]-N,N'-dimethylurea) applied in spring 1993. Total N was measured during a 21-month period (June 1993 to February 1995), in 15- X 25-m plots, within 8 compartments; soil (0 to 60 cm), roots (0 to 60 cm), litter, top growth of herbaceous plants, woody plants <2.5 cm in diameter, and leaves, branches, and boles from trees >2.5 cm in diameter. Stored N in tall fescue forage was 6 to 7 times greater than in Old World bluestem or native vegetation by June 1994 and was 2 times greater in October 1994 and February 1995. Above-ground biomass of tall fescue and Old World bluestem was not different in October 1994 or February 1995, but both were greater than native vegetation. Litter biomass and total N in litter decreased, especially in the tall fescue overseeding treatment. Total N in the soil for all treatments averaged 5,100 kg ha(-1) and fluctuations were not detectable among treatments. Total N changes in other compartments were not observable or were minimal. Brush kill and overseeding with grass had little influence on total N stored within the ecosystem for 21 months after treatment. N was redistributed to the herbaceous biomass compartment and away from the litter compartment after herbicide application, regardless of the overseeding treatment applied.
    • Effects of ruminant digestion on germination of Lehmann love-grass seed

      Fredrickson, E. L.; Estell, R. E.; Havstad, K. M.; Ksiksi, T.; Va, J.; Remmenga, M. D. (Society for Range Management, 1997-01-01)
      Lehmann lovegrass (Eragrostis lehmanniana Nees) seed (germination 96%, dormant 0%) was used in 4 experiments to study the potential of sheep as a dispersal agent. Five, 4-year-old, ruminally cannulated wethers were used to examine effects of ruminant digestion on seed recovery and germination. All wethers were ruminally evacuated, and rumens were cleansed and reinoculated with strained ruminal fluid. After a 21-day adaptation to pelleted alfalfa, 4 experiments were conducted. Experiment 1 was designed to test viability of Lehmann lovegrass seeds exposed to ruminal and postruminal digestion. Lehmann lovegrass seed (10 g) was dosed intra-ruminally via ruminal fistula, and total fecal collections made. Of the viable seed ruminally dosed, 37% germinated within 21 days after recovery. Also, 98 to 100% of the seed that germinated was recovered within 72 hours of dosing. Experiment 2 was designed to test the influence of ruminal microbial digestion on seed degradation and viability, using in sacco nylon bag techniques. In sacco dry matter disappearance increased linearly from 5.5% at 3 hours of incubation to 16% at 120 hours. Germination of seed was not greatly affected until after 72 hours of ruminal incubation. Experiment 3 was designed to examine the effect of mastication on viability of Lehmann lovegrass seeds. Seeds were mixed with seed-free Lehmann lovegrass straw in a proportion of 1 to 10 (seed to straw) and 10 g fed to each wether. Boli were recovered manually via ruminal fistula. Thirty five percent of the seed fed entered the rumen without damage due to mastication. Experiment 4 compared in vitro techniques and in sacco techniques used to estimate the effect of digestion on seed viability. In vitro incubation techniques yielded similar results as in sacco techniques. We conclude that ruminants are potential disseminating agents of Lehmann lovegrass seed.
    • Actinorhizal plants in rangelands of the western United States

      Paschke, M. W. (Society for Range Management, 1997-01-01)
      Actinorhizal plants are a diverse group of trees and shrubs that have the ability to form a dinitrogen-fixing symbiosis with Frankia bacteria. Actinorhizal plants are found throughout the world and are a significant component of rangelands in the western United States. Many actinorhizal species play important ecological roles in the habitats where they occur. Actinorhizal shrubs such as bitterbrush (Purshia tridentata [Pursh DC.]), mountain mahogany (Cercocarpus spp), and Ceanothus spp. are among the most important wildlife browse species in the western U.S. Other actinorhizal taxa such as alders (Alnus) and dryads (Dryas) play important roles in soil development and community succession following disturbance. Despite their importance, the biology of these plants in rangeland ecosystems is poorly understood. Particularly lacking is understanding of the dinitrogen-fixing ability of these plants and how symbioses with Frankia bacteria affects the ecology of these plants in western U.S. rangelands. Difficulty in isolating and culturing Frankia bacteria and in measuring inputs of fixed N from actinorhizal plants has contributed to slow progress in this field. In spite of these shortcomings, the actinorhizal plants of western U.S. rangelands represent a valuable resource for expanded utilization. This review is a summary of current knowledge of actinorhizal range plants and their Frankia symbionts. It is intended to provide a scientific basis for the study and utilization of this symbiosis for those involved in rangeland research and management.
    • A digital technique for recording of plant population data in permanent plots

      Roshier, D.; Lee, S.; Boreland, F. (Society for Range Management, 1997-01-01)
      A mobile system to rapidly record demographic and spatial data of plant populations on permanent plots has been developed based on digital image processing equipment for personal computers. It offers considerable savings in field and data handling time and can record data from large plots. This system will facilitate broader application of plant demographic studies to arid and semi-arid ecosystems.
    • Effect of weed seed rate and grass defoliation level on diffuse knapweed

      Sheley, R. L.; Olson, B. E.; Larson, L. L. (Society for Range Management, 1997-01-01)
      Diffuse knapweed (Centaurea diffusa Lam.), an invasive weed, has reduced forage production and biodiversity, and increased soil erosion on over a million hectares of rangeland in the western United States. This study evaluated the effects of a single grass defoliation on establishment of diffuse knapweed seeded at 2 rates into a bluebunch wheatgrass (Pseudoroegneria spicata [Pursh.] Scribn and Smith)/needle-and-thread (Stipa comata Trin. &Rupr.) community and a crested wheatgrass (Agropyron cristatum (L.) Gaertn.) community. Six defoliation levels (0, 20, 40, 60, 80, 100%) and 2 seeding rates (3,000, 6,000 diffuse knapweed seeds) were applied to 1 m2 plots in a randomized-complete-block design (n=4). Diffuse knapweed was seeded in the fall of 1992, and grasses were defoliated on 28 April 1993. The number of flowering culms and weed seedlings were counted in September 1993. Densities of diffuse knapweed seedlings, juveniles, and adults, as well as plant standing crop, were determined in May 1994. Seed rate had minimal effect on diffuse knapweed density. By May 1994, densities of diffuse knapweed were about 20 and 30 plants m-2 on undefoliated bluebunch wheatgrass and crested wheatgrass plots, respectively, indicating that defoliation is not required for this noxious weed to become established. Higher levels of grass defoliation (>60%), especially of bluebunch wheatgrass, enhanced diffuse knapweed establishment, indicating that moderate (less than or equal to 60%) defoliation would not necessarily accelerate invasion by diffuse knapweed.
    • The economic impacts of increased grazing fees on Gila National Forest grazing permittees

      Torell, L. A.; Drummond, T. W. (Society for Range Management, 1997-01-01)
      The purpose of this research was to estimate the impacts of increased federal grazing fees on current holders of grazing permits on the Gila National Forest (GNF) in western New Mexico. A multi-period linear programming (LP) model was developed using 1992 national forest ranch budgets as baseline data. Discounted net returns (returns over variable costs) were maximized over a 60-year planning horizon under current fee regulations, and with alternative fees computed for various recent legislative and administrative grazing fee proposals. Small, medium, and large ranches were considered in the impact assessment. In addition to livestock income and expenses, off-ranch income, family living expenses, and debt obligations were directly considered in the analysis. An estimated 7% of the current Gila National Forest grazing permit holders—those medium and large ranches with high debt—would be expected to go out of business even if the current grazing fee were continued. At a federal grazing fee of 3.96/AUM as proposed by Rangeland Reform '94, an additional 20% of GNF permittees would be expected to go out of business. These would be the small high-debt ranches and large ranches with intermediate levels of debt. A grazing fee of 8.70/AUM would be expected to cause all current GNF ranchers with debt to go out of business. Average annual USFS grazing use by existing permit holders was estimated to decrease by about 120,000 AUMs when the grazing fee was increased to 3.96/AUM, but grazing fee receipts would increase by 31% with the higher fee, assuming no new permit holders or consolidations occurred. The largest grazing fee receipts were generated at the 3.96/AUM fee.
    • Influence of Japanese brome on western wheatgrass yield

      Haferkamp, M. R.; Heitschmidt, R. K.; Karl, M. G. (Society for Range Management, 1997-01-01)
      Japanese brome (Bromus japonicus Thunb.) has invaded many northern mixed-prairie plant communities. Understanding interactions of population dynamics of this and associated species is critical for proper management of communities infested with this annual. Objectives of this study were to determine the effect of Japanese brome removal on aboveground forage production and daily plant water relations of western wheatgrass [Pascopyrum smithii Rydb. (Love)] and Japanese brome in a western wheatgrass dominated northern mixed grass prairie community. During early spring of 1991, a wet year, and 1992, a dry year, 2 treatments, undisturbed and complete (total) removal of Japanese brome seedlings, were applied by hand at silty clay loam and clay field sites in circular, 1-m2 quadrats. Vegetation in additional quadrats was left undisturbed or Japanese brome was removed to assess plant water relations at each site in 1992. Total standing crop was reduced 500 kg ha-1 with removal of Japanese brome, while standing crop of western wheatgrass was increased 220 kg ha-2 with Japanese brome removal. Increased standing crop of western wheatgrass appeared to result from increased tiller density of 153 tillers m-2 rather than increased weight per tiller. Western wheatgrass water relations were essentially unaffected by Japanese brome removal in 1992. Removal of Japanese brome from Northern Great Plains plant communities may increase production of associated perennial grasses, but managers should also expect a short-term decrease in total standing crop.