The objective of this study was to determine the variability of Ca, Mg, K, Cu, Zn, and K/(Ca+Mg) ratio in 'Jose' tall wheatgrass [Thinopyrum ponticum (Podp.) Barkw. & D.R. Dewey], 'Luna' pubescent wheatgrass [T. intermedium subsp. barbulatum (Schur.) Barkw. & D.R. Dewey], and 'Hycrest' crested wheatgrass [Agropyron cristatum (L.) Gaertn. × A. desertorum (Fisch. ex Link.)]. Each grass was grown alone and in paired rows with 'Renumex' sainfoin (Onobrychis viciifolia Scop.) on a Pullman clay loam soil (a fine, mixed thermic Torrertic Paleustoll). Each species or mixture was evaluated under 3 cutting schedules in 1985 and 1986 and their mineral concentrations were compared to the recommended daily requirements of beef cattle. The concentration of minerals was similar in grasses grown as monocultures and in binary mixtures. The concentrations of all minerals and the ratio varied with harvest time, phenological stage, and year. Therefore, seasonal dynamics of mineral concentrations should be kept in mind when evaluating the mineral status of different forages. Among grasses, Hycrest had a better mineral profile for beef cattle than Luna or Jose. Sainfoin had higher concentrations of Ca, Mg, Cu, and Zn and much lower K/(Ca+Mg) ratio than the grasses. Hence, sainfoin-Hycrest mixtures may provide mineral concentrations more in balance with beef cattle requirements and help alleviate the problem of hypomagnesemia.

This study assesses survival and agronomic performance of 7-year-old stands of 25 alfalfa (Medicago sativa L.) cultivars and experimental strains interseeded into rangeland near Mandan, N.Dak. Associated grasses consisted primarily of crested wheatgrass [Agropyron desertorum (Link) Schulte.], western wheatgrass [Pascopyrum smithii (Rydb.) Löve], needle-and-thread (Stipa comata Trin. & Rupr.), and blue grama [Bouteloua gracilis (H.B.K.) Lag.]. Soil was a Chama silt loam (Typic Haplustolls), an upland soil with moderate water holding capacity. Each entry was replicated 4 times in a randomized complete block design in plots consisting of 3 interseeded rows 6.1 m long with 90 cm between rows. Alfalfa cultivars and experimental strains with a high proportion of falcata [M. sativa subsp. falcata (L.) Arcang.] parentage were better adapted to interseeding into rangeland at a semiarid site in the northern Great Plains than traditional hay-type cultivars which have a high proportion of sativa (M. sativa L. subsp. sativa) parentage. Sativa-types with high levels of known winterhardiness had low survival in this test. Seven years after plant establishment, the 12 falcata-type entries averaged 100% more plants or propagules m-2, 124% wider foliage spread of plant rows, and 68% more dry matter yield, respectively, than the 13 sativa-type entries. Traits associated with falcata parentage such as plant spread by root proliferation and broad crown development, dormancy during midsummer drought, and slow, decumbent regrowth may help to enhance alfalfa survival in semiarid rangeland in the Northern Great Plains. These traits have no known utility in more humid environments where maximum forage yields from multiple harvests is a primary objective.

Research was conducted on the effects of rotational grazing (RG) compared to continuous grazing (CG) on the behavior of cattle grazing on rangelands. Different livestock densities in the RG treatments were created by varying the size of paddocks in a 465-ha, 16-paddock, cell designed RG treatment stocked at a rate of 3.6 ha/cow/yr. Paddock sizes of 30 and 10-ha were used to simulate RG with 14 (RG-14) and 42-paddocks (RG-42), respectively. The CG treatment consisted of a 248-ha pasture stocked at 5.9 ha/cow/yr. Data were collected using vibracorders, pedometers and observation to estimate time (min/day) spent: intense grazing, search grazing, trailing, or sleeping; distance walked (km/day), and individual animal space ( m2/animal) in grazing subherds. Total grazing time did not vary among grazing treatments, but the components of total grazing (i.e., intense and search grazing) did vary among treatments. Cattle in the RG-14 paddocks spent less time search grazing compared to the ones in the other treatments presumably because the rotational grazed paddocks were more uniform because of less mixing of live and dead forage. Search grazing was highest in the RG-42 paddocks which may be due to the high stock density in this treatment coupled with an attempt to maintain individual animal space. Grazing time tended to be longer the first day in a RG-14 paddock than the last. Time spent trailing and the distance walked increased as the frequency of rotation increased among the different treatments. Sleeping was similar among grazing treatments. Individual animal space within a grazing subherd decreased as the stock density increased because of the grazing treatment.

Percent of seeds filled for alpine grasses and seed viability and longevity for alpine grasses and forbs with different life history and physiological traits were evaluated for seeds collected in 1983, 1984, 1985, and 1986 on the Beartooth Plateau, Mont. Significant (p<0.001) differences existed in the percent of seeds filled for grass species and in the seed viability of both grass and forb species among years. The high variability in seed viability among years is attributed to the severe and unpredictable nature of the environment. Seed viability differed among species within most years. In general, grass species had lower and more variable seed viability than forb species. Low seed viability years for the grass species coincided with low seed fill years, indicating poor seed development. Longevity of seeds collected in 1983 varied among species and was related to seed characteristics and the overall life history and physiological traits of individual species. Seed longevity of species with life history and physiological traits typical of late seral species was shorter than that of species with traits typical of early seral species.

A field study was conducted from 1981 through 1986 on an established stand of grass and legume species on topsoiled coalmine spoils in northwest Colorado to evaluate the effects of N and P fertilization on dry matter production, species composition, canopy cover, and forage crude protein and P concentrations. Fertilizer treatments included annual fall applications in 1981 through 1985 of: 0, 28, 56, 112, and 224 kg N ha-1; 56 kg P ha-1; and 112 kg N ha-1 + 56 kg P ha-1. Additionally, single fall applications of N were applied in 1981 through 1983 at rates of 0, 28, 56, 112, 224, and 448 kg N ha-1 to other plots that had not been previously fertilized. Plots were harvested at grass anthesis in 1982 through 1986. Fertilizer P significantly increased forage P concentration but did not significantly affect yield, crude protein concentration, or species composition. Fertilizer N did not significantly affect species composition or forage P concentration but did significantly increase dry matter production and crude protein concentration with increased N rate. Averaged over the 5 years of the study, annual application of 28, 56, 112, and 224 kg N ha-1 increased herbage production by 23, 19, 19, and 11 kg per kg N applied, respectively. On those plots receiving a single application of fertilizer N, significant increases in dry matter production with increased N rate were noted only during the first growing season after N fertilization. Significant yield response to carry-over fertilizer N was noted in the second (and occasionally third) growing seasons only at the 448 kg N ha-1 rate. The data indicate that annual applications of fertilizer N would be more effective than infrequent applications of high rates of N on these reclaimed mined lands.

We discuss what concepts or models should be used to organize research and management on rangelands. The traditional range succession model is associated with the management objective of achieving an equilibrium condition under an equilibrium grazing policy. In contrast, the state-and-transition model would describe rangelands by means of catalogues of alternative states and catalogues of possible transitions between states. Transitions often require a combination of climatic circumstances and management action (e.g., fire, grazing, or removal of grazing) to bring them about. The catalogue of transitions would describe these combinations as fully as possible. Circumstances which allow favorable transitions represent opportunities. Circumstances which threaten unfavorable transitions represent hazards. Under the state-and-transition model, range management would not see itself as establishing a permanent equilibrium. Rather, it would see itself as engaged in a continuing game, the object of which is to seize opportunities and to evade hazards, so far as possible. The emphasis would be on timing and flexibility rather than on establishing a fixed policy. Research under the state-and-transition model would aim to improve the catalogues. Frequencies of relevant climatic circumstances would be estimated. Hypotheses about transitions would be tested experimentally. Often such experiments would need to be planned so that they could be implemented at short notice, at an unknown future time when the relevant circumstances arise.

The establishment of several high yielding grasses was examined on the Texas High Plains as an alternative to row crop agriculture. The species were Blackwell switchgrass (Panicum virgatum), El Reno sideoats grama (Bouteloua curtipendula), Morpa weeping lovegrass (Eragrostis curvula) and 4 old world bluestem selections including Caucasian (Bothriochloa caucasica), WW517 (B. intermedia var. indica), Ganada (B. ischaemum var. ischaemum), and WWspar (B. ischaemum var. ischaemum). Each species was seeded in mid-May 1981 and 1982 in Garza County on a fine sand and in Lubbock and Terry Counties on sandy loam soils. Number of seedlings 1 month after planting ranged from 129.7/m at Brownfield in 1981 to 7.5/m at Post in 1982. At the end of the first growing season, biomass ranged from 930 kg/ha at Lubbock in 1981 to 11 kg/ha at Post 1982. At the beginning of the second growing season, basal cover had increased, indicating these species were adapted to the winter conditions in the area. The seedings were successful, and adequate stands of all species were established the first year except for the 1982 Post planting. The year and location were the most important factors in establishment success during this study. There were differences among species, but no one species was superior over locations or years for all the characteristics measured. On the fine sand weeping lovegrass was superior.

The effect of varying price ratios between liveweight and supplementary feed on the optimum stocking rate (SR) of a beef herd on range is analyzed in relation to the net value of weaned calf live weight. While the basis for determining optimum stocking rate is generally the value of production and costs per unit area, the animal performance per se is often a major management criterion, especially where the capital investment in livestock is high and where risk avoidance is an important consideration. Consequently, equations expressing the net value of beef production per unit of land and per animal unit are formulated as a function of SR. Parameter values for the equations were taken from a grazing trial conducted in the Galilee in Israel where a beef herd was maintained yearlong on native range 5 years at 3 different SR's, 0.50, 0.67, and 0.83 cows/ha. The animals were supplemented ad libitum with poultry litter during the dry summer months. During the transitional period between the opening rains and range readiness, poultry litter was enriched with 20% barley grain. In addition, straw was given at an average rate of 80 to 375 kg/ha in the intermediate and highest stocking rates. Over the range of SR's studied, it was shown that when supplementary feed and other per animal costs are high, net value of production per unit area of range declines with SR even though total production increases. On the other hand, when fixed range and management costs are high, the net economic benefit per cow increases with SR even though production per cow decreases. It is concluded that the optimum SR for a given situation depends not only on the input/out price ratios but also on the criterion for evaluating economic value that is most revelant to the manager.