Under usual range conditions, the time between blue grama (Bouteloua gracilis) germination and adventitious roots development is such that it is rare that both of these events occur with moist soil conditions, and seedling survival is infrequent. Establishment could be enhanced if the time between germination and adventitious root development were reduced. Dehulling followed by pretreatment of seeds with selected hormones such as indoleacetic acid reduced the time between these 2 events, and may increase the probability of successful seeding. These treatments also increased the length and number of adventitious roots during early stages of development. Water injection into the planting rows at seeding time added to the beneficial effects of seed treatment, while chemical mulching detracted from these responses.

Success in establishing fourwing saltbush [Atriplex canescens (Pursh) Nutt.] is often limited by competition from associated vegetation. Fourwing saltbush is reported to have abundant natural genetic variation, hence selection for plant vigor or competitiveness may be an effective tool for cultivar improvement. We observed distinctive within-accession variation in the apparent ability of fourwing saltbush seedlings to tolerate competition from sideoats grama [Bouteloua curtipendula (Michx.) Torr.] in a 1982 field planting. Superior and inferior parental saltbush phenotypes in the field planting were cloned in 1984 by rooting stem cuttings, and the cloned propagules were transplanted into plots with or without competition to test the hypothesis that the competitiveness trait was genetically controlled. Survival and canopy development of superior and inferior clones planted at the same time in competition regimens were similar, suggesting that the parental phenotypes were not genetically different in their ability to tolerate competition. Differences observed in the parental phenotypes may have been environmentally induced, or genetic differences in the clonal material may have been masked by using rooted cuttings rather than seedlings, by excessive competitive pressure in the competition regimens utilized, or both. Clones from the 2 parental phenotypes performed similarly when transplanted into competition-free regimens in November when growing conditions were favorable, but canopy development of clones from superior parental phenotypes exceeded that of those from inferior parental phenotypes when transplanted into competition-free regimens in April when growing conditions were poor.

The Water Erosion Prediction Project (WEPP) is a new water erosion prediction technology being developed by the USDA-Agricultural Research Service to replace the Universal Soil Loss Equation. Rangeland field experiments were designed to parameterize the WEPP rangeland erosion model. Included in the field experiments were plot treatments designed to separate direct from indirect effects of vegetation canopy on runoff and soil erosion. Nine rangeland sites from a wide range of soil and vegetation types were evaluated using rainfall simulation techniques. Natural versus clipped treatment surface characteristics and runoff and erosion responses were compared using regression analyses. These analyses showed that there were no significant differences between natural and clipped plot surface characteristics, runoff ratios, final infiltration rates, or initial rainfall abstractions. Erosion rates were different between treatments with the clipped plots having slightly less erosion than the natural plots. Results indicated that, under the rainfall conditions simulated, canopy cover was not directly contributing to initial abstractions through rainfall interception loss or significantly affecting runoff or erosion.

Variable weather, forage production, weed and pest problems, and livestock prices contribute to uncertainty in range livestock production. Because returns from livestock production, in which producers invest money and other resources, are uncertain, these variables are sources of risk. The STEERISK spreadsheet gives producers a tool to estimate the chances of different levels of forage production, test different management and marketing strategies, and estimate returns from them. Examples of STEERISK applications include selecting the most profitable stocking rate and evaluating the profitability of weed and insect control.

Brush is an important component of white-tailed deer (Odocoileus virginianus Raf.) habitat. We determined the long-term effects of offset disking on canopy cover, density, and diversity of brush species browsed by white-tailed deer. In 1989, we sampled vegetation in untreated strips and strips disked in 1973 in Jim Hogg County, Texas. Strips disked in 1974-1975 were sampled in Duval County, Texas, in 1985. Brush density was used to calculate species richness, evenness, and Shannon's index. In Jim Hogg County, Texas pricklypear (Opuntia lindheimeri Engelm.) density and canopy cover was greater in disked than in untreated strips. Density of other brush species was similar in disked and untreated strips. In Duval County, agarito (Berberis trifoliata Moric.) was the only brush species with lower density on disked (56 plants/ha) than on untreated (222 plants/ha) strips. Brush species richness and diversity were similar in the untreated and disked strips in both study areas. Landowners should consider disking for managing brush if they want to maintain brush diversity and browse for white-tailed deer.

Grazing systems and stocking rates are used to influence livestock grazing behavior with the intent of improving livestock and vegetation performance. In 1982, a study was initiated to determine effects of continuous, rotationally deferred, and short-duration rotation grazing and moderate and heavy stocking rates on steer gains, range vegetation, and distance traveled by and activity patterns of steers. Steers were observed from dawn to dark on 12 dates during 1983, 1984, and 1985, and activity recorded every 15 minutes. Eight steers per treatment (system X stocking rate combination) per date were observed in 1983 and 1984, and 10 per treatment in 1985. In 1984 and 1985, map locations of all steers were recorded at the same times as activity, and distance traveled summed from distances between successive map locations. In 1984, activity of 3 steers per treatment was electronically monitored during darkness. Steers grazed approximately 8.6 hr per day during daylight and 1.6 hr during darkness. Steers grazed an average of 8.9 hr/day during daylight under moderate vs 8.1 hr under heavy stocking, but stocking rate interacted with date in 1984 and grazing system in 1985. Steers traveled farther under continuous than under short-duration rotation grazing at both stocking rates in 1984, but only at the high stocking rate in 1985. Steers had to travel farther to water in the continuous pastures, and may have had to cover a greater area in an effort to select a more desirable diet, particularly under heavy stocking. These differences were not reflected in differences in gain among stocking rates or grazing systems.

Stand establishment from neoteric switchgrass (Panicum virgatum L.) seed can be hindered due to dormancy. The objective of this study was to evaluate the effect of mechanical scarification on germination and seedling emergence of neoteric (1- to 19-month-old) switchgrass seed. Scarification for 15 or 30 seconds in a Forsberg cylinder scarifier significantly increased 14-day germination percentage for 1- to 5-month-old seed of 5 cultivars. The magnitude of increase in seedling emergence due to scarification varied across cultivars. Four-month- and 18-month-old seed lots of 'Sunburst' and a North Dakota ecotype (NDE) exhibited significant increases in germination and seedling emergence after scarification. Scarification increased overall mean germination percentage for 3 lots of Sunburst and 2 lots of NDE by 73%. Field studies are needed to determine the usefulness of mechanical scarification as a preplant treatment for neoteric seed.

Efficacy of a continuous release marker device (CRD) containing chromium oxide to estimate fecal output was evaluated in two 12-day grazing trials with beef steers (n = 10, trial 1; n = 7, trial 2). Trial 1 was conducted on mature green irrigated tall wheatgrass (Elytrigia pontica [Podp.] Holub) pasture during September. Trial 2 was conducted on dormant native range during December. Fecal output was determined by total fecal collection (TFC) and the CRD for each steer. Fecal output estimates from the CRD were based on a chromium release rate (980 mg/day) provided by the manufacturer. Estimates of daily fecal dry matter output (kg) in trial 1 were 2.70 and 2.69, and in trial 2 were 3.19 and 2.89 from the TFC and CRD, respectively. Differences between TFC and CRD were not significant in trial 1 (P = 0.59) but were significant in trial 2 (P < 0.01). When averaged over days and animals, estimates of daily fecal dry matter from CRD were within 1% of TFC in trial 1 and 10% of TFC in trial 2. Estimates of daily fecal dry matter from CRD were influenced by sampling day and steer (P < 0.01); however, there was no consistent pattern to day or animal variation. Multiple days and animals are required for both TFC and CRD. We conclude that CRD provides an acceptable estimate of daily fecal output. However, to improve accuracy, TFC can be used on a subsample of animals as a double sampling technique to adjust estimates derived from CRD.

Panspots and transition zone panspots (slickspots) from a Leptic/Typic Natriboroll soil complex in western North Dakota were compared to determine the effects of secondary plant succession upon soil properties. Herbage and rooting characteristics were evaluated among panspot, transition zone, and adjacent well-vegetated Belfield soils using point frame data and a modified dry ashing technique. The effects of vegetation upon soil electrical conductivity (EC) were tested using gradient transects aligned perpendicular to boundaries between panspots and transition zones. Transition zones had 40% more total forage and twice the litter found in panspot areas. Thirteen of 17 gradient transects showed an inverse relationship between soil EC and distance into transition zones at the 0 to 5 cm depth. Significantly higher root-mass was obtained in the 0 to 5 cm depth in transition zones compared to panspots. A conceptual model based on subsurface water flow is presented to explain the polygonal cracking that was observed only in transition zone surfaces initiating a series of interactions resulting in natural reclamation of the transition zone soil.