James T. Nichols

Grazing date and frequency effects on prairie sandreed and sand bluestem.

A 5 year study was conducted during 1988-1992 to quantify the effects of grazing date and frequency on total organic reserves of prairie sandreed [Calamovilfa longifolia (Hook.) Scribn.] and sand bluestem (Andropogon hallii Hack.). Treatments consisted of mid-month grazing periods in (1) June, (2) July, (3) August, (4) October, (5) June and July, (6) June and August, (7) July and August, or (8) June, July, and August. Seasonal stocking rates were equal among treatments and divided equally over multiple grazing periods. Grazing treatments were applied to the same pastures during 4 consecutive years with yearling cattle and 4-7 day grazing periods. Mean tiller weight of etiolated initial-spring growth was used to estimate total organic reserves in the fifth year. Dormant season grazing in October was not different from 4 years of rest for either species. Total organic reserves in prairie sandreed decreased when paddocks were grazed in June or July regardless of the number of grazing periods per treatment. Reserves in sand bluestem were maintained by grazing once in June or August. Rotationally grazing pastures 2 or more times during June-August is least likely to maintain or increase total organic reserves in either species. Multiple grazing periods initiated in June reduced reserves by about 38% in prairie sandreed and 30% in sand bluestem. When stocking rates are similar to this study, deferment periods should be longer than 60 days after grazing in June to avoid measurable reductions in total organic reserves in both species. Periodic deferment of grazing until mid-August or later will be required to maintain simultaneously high levels of reserves in prairie sandreed and sand bluestem.

Grass hay as a supplement for grazing cattle. I. Animal performance.

Regrowth grass hay produced on subirrigated meadows in the Nebraska Sandhills was evaluated as a supplement for gestating beef cows grazing winter range. Ninety-six crossbred spring calving, gestating beef cows were used in a winter supplementation study on upland Sandhills range from 5 November to 27 February in 1990 and again in 1991. Cows were divided into 4 treatments (24 cows/treatment): 1) control (range forage only, no supplement); 2) range forage and 2.2 kg cow-l day-1 of meadow regrowth hay (15.5% crude protein); 3) range forage and 1.2 kg cow-1 day-1 of a 30% wheat grain and 70% soybean meal:30% wheat supplement (36.0% crude protein); and 4) range forage with supplements in treatments 2 and 3 fed on alternate days. Meadow hay and soybean meal:wheat supplements provided 0.32 kg of crude protein/cow daily. Supplemented cows gained 3 to 53 kg body weight/year and maintained body condition, while control cows lost an average of 24.5 kg body weight/year and lost body condition. Intake of range forage was less (P 0.05) for all treatments. We concluded that subirrigated meadow regrowth grass hay was an effective alternative to traditional soybean meal-based supplements for maintaining body weight and body condition of gestating beef cows grazing winter range.

Effect of grazing strategies and pasture species on irrigated pasture beef production.

Irrigated cool-season grasses can be used as complementary forages with other forage resources. Improved efficiency of animal production from irrigated pasture could increase their utility as a complementary forage. The factors of species composition, grazing management, irrigation, and fertilization all have the potential to affect efficiency of irrigated pasture production. Specific objectives of this study were: (1) to determine the effect of deferring irrigated pasture and restricting irrigation water and fertilization during mid-summer on pasture and livestock production; and (2) to evaluate different pasture stands for adaptability to different grazing strategies. Eight, adjacent 1.25-ha pastures were established as 2 replications of 2 different pasture stands grazed under 2 grazing management strategies. Pasture stands consisted of intermediate wheatgrass (Agropyron intermedium Host. Beauv.) as a monoculture (IWG) and a 4-species mixture (MIX) of orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), meadow bromegrass (Bromus biebersteinii R. & S.), and Garrison creeping foxtail (Alopercurus arundinaceus Poir.). Grazing treatments with yearling steers consisted of season-long grazing (SLG) and a graze-defer-graze (GDG) strategy. For the GDG pastures, 38% less fertilizer and 34% less irrigation water were applied, but animal days of grazing were reduced only 16% over the 3-year study. Animal weight gains were comparable between pasture types when considered over the entire grazing season but were higher for IWG early in the growing season and for MIX late in the season. Persistence of pasture stand was better for the MIX pastures than IWG pastures which were invaded by annual weeds after the first grazing season. Highest gains ha-1 were from the SLG pastures because of more days of grazing, but animal productivity was not proportionally reduced for the GDG strategy. The MIX pastures were suited for either grazing strategy.

Relationships between physical and chemical characteristics of 3 Sandhills grasses.

Physical and chemical traits of grass tillers can be strongly correlated. Understanding such patterns would help define physiological development of tillers and changes in quality of forage in Sandhills grasses. Physical and chemical traits were quantified for sand bluestem (Andropogon hallii Hack.), prairie sandreed [Calamovilfa longifolia (Hook.) Scribn.], and little bluestem [Andropogon scoparius (Michx.)] on 3 sites at 4 times (mid-June, July, August, and October) during the 1990 and 1991 growing seasons. Thirty tillers were identified along two, 50-m transects (30 tillers/species/transect) within each site and tiller growth stage, length, and erectness determined. Tiller weight was defined from plants collected within 20 quadrats/site. Protein content, in vitro dry-matter digestibility (IVDMD), hemicellulose, total cell wall, acid detergent fiber (ADF), lignin, ash, total chlorophyll, and nonstructural carbohydrates (TNC) were determined on plant materials representing the dominant growth stages. Relationships among traits of the 3 species were determined by Spearmans rank correlation, and among linear combinations of sets of chemical and physical traits by canonical correlation analysis. Tiller length, weight, and growth stage were positively correlated (P < 0.05) and increased with length of growing season. Crude protein, digestibility, hemicellulose and chlorophyll were positively correlated and declined, but negatively correlated with lignin and ash. Significant (P < 0.05) correlations between the first canonical variates indicated a strong relationship between tiller maturity/architectural development (physical canonical variate) and forage quality (chemical canonical variate) was present, and large portions of variance in the original variables was defined. Results of this study defined large-scale multi-dimensional relationships between declining forage quality and increasing tiller maturity/architectural development, previously noted in many univariate analyses of limited sets of characteristics.

Contour-furrowing and seeding on nuttall saltbush rangeland of Wyoming.

Highlight: A Nuttall saltbush (Atriplex gardneri) site in the Big Horn Basin of Wyoming was contour-furrowed and seeded to crested wheatgrass (Agropyron cristatum) by the Bureau of Land Management in 1957 as part of a range improvemenf and watershed management program. In 1962 total herbage produc fion on the treated area was 972 /b/acre compared to 412 Jblacre for untreated range. Greater production was due to both the yield of crested wheatgrass and improved vigor of Nutfall saltbush. By 1972 total production of the treated orea declined to 590 lbjacre but was still 54% greater than the control. Coincident with decreased production, foliage cove? of crested wheatgrass decreased by 74% and Nufrall saltbush 50%. part of which can be attributed to reduced waterholding capacity of the furrows by about 30% from their original capability. The untreated native range produced 384 lb/acre in 1972, which W(IS nof appreciably different from production IO years previously. Likewise, foliage cover percentages remained relatively stable.

A Containerized Technique for Studying Root Systems

Quantifying root responses of naturally growing range plants to treatments is difficult. The objective of this study was to develop a containerized technique to study individual plants growing in the field under near natural environmental conditions. Three containers were evaluated: 15 X 100 cm nylon (2,000 pores/cm(2)) sacks, 15 X 100 cm polyvinyl chloride (PVC) tubes, and 30 X 100 cm PVC tubes. The 15 X 100 cm PVC tubes were easiest to handle, and plants grown in these containers appeared similar in size and growth form to adjacent, undisturbed plants. Survival rate for 165 sand bluestem (Andropogon hallii Hack.) plants grown for 2 years in the 15 X 100 cm PVC tubes was 98.8%. This survival rate was achieved despite clipping treatments during the second year.

Technical Note: Field Measurement of Etiolated Growth of Rhizomatous Grasses

Defoliation effects on grasses have been quantified with measurements of etiolated growth since the 1960s, however, field techniques for measuring etiolated growth of rhizomatous grasses with dispersed tillers have not been reported. Tents constructed with landscape fabric were used in a field study of 2 species of rhizomatous grass. When manufactured, the woven polypropylene fabric is needle punched for air and water permeability. Light that may pass through perforations has no measurable effect on etiolated growth as indicated by a test of single and double layers of fabric. Tents can be sized to shade borders around interior sample areas to prevent translocation from outside tillers to harvested tillers. Landscape fabric tents are light weight and reusable and eliminate breakage, water vapor, and storage problems associated with other covers.

Range Productivity as Influenced by Biennial Sweetclover in Western South Dakota.

Biennial sweetclover was seeded into a Dense Clay Range Site that was severely depleted by drought and overgrazing. Seeded in 1962 without seedbed preparation, sweetclover has reseeded naturally, and remained a compatable associate with the native vegetation during the five-year study. Combined grass and sweetclover production averaged 1804 lb/acre annually compared to 750 for the control. The grass component was increased by an average of 373 lb/acre as a result of legume supplied nitrogen. Western wheatgrass vigor and forage protein were also improved. Native perennial grasses were not reduced in abundance by sweetclover competition. Sweetclover appears well adapted as a legume for rangelands with heavy clay soils in western South Dakota.

Range Recovery and Production as Influenced by Nitrogen and 2,4-D Treatments.

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