Now showing items 8603-8622 of 20719

    • Growth of Chickasaw Plum in Oklahoma

      Dunkin, Stacy W.; Githery, Fred S.; Will, Rodney E. (Society for Range Management, 2008-11-01)
      Management of rangelands for wildlife and livestock entails understanding growth of clonal shrubs such as Chickasaw plum (Prunus angustifolia Marsh.). We studied growth of this species in one county in north-central (Payne) and two counties in northwestern Oklahoma (Ellis, Harper) during 2006 and 2007. We estimated age of stems and roots by growth rings and area of stands with the use of a handheld GPS unit. Based on zero-intercept regression models, stands grew at similar rates (overlapping 95% confidence intervals [CIs]) among counties with a pooled estimate of 31.0 m2 yr-1 (95% CI = 26.5–35.6 m2 yr-1; n = 95). This rate showed considerable variability within and among study sites (r = 0.52). Stem diameter increased (zero-intercept models) more rapidly in north-central Oklahoma (5.27 mm yr-1; 95% CI = 5.01– 5.53 mm yr-1; r = 0.90; n = 53) than in northwestern Oklahoma (3.68 mm yr-1; 95% CI = 3.55–3.81 mm yr-1; r = 0.91; n = 102); data were pooled because of similar rates in Ellis and Harper counties. Stem height was a power function of stem age (y = 0.97x0.28; r = 0.56), indicating rate of growth in height (m y-1) declined with age according to dy/dx = 0.27x-0.72. Knowledge of the area expansion rate of Chickasaw plum clones aids in management planning to increase or decrease canopy coverage by this shrub. 
    • Growth of Forbs, Shrubs, and Trees on Bentonite Mine Spoil Under Greenhouse Conditions

      Uresk, D. W.; Yamamoto, T. (Society for Range Management, 1986-03-01)
      Revegetation on raw bentonite spoil with or without treatments is often more practical than replacing topsoil in areas where it is scarce or nonexistent. The effect of raw bentonite spoil treated with ponderosa pine sawdust on plant survival and growth was compared to other treatments including perlite, gypsum, straw, vermiculite, and no treatment. Plants tested were the drought- and salt-resistant species of fourwing saltbush (Atriplex canescens (Pursh) Nutt.), rubber rabbitbrush (Chrysothamnus nauseousus (Pallo) Britt.), big sagebrush (Artemisia tridentata tridentata Nutt.), common winterfat (Ceratoides lanata (Pursh) Moq.), Rocky Mountain juniper (Juniperus scopulorum Sarg.), Russian olive (Elaegnus angustifolia L.), common yarrow (Achillea millifolium L.), and desert globemallow (Sphaeralcea ambigua Gray). Desert globemallow, fourwing saltbush, and rubber rabbitbrush had substantial growth and survival on sawdust, perlite, and vermiculite treated spoil. The growth promoting effect of sawdust is particularly promising; it is readily available and cost is minimal.
    • Growth of Gutierrezia sarothrae seedlings in the field

      Osman, A.; Pieper, R. D. (Society for Range Management, 1988-01-01)
      Broom snakeweed (Gutierrezia sarothrae [Pursh] Britt. and Rusby) has increased in density and distribution on many southwestern ranges. The objective of this study was to determine root and shoot development of snakeweed seedlings as an aid in understanding the establishment of the species. Broom snakeweed seedlings were excavated from the field from March through September at approximately monthly intervals to determine biomass of roots and shoots. Root and shoot biomass growth was comparable from March to July, but shoot growth exceeded that by roots for the rest of the growing season. Root:shoot ratios were below 0.6 for the entire growing season, suggesting that rapid root development is not the primary mechanism for colonizing disturbed areas.
    • Growth of Introduced Temperate Legumes in the Edwards Plateau and South Texas Plains

      Holt, E. C.; Haferkamp, M. R. (Society for Range Management, 1987-03-01)
      A study was conducted to evaluate production of 2 temperate, annual legumes at locations where temperature and moisture may seasonally place severe constraints on growth. Arrowleaf (Trifolium vesiculosum Savi) and subterranean (Trifolium subterraneum L.) clovers were grown at Beeville, in south Texas, and at Brady, 230 miles north of Beeville. Standing crop samples were collected at approximately 2-week intervals, starting 30 days post emergence and continuing to plant maturity during 2 years. Very little growth was made prior to 1 March at Brady in either year or at Beeville the first year. Total production was minimal (<1,500 kg/ha) at Brady. Arrowleaf produced about twice as much standing crop as subterranean at Beeville, 3,900 to 8,800 kg/ha (arrowleaf) versus 2,800 to 4,600 kg/ha (subterranean). No environmental variable showed a close association with growth rate when the data for 2 years and 2 species were included in simple correlations. In stepwise multiple regression equations, daily heat units was the most important variable followed by soil water. Early fall emergence and the development of a supraminimal canopy prior to the advent of growth-limiting winter temperatures had an overriding effect on winter growth as indicated by production differences in the 2 years at Beeville. The study shows that temperate annual clovers can be grown further west in the Southern region than current usage indicates.
    • Growth of Replacement Heifers on Shortgrass Ranges of Colorado

      Shoop, M. C.; Hyder, D. N. (Society for Range Management, 1976-01-01)
      We examined records of young cattle produced on shortgrass range in Colorado to evaluate the problem of inadequate growth of replacement heifers-a problem that forces ranchers to delay first calving until heifers are 3 years old. Weaning weights of calves produced on 44 ranches did not increase from 1950 through 1970 in spite of improved breeding practices. Hence, summer range conditions may limit growth of heifer calves. Weaner heifers gained an average of only 0.4 lb/head/day during their first winter. Whereas, to be large enough for successful breeding, heifers should gain 1.2 lb/head/day. March, April, and May forage conditions were identified as critical to reproduction of cattle because of inadequate herbage, poor quality of old herbage, excessive energy expenditure in the search for scarce green herbage, teeth shedding by 2-year-old heifers, and increased nutritional needs for milk production and readiness to breed. The data identify two criteria for attaining a goal of successful breeding of yearling heifers raised on shortgrass range: (1) place all brood cows, especially 2-year-old heifers with first calf, on gain-promoting forage and feed in March, April, and May, and (2) increase winter daily gain of weaner heifers by at least 0.83 lb. Research is needed to determine if these criteria can be attained profitably.
    • Growth of Selected Plants on Wyoming Surface Mined Soils and Flyash

      Howard, G. S.; Schuman, G. E.; Rauzi, F. (Society for Range Management, 1977-07-01)
      This greenhouse study was initiated to determine potential plant growth on three surface-mined soils and their overburden, and on coal flyash mixtures from sites in Wyoming prior to field studies and plant establishment trials. There was no indication that either topsoil or overburden from the active mine sites in Gillette, Hanna, or Shirley Basin, was detrimental to plant growth when water and temperature were not limiting. Forage plants and range shrubs on each soil benefited from the addition of N and/or P fertilizer. The addition of sewage sludge or manure also greatly increased growth. The study indicated that certain mixtures of flyash in soil and sludge can be successfully revegetated. The application of this data may be extensive in the reclamation and revegetation of surface-mined soils in those areas tested.
    • Growth of the Annual Grass Plant in Response to Herbage Removal

      Laude, H. (Society for Range Management, 1957-01-01)
    • Growth of winterfat following defoliation in Northern Mixed Prairie of Saskatchewan

      Romo, J. T.; Redmann, R. E.; Kowalenko, B. L.; Nicholson, A. R. (Society for Range Management, 1995-05-01)
      An observed increase in winterfat (Ceratoides lanata (Pursh) J.T. Howell) on ungrazed rangeland suggests that this shrub may potentially be an important forage resource in the Northern Mixed Prairie under improved grazing management. The objectives of this study were to: 1) compare density, frequency, and cover of winterfat in a grazed pasture and site that had been protected from grazing for about 30 years; and 2) evaluate regrowth of winterfat following defoliation during the growing season on a clayey range site in Saskatchewan. Density, frequency, canopy cover, and basal cover were significantly greater in the protected range than the grazed pasture. Density (1.1 SE +/- 0.01 plants m-2) and frequency (70% SE +/- 3.6) were about 2-fold greater, while canopy cover (7.0% SE +/- 1.4) and basal cover (1.7% SE +/- 1.5) were 7- to 8-fold greater, in the protected versus grazed range. When defoliated to a 5-cm stubble in May, June, or July plants produced significant amounts of regrowth but not when herbage was removed in August. When defoliated in late July or August current year production the following year was significantly lower than control and earlier defoliations. Current year production peaked in late July and August. Total standing crop was 2- to 4-fold greater in the control than the defoliation treatments because the biomass produced in previous years was removed from clipped plants. Because winterfat produces substantial amounts of new growth following defoliation in May, June, or July it is recommended that this shrub be grazed only once during the growing season to prevent grazing of this regrowth. Plants defoliated in May can potentially produce biomass equal to control the following year whereas plants defoliated in June, July, or August will likely require more than 1 year of rest to recover their annual productivity.
    • Growth Parameter Differences between Populations of Blue Grama

      Samuel, M. J. (Society for Range Management, 1985-07-01)
      Samples of blue grama were obtained from disturbed and undisturbed areas of native rangeland in southeast Wyoming. Assumed 'slow-spread' populations were selected along a 50-year-old plowline from blue grama sod which had spread only a few centimeters into the plowed area. Assumed 'fast-spread' populations were selected from large plants within the plowed area. Control populations were selected at random from the undisturbed native range. Plants from 15 populations were grown in a dryland, uniform garden where basal spread was measured to determine if there were differences in rate of spread between populations of blue grama. Herbage production, plant height, and phenology were also compared. By the end of the second and fourth seasons of growth in the uniform garden, the fast-spread populations had spread 21 and 20% more than the slow-spread populations. The random populations were 17 and 11% larger than the slow-spread populations during the same year. The fast-spread and random populations were not different.
    • Growth Patterns and Biomass Relations of Xanthocephalum sarothrae (Pursh) Shinners on Sandy Soils in Southern New Mexico

      Nadabo, S.; Pieper, R. D.; Beck, R. F. (Society for Range Management, 1980-09-01)
      Growth patterns of broom snakeweed were studied on three areas of sandy range sites in southern New Mexico by measuring plant canopy biweekly during the growing season and calculating canopy volume. Canopy volume increased during the summer of 1977 on all three study areas. In 1978, canopy volume declined throughout much of the growing season because effective rainfall came late in the season. More than 60% of the canopy biomass was contributed by brown stems and leaves, about 30% by green leaves and stems, and less than 10% by inflorescences on most dates. Coefficients of determination relating canopy volume to canopy biomass were less than 0.70. Growth forms and patterns were quite variable among the populations studied.
    • Growth patterns of yearling steers determined from daily live weights

      Currie, P. O.; Volesky, J. D.; Adams, D. C.; Knapp, B. W. (Society for Range Management, 1989-09-01)
      Growth patterns for free-ranging yearling steers were quantified from daily live weights obtained with automatic scales which animals entered to obtain drinking water. Forty steers were monitored during each summer grazing period of 1986 and 1987. Frequency of watering and, thus, weighing on the automatic scales averaged 2.4 times/day. Significant (P < 0.01) quadratic relationships between live weight and Julian date were obtained. In 1986, predicted live weight of the steers peaked in late July to early August and then decreased through to the end of the grazing period in September. Live weight of the steers in 1987 followed a similar pattern although the late summer decrease was not as great as in 1986. When animals were periodically weighed using manual procedures, a lower rate of gain was measured in the second half than in the first half of the summer grazing period every year from 1983 through 1987. However, we were unable to specifically identify when these weight changes occurred until the automatic scales were used in 1996 and 1987. The automatic weighing equipment documented substantial within-day live weight variability among steers. This variability changed over the grazing period on a day-to-day basis. Within-day variability must be considered when establishing manual weighing schedules with conventional equipment. Live weight data in conjunction with other measurements will permit development of a more comprehensive animal-plant-climate model.
    • Growth Performance Comparisons among 18 Accessions of Fourwing Saltbush (Atriplex canescens) at Two Sites in Central Utah

      McArthur, E. D.; Stevens, R.; Blauer, A. C. (Society for Range Management, 1983-01-01)
      Growth characteristics of 17 accessions and 1 selection of fourwing saltbush (Atriplex canescens [Pursh] Nutt.) at 2 sites in Sanpete Valley, central Utah, were scored on 6-year-old mature plants. There was no difference in survival at the 2 sites, but plants at the Snow Field Station near Ephraim grew taller, were more vigorous, and exhibited more reproductive capacity than those at the Peacock Plot near Manti. The plants at Peacock Plot had a more upright growth habit, were more uniform, and exhibited less insect and disease damage than the Snow Field Station plants. A composite quality index (QI) revealed highly significant site and accession differences but little site × accession interaction. The individual traits (height, growth habit, uniformity, vigor, reproduction, and insect and disease damage resistance) all showed significant site effects and site × accession interaction. An accession and its selection from Rincon Blanco, Rio Arriba County, New Mexico, performed well at both sites. Also performing well at both sites were a local accession from Excell Canyon, Sanpete County, Utah, and the gigas accession from the Little Sahara Sand Dunes, Juab County, Utah. In general, accessions from elevations higher than the test sites performed best. Accessions with high QI's are recommended for revegetation plantings of sites comparable to the 2 study sites. The Rincon Blanco material has good growth characteristics and may also be broadly adapted.
    • Growth rate and climatic response of Machaerium scleroxylonin a dry tropical forest in southeastern Santa Cruz, Bolivia

      Paredes-Villanueva, K.; Sánchez-Salguero, R.; Manzanedo, R.D.; Quevedo Sopepi, R.; Palacios, G.; Navarro-Cerrillo, R.M. (Tree-Ring Society, 2013-07)
      Machaerium scleroxylon (morado) is an important timber species from the lowland tropical dry forests in Bolivia. We followed a dendrochronological approach to (i) evaluate the responses of radial growth to climatic variables and atmospheric circulation patterns, and (ii) quantify the growth rate in order to estimate the Minimum Logging Diameter (MLD), age, and optimal cutting rotation. We measured tree-ring width in wood discs taken from ten randomly selected mature individuals. We used previous histological analyses to distinguish and visually crossdate tree rings. Despite the existence of false rings, lenses and wedging rings, the species showed defined annual ring boundaries, thus enabling a tree-ring chronology analysis. Correlations between residual ring-width indices and monthly climatic variables (temperature and rainfall) and atmospheric circulation patterns (El Niño-Southern Oscillation) index were calculated. Growth showed a significant positive correlation with monthly rainfall and a negative correlation with mean temperature during the late rainy season (i.e. from December up to March). A positive correlation found between the ring width and ENSO indices indicates that the growth of M. scleroxylon was significantly affected by atmospheric circulation patterns. Growth rate is slow in morado, suggesting a MLD of 50 cm and an optimal cutting cycle longer than 40 years depending on each site.
    • Growth Rate Differences among Big Sagebrush (Artemisis Tridentata) Accessions and Subspecies Utah

      McArthur, E. D.; Welch, B. L. (Society for Range Management, 1982-05-01)
      Even-aged plants of 21 big sagebrush (Artemisia tridentata) accessions were grown in a uniform garden to test growth parameter variation. Growth parameters measures (height, crown diameter, yield, and annual nonfloral leader growth) were scored after the 1975, 1976, and 1977 growing seasons. Nested analyses of variance and mean comparison tests showed significant (p<0.05) accession and subspecies differences in each measure, each year. On a subspecies level, basin big sagebrush (A.t. ssp. tridentata) exceeded the other two subspecies (mountain big sagebrush = A.t. vaseyana, Wyoming big sagebrush = A.t. wyomingensis) for each character. In general, the values for the last two subspecies were not significantly different, but mountain big sagebrush tended to have larger values. Using 1975 data for yield and 1976 data for the other growth parameters, basin big sagebrush accessions averaged 147.9 +/- 14.7 (se) cm in height, 193.0 +/- 12.1 cm in maximum crown spread, 2217 +/- 444 g current yield, and 12.7 +/- 1.1 cm in annual leader growth. Corresponding values for mountain big sagebrush were 95.8 +/- 2.2 cm, 157.3 +/- 3.4 cm, 890 +/- 77 g, and 8.8 +/- 0.6 cm. For Wyoming big sagebrush the values were 77.1 +/- 4.1 cm, 129.6 +/- 6.4 cm, 545 +/- 84 g, and 8.5 +/- 1.1 cm. Comparison of three accessions' performances at two uniform gardens and their native sites indicated that growth parameters, while subject to environmental influences, are under genetic control. The fastest growing and largest growing plants of this study were diploid, 2n = 18, whereas, the slowest growing ones were tetraploid, 2n = 36. Growth rate characteristics of big sagebrush should be considered for management purposes and in plant improvement programs.
    • Growth Rate of Mixed Prairie in Response to Nitrogen and Phosphorus Fertilization

      Lorenz, R. J.; Rogler, G. A. (Society for Range Management, 1973-09-01)
      Earlier initiation of spring growth and increased dry matter production of mixed prairie are important to the livestock industry, particularly in the northern Plains where the winter feeding period is often prolonged. The effect of N and P levels on growth rate and production of mixed prairie was studied over an 8-year period at the Northern Great Plains Research Center near Mandan, North Dakota. Annual application of N had no effect on growth rate prior to May 1; however, during the May 1-May 15 period, and during each successive growth period, rate of growth increased as N level increased up to 160 lb elemental N/acre (160-N). By May 15, plots receiving 40-N produced more dry matter than did plots without N by June 1. As the season progressed, the production lag of the nonfertilized plots became greater. The yield level reached on June 15 by plots receiving 40-N was not attained by the 0-N plots until July 15. Yield levels reached by fertilized plots on July 1 were never attained by nonfertilized plots.
    • Growth Rates and Phenology of Some Southern California Grassland Species

      Hufstader, R. W. (Society for Range Management, 1978-11-01)
      Growth rates of southern California grassland species showed significant correlation with rainfall from November 1972 to June 1973. Maximum growth for the species ripgut grass, foxtail chess, wild oats, black mustard, and geniculate mustard occurred during winter and early spring. Plant development for these species began in late fall and ceased by mid-spring. It was hypothesized that species characteristics and slope exposures are important factors in plant development subsequent to germination, whereas, rainfall is critical to germination and growth rates.
    • Growth Rates of a Cheatgrass Community and Some Associated Factors

      Uresk, D. W.; Cline, J. F.; Rickard, W. H. (Society for Range Management, 1979-05-01)
      Abiotic and biotic factors were found to be related to growth rates of a cheatgrass sward using stepwise regression analyses. Soil temperature and plant tissue nitrogen showed a strong relation with growth rates from initiation of growth to peak production. After peak production, soil temperature was related to declining growth rates. Water stored in the soil profile had a weak relationship with growth rates and plant growth was completed before soil water became limiting. Equations were developed using soil temperature, nitrogen content of plant tissues, and live herbage production to estimate future production of cheatgrass.
    • Growth Rates of Natural Amazonian Forest Trees Based on Radiocarbon Measurements

      Mozeto, A. A.; Fritz, Peter; Moreira, M. Z.; Vetter, E.; Aravena, Ramon; Salati, Eneas; Drimmie, R. J. (American Journal of Science, 1988-01-01)
      Evergreen trees in the tropical rain forest of the Amazonas Basin can produce growth rings which are not necessarily related to annual events. Therefore, estimation of growth rate cannot be done by dendrochronology. This report presents a technique for determining the growth rate of these trees based on radiocarbon measurements of two segments of equal radial distance from the outer part of the tree trunk. The measured 14C activity is compared to local 14C fallout and growth rates are derived from models taking into account bomb 14C effects. Eleven trees from various parts of the Amazon Basin were analyzed. The average growth rates range from ca 5 to > 40 yr per centimeter corresponding to extrapolated ages from ca 60 to > 400 yr.