• Abundance, seed pod nutritional characteristics, and seed germination of leguminous trees in South Kordofan, Sudan

      Hashim, I. M. (Society for Range Management, 1990-07-01)
      Seed pods of leguminous trees are a potential source of livestock feed in Sudan. Abundance, seed pod nutritional characteristics, and seed germination of leguminous trees in south Kordofan were examined. In the study area, densities of all trees and leguminous trees were 99.8 and 24.0 trees/ha, respectively. Percentages of crude protein in seed pods, after seeds were removed, ranged from 0.1 to 27.2, in vitro dry matter digestibility from 28.1 to 59.8, in vitro organic matter digestibility from 23.3 to 59.9, and neutral-detergent fiber from 50.8 to 79.3 during the dry season. Seeds of sunut (Acacia nilotica) and girfaldud (Albisia anthelmintica) germinated only after soaking in a large volume of water; they may have contained chemical inhibitors that restricted germination. Undamaged seeds of other tree speciea required scarification with concentrated sulphuric acid for 5 to 150 minutes to give optimum germination in 2 to 9 days. Seeds damaged by Bruchid beetles failed to germinate if their embryos were eaten, but germination of damaged seeds whose embryos were not eaten was sometimes as high as that of the controls. Bores made by the Bruchids in seeds may have facilitated moisture inbibition.
    • Acacias in the New Mexico Desert

      Ishaque, Muhammad; Beck, Reldon; Pieper, Rex (Society for Range Management, 2002-12-01)
    • Biological and physical factors influencing Acacia constricta and Prosopis velutina establishment in the Sonoran Desert

      Cox, J. R.; Alba-Avila, A.; Rice, R. W.; Cox, J. N. (Society for Range Management, 1993-01-01)
      Over the past century woody plants have increased in abundance on sites formerly occupied by grasslands in the Sonoran Desert. Woody plant invasion has been associated with a multitude of biological and physical factors. This study was conducted to determine temperature, soil, fire, rodent, and livestock effects on the germination and establishment of whitethorn acacia (Acacia constricta Benth.) and velvet mesquite (Prosopis velutina (Woot.) Sarg.). Optimum termination temperatures for both shrubs ranged from 26 to 31 degrees C, and seedling emergence was greatest from seed sown at 1 to 2 cm depths in sandy loam soil. Merriams kangaroo rats (Dipodomys merriami) fed seeds in the laboratory removed seed coats and planted embryos at 2 to 4 cm depths in a sandy loam soil. Prescribed fire killed 100% of seed placed on the soil surface but had no measurable effect on the germination of seed planted at 2 cm. After passage by sheep, about 6% of the A. constricta and 13% of the P. velutina seeds germinated while after passage by cattle, only 1% of the A. constricta and 3% of the P. velutina seed terminated. Embryo planting by rodents may improve survival efficiencies for these legunminous shrub seedlings, but seed consumption and passage by sheep and cattle appear to adversely affect seed germination. Dipodomys merriami, rather than domestic livestock, may be responsible for the spread of these shrubs in the Sonoran Desert.
    • Characterization and habitat preferences by white-tailed deer in Mexico

      Bello, J.; Gallina, S.; Equihua, M. (Society for Range Management, 2001-09-01)
      We analyzed the habitat preferences of white-tailed deer in a 1,000 ha area in an arid region of northeastern Mexico where drinking water is abundant throughout the year (via 33 water troughs). Seven habitat types in the study area were identified and characterized. Within each habitat, feeding, searching, and bedding activities were evaluated during the reproduction, postreproduction and fawning seasons of the annual deer cycle. The Acacia-Celtis habitat provided the greatest amount of hiding and thermal cover and edible food. The Prosopis habitat also provided significant hiding and thermal cover. Hilaria and Opuntia were the most open habitats. Habitat preferences, evaluated by radiotracking 14 deer over a period of 2 years, varied between sexes and years (P << 0.00001), but not among seasons (P > 0.05). Male deer preferred open habitats, while females preferred more densely covered ones. Males and females avoided Prosopis during 1996. Both sexes distributed the 3 activities more evenly during 1996 than during 1995. In 1995, females preferred Flourensia and Acacia-Celtis habitats for all activities, and during 1996 males preferred Hilaria and Leucophyllum. Between year changes in precipitation could explain the observed variability: during 1995 rainfall was 136 mm, as compared to 276 mm in 1996. Requirements for cover increased markedly in 1995 due to high predation and extremely dry conditions. Overall, our study shows that under good weather conditions, habitat preferences are best explained by variables associated with food availability, while thermal cover is more important under harsh weather conditions, even when drinking water is abundant.
    • Control of woody plants in grazing lands on the Pacific Coast of Mexico

      Garcia-Holquin, M.; Bovey, R. W.; Schuster, J. L. (Society for Range Management, 1991-09-01)
      Greenhouse and field experiments were conducted to evaluate herbicides for control of Palma de llano (Sabal rosei Mart.), jarretaders (Acacia hindsii Benth), huinol (Acacia cymbispina Sprague & Riley), and guazima (Guazuma ulmifolia Lam.), woody species encroaching in grazing lands on the Pacific Coast of Mexico. In the greenhouse, picloram at 0.14 and 0.28 kg ae/ha killed all jarretadera, huinol, and guazima plants. Mixtures of picloram + clopyralid, dicamba, or triclopyr at 0.07 + 0.07 and 0.14 + 0.14 kg/ha also killed most plants. Trielopyr killed all huinol at 0.14 and 0.28 kg/ha but not all jarretadera or guazima. Clopyralid was effective on jarretadera and huinol but not as effective as picloram. Dicamba was ineffective on jurretadera and killed 88 to 100% of the huinol and gunzima plants at 0.28 kg/ha. The palm could not be grown in the greenhouse. In the field, foliar sprays of triclopyr or picloram st 0.4 and 0.3 g ae/L water, respectively, killed 70% or more of the jarretadera, huinol and gunzima but 77% or less of the palm. No herbicide successfully controlled jarretadera in 1988. Hexazinone applied to the soil killed 82% or more of the palm plants at 0.5 g ai/2.5 cm of stem diameter. Soil-applied tebuthiuron pellets were not effective on jarretaders or palm, but the briquettes (Brush Bullets) at 2 and 4 g/ 2.5 cm of stem diameter killed 50, 60, and 83% or more of the huinol, palm, and guazima plants, respectively.
    • Creosotebush control and forage production in the Chihuahuan and Sonoran deserts

      Morton, H. L.; Ibarra-F, F. A.; Martin-R, M. H.; Cox, J. R. (Society for Range Management, 1990-01-01)
      Creosotebush (Larrea tridentata [Sesse & Moc. ex DC.] Cov) and other shrubs have spread into semidesert grasslands of the southwestern United States and northern Mexico; and as creosotebush increases, perennial grasses decrease. This study evaluated 3 rates of tebuthiuron and 4 mechanical treatments in 1981 and 1982 for creosotebush control at 4 locations, 3 in Chihuahua, Mexico, and 1 in Arizona, U.S.A., and compared forage production after treatment with untreated checks. Creosotebush mortalities averaged across locations and years were 75, 87, 93, 3, 33, 68, and 68% for the 0.5, 1.0, and 1.5 kg ai/ha tebuthiuron (N-(5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea), land imprinting, 2-way railing, disk plowing, and disk plowing with contour furrowing treatments, respectively. Forage production averaged across locations and years was 529, 524, 606, 303, 344, 290, 330, and 302 kg/ha for the 0.5, 1.0, and 1.5 kg ai/ha tebuthiuron, land imprinting, 2-way railing, disk plowing, disk plowing with furrowing, and untreated check treatments, respectively. Precipitation was below long-term means at all Chihuahuan locations in 1983, and forage production was significantly greater on most treated plots where brush was controlled than on untreated checks. At the Arizona location precipitation was above the long-term mean in 1983 and all plots treated in 1981, except the disk plowing and disk plowing with furrowing which destroyed perennial grasses, produced significantly more grass forage than the untreated checks. Precipitation was above the long-term means at all locations in 1984 and about half of the plots treated with tebuthiuron produced significantly more forage than the untreated checks but not any mechanically treated plots. When treatments reduced shrub density and remnants of native forage grasses were present, forage production increased in both wet and dry years.
    • Cultivated and native browse legumes as calf supplements in Ethiopia

      Coppock, D. L.; Reed, J. D. (Society for Range Management, 1992-05-01)
      Efficient use of roughages is important for calf management in the Boran pastoral system. Using local legumes as protein supplements may improve fiber utilization and thus be an appropriate intervention. Fruits (pods and seeds) of Acacia tortilis (Forsk.) Hayne subsp. spirocarpa (Hochst. ex A. Rich) Brenan, leaves of A. brevispica (Harms), and cowpea [Vigna unguiculata (L.) Walp] hay were compared with alfalfa (Medicago sativa L.) hay as protein supplements for calves using 2 approaches. Sheep fed native grass hay under confinement were used for a controlled evaluation in growth and metabolism trials. Calves grazing dry-season forage under simulated pastoral management provided in evaluation under field conditions. All supplements increased (P<0.05) nitrogen (N) intake, growth rate, and conversion of dry-matter intake into liveweight for sheep compared to unsupplemented animais. Calf growth and water intake were increased (P<0.05) relative to the control by ail supplements except cowpea hay. When statistically adjusted to a common level of N intake, N retention was similar (P>0.05) among all groups of supplemented sheep. Compared to alfalfa and cowpea diets, tanuinfferous Acacia diets had a negative effect (P<0.05) on true-N digestibility, but this was offset by their positive effect (P<0.05) on reducing loss of urinary N. The A. tortilis diet had a lower (P<0.05) true-N digestibflity than the A. brevispica diet, which was probably influenced by soluble phenolics in pods and seeds. On a nutritional basis these Acacia and cowpea materials art suitable for inclusion in improved feeding systems for Boran calves
    • Effects of nurse-plant canopy light intensity on shrub seedling growth

      Fulbright, T. E.; Kuti, J. O.; Tipton, A. R. (Society for Range Management, 1997-11-01)
      Spiny hackberry (Celtis pallida Torr.) occurs almost exclusively beneath honey mesquite (Prosopis glandulosa Torr.) canopies. We hypothesized that maximum early seedling growth of spiny hackberry occurs at light intensities similar to those beneath honey mesquite, whereas maximum growth of huisache (Acacia smallii Isely), a plant characteristic of nonshaded habitats, occurs at light intensities near full sunlight. Photosynthetic photon flux densities (PPFD) under 4 honey mesquite canopies and in adjacent interspaces were recorded during July 1990 to July 1992. Seedling growth indices of spiny hackberry and huisache were determined at PPFDs characteristic of those found under honey mesquite canopies and in herbaceous interspaces. In contrast to our prediction, relative growth rate (Kw), net assimilation rate (NAR), and seedling mass of spiny hackberry were greater in sunlight than in shade characteristic of honey mesquite canopies. Huisache also had greater Kw, NAR, and total seedling mass in sunlight. Aggregation of spiny hackberry beneath honey mesquite canopies does not result from an ability to maintain maximum seedling growth at low light intensities.
    • Nutrient utilization of acacia, haloxylon, and atriplex species by Najdi sheep

      Bhattacharya, A. N. (Society for Range Management, 1989-01-01)
      Two digestibility and nitrogen balance studies were conducted to evaluate nutrient utilization of 3 commonly browsed range plants by the desert sheep in Northern Saudi Arabia. In experiment 1, 15 Najdi wether lambs (40 kg) divided in 3 lots of 5 were randomly allotted to 3 diets of 200 g ground barley (Hordeum vulgare L.) grain and 800 g either alfalfa hay (Medicago sativa L.), dried Acacia cynophylla Lind., or Haloxylon persicum Bge. clippings. In experiment 2, 8 Najdi wethers were randomly alloted to treatments of 2 kg green alfalfa or 2 kg green Atriplex halimus L. clippings per day. Salt content of the soil and salt bush, Atriplex sp., were also determined. The organic matter (OM), crude protein (CP), and crude fiber (CF) on dry matter basis (DMB) were, respectively, 90, 15, 31% for alfalfa; 90, 13, 30% for acacia forage; and 87, 10, 37% for haloxylon shrub. In experiment 1, the OM digestibility was 66, 56, 53%; CP digestibility was 73, 68, and 55%; and CF digestibility was 44, 33, and 16%, respectively, for alfalfa, haloxylon, and acacia diets. The daily nitrogen balance was +4 g for both alfalfa and acacia groups. The haloxylon group had a negative nitrogen balance (-1.9%), showing no apparent retention of absorbed nitrogen. In experiment 2, the atriplex clippings contained 73% OM, 18% CP, and 24% CF on DMB, the respective digestibility values being 61, 79, and 39%. Even though the digestibility of as well as percent retention of absorbed nitrogen in atriplex group were markedly higher than those in alfalfa group, the digestibility of CF was lower (P<.01) in the former (39%) as compared to that in latter group (54%). The sodium, potassium, and chloride concentration of soils of high and low salinity had no influence on their contents in atriplex forage, with average values being 10, 2.5, and 16.5% respectively.
    • Shrub Invasion of Southern Arizona Desert Grassland

      Brown, A. L. (Society for Range Management, 1950-07-01)
    • Technical Note: Root-plowing effects on nutritional value of browse and mast in south Texas

      Ruthven, D. C.; Hellgren, E. C. (Society for Range Management, 1995-11-01)
      Leaf and mast material was collected from mesquite (Prosopis glandulosa Torr.), huisache (Acacia smallii Isely), granjeno (Celtis pallida Torr.), and hog plum (Colubrina texana (T.& G.) Gray) on both root-plowed and untreated sites in south Texas. Forages were analyzed for nitrogen (N), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD). Forages differed among species for N, NDF, and IVDMD. Leaf IVDMD of huisache and hog plum was higher on untreated sites. Huisache mast was higher in N and NDF concentrations, but not IVDMD, on untreated sites. Browsers on root-plowed sites may be forced to use forages of fewer digestible nutrients than on untreated sites. The cause of changes in browse quality following brush manipulation should be examined.
    • Vegetation dynamics following seasonal fires in mixed mesquite/acacia savannas

      Owens, M. K.; Mackley, J. W.; Carroll, C. J. (Society for Range Management, 2002-09-01)
      Fires were once a natural part of most savanna ecosystems, but lack of fine fuel and an active suppression policy have changed fire frequency and seasonality. Re-introducing fires to these systems has been touted as a cost-effective means to reduce woody cover while increasing herbaceous growth. We compared the effects of single, recurring annual, and biennial fires on the vegetation dynamics of a mixed mesquite/acacia (Prosopis/Acacia) savanna in southern Texas. Fires were conducted either during the growing season or the dormant season from 1991 through 1995. Some of the fire treatments were statistically unreplicated to permit a sufficient plot size for natural fire behavior. All plots showed a successional trajectory from short-grasses towards mid-grasses regardless of the fire season or frequency. The population size structure of perennial grasses was unaffected by the fires, with the basal area of most plants being less than 25 cm2. Forb diversity was high with over 100 different species identified in the experimental area. Forb composition, however, was unaffected by either the season or frequency of fire, but was related to the year of observation. Shrubs in this community typically sprout after disturbance, so little mortality was expected. The only observed mortality was of small shrubs or saplings (diameter < 3 cm) and of large trees which had woodrat (Neotoma micropus) nests at the base. Reintroducing growing season fires into mesquite/mixed acacia shrublands did not conclusively alter plant community composition. Burning during the growing season when environmental conditions were hotter and drier did not accelerate succession toward grass-dominated communities.