• Nutritional quality of browse after brush management on cross timbers rangeland

      Soper, R. B.; Lochmiller, R. L.; Leslie, D. M.; Engle, D. M. (Society for Range Management, 1993-09-01)
      We evaluated seasonal changes in browse quality 5-6 years after experimental manipulations to control unwanted woody vegetation using combinations of herbicide and fire on cross timbers rangeland in central Oklahoma. The study area consisted of two 32-ha replications of untreated controls and 4 brush treatments (tebuthiuron and triclopyr used singly or in combination with periodic prescribed burning); herbicides were applied in 1983 and fires initiated in 1985. Nutritional quality of blackberry (Rubus spp.), coralberry, (Symphoricarpos orbiculatus Moench), rough-leaf dogwood (Cornus drummondii Meyer), elm (Ulmus spp.), greenbrier (Smilax spp.), hackberry (Celtis spp.), and smooth sumac (Rhus glabra L.) were assessed by measuring crude protein, in vitro dry matter digestibility, neutral detergent fiber, acid detergent fiber, and moisture content. Crude protein concentrations of browse were 14% higher on herbicide-treated areas compared to untreated controls and 11% higher on triclopyr treatments compared to tebuthiuron treatments. In vitro dry matter digestibility was 9% higher on herbicide-treated areas compared to untreated controls. Fiber constituents and moisture content were not influenced by brush treatments. Prescribed burning combined with herbicide applications did not improve the quality of browse. Our results indicate that browse quality can be improved for white-tailed deer by applications of tebuthiuron or triclopyr and improvements persist for up to 6 years post treatment.
    • Old World bluestem response to fire and nitrogen fertilizers

      Berg, W. A. (Society for Range Management, 1993-09-01)
      Old World bluestem (Bothriochloa ischaemum L.) is being extensively established on marginal farmland in the Southern Plains. This 4-year field study in western Oklahoma developed guidelines for burning and N fertilization of Old World bluestem on calcareous and noncalcareous soils. Plots were on 'lron Master' Old World bluestem on a calcareous soil (Quinlan loam, shallow Typic Ustochrepts) and a noncalcareous soil (Carey loam, Typic Argiustolls). On each soil 4 blocks were split (spring burned, unburned) and N treatments (none, urea, ammonium nitrate) and time of N application (early, late) were randomly assigned within each burn treatment. Burning decreased (P<0.01) herbage yields by 6 to 30% per year. Nitrogen fertilizer broadcast at the rate of 50 kg N ha-1 increased herbage production about threefold. Ammonium nitrate fertilization resulted in 20% more herbage production than urea fertilization 1 year, and in equal production 2 years. The 4th year, application of ammonium nitrate in early April increased production by 20% compared to early April application of urea, urea was as effective as ammonium nitrate when either was applied in late April. Burning or calcareous soil had no adverse influence on the effectiveness of urea as compared to ammonium nitrate. Management implications for western Oklahoma and adjacent areas include: burn Old World bluestem only when necessary to remove substantial amounts of standing dead herbage, and broadcast urea 3 to 4 weeks after grass initiates growth when seasonal rains are more likely to move the urea into the soil, thereby decreasing potential for N loss by volatilization.