Browsing by Author "J. Paul Mueller, Committee Chair"

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    Evaluation of Robinia Pseudoacacia L. as Browse for Meat Goat Production in the Southeastern USA
    (2004-11-25) Snyder, Lori June Unruh; Larry D. King, Committee Member; James T. Green, Committee Member; Cavell Brownie, Committee Member; Jean Marie Luginbuhl, Committee Member; J. Paul Mueller, Committee Chair
    Demand for goat meat in the southeastern USA is steadily increasing as a result of preferences exhibited by expanding ethnic communities. Feeding systems can be developed to take advantage of the natural preference of goats for browse. A field study was undertaken in Raleigh, NC to measure the effects of spacing (1.0 or 0.5 m) and coppice height (0.25 or 0.5 m) of a 5-year old stand of black locust (BL; Robinia pseudoacacia L.) on growth characteristics such as herbage mass (HM), canopy height (H) and width, number and size of main branches, above ground woody biomass, and root collar diameter. A second objective was through regression analysis to identify one or more of the previously mentioned characteristics as a rapid method to estimate HM. The third objective was to determine the relationship between growing-degree-days (GDD) and HM, H, herbage quality indicators (N, in vitro true dry matter disappearance, neutral and acid detergent fiber (NDF and ADF), cellulose, and 72% sulfuric acid lignin) and anti-quality indicators (Folin-reactive phenolics, condensed and hydrolyzable tannins) of BL. The final objective was to evaluate the N metabolism of goats fed BL foliage. Results indicated that coppicing BL trees at 0.5 m and planting at the widest spacing (1.0 m) produced the greatest plant growth. Average HM (2,600 kg ha-1) was observed for the highest coppice height (0.5 m). The character most closely related to HM was size of main branches. In 1999, a dry year, there was a significant relationship between GDD and NDF, ADF (r2 =0.90 and 0.80, respectively). In 2000, a wet year, GDD was a poor predictor of NDF and ADF. For 1999 and 2000, GDD was a poor predictor of BL tannin concentrations. From the conclusions of the N metabolism trial, goats consuming BL had lower digestibilities and higher content of N in the feces. Overall, BL contributes well to a silvopastoral system.
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    Utilizing Rolled Rye Mulch for Weed Suppression in Organic No-Tillage Soybeans
    (2010-04-27) Smith, Adam Nelson; J. Paul Mueller, Committee Chair; S. Chris Reberg-Horton, Committee Co-Chair; Consuelo Arellano, Committee Member
    Rising demand for organic soybeans (Glycine max L.), coupled with high price premiums for organic products, has producers interested in making the transition to organic soybean production. However, organic soybean producers and those making the transition cite weed management as their biggest limitation. Current organic weed management relies heavily on cultivation. Cultivation has negative consequences on soil health and producers are interested in organic reduced and no-till production. Rye (Secale cereal L. cv. Rymin) cover crop was evaluated for weed suppression abilities and effects on soybean yield. Experiments were planted in 2008 and 2009 at three site locations. Rye was planted in the fall of each year and killed at soybean planting with a roller-crimper or flail-mower, creating thick weed-suppressing mulch with potential allelopathic properties. The mulch was augmented with one of three additional weed control tactics: pre-emergence corn gluten meal (CGM), post-emergence clove oil, or post-emergence high-residue cultivation. Rolled-crimped and flail-mowed treatments had similar weed suppression abilities. There were no differences between CGM, clove oil, or cultivation at most sites. Rye biomass level was the only independent variable that affected weed control. Rye biomass levels higher than 9,000 kg ha-1 were sufficient in controlling weeds. Organic soybean yields were similar to weed-free soybean yields at rye biomass levels higher than 9,000 kg ha-1. Goldsboro 2008, where rye biomass was 10,854 kg ha-1, the organic rye-only treatment yielded at 2,190 kg ha-1 and the weed-free treatment yielded at 2,143 kg ha-1. Plymouth 2008, where rye biomass was 9,526 kg ha-1, the organic rye-only treatment yielded 2,694 kg ha-1 and the weed-free treatment yielded at 2,809 kg ha-1. On the contrary, at low rye biomass levels (4,450- 6,606 kg ha-1), the organic rye-only treatment yielded 628- 822 kg ha-1 less than the weed-free treatment. High rye biomass levels are critical to the success of this production system. However, at rye biomass levels greater than 10,000 kg ha-1, severe soybean lodging was induced and potentially limited yield potential.