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Student Number : 9906840R - MSc research report - School of Animal, Plant and Environmental Science / The global increased demand for forest products has led to an increase in the area of exotic fast-growing forest plantations. An understanding of nutrient cycling in plantations is essential to enhance their productivity. Sustainable forest productivity involves the managing of nutrients and genetic factors to maximize yields such that they are increasing or non-declining through the maintenance of soil quality and selection of superior tree species and breeds. Komatiland Forests Limited (KFL), a South African forestry company, initiated a permanent sampling plot (PSP) programme in 1998, where it monitors over 30 foliar and soil parameters, as well as tree growth parameters. This study utilized a subset of the permanent sample plots (PSPs) database to compile a suite of foliar and soil parameters that can be used to better interpret stand productivity in pine plantations. Data from PSPs of pine species Pinus patula, Pinus elliottii and the hybrid Pinus elliottii x caribaea planted on dolomite, granite and shale were used in the statistical analyses as they were well represented in the dataset. The geological analysis revealed that parent material significantly affects soil organic carbon content; soil exchangeable K, soil Fe, soil Mn and foliar Mn concentrations. Exchangeable K was found to be low across the geologies ranging on average from 0.08 – 0.11cmol/kg. An accumulative effect was found in foliar concentration of Mn across the geologies and species, with average foliar Mn concentrations being as high as 1086ppm. No statistically significant differences were found at the geological level in soil N, P, exchangeable Ca, Mg & Na, Al, pH or soil texture. Neither were there any significant differences in foliar concentration of N, P, Ca, Mg, Na, Cu, Fe, Zn, B and S at the geological level of analysis. However significant correlations were found between soil cation exchange capacity, soil pH and foliar concentration of Zn, Mn, Mg and Ca. Pinus patula had significantly higher foliar concentrations of N (p<0.001), P (p<0.001). Mg (p=0.001), B (p=0.001) and S (p<0.001) than the other pine variants under analysis. However when species x geology interaction analysis was used P. patula only had significantly higher foliar concentrations with regard to N (p<0.001) and P (p<0.001), and lower foliar concentrations of Zn (p<0.001) and Na (p=0.041) than the other pine variants under analysis. Across the species and geologies, soil acidification resulted in low Ca (0.15-1.6 cmol/kg) and Mg (0.1-0.7cmol/kg) availability. Positive and significant correlations were found between foliar and soil concentrations of N (p=0.022), P (p=0.030), Mg (p<0.001) and Ca (p<0.001). Productivity of the hybrid was significantly higher than the other two species (p<0.001), while P. elliottii had significantly lower productivity than P. patula (p=0.001). Regression models and a principal component analyses revealed that from the dataset of soil and foliar chemical and physical parameters Mg Soil, CEC, N soil, N foliar, P foliar, K foliar, Cu foliar, B foliar, S foliar, C:N soil, Ca:Al soil, N:Ca foliar, N:K foliar, clay and silt are best correlated with stand productivity.

The objective of this study was to update the existing nutritional data available in the USDA National Nutrient Database for Standard Reference by providing revised nutritional information on the round and loin cuts evaluated in Phase III of the Nutrient Database Improvement Project. A total of 20 carcasses were selected from three packing plants across the United States, and round and loin subprimals from these carcasses were collected and transported to Texas A&M University. These subprimals were fabricated 14 to 21 d postmortem, dissected either raw or cooked, and divided to determine the amount of separable lean, separable fat, and refuse amounts per cut. Separable lean from these cuts was homogenized and proximate analyses were conducted in order to determine percent total chemical fat, protein, moisture, and ash. Cooking yields and fat retention values were determined for the cuts that were grilled and roasted. Cuts with external fat had higher cooking yields than cuts with external fat removed. Cuts with external fat had higher fat retention values than the cuts with no external fat. Dissection data indicated that cuts trimmed to lower levels of external fat had the highest values for percent lean and the lowest values for percent seam and external fat and bone-in cuts had the lowest values for percent lean and the highest values for percent refuse. Proximate analyses indicated a decrease in percent moisture as the percentage of total chemical fat increased. Also, round cuts evaluated in the study contained a lower percentage of total chemical fat than loin cuts on a raw basis. When total chemical fat was stratified by USDA quality grade, it was evident that there was a clear separation between upper Choice, lower Choice, and Select cuts. Data resulting from this study will be used to update the existing nutritional database and will provide a current nutritional profile for beef loin and round products.

Temporary changes in macroalgal abundance, percentage cover and areal biomass were surveyed on Nanwan (GPS: 21o56'00'N; 120o50'10'E) and Tiaoshi (GPS: 21o55'30'N; 120o 50'40'E) reefs (Kenting, Taiwan, Republic of China), during 1999-2000. Community structure and areal biomass showed significant changes in time and the maximal biomass was observed during March-April due to Sargassum spp. at Nanwan and Codium spp. at Tiaoshi. The maximal total areal biomass is not different between two years for Nanwan but significantly different for Tiaoshi mainly due to a marked biomass of Codium edule during 2000. Eutrophication on Nanwan and Tiaoshi reefs is the main cause for macroalgal blooming. Tissue composition analysis, nutrient enrichment and starvation treatments, bioassay and in situ extracellular alkaline phosphatase activity determination showed that growth of Sargassum duplicatum, Codium edule and Ulva latuca were limited by phosphorus during the early growth period while nitrogen during the fast growth period. Growth of Enteromorpha linza, Gracilaria coronopifolia and Laurencia papillosa were limited by phosphorus. Water temperature is the factor affecting the time for the start of development of young shoots and also for the peak of areal biomass and subsequent die-off of thallus. This investigation suggests that the reduction of water nutrient levels is an effective way in the retardation of over-growth of macroalgae on Nanwan and Tiaoshi reefs.

In north central Texas, USA, free-water surface wetlands have been constructed to treat pre-treated wastewater effluent from the Trinity River. Water quality and vegetation data from the first two years of operation (June 2003 to May 2005) were used to determine cell-to-cell and system-wide removal efficiency of total suspended solids (TSS), total phosphorus (TP) and total nitrogen (TN). The wetland system consisted of one non-vegetated sedimentation basin and a series of four connected, vegetated wetland cells. Temporal analyses displayed varying monthly, seasonal and yearly trends of the wetlands’ concentration of the three parameters. Spatial analysis results confirmed that TSS, TP and TN concentrations were greater at the beginning of the system as compared to the end of the wetland system. Percent reduction analyses showed that the second wetland cell (WC2) was the most efficient in TSS, TP and TN removal, while the last wetland cell (WC4) had the lowest reduction of the three parameters. TSS removal was significant (α = 0.05) moving consecutively among the sites in the wetland system, with exception to the last wetland cell. TP removal was only significant (α = 0.05) moving from the third wetland cell (WC3) to WC4, while TN removal was significant (α = 0.05) moving from the sedimentation basin to the first wetland cell (WC1) and then again moving from WC3 to WC4. Overall removal efficiency of the wetland system (from the Trinity River to WC4) was quite high, with reductions over 97% for TSS, 47% for TP and 67% for TN. N:P ratios decreased moving consecutively throughout the field-scale wetlands. Vegetation analyses found WCs 1 and 3 to contain the greatest vegetation species richness, while WC2 had the lowest richness. The vegetative composition of the four cells was mostly the same. A comparison was conducted between the nutrient reduction efficiency and vegetation data of this wetland system with data from a pilotscale wetland system that was operated from 1992 to 2000. The findings of this study suggest that during the first two years of operation, the wetland system’s performance is comparable to the pilot-scale wetlands which were operated for eight years.

Thesis (Ph.D.) -- University of Texas at Arlington, 2008.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 148-154).

2 pp.

In a field study of irrigated chile (Capsicum annum L.) production in southeastern Arizona and southwestern New Mexico from 2008 through 2009, soil and tissue test samples were analyzed for a full spectrum of nutrients at 16 different sites, including nitrogen (N) phosphorus (P), potassium (K), zinc (Zn), iron (Fe), and boron (B), with the objective of evaluating soil and tissue nutrient testing procedures and establishing basic testing guidelines and recommendations with respect to yield potentials. Results for soil and tissue analysis were correlated to yield results. The results provide estimates for baselines which can be tested through subsequent calibration experiments for the development of recommendations for critical soil and tissue test values. These soil test and plant nutrients values will be evaluated in subsequent experiments in an effort to better define fertilizer nutrient inputs in order to gain better nutrient management efficiencies in irrigated chile production systems.

The effects of straw burning and drying-rewetting cycles on nutrient availability were studied in an attempt to assess the practical importance of the yearly precropping practice by farmers of burning off excess crop residues and of the seasonal climate of North-East Nigeria. Changes in soil properties resulting from heating three soils up to 700°C and from field burning of straw on three soils were determined. Heating to 250° did not affect soil texture but increased exchangeable NH4+-N, available P, Fe, Mn and phosphate adsorption. A peak of NH4+-N representing decomposed organic N, retained by cation exchange sites was observed after heating at 250°. Soil physical and chemical properties were changed by heating to ≥500^o, resulting in fusion of clay particles into sand-sized particles, decomposition of soil organic matter and alteration of soil minerals with a corresponding increase in non-exchangeable cation status of the soils. The changes observed after field burning of straw were mainly due to deposition of ash; these include a dramatic increase in phosphate adsorption and addition of considerable amounts of inorganic P and exchangeable cations. The availability to maize of the inorganic P returned in ash after field burning or released as a result of laboratory heating of soils was assessed over a 7 day period. The increased P status of the soils after straw burning or heating was not significantly reflected in plant uptake of P but K adsorption was enhanced from the ash. Fertilization of heated and field burnt + overlying ash soil samples resulted in adsorption of P with a corresponding reduction of P concentration in the soil solution and P uptake. The N mineralized after rewetting air-dried clay soils or those containing very low organic matter was insignificant. Investigations also showed that, when dried soils were rewetted, the flush of mineral N was derived mainly from soil organic matter and not from killed microbial cells.