Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Florida is the second leading horticulture state in the United States with a total annual industry sale of over $12 Billion. Due to its competitive nature, agricultural plant production represents an extremely intensive practice with large amounts of water and fertilizer usage. Agrochemical and water management are vital for efficient functioning of any agricultural enterprise, and the subsequent nutrient loading from such agricultural practices has been a concern for environmentalists. A thorough understanding of the agrochemical and the soil amendments used in these agricultural systems is of special interest as contamination of soils can cause surface and groundwater pollution leading to ecosystem toxicity. The presence of fragile ecosystems such as the Everglades, Biscayne Bay and Big Cypress near enterprises that use such agricultural systems makes the whole issue even more imminent. Although significant research has been conducted with soils and soil mix, there is no acceptable method for determining the hydraulic properties of mixtures that have been subjected to organic and inorganic soil amendments. Hydro-physical characterization of such mixtures can facilitate the understanding of water retention and permeation characteristics of the commonly used mix which can further allow modeling of soil water interactions. The objective of this study was to characterize some of the locally and commercially available plant growth mixtures for their hydro-physical properties and develop mathematical models to correlate these acquired basic properties to the hydraulic conductivity of the mixture. The objective was also to model the response patterns of soil amendments present in those mixtures to different water and fertilizer use scenarios using the characterized hydro-physical properties with the help of Everglades-Agro-Hydrology Model. The presence of organic amendments helps the mixtures retain more water while the inorganic amendments tend to adsorb more nutrients due to their high surface area. The results of these types of characterization can provide a scientific basis for understanding the non-point source water pollution from horticulture production systems and assist in the development of the best management practices for the operation of environmentally sustainable agricultural enterprise

No description available.

Graduation date: 1994

Call number: LD2668 .T4 1984 M84 / Master of Science

The effects of sulfur-containing amendments (H₂SO₄,Al₂(SO₄)₃ and gypsum) or crust formation, soil chemical properties, seedling emergence and yields of onions (Allium cepa), tomatoes (Lycopersicum esculentum) and chili peppers (Capsicum sp.) were studied on a Pima clay loam soil. Treatments were surface applied on a strip above the seeds. The chemicals influenced the penetrometer index, soil-pH, electrical conductivity, DPTA-extractable soil Fe, Cu, Zn, Mu and seedling emergence in two greenhouse experiments. Gypsum and H₂SO₄ increased seedling emergence while Al₂(SO₄)₃ reduced the soil-pH and EC more than H₂SO₄ and gypsum. Based upon penetrometer readings, H₂SO₄ was the best anti-crusting agent tested followed by gypsum and Al₂(SO₄)₃. At the end of the study, all soil samples were very low in KCl extractable Al, showing that Al toxicity was not responsible for seedling damage. Gypsum decreased levels of Mn and Zn but did not affect Fe and Cu. Al₂(SO₄)₃ increased Fe and Zn, decreased Cu but did not affect Mn. H₂SO₄ did not affect extractable Mn, Cu, Zn and Fe levels. In a field study using two water qualities at Safford, gypsum produced the most tomato seedlings whereas Al₂(SO₄)₃ and H₂SO₄ produced the least. Onion stand counts were not affected by the chemicals with either water. Gypsum, H₂SO₄ and Al₂(SO₄)₃ polymer produced the highest pepper stand counts with the saltier water but there were no differences with lower salt water. Tomatoes produced the highest yield with gypsum and lowest with H₂SO₄ and Al₂(SO₄)₃ with saltier water. With lower salt water, gypsum produced highest yield, followed by the H₂SO₄. Both H₂SO₄ treatments produce low yields. Onions showed no treatment response under lower salt water, while with saltier water, gypsum and H₂SO₄ produced the highest yields. Pepper yields were not affected by amendments with the lower salt water. Al₂(SO₄)₃ polymer, H₂SO₄ and gypsum increased yields with the saltier water. Varieties of peppers and tomatoes produced different yields in response to water quality in a supplementary field study.

No description available.

This study examined the effects of replicating woodland soil surface horizonation on the nutrient status of underlying soils and the initial establishment and growth of trees. A total of 283 container grown trees were planted in a bufferzone around a future landfill site. Control amendments consisted of an 8 cm layer (0.5 m3) of wood chips applied in a circular area of 4.6 m2 around the trees' planting pit. For the treatment, a 2.5 cm layer of composted biosolids (0.15 m3 or 80 Mg/ha) was applied in a circular area of 4.6 m2 around the trees' planting pit followed by an 8 cm layer (0.5 m3) of wood chips. The results indicate that the replication of woodland soil surface attributes using composted biosolids can significantly improve the nutrient status of underlying soil. Some significant effects were seen under control conditions, too. However, the effects on tree establishment and growth parameters were, for the most part, not statistically significant.

This dissertation examined the microbial ecology of Listeria monocytogenes in three distinctly different environments: a cheese microbial community; a farm environment; and a soil microbial community. The aim of the first study was to investigate the effects of L. monocytogenes on the composition of the surface microflora on washed rind soft cheese. Two trials with washed rind cheeses that were inoculated with 100cfu cm⁻² of a L. monocytogenes six strain cocktail were conducted. The first trial had to be terminated early (day 28) as contamination of Pseudomonas spp. from the initial brine did not produce the expected characteristics of the cheese during the aging period. For the second trial, cheese samples were aged in the lab for 60 days according to the cheesemakers specifications. Surface cheese rind samples were collected from both control and inoculated cheeses every 7 days. Cheese rind samples were analyzed through the standard BAM method for enumeration of L. monocytogenes and through amplification of the V4 region of 16S rRNA and ITS regions for identification of the surface rind bacterial and fungal communities, respectively. Our data showed that Pseudomonas spp. significantly changed the composition of the microorganisms found on the surface of the rind while L. monocytogenes had little effect. In addition, although the concentration of L. monocytogenes increased to levels of 10⁶ cfu cm⁻² based on the enumeration data, the genetic data was not able to identify it in the flora due to the fact that other genera were found at much higher concentrations, which is a limitation of molecular methods used for identification of pathogens in foods. For the second study the presence and incidence of L. monocytogenes on farms that either produce raw milk cheese or supply the milk for raw milk cheese production was investigated. Five farms were visited and in total 266 samples were collected from barn, environmental, and milk sites. L. monocytogenes prevalence was found to be at 6% from all the farms tested with 10 isolates found in the barn samples, 5 from environmental sites and 1 from milking equipment. Samples were identified to the genus level through a modified BAM method and speciated though multiplex PCR. Included in the pathogenic isolates was a DUP-1042B L. monocytogenes strain that has been implicated in major outbreaks, which emphasizes the adaptability and persistence of highly pathogenic stains in food manufacturing environments. Results from this study continue to support the fact that contaminated silage can be an important reservoir of the pathogen in a dairy farm setting. From our data and field observations we identified that drinking water sources for the animals is also an important reservoir of L. monocytogenes in farm environments. More importantly this study has shown the importance of continuous monitoring of environmental sites for the presence of the pathogen, particularly in silage. Lastly manure amended soils in the northeastern U.S. were tested for the presence and survival of rifampicin resistant Escherichia coli (rE. coli), generic E. coli (gE. coli) and Listeria spp.. Both gE.coli and rE.coli samples were processed using either direct enumeration, MPN or bag enrichment methods. Samples were taken from both tilled and surface dairy solid manure-amended plots. Listeria samples were processed using a modified BAM method. Listeria presence was constant throughout the study. In contrast, rE. coli and gE. coli levels declined with time. The main conclusions of this study were that soil type, location and physical characteristics have a significant role in the survival of bacterial populations of rE. coli, gE. coli and Listeria spp. in soil. Dairy solids application does not seem to have a long term effect on the natural microbial population of soils. Tilling of soils results in increased survival of the bacterial population due to the fact that it increases soil pore size and facilitates moisture entry, which in turn has been shown to increase bacterial survival rates. Data from this research will assist in the creation of preventative measures that lead to the elimination of pathogen reservoirs. It will be further used to verify that a 120 day interval following manure application should be sufficient to ensure food safety of edible crops subsequently planted on these soils.

by Ngar, Yuen-ngor. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 186-196). / Chapter Chapter 1 --- Introduction Page / Chapter 1.1 --- Sludge as a waste problem --- p.1 / Chapter 1.2 --- The degraded geological environment of Hong Kong --- p.2 / Chapter 1.3 --- Use of weathered granitic material and sand as planting media --- p.3 / Chapter 1.4 --- Need of soil improvement material --- p.4 / Chapter 1.5 --- Potential for land application of sewage sludge --- p.5 / Chapter 1.6 --- Objectives of study --- p.6 / Chapter 1.7 --- Significance of study --- p.6 / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Soil organic amendment for vegetation establishment --- p.9 / Chapter 2.2 --- Types and properties of sewage sludge --- p.10 / Chapter 2.3 --- Guidelines for land application of sludge --- p.12 / Chapter 2.3.1 --- Cation exchange capacity --- p.13 / Chapter 2.3.2 --- Zinc equivalent concept --- p.14 / Chapter 2.4 --- Effects of sludge on soil chemical and physical properties --- p.15 / Chapter 2.4.1 --- Chemical properties --- p.15 / Chapter 2.4.2 --- Physical properties --- p.18 / Chapter 2.5 --- Effects of sludge application on vegetation --- p.19 / Chapter 2.5.1 --- Germination --- p.19 / Chapter 2.5.2 --- Grass growth --- p.20 / Chapter 2.6.1 --- Choice of heavy metals for study --- p.21 / Chapter 2.6.2 --- Factors governing heavy metal availability --- p.25 / Chapter 2.6.3 --- Effects of lime on sludge-amended soil and the heavy metal availability --- p.26 / Chapter 2.6.4 --- Assessing available sludge-borne heavy metals --- p.27 / Chapter Chapter 3 --- Germination and seedling growth of bermudagrass in sludge-amended sand and CDG / Chapter 3 .1 --- Introduction --- p.30 / Chapter 3.2 --- Experimental design --- p.31 / Chapter 3.3 --- Experimental results --- p.34 / Chapter 3.3.1 --- Seed germination --- p.34 / Chapter 3.3.2 --- Seedlings and biomass growth --- p.35 / Chapter 3.3.3 --- DTPA-Extractable heavy metals --- p.39 / Chapter 3.3.4 --- Total heavy metals in plant tissue --- p.44 / Chapter 3.3.5 --- Chemical properties of the soil substrates --- p.49 / Chapter 3.4 --- Discussion --- p.54 / Chapter 3.4.1 --- Germination --- p.54 / Chapter 3.4.2 --- Nutrient effect --- p.56 / Chapter 3.4.3 --- Heavy metal availability from substrates --- p.59 / Chapter 3.4.4 --- Heavy metal uptake by the seedlings --- p.61 / Chapter 3.4.4.1 --- Metal uptake efficiency --- p.61 / Chapter 3.4.4.2 --- Amount of heavy metal uptake --- p.63 / Chapter 3.4.5 --- Textural characteristics --- p.66 / Chapter 3.5 --- Conclusions --- p.67 / Chapter Chapter 4 --- Growth and heavy metal uptake by bermudagrass grown in sludge-amended substrates / Chapter 4.1 --- Introduction --- p.70 / Chapter 4.2 --- Experimental design --- p.71 / Chapter 4.3 --- Results --- p.74 / Chapter 4.3.1 --- Biomass growth --- p.74 / Chapter 4.3.2 --- Heavy metal content of plant tissues --- p.82 / Chapter 4.3.2.1 --- Heavy metal content of the shoot --- p.83 / Chapter 4.3.2.2 --- Heavy metal content of the root --- p.89 / Chapter 4.3.3 --- Comparing the heavy metal levels in the shoot and root portions --- p.93 / Chapter 4.3.4 --- DTPA-extractable heavy metal content in soil substrates --- p.94 / Chapter 4.3.5 --- Chemical properties of the substrates --- p.100 / Chapter 4.4 --- Discussion --- p.103 / Chapter 4.4.1 --- Shoot biomass (First clipping) --- p.104 / Chapter 4.4.2 --- Shoot biomass (Second clipping) --- p.105 / Chapter 4.4.3 --- Shoot biomass ratio between the two clippings --- p.107 / Chapter 4.4.4 --- Total shoot biomass --- p.108 / Chapter 4.4.5 --- Root biomass and root: shoot ratios --- p.112 / Chapter 4.4.5.1 --- Nutrient effect --- p.113 / Chapter 4.4.5.2 --- Heavy metal phytotoxicity --- p.115 / Chapter 4.4.6 --- Total biomass production --- p.117 / Chapter 4.5 --- Conclusions --- p.118 / Chapter Chapter 5 --- Effect of lime on the growth and heavy metal uptake of bermudagrass in sludge-amended substrates / Chapter 5.1 --- Introduction --- p.121 / Chapter 5.2 --- Experimental design --- p.123 / Chapter 5.3 --- Results --- p.125 / Chapter 5.3.1 --- Biomass growth --- p.126 / Chapter 5.3.2 --- DTPA-extractable heavy metals --- p.133 / Chapter 5.3.3 --- Heavy metal uptake by the shoot portion --- p.138 / Chapter 5.3.4 --- Heavy metal uptake by the root portion --- p.147 / Chapter 5.3.5 --- Comparing metal uptake between shoot and root portions --- p.151 / Chapter 5.3.6 --- Chemical properties of substrates --- p.155 / Chapter 5.4 --- Discussion --- p.157 / Chapter 5.4.1 --- Effect of sludge and lime treatments on pH --- p.158 / Chapter 5.4.2 --- Patterns of DTPA-extractable metals and plant uptake --- p.159 / Chapter 5.4.2.1 --- Variation of heavy metal levels with liming rates --- p.160 / Chapter 5.4.2.2 --- Variation of heavy metal levels with sludge loading rates --- p.161 / Chapter 5.4.2.3 --- Bermudagrass as metal accumulator --- p.162 / Chapter 5.4.3 --- Metal uptake by the root and shoot --- p.162 / Chapter 5.4.3.1 --- Antagonistic interactions --- p.163 / Chapter 5.4.3.2 --- Parititioning of heavy metals in shoot and root --- p.163 / Chapter 5.4.4 --- Poor biomass growth --- p.166 / Chapter 5.4.4.1 --- Heavy metal toxicity --- p.166 / Chapter 5.4.4.2 --- Effect of poor soil conditions --- p.167 / Chapter 5.5 --- Conclusions --- p.177 / Chapter Chapter 6 --- Conclusions / Chapter 6.1 --- Summary of findings --- p.179 / Chapter 6.2 --- Implications of the study --- p.180 / Chapter 6.3 --- Limitations --- p.182 / Chapter 6.4 --- Suggestions for further studies --- p.184 / References --- p.186 / Appendix