Previous research has shown that treatment of poultry litter with alum is an effective management strategy to reduce phosphorus (P) solubility in litter thereby reducing potential P losses to surface runoff after surface applications. However, limited data are available evaluating alum-treated poultry litter (ATPL) environmental impact in cultivated systems and how its application will affect crop production. In addition little is known as to how its application affects various P fractions or exchangeable Aluminum (Al) content in treated soils. Two, 3-yr field trials with corn (Zea mays L.) were used to show that, when applied at rates based on current litter management strategies, ATPL resulted in yields similar to those achieved through applications of non-treated poultry litter (NPL). These trials also showed that ATPL applications resulted in lower soil P status and decreased P losses in surface water runoff compared to application of NPL. A 4-yr field trial with fescue (Festuca arudinacea) also showed no significant differences in productivity when comparing ATPL and NPL. This trial was utilized to evaluate the distribution of P in soils receiving ATPL. Soil analysis data showed that ATPL applications result in decreased water-extractable P (H2O-P) and that this decrease was associated with an elevation in NaOH extractable organic soil P. A laboratory incubation was utilized to evaluate the short and long-term impact of ATPL application on soil pH, exchangeable soil Al and H2O-P. Data from this incubation confirmed that the relationship between soil pH and exchangeable Al is not adversely affected by ATPL applications. Also, variations in the H2O-P content of soils treated with two different ATPL sources could not be associated with differences in Al:P ratio or soluble P content of the two litters, providing evidence that additional characteristics also control P availability after incorporation in soil. / Ph. D.

Little is known about the effect of biochar created from poultry litter on soil properties and plant growth. Five studies were conducted using biochar made by the fast pyrolysis of poultry litter. Two were greenhouse studies and three were field studies. The greenhouse studies were conducted with a sandy loam soil and a silt loam soil. First, lettuce (Lactuca sativa L) seeds were germinated in the greenhouse across biochar incorporation rates from 0 to 100%, and secondly a trial was conducted in which green peppers (capsicum annum L) were grown in soils with up to 5% biochar by weight. Elemental analysis was completed on the biochar and the soils were analyzed for bulk density (BD), water holding capacity (WHC), pH, cation exchange capacity (CEC), soluble salts (SS) and extractable nutrients. The field studies all used the rates of 0, 4.5, and 9 Mg ha-1 biochar and the rates were applied in the early spring of 2009 and 2010. Biochar was surface applied on a tall fescue pasture [Lolium arundinaceum (Schreb.) Darbysh. (=Festuca arundinacea Schreb. subsp. arundinacea)] and tilled in on two green pepper field sites. The soils were analyzed for carbon (C) content, pH, CEC, Mehlich 1 P, and SS. No significant difference was found in yields at any of the three sites, but differences in forage quality were found. Biochar made from poultry litter showed several benefits as a soil amendment in all the studies, but application rates would be limited by soil test P and pH. / Master of Science

Manure from turkey poults on five diets were extracted both fresh (wet) and after drying. Soils amended with wet manure were also extracted. Phosphorus, Cu, and Zn were extracted with 0.01 M CaCl₂ and acidic Mehlich III extractant (Zn in soil extracts was not evaluated). Dietary treatments were (1) normal phytic acid (NPA) corn and 0.135% inorganic P (NPA diet); (2) NPA corn, 600 units phytase enzyme, and 0.135% inorganic P (NPA+Phyt diet); (3) High available phosphorus (HAP) corn and 0.135% inorganic P (HAP diet); (4) HAP corn, 600 units phytase, and 0.135% inorganic P (HAP+Phyt diet); (5) NPA corn and 0.345% inorganic P (NPA+P diet). The NPA+P diet was similar to conventional diets being fed commercially. The NPA+Phyt diet was similar to alternative, phytase-amended diets being fed commercially. Feeding the alternative NPA+Phyt, HAP, and HAP+Phyt diets instead of the NPA+P diet reduced total P in manures by 40%, but increased the percentage of total manure P extracted with 0.01 M CaCl₂ from fresh excreta (P < 0.05). Soils amended with wet NPA+Phyt, HAP, and HAP+Phyt manures released 29 to 49% more water-soluble P than soils amended with NPA+P manure on an equal-P basis (P < 0.05). Feeding the NPA+Phyt diet instead of the NPA+P diet did not affect the percentage of total P manure extracted by Mehlich III from wet excreta, while feeding the HAP and HAP+Phyt diets increased the percentage of total manure P soluble in Mehlich III (P < 0.05). Soils amended with wet NPA+Phyt manure did not release more Mehlich III-extractable P than soils amended with NPA+P manure on an equal-P basis. Soils amended with wet HAP and HAP+Phyt manures released more Mehlich III-extractable P than soils amended with NPA+P manure on an equal-P basis (P < 0.05). Treatment-induced differences in extractability of manure and soil P appeared to be caused by a higher proportion of P in calcium phosphate form in the NPA+P manure. Drying manures prior to extraction generally heightened differences in solubility of P between the NPA+P and other manures. Feeding the alternative NPA+Phyt, HAP, and HAP+Phyt diets instead of the NPA+P diet did not affect total Cu levels in manure or the percentage of total Cu extracted from manure with 0.01 M CaCl₂. After soils were treated with manure on an equal-Cu and equal-N basis, soils amended with NPA+Phyt, HAP, and HAP+Phyt manures released more water-soluble Cu than NPA+P-amended soils (P < 0.05). Under P-based manure management, soils amended with the three alternative manures released 92 to 108% more water-soluble Cu than NPA+P-treated soils (P < 0.05). Extractable Cu increased so dramatically because conversion to the alternative diets boosted total manure loadings by 67%. Mehlich III extraction of soils amended with manure on an equal-N and -Cu basis indicated no effect of manure type on Cu availability. Feeding the NPA+Phyt, HAP, and HAP+Phyt diets instead of the NPA+P diet did not affect total Zn levels in excreta, but caused at least a five-fold increase in the percentage of total manure Zn extracted by 0.01 M CaCl₂ from fresh excreta (P < 0.05). Feeding the NPA+Phyt, HAP, and HAP+Phyt diets did not alter the percentage of total manure Zn extracted by Mehlich III from wet excreta. / Master of Science

Despite high volumes of manure production in the Shenandoah Valley, there are still areas of forage production in the Shenandoah Valley that are nutrient deficient, because manures have traditionally been applied to higher value row crops. Furthermore, anecdotal reports have suggested that application of poultry litter to pastureland may increase the abundance of weeds. This study was conducted to compare the effects of poultry litter and inorganic fertilizers on soil fertility, aboveground botanical composition and soil seed bank composition of established mixed naturalized pastures. Two sites each had the following treatments applied for two consecutive years: 1) split application of litter: 3.36 Mg ha-1 in spring and 3.36 Mg ha-1 in summer; 2) inorganic fertilizer at same N, P and K rates as Trt. No. 1; 3) single application of litter: 6.72 Mg ha-1 in spring; 4) inorganic fertilizer at same N, P and K rates as Trt. No. 3; 5) unfertilized control. Forage yield, soil pH, Mehlich 1 P (M1P), P balance, water soluble phosphorus (WSP), shifts in aboveground botanical composition, seed bank composition, and species richness (SPR) were monitored during this experiment. In addition, we examined whether poultry litter carries germinable weed seeds that can be transferred to forage systems after application. On average, soil pH was 0.2 higher for litter than chemical fertilizer treatments, but this difference was not significant. Mehlich 1 P and WSP both increased throughout the two years, but no significant differences were found amongst split and single application or litter and inorganic fertilizers. Phosphorus balance analysis indicated that forage yield did not remove adequate P to prevent environmental concerns, when using N based applications. Fertilization increased yield 3.5 Mg ha-1 on average and yield responses to application timing and fertilizer types were similar. Desirable species abundance increased significantly (linear regression, P< 0.05) over time in both fertilizer and poultry litter application treatments. Furthermore at one site, Shenandoah County, poultry litter application actually reduced the number of weedy species in plots (P=0.04). Weedy plant abundance did not differ at either site, and no significant change in species richness (number of species/area) was observed at Rockbridge County for any treatment. No treatment effects were found for seed bank species richness and number of germinated seeds (m-2). No seedlings germinated directly from poultry litter collected from several sites in Virginia. Poultry litter was comparable to inorganic fertilizer in terms of increasing soil WSP, M1P, forage yield, and above ground composition of desirable forage species. Timing of application made no difference. Additionally, our results indicate that poultry litter has no viable seed and does not increase weed abundance in mixed naturalized pastures. / Master of Science

In the past twenty years the grain industry has experienced production declines in Virginia due to inability to compete with Midwestern grain producers. During this same time, consumption of grain by the poultry industry in Virginia has expanded rapidly. The levels of production and consumption of grain in Virginia are calculated and described on a state, regional, and county basis. Handling, storage, and marketing practices of grain in Virginia are assessed and described. Several different alternatives are presented and evaluated to determine their ability to improve the competitive position of Virginia corn with Midwestern states through the use of poultry litter to decrease production costs and present opportunities for producers to achieve better prices. / Master of Science

The objectives of this study were: 1) To evaluate short-term composting of hardwood bark with combinations of poultry litter and ammonium nitrate and 2) To determine the suitability of composted material for ornamental plant media. In a 3-month accelerated composting study, hardwood bark was amended with (20% & 40%) poultry litter, (1% & 2%) ammonium nitrate, or unamended. Composting was run in fifteen 35- gallon containers and samples were collected at day 0, 45, and 90 for pH, moisture content, carbon-to-nitrogen ratio, compost maturity, toxicity, and green house evaluations. The amendment containing 40% poultry litter showed significantly higher weight reduction than others at days 45 and 90. Also, this treatment showed significantly higher mass weight in transplanted zinnia and gardenia than other treatments and was comparable to commercial media. Overall, results indicated that the amendment of hardwood bark with poultry litter could produce comparable product to currently used commercial container media.

The accumulation of P in soil from land-applied biosolids and manure increases the risk for P enrichment of agricultural runoff. Transport of these residuals to areas where P may be efficiently utilized is necessary to reduce the threat to water quality. Composting can improve biosolids and manure handling characteristics to make their transportation more feasible; however, little is known about P dynamics in compost-amended soil. We investigated the factors controlling P solubility and plant availability in two soils, a Kempsville fine sandy loam (Typic Hapludult) and a Fauquier silty clay loam (Ultic Hapludalf), amended with one of 4 composts (2 biosolids composts and 2 poultry litter - yard waste composts), poultry litter, or inorganic P (as KH2PO4) in incubation and greenhouse pot studies. We also compared the effects of compost, poultry litter and commercial fertilizer on surface P runoff from a Fauquier silty clay loam that had received compost, poultry litter, or commercial fertilizer for 5 years. Organic amendments with higher concentrations of Fe, Al, and Ca had lower relative P solubility/availability. Phosphorus solubility in the Kempsville fine sandy loam, having far lower native P binding capacity, was more affected by Fe, Al, and Ca applied with the organic amendments. The concentration of P in runoff from the compost treatments was higher; however, infiltration was increased and runoff decreased so the mass loss of P and sediment was lower. Improved soil physical properties associated with compost applications aid to limit P runoff. / Master of Science

Teff (Erogrostis tef (Zucc.)), an annual warm-season grass from Ethiopia, has potential to provide forage during periods when cool-season grass growth is limited by high temperatures. An experiment was conducted at three Virginia locations in 2009 and 2010 to determine the effect of nitrogen (N) fertilization rate and source on the yield, nutritive value, and nitrate content of teff. Nitrogen (N) was applied at 0, 45, 90, and 135 kg plant available N ha-1 as a single application of either ammonium nitrate (AN) or broiler litter (BL) at seeding. The experimental design was a randomized complete block with a two-factor factorial treatment design (N rate and source) and four replications. Biomass yield typically peaked at the 90 kg N ha-1 rate, but rarely showed an increase beyond the 45 kg N ha-1 rate. Yield ranged from 2325 to 7542, 1477 to 6151, and 1805 to 8875 kg DM ha-1 for the Blacksburg, Southern Piedmont, and Shenandoah Valley locations, respectively. Crude protein and total digestible nutrients ranged from 70 to 240 g kg-1 and 460 to 700 g kg-1, respectively. Nitrate concentrations increased with increase in N fertilization but source had no effect on nitrate concentration. Typically, nitrates only posed a health risk for ruminant livestock at N rates above 90 kg N ha-1, but dangerous levels were present occasionally at the 0 and 45 kg N ha-1 rates. The results from this study indicate that teff responds to moderate rates of N and could provide summer forage for grazing livestock in the mid-Atlantic region. / Master of Science in Life Sciences

Phosphorus (P) is a nutrient of concern in the Chesapeake Bay watershed due to nutrient imbalances in areas with confined animal feeding operations. By converting poultry litter to an ash via thermal conversion, nutrients are concentrated and are economical to ship out of nutrient surplus watersheds to nutrient deficient regions, such as the corn-belt. We initiated incubation and field studies on sandy loam soils to test P and potassium (K) availability from poultry litter ash (PLA). Four PLA products, derived from different sources using different combustion techniques, and 2 biochar products were characterized. Poultry litter (PL) co-products were compared to a no-fertilizer control and inorganic P (triple super phosphate; TSP) and inorganic K (muriate of potash; KCl) fertilizer at similar rates. In the incubation study, standard fertilizers (TSP and PL) had the greatest initial availability for P (55.50% TSP; 9.13% PL) and K (97.99% PL), respectively. The PL co-products varied in availabilities based on thermo-conversion system from 1.60- 8.63% for P to 8.14- 88.10% for K. One ash co-product (ASH4) produced similar availabilities to the industry standard fertilizers after 56 days. In conclusion, co-products from combustion thermo-conversion systems were found be superior to gasification and pyrolysis systems when the desire was to produce the most plant available P and K dense PL co-products. In the field studies, yield, Mehlich-I extractable soil nutrients, plant tissue and grain samples, and organic matter content was used to compare treatments. Poultry litter ash co-products were highly variable due to the thermo-conversion system and feedstock of formation. If all ideal combustion criteria are met, then PL co-products are feasible to use as fertilizer sources, but will need to be individually analyzed for nutrient content before making application recommendations. A greater amount of the co-products will have to be applied to meet the same nutrient availability of the standards due to their lower availability. Fresh PL tends to be the better fertilizer due to its added N content, which is lost in thermo-conversion systems and would have to be supplemented with the ash co-products. Biochars tend to be less available than their ash counter parts. More research using the water soluble availabilities instead of the total concentration nutrients of the co-products are needed to be able to identify stronger relationships with standard fertilizers. / Master of Science

Poultry litter can harbor pathogenic bacteria, including avian pathogenic Escherichia coli (APEC). Applying litter amendments is one strategy to improve bird health and potentially reduce pathogens. Biochar and PLT were applied as litter amendments in a live bird trial to study their effects on E. coli populations, APEC virulence genes (VAG), and antimicrobial resistance (AMR) genes. Samples were collected at days 0, 17, 29, and 41 to enumerate E. coli and store bacterial isolates for antimicrobial-resistance gene analysis. Data analysis showed litter amendments did not significantly affect overall E. coli populations. Grow-out time impacted E. coli populations, with reductions occurring over time. Litter treatment had no impact on the prevalence of VAG or AMR. Time showed VAGs were absent at d 0 while AMR genes were prevalent at d 0. This indicates chicks may have been the source of VAG, while AMR genes were prevalent in used litter.