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

Conservation tillage production systems for flue-cured tobacco (Nicotiana tabacum L.) have been studied for many years. Inadequate chemical weed control and lack of acceptable pesticide and fertilizer application resulted in consistently lower yields and inferior cured leaf quality. The development of new conservation tillage equipment, improved methods of fertilizer application, and new herbicides, have resulted in a renewed interest in conservation tillage labeled for tobacco. This research investigated management practices to address slow early season growth characteristic of strip-tillage tobacco production. Objectives of the first study were to evaluate the methods of starter fertilizer application and determine the optimal rate. A transplant water treatment (11 kg ha⁻¹) and 3 rates (11, 22, and 45 kg ha⁻¹) of injected 9-45-15 (N:P₂O₅:K₂O) water soluble starter fertilizer were evaluated for early season plant growth and time of topping. Starter fertilizer treatments increased tobacco root weight by 22% and leaf area up to 41%. Earlier topping was observed as a result of starter fertilizer with 23 and 6% more plants topped during the initial topping date in 1999 and 2000, respectively. Starter fertilizer did not consistently increase the yield of either strip-tillage or conventional tillage tobacco. The objectives of the second study were to compare the use of raised beds with flat-planting and investigate cover crop residue management techniques. Residue management treatments minimized residue within the strip-tilled area with an early hooded spray application (strip-killed) of a burndown herbicide as opposed to the traditional broadcast burndown application. The use of raised beds for strip-tillage production of tobacco showed no clear benefit when compared to flat-planting. Strip-tillage plots were similar to conventional tillage for cured leaf quality and yield. Early season strip-kill burndown herbicide applications proved beneficial in reducing difficulties incorporating residue into the strip-tilled area thus improving the quality of the prepared seed bed. This research has added to the present knowledge regarding strip-tillage tobacco production, and refined necessary cultural practices. Transplant starter fertilizer is recommended to overcome the typical slow early season growth characteristic of strip-tilled tobacco. However, increased rates (greater than 11 kg ha⁻¹) or under-row injection of the material had no added benefit. The research also demonstrated that the use of raised beds should not be considered a necessary practice with the use of a strip-till implement that incorporates under-row subsoil tillage. This research has demonstrated that tobacco yields and quality comparable to conventional tillage can be realized using strip-tillage production techniques. / Master of Science

No description available.

No description available.

No description available.

Fruit tree leaf nutrient concentrations are commonly used to determine fertilizer rates, but information is limited regarding nutrient requirements, seasonal N uptake and removal rates, and soil N dynamics for pomegranate. Relationships between fertilizer rates, leaf nutrient concentrations, fruit yield and quality were examined in five mature, commercial California ‘Wonderful’ pomegranate orchards. Site 1 was observed for two growing seasons (2018-2019) and sites 2-5 were observed for one season (2018 or 2019). In 2018, 150, 300, or 450 g N/tree was applied at sites 1-3 in a single application at early fruit development or in two equal applications at early and mid-season fruit development. In 2019, fertilizer rates were adjusted based on site-specific leaf nutrient analysis and crop load and applied at mid-season fruit development (158, 185, 225, 286, 392, or 625 g N/tree at site 1; 115, 130, 150, 175, 212, or 270 g N/tree at site 4; and 107, 122, 142, 171, 214, or 286 g N/tree at site 5). A randomized complete block design was used for all experiments. Leaves were collected from all data trees during early, mid-season and late fruit development and analyzed for leaf nutrient concentrations. At harvest, total fruit weight per tree and individual fruit weight and diameter were measured. Canopy volume was measured during the dormant season prior to pruning. Nitrogen partitioning, uptake and removal rates were studied by analyzing plant tissue, soil, and lysimeter water samples in 2019 at site 5. Fruit yield and average diameter varied significantly depending on site and fertilizer treatments. Average fruit yield per tree ranged from 5-90 kg fruit/tree (site 1: 78.5 kg fruit/tree in 2018 and 91.1 kg fruit/tree in 2019, site 2: 55.6 kg fruit/tree, site 3: 29.7 kg fruit/tree, site 4: 5.6 kg fruit/tree, site 5: 9.1 kg fruit/tree). Sufficiency ranges and significant relationships were determined between certain nutrients, including nitrogen and potassium, to fruit yield and diameter. Higher fertilizer treatments were associated with higher residual soil N compared to the low fertilizer treatments within the root zone (2.25-19.33 mg/L NO3-N) and below the root zone (2.25-9.17 mg/L NO3-N) suggesting a higher likeliness of nitrogen leaching with fertilizer applications exceeding the crop’s nitrogen demand. Overall, variability between sites in fertilizer treatment effects, leaf nitrogen concentrations, and yield suggests that setting site-specific yield goals based on estimated N uptake and removal is necessary to develop effective pomegranate fertilizer programs.

The population of the world is increasing exponentially each year with a large population base. Agricultural fields are facing the pressure of dealing with food insufficiency, whereas the challenges of limited resources of arable land and fresh water on the earth should be taken into account at the same time. Smart farming was born at the right time to cope with the problem and has become one of the most powerful approaches to reducing the ecological footprint of farming and improving agricultural yield. The four most important variables that impact crop yield are soil productivity, the accessibility of water, climate, and pests or diseases. This thesis emphasizes the application of chemical fertilizers to corn and disregards the impact of water, pests, and disease for the moment. In this study, three scenarios are explored deeper one by one. The only factor that varies among the three scenarios is the nitrogen amount available to the plant. Fertilizers have outstanding performance in improving the yield and quality of plants in agricultural fields, and this is the emphasis of this thesis. Compared with the fertilizer properties and characteristics of frequently used commercial fertilizers, polymer-coated urea was selected as the fertilizer in this study because the feature of nitrogen can be released into the soil slowly and in a controlled manner. Scenario 1 created an ideal condition where unlimited nitrogen was provided to the corn. Scenario 2 assumed that a fixed amount of polymer-coated urea was applied at the beginning of the sowing season only. Scenario 3 figured out an optimal yield by separating the fertilizer application at the beginning and in the middle of the growing days with the same amounts of fertilizer used in Scenario 2. The model was performed based on historical data from Oklahoma and Ottawa using IoT sensors. The simulation model generated with Python figured out that approximately the end of June to the start of July is the best time to apply the remaining fertilizer, assuming that the sowing stage starts on May 1. The percentage of polymer-coated urea applied initially was found to usually be around 10% in the tested regions. The model was used to predict the yield in Ottawa using from 40.94 g/(m^2) in Scenario 2 to 55.43 g/(m^2) in Scenario 3, achieving an outstanding increasing rate of 35.38%.

No description available.

Effects of media, soil moisture, fertility rate, and plant growth regulators on plant growth were investigated for 13 taxa of succulents. Media: Liners were grown in five common greenhouse substrates: 80% peat, 60% bark + 30% peat moss, 80% pine bark/20% Permatil (v/v), 100% composted pine bark, or whole tree substrate until market ready. Overall, higher percentage bark mixes yielded smaller plants, with lower shoot dry weights, shoot heights and widths. Soil Moisture: Liners were potted into a 60% bark/30% peat soilless potting mix. In group 1 , irrigation to container capacity occurred when volumetric soil moisture content fell below 30%, 20%, or 10%,. Group two (seven species) irrigation thresholds were shifted to 35%, 25%, and 15%. Effects of irrigation rate were significant in three of the 13 species studied, and those effects were species-specific. Fertility Rate: Liners were potted into60% bark/30% peat substrate. Fertility reatments in group were 0, 50, 100, or 200 mg.L-1 nitrogen. Group 2 plants received treatments of 50, 150, 250, or 350 mg.L-1 nitrogen. Four of the 11 species studied were affected by nitrogen rate, with rates up to 200 mg.L-1 generally producing the largest plants. PGRs: Seven species were potted into a 60% bark/30% peat substrate. Group one plants were treated with a foliar application of benzyladenine (Configure) at rates of 0, 400, 800, or 1600 mg.L-1. Group 2 plants were treated either BA at 0, 250, 500, or 1000 mg.L-1, dikegulac sodium (Augeo) at 400, 800, or 1600 mg.L-1, or a tank mix of 500 mg.L-1 Configure and 800 mg.L-1 Augeo. BA caused an increase in branches leaders or offsets in two species. / Master of Science

Container grown perennials are a popular product offered by nurseries and greenhouses and included in their production but little research has been reported on proper overwintering techniques for herbaceous perennials and ornamental grasses. In the first experiment rooted liners of Pennisetum alopecuroides, Pennisetum "Hameln" and Pennisetum "Little Bunny," were potted. Treatments included, utilizing two overwintering covers, two fertilizer rates (low or high) and two substrate moisture contents (wet or dry). Covering with either a double layer of Dewitt N-Sulate™ insulation fabric or a double layer of Dewitt N-Sulate™ insulation fabric and a single sheet of 4 mil white polyethylene plastic on top of the insulation fabric, wet substrate treatments, low fertility rates and combinations of both, improved survival and vigor for all three tested Pennisetum species and cultivars. In the second experiment, rooted liners of P. alopecuroides, P. "Hameln" and P. "Little Bunny," were potted. Treatments included, two transplanting times (young or old), two fertilizer rates (low or high) and two substrate moisture contents (wet or dry) at the UHC and Poplar Ridge Nursery (Montross, VA) (PR). Vigor was improved for P. alopecuroides (at PR) and P. "Little Bunny" (at both locations) with the young transplanting time. In the third experiment, older plant material of P. alopecuroides, P. "Hameln" and P. "Little Bunny," were subjected to fertility treatments of no additional fertilizer or top-dressed at a low, medium or high rate . A high fertility rate reduced survival and vigor for P. "Little Bunny." In the fourth experiment rooted liners of Echinacea purpurea "Hot Papaya," Echinacea purpurea "Milkshake," Gaillardia x grandiflora "Gallo Peach," Heuchera x villosa "Pistache," Heuchera x villosa "Brownies," P. alopecuroides, P. "Cassian," P. "Hameln" and P. "Little Bunny," were potted and overwintered at the UHC or Poplar Ridge Nursery (Montross, VA) (PR) or Riverbend Nursery, Inc. (Riner, VA) (RB). Treatments included, utilizing two overwintering covers, two fertilizer rates (low or high) and two substrate moisture contents (wet or dry). Vigor at the UHC, was reduced with the high fertility rate for E. "Hot Papaya" and H. "Brownies." A double layer of Dewitt N-Sulate™ insulation fabric and white polyethylene plastic on top of the cover, in combination with the wet substrate moisture treatment improved vigor of E. "Hot Papaya."A double layer of Dewitt N-Sulate™ insulation fabric in combination with the wet substrate moisture content and the high fertility rate reduced P. "Cassian" vigor. No overwintering cover reduced P. "Hameln" vigor. No overwintering cover and the high fertility rate reduced P. "Little Bunny" vigor. Vigor at PR was improved with the high fertility rate for E. "Milkshake," G. "Gallo Peach" and H. "Brownies." At RB, a double layer of Dewitt N-Sulate™ insulation fabric in combination with the low fertility treatment and no cover in combination with the high fertility treatment reduced vigor for E. "Milkshake" and P. "Little Bunny," respectively. No cover in combination with the wet substrate moisture treatment reduced vigor for G."Gallo Peach." / Master of Science