Significant variability in cured leaf tobacco-specific nitrosamine (TSNA) content is commonly observed when sampling within dark air-curing barns. This variability may be due to inconsistency in the curing environment within different areas of the barn. A study was initiated in 2012 through support from a CORESTA Study Grant to evaluate if leaf TSNA content is related to microenvironmental conditions in the barn. Seed screened for low conversion of nicotine to nornicotine (sc) and high converter (HC) selections of TR Madole dark tobacco were cured in barns near Princeton and Lexington, Kentucky in 2012 and 2013. Temperature and relative humidity were measured with data loggers placed at 27 locations within each barn for the duration of curing. TSNA content was determined from 20-leaf samples collected from each selection at each of the 27 locations within each barn. There were no significant effects of individual data logger placement in either variety selection on hours above 24°C temperature, hours above 80% relative humidity, or TSNA; therefore, we investigated these data within 3-dimensional aspects of tier, room, and bent within each barn. There were various effects of tier, room, and bent on temperature, relative humidity, and TSNA; but limited significant relationships between temperature, relative humidity, and TSNA.

AtPAP15 is one of the purple acid phosphatases expressed by Arabidopsis thaliana that has been extensively studied. Purified AtPAP15 has been shown to exhibit both phytase and phosphomonoesterase activities in acidic pH with maximal activity at pH 4.5. AtPAP15 is a phosphorus starvation inducible (PSI) gene that is expressed highly during phosphorus deficient conditions. In the current study, AtPAP15 was overexpressed in Nicotiana tabaccum under cauliflower mosaic virus (CaMV35S) constitutive promoter. After PCR confirmation of the gene, plants were transferred to the greenhouse and allowed to grow in pots. The pots contained Sta-Green potting mix (Lowe’s Inc., Mooresville, North Carolina,U.S.). Individual flowers were covered to ensure selfpollination. Seeds that were generated (T1 generation) were used for functional analyses. The T1 seeds were germinated in different phosphorus conditions- phosphorus deficient (0mM), optimum inorganic phosphorus (1.25mM), high inorganic phosphorus (20mM) and high organic phosphorus (20mM AMP and IHP)- and analyzed for total biomass, primary root length, soluble phosphorus (Pi) content and acid phosphomonoesterase (Apase) activity. Results demonstrated that under high organic phosphorus conditions, transgenic lines presented increased biomass, longer primary root length, high total soluble phosphorus and high Apase activity than the wild-type. These findings will have important implications for soils with high phosphorus content since most phosphorus in soil is available in organic form. As part of this thesis, Agrobacterium-mediated in planta transformation protocol for transformation of Medicago sativa (alfalfa) was standardized. The protocol would be used to develop transgenic alfalfa expressing AtPAP15. In this protocol, shoot apical position of 2d old seedling is excised followed by infection by Agrobacterium tumefaciens strain EHA 105 for TDNA transfer. The construct used was pCAMBIA1302 harboring mGFP reporter gene. The construct also contained kanamycin, rifampicin and chloramphenicol selection markers. Confirmation of mGFP expression in the transformed alfalfa seedling was performed using Zeiss microscope fitted with GFP filters. Results showed that this protocol is replicable and efficient. In planta transformation method, therefore, may be used for the development transgenic alfalfa.

The objective of this study was to determine dairy cattle preference amongst four species of cool-season forage grasses: eight orchardgrasses (Dactylis glomerata L.), five tall fescues [Schedonorus arundinaceus (Schreb.) Dumort.], five perennial ryegrasses (Lolium perenne L.), and six festuloliums [xFestulolium braunii (K. Richt.) A. Camus.]; 24 cultivars in total. Each grazing trial utilized four Holstein-Friesian heifers over six hours. Maturity differences were eliminated by having animals graze only vegetative material. After six grazing trials (three each in 2014 and 2015), consistent results in animal preference were not found; three of the six trials did show preference (P

Ensiling is one of the most common processes used as a conservation method for forages on farms and plays an important role in farm economics. Therefore, with the aim to improve the conservation and the nutritive value of silage, the utilization of silage additives such as fibrolytic enzymes (FE) and lactic acid bacteria (LAB) inoculants has been a common on-farm practice. FE are enzymes capable of breaking down complex polysaccharides such as cellulose and hemicellulose. The latter results in an increased substrate availability for epiphytic and inoculated LAB during silage fermentation, thus promoting a higher production of organic acids such as lactic acid and volatile fatty acids such as acetic acid, which are key acids to improve the conservation of the forage by reducing dry matter losses and improving aerobic stability. The degradation of cellulose and hemicellulose results in a partial degradation of fiber measured by the neutral detergent fiber (NDF) and acid detergent fiber (ADF) extraction technique. Therefore, FE could have the potential to improve ruminal fiber digestibility of treated forages. Alternatively, LAB inoculants are used as silage additives with the primary objective to dominate over the epiphytic bacteria present in silage, to accelerate the fermentation process, and to reinforce aerobic stability of the forage at feed out. Additionally, recent research has shown that certain strains of LAB might have the potential to partially degrade NDF and ADF during ensiling, therefore improving fiber digestibility. The first objective of this research project was to evaluate the effects of different mixtures of FE (a mixture of cellulase and xylanase (C+X); xylanase (X); ß-glucanase (G); a mixture of ß-glucanase and xylanase (G+X); and a negative control) on alfalfa harvested at early and late maturity, and stored for 40 or 120 d of ensiling. Alfalfa harvested at early maturity, treated with FE and ensiled for 40 d did not show significant improvements during ensiling in fiber degradability, fermentation characteristics or fiber digestibility in vitro assessed by the Tilley and Terry methodology. However, when harvested at late maturity and treated with a mixture of C+X; X and G+X, the NDF and ADF content at 40 d of ensiling tended to decrease. FE improved total volatile fatty acid production at 40 and 120 d of ensiling. Improvements in fiber digestibility were observed in vitro at 24 h for the C+X treatments. The results of this study suggest that the effects of FE are more pronounced in silages higher in fiber concentration, such as in the late-maturity alfalfa cut. The second objective of this research was to evaluate the effects of two homofermentative LAB (hoLAB) strains, and two heterofermentative LAB (htLAB) strains on alfalfa harvested at late maturity and stored for 40 or 120 d of ensiling. At 40 d of ensiling, hoLAB-treated silages had the greatest DM recovery and the lowest ADF concentration. Lactic acid production was greater for hoLAB-treated silages. At 120 d of ensiling, hoLAB-treated silages had the highest concentration in lactic acid whereas htLAB had the highest concentration in acetic acid and hoLAB-treated silages had the lowest ADF and NDF concentrations while htLAB tended to have higher NDF concentrations. Overall, it appears that the fiber degradation promoted during ensiling influenced digestibility depending upon hoLAB or htLAB inoculation, with hoLAB showing improved digestibility levels. The presented work suggests that certain FE can have the potential as a management resource on farms aiming to improve the nutritive value of forages with a high fiber concentration. As expected, hoLAB and htLAB inoculants improved the fermentation characteristics of alfalfa silage, but it was shown that LAB may exert a differential effect on fiber digestibility depending on their specific metabolism.

Soybeans have traditionally been grown in rows wide enough to allow mechanical cultivation and to increase lodging resistance. Improved cultivars and herbicides have permitted farmers to obtain yield advantages from narrower rows. The growth response of soybeans to variations in row width and seeding rates depends upon the cultivar and geographic location. “Williams,” “Mitchell,” and “Essex” cultivars were planted at row widths of 18, 36, 54, and 72cm. at seeding rates of 33, 67, 100 and 134 kg/ha in multi-row plots. Data were collected from each plot for seed yield, lodging, plant height, height of lowest pod, seed and population per square meter. Results indicate that soybeans grown in 18 cm. rows produce higher yields than those grown in 72 cm. rows. The only effect on yield due to seeding rates was found within the cultivar Mitchell where intermediate seeding rates produced highest yields. Lower seeding rates were found to result in podding closer to the ground and to cause a decrease in seed size. Row width, seeding rate, and cultivar had no effect on lodging or plant height. Row width and seeding rate had no effect on maturity date.

Johnsongrass (Sorghum halepense L.) presents a serious problem in the production of corn and soybeans in Kentucky. Various rates of the thiocarbamates, dinitroanilines, carbamates, amides, ureas, and triazines were used in association with the crops corn (Zea mays L.) and soybeans (Glycine max L.) to determine the degree of suppression on rhizomatous johnsongrass infesting the previously named crops. Suppression was determined by selecting areas within each treated plot, counting the number of culms, then harvesting johnsongrass rhizomes. Dry weights of rhizomes were then determined as a measure of rhizome suppression. Results show that of the various herbicides and rates used, none were significantly different in their degree of rhizome suppression.

Johnsongrass is one of the more limiting factors in soybean production and is the most serious weed problem in the Southeastern United States. Actually, different herbicides are used in johnsongrass control, and still there are new herbicides which are being tested. Two experimental herbicides for johnsongrass control in soybeans are BAS 9052 and S-734. The experiments were conducted in 1980 and 1981 with the objective to evaluate the effectiveness of S-734 alone and in combination with mefluidide and BAS 9052, BAS 9052 applied early or late postemergence, trifluralin, alachlor, and fluchloralin for seedling and rhizome johnsongrass control. In both areas S-734 was applied at 0.8, 1.1, and 1.7 kg/ha, S-734 at rates of 0.8, 1.1, and 1.7 kg/ha was combined with mefluidide at 0.3 kg/ha, S-734 at rates of 1.1 and 1.7 kg/ha was also combined with BAS 9052 at 0.6 kg/ha, BAS 9052 was applied at 0.6, 0.8, and 1.1 kg/ha early or late postemergence. Trifluralin and fluchloralin were applied at rate of 1.1 kg/ha in seedling study and 2.2 kg/ha in rhizome study. Alachlor was applied at rates of 3.4 and 4.5 kg/ha in seedling study. The results of the experiments showed that there were similarities and differences in the response of rhizome and seedling johnsongrass to the treatments. The control of johnsongrass, and the resulting soybean yields, was higher in the seedling area than in the rhizome area. There were no differences among rates of herbicides. Good seedling johnsongrass control was obtained with all treatments although there were differences among herbicides. In 1980 there were differences between BAS 9052 applied early and late postemergence, but there were no differences in 1981. BAS 9052 might be used as a late postemergence application for best seedling johnsongrass control. There were no differences among herbicides on soybean yields. In both years good rhizome johnsongrass control was obtained with BAS 9052 applied early or late postemergence. Poor rhizome johnsongrass control was obtained with S-734, trifluralin, and fluchloralin. High soybean yields were obtained with BAS 9052.

Broiler litter (BL) is a high value manure available to Kentucky crop producers to utilize as a fertilizer. The rate of BL application, timing of application, and method of application are all important factors to take into account when utilizing BL. A laboratory incubation was conducted to observe nitrogen (N) mineralization rates of BL amended soils over time under different conditions. Different application methods, application rates, watering frequencies, and bedding materials were used to determine their influence on N mineralization. Broiler litter applied on the soil surface, at lower rates, at lower watering frequency resulted in lower mineralization rates than BL that was incorporated, at higher rates and higher watering frequency. The rice hull bedding BL treatments had a significantly higher initial amount of NH4+-N than the wood-based bedding materials. The increased NH4+-N content produced a lower pH due to higher rates of nitrification. The difference in NH4+-N resulted in the rice hull BL treatments containing more inorganic N throughout the incubation. The wood-based BL contained significantly more carbon (C), zinc (Zn), and potassium (K). The results collected will help improve current nutrient recommendations and provide information that will help utilize BL more efficiently and economically.

Saprophytic fungi can be paired with companion crops in interplant systems to increase production efficiency. However, fungal species/strain, substrate, and inoculation rate can affect the growth of companion crops. This project investigated the viability of open-field mushroom production by interplanting three strains of Pleurotus ostreatus (Elm A, Elm B, and 8801) with kale (B. oleracea var. acephala) and forage radish (Raphanus raphanistrub sub. sativus), and measured the effect of interplanting on plant yield over two field seasons. In the field, Elm A showed an increase in plant yield at a low inoculation rate and decrease in plant yield at a high inoculation rate, compared to the untreated. Conversely, 8801 showed a reduction in plant yield at high and low inoculation rates in the field. Elm B at a high rate showed a reduction in plant yield both in the field and greenhouse. Kale was grown in hydroponics with fungal secretions added at a range of concentrations (10, 100, 1,000 and 10,000 ppm). Elm A showed an overall increase in plant yield in hydroponics, and Elm B showed an overall decrease in plant yield, compared to the untreated. Mushroom production was low in field plots and was not a commercially viable option. Pleurotus ostreatus interplanting methods with companion crops need improvement to make this a commercially viable practice.

The American Cranberry (Vaccinium macrocarpon Ait.) represents a vital sector of the economy of southeastern Massachusetts. Due to the hydrogeological and edaphic characteristics of peatlands, variations in soil drainage and soil moisture represent major management challenges for growers in Massachusetts. An emerging trend of upland (mineral soil) cranberry farms planted with new hybrid cultivars has the potential to enhance the profitability and long-term viability of cranberry production in Massachusetts. However, sparse data exist on soil moisture characteristics of peatland and upland cranberry farms. The purpose of this research was to elucidate the differences in soil moisture between upland and peatland cranberry farms, to evaluate the soil temperature-moisture relationship and its use for inferring soil moisture, and to explore the use of unmanned aircraft systems (UAS) as a soil moisture management tool in cranberry agriculture.In this thesis, we found that volumetric soil water content (qv) in upland farms ranged from 5-15%, contrasting with values of 10-40% for peatland farms. In general, soil moisture in upland farms was two times drier and four times more uniform than peatlands farms. Our results suggest that open ditches should be dredged to at least 50 cm to obtain irrigation setpoints of -5 to -2 kPa for Massachusetts cranberry farms. We found that soil temperature and near-surface temperature were accurate predictors of soil moisture but were also strongly dependent on the magnitude of differences between air and water temperature. Soil and near-surface temperatures were also better predictors of moisture in soils with lower vegetation coverage and organic matter content. Near-surface temperature collected with a UAS was consistent with field measurements of qv, suggesting that UAS could be used to assist Massachusetts cranberry farmers by predicting large-scale variation in q v and offering management insights.