<p> Weeds are one of the biggest challenges for organic growers because of the alternative weed control methods. Air-propelled abrasive grit management has been reported to control weed seedlings in corn and soybeans while maintaining yield. This research examined the weed control, corn and soybean yields, nitrogen mineralization, and nitrogen yield responses from grits. The grits used in this research included: Phytaboost Plant Food 7-1-2 (soybean meal), Sustane 8-2-4 and 4-6-4 (turkey litters), and two non-fertilizer grits: Agra Grit (walnut shells) and corn cob meal. Field studies were conducted from 2015 to 2017 in Aurora, SD, Beresford, SD and Morris, MN. Nitrogen mineralization and total nitrogen release from selected grits in two different soils were evaluated in 100 d incubations. The response of corn, wheat, red russian kale and velvetleaf to Sustane 8-2-4, Agra Grit and corn cob meal amended soil was investigated. Agra Grit consistently reduced in-row broadleaf weed biomass in all four site years, whereas when grass weeds were dominant, in-row weed biomass was not reduced with two grit applications. When grit treatments reduced in-row weed density, corn yield increased with fertilizer grits higher than the weed-free check. In-row weed biomass in soybeans was similar among treatments, but when total weed biomass was reduced, the soybean yields were 31 to 55% greater in the grit treatments than weedy checks. Organic fertilizer grits increased soil available nitrogen with 50 to 70% of nitrogen mineralized. Non-fertilizer grits immobilized soil available nitrogen. Plant height and dry weight of wheat, red russian kale, and velvetleaf were greater when the soil was amended with Sustane 8-2-4 compared with Agra Grit, corn cob meal, and no-grit control, although fresh weights and relative greenness were similar among treatments. The use of organic fertilizer grits provide a source for nitrogen for all plants in the targeted area, whereas non-fertilizer grits may immobilize nitrogen. Corn and soybean yields can be increased when two applications of air-propelled grits reduce weed density, regardless the type. Grits may provide nitrogen for the crop but weed control is critical as additional nitrogen also may stimulate weed growth.</p><p>

<p> The Mississippi River Valley Alluvial Aquifer (MRVAA) aquifer is the principal water source for Mid-South irrigators, but the current rate of withdrawal from the aquifer is not sustainable. Means to increase the sustainability of the MRVAA is to improve corn&rsquo;s water use efficiency (WUE) while, concurrently, maintaining or improving profitability. The objectives of this experiment were to determine the effects of sensor-based irrigation threshold, planting date, and hybrid on corn grain yield, WUE, and net returns above seed and irrigation cost. Season long irrigation thresholds of -50 kPa full irrigation (FI) and -125 kPa limited irrigation (LI) were used, utilizing furrow irrigation. In conclusion, utilizing a delayed irrigation trigger of -125 kPa decreases grain yield and, ultimately, net returns in years with less naturally occurring rainfall, but increases WUE. Shifting the planting date earlier and using full-season (FS) hybrids, increases grain yield, WUE, and net returns.</p><p>

[No abstract available] / Land and Food Systems, Faculty of / Graduate

Gallic acid esters (GAE) of varying alkyl chain length were used to determine how antioxidant physical location and partitioning influence hemoglobin-catalyzed lipid oxidation. Specific GAE used were propyl gallate (PG), octyl gallate (OG), and lauryl gallate (LG). GAE partitioning experiments were performed with either isolated cod muscle membranes or washed cod muscle, which primarily contain polar membrane lipids and myofibrillar proteins. Canola oil was used in some experiments to determine how neutral lipids impact partitioning behavior. GAE distribution was determined spectrophotometrically in the recovered membranes, aqueous phase, and oil layer after employing differential centrifugation. Oxidation was monitored by measuring thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides development. When GAE were added to the membrane suspensions, significant differences (p < 0.05) in GAE partitioning were observed in the aqueous phase and membrane sediment, where increases in GAE alkyl chain length corresponded with a decrease in aqueous phase concentrations and increases in the membranes. GAE partitioning in the oil fraction did not show significant differences. Also, increases in GAE alkyl chain correlated with increases in GAE membrane detection when GAE were added to the washed fish muscle (p < 0.05). Adding GAE to the washed cod muscle before the canola oil was the most effective sequence of addition for extending the storage time before lipid oxidation was detected. Among the three GAE tested, PG showed the greatest inhibition against lipid oxidation. The effectiveness of the GAE in the washed cod-canola oil system follows the order, PG > OG > LG, which corresponds with decreasing hydrophobicity. The conclusions of this study are twofold. First, GAE partitioning into the muscle membranes was not the primary factor for delaying the onset of lipid oxidation. Rather, solubility in the aqueous phase showed the greatest impact on extending storage time. Secondly, the order in which GAE and canola oil were added to the washed cod (WC) muscle system influenced hemoglobin-catalyzed lipid oxidation behavior. Adding GAE before the neutral oil may have allowed the GAE to partition more easily into the polar regions of the washed muscle, which in turn provided the most effective protection against oxidation.

Mixed solutions of β-lactoglobulin and anionic polysaccharides, specifically pectin, were formed into associative complexes through pH reduction from neutral conditions. Thermal treatment of these associative complexes was investigated as a function of biopolymer composition, heating conditions, pH, and ionic strength. Thermal treatment of β-lactoglobulin-pectin complexes at pH 4.5–5.0 was found to create protein-based particulates of consistent and narrow size distribution (diameter ∼ 150–400 nm). These particulates were relatively stable to further pH adjustment and to high levels of salt (200 NaCl). Particle characteristics were maintained after re-suspending them in aqueous solutions after they have been either frozen or lyophilized. Thermal analysis of β-lactoglobulin-pectin complexes using calorimetry (DSC) and turbidity-temperature scanning indicated that the denaturation of β-lactoglobulin was unaffected by pectin, but protein aggregation was limited by the presence of pectin. Biopolymer particles formed using two different methods were compared: Type 1 – forming β-lactoglobulin nanoparticles by heating, then coating them with pectin; Type 2 – forming particles by heating β-lactoglobulin and pectin together. Type 2 particles had smaller diameters and had better pH and salt stability than Type 1 particles. It was proposed that Type 2 particles had a pectin-saturated surface that limited their aggregation, whereas Type 1 particles had "gaps" in the pectin surface coverage that led to greater aggregation. Finally, the possibility of controlling the size and concentration of biopolymer particles formed by heating β-lactoglobulin-pectin complexes by controlling preparation conditions was studied. Biopolymer particle size and concentration increased with increasing holding time (0 to 30 minutes), decreasing holding temperature (90 to 70°C), increasing protein concentration (0 to 2 wt%), increasing pH (4.5 to 5.0), and increasing salt concentration (0 to 50 mol/kg). The influence of these factors on biopolymer particle size was attributed to their impact on protein-polysaccharide interactions, protein denaturation, and protein aggregation kinetics. The knowledge gained from this study will facilitate the rational design of biopolymer particles with specific physicochemical and functional attributes that can be used in the food and other industries, e.g., for encapsulation, texture modification, optical properties modification.

Cover crop mixtures were evaluated as alternatives to fertilizer nitrogen (N) in sweet corn. Five legume species were investigated in three separate experiments from 1990 to 1993 at the UMass Research Farm in S. Deerfield, Mass. These were hairy vetch (Vicia villosa Roth), lana vetch (Vicia dasycarpa MacLeod), purple vetch (Vicia benghalensis L.), field pea (Pisum sativum spp. Arvense (L.) Poir) and white lupin (Lupinus albus L.). Oat (Avena sativa L.) was used as a companion crop with all five legume species investigated. With conventional tillage, legumes seeded in combination with oats provided significant amounts of N to sweet corn seeded early the following spring. Hairy vetch was the only legume species to survive the winter in these trials. This made it the most effective of the legume species investigated since the regrowth in the spring accumulated more N compared to the legumes that did not survive the winter. Research studies also evaluated hairy vetch interseeded with rye (Secale cereale L.). Results suggest that a combination of oat-vetch may be superior to rye-vetch due to the competition observed from rye in the spring. Oat would provide necessary erosion control since it germinates and grows faster than vetch in the fall and it would add more soil organic matter than the legume grown alone. The pre-sidedress nitrate test and the SPAD-502 chlorophyll meter were evaluated as predictors of N needs in sweet corn. Soil samples and chlorophyll meter readings were taken in sweet corn following different cover crop treatments when the plants were approximately 30 cm high. The data were compared to relative yield of sweet corn. Neither the pre-sidedress nitrate test or a chlorophyll meter proved to be effective predictors of N needs in sweet corn. Most of the nitrate-N levels observed in this work were far below the critical levels of 20 to 30 mg NO$\sb3\sp-$-N/kg of soil established by other researchers. It is speculated that the majority of the mineralization of N from the soil-incorporated cover crop tissue took place before the pre-sidedress nitrate test samples were taken and therefore was not in the 0-30 cm soil depth. (Abstract shortened by UMI.)

Type 2 diabetes, hypertension and Helicobacter pylori -linked ulcer are among the important global health challenges. Healthier food and ingredient design for addressing above health challenges could be combined with traditional drug therapies for disease management. Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus and Escherichia coli are food-borne pathogens associated with infectious disease outbreaks. However, the development of antimicrobial resistance and the limited success of relatively narrow spectrum of antimicrobials, results in microbial contamination of food and poses public health and economic challenge. Therefore, the aim of this dissertation was to develop metabolic strategies for designing milk and soymilk fermented diets and ingredients enriched in phenolic phytochemicals for managing type 2 diabetes, hypertension, ulcer and controlling food-borne pathogens. This was investigated through understanding the in vitro inhibitory potential of hyperglycemia and hypertension linked enzymes as well as critical metabolic pathways contributing to the cellular breakdown of bacterial pathogens. Based on structure-function rationale, the potential antioxidant, anti-hyperglycemia and anti-hypertention functionality of herb and fruit extracts, fruit enriched dairy and soy yogurts and herb and fruit enriched cheeses were investigated. Results indicated that specific extract profiles had high anti-hyperglycemia and anti-hypertension potential which generally corresponded to total phenolic content and free radical scavenging-linked antioxidant activity. Further it was observed that lactic acid bacterial fermented milk and soymilk have potential for hyperglycemia and hypertension management, which is enhanced with phenolic phytochemical enrichment. However, it was determined that soymilk fermented products had superior potential for hypertension management and further that the anti-hypertension potential of fermented milk depended strongly on the lactic acid produced during fermentation. Furthermore these fermented extracts had potential to inhibit L. monocytogenes, S. aureus , V. parahaemolyticus, and ulcer related H. pylori. Results also indicated that oregano-cranberry synergies with sodium lactate had the best potential for L. monocytogenes inhibition in broth and cooked meat substrate and that this inhibition recovered with the addition of proline. Finally the mode of action of cranberry phenolics and L-lactic acid was investigated in L. monocytogenes and E. coli based on the concept of disruption of critical proline-linked pentose phosphate pathway and the role of this pathway was confirmed.

The objective of this study was to better understand the impact of model polyol cosolvents (glycerol and sorbitol) on the physicochemical properties and functionalities of a model globular protein (β-lactoglobulin) at neutral pH. The influence of the cosolvents on the protein's properties in aqueous solutions (solubility, aggregation, molar volume, molar compressibility and thermal denaturation temperature), at interfaces (surface and interfacial tension), in emulsions (emulsion formation and stability) and in gels (gel strength, appearance and water holding capacity) were studied. The results showed that both glycerol and sorbitol increased the thermal stability of β-lactoglobulin, increased the attraction between protein molecules and altered protein functionality, but by different amounts. These results can be mainly attributed to the steric exclusion of sorbitol and glycerol molecules from the protein molecule surface. However, glycerol molecules can preferentially accumulate around hydrophobic parts on the protein surface, which decreases the thermal stability of the protein, thereby partially compensating for the steric exclusion effect. Thus, sorbitol had more impact on the thermal stability of the globular protein than glycerol. Overall, the impact of the cosolvents on globular protein functionality can be attributed to (i) the increase in the thermal stability of the globular protein, (ii) an alteration of the molecular interactions between protein molecules, and (iii) an increase in the viscosity of the intervening medium. These results can be used to design protein-containing food materials that have improved functional properties.

To evaluate paper sludge as a soil amendment, different amounts of sludge were applied once to corn field plots. The soil was Hadley fine sandy loam (Typic Udifluvent, coarse-silty, mixed, nonacid mesic) with an average pH of 6.8. Sludge additions suppressed corn germination and early growth, but corn recovered so that final yields were not suppressed. Sludge effects on corn growth were investigated in greenhouse experiments. Mixtures were made from different amounts of sludge and soil with or without N. Seeds were sown immediately or at 21 days after mixing. Addition of sludge increased media organic matter and P contents. At 21 days, C:N ratio, pH, and salinity of media declined relative to initial values whereas total N concentration was higher. Germination was hindered for seeds sown immediately after mixing, but delaying seeding for 21 days eliminated this problem. Biomass declined as amounts of sludge increased. More than 200 kg N/ha were needed to overcome N immobilization. In another greenhouse experiment, soil (Hadley fine sandy loam) was collected at the University of Massachusetts Research Farm (on-site), and another soil of the same type was from a site not on the Farm (off-site). Different sludge levels were mixed with or without N in on-site soil, off-site soil, or off-site soil with P. Increasing amounts of sludge in the on-site soil hindered seedling emergence. Biomass declined as sludge increased, and the least biomass was produced in on-site soil. Sludge additions decreased the average leaf total N. Paper sludge as a topsoil component for the production of wildflower sods on plastic was investigated. Sludge was mixed with sand, cranberry presscake, rockdust or compost. Establishment and growth of wildflowers were suppressed in mixtures of sludge and sand. The best sods with respect to stand establishment and biomass production were with mixtures of sludge, sand, and compost or with the mixture of sludge, sand, compost, and cranberry presscake. Additions of compost generally improved the capacity of media to support sod production. Paper sludge is a suitable soil amendment, but conditions for maximizing the effective use of sludge must be met according to use and soils characteristics.

No description available.