Open Access. Powered by Scholars. Published by Universities.®

Agricultural Science Commons

Open Access. Powered by Scholars. Published by Universities.®

2021

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 121 - 150 of 1783

Full-Text Articles in Agricultural Science

Effect Of Application Of Farmyard Manure To Ley On Forage Yield And Quality Of Grass Silage, T. M. Pauly, L. Rodhe Dec 2021

Effect Of Application Of Farmyard Manure To Ley On Forage Yield And Quality Of Grass Silage, T. M. Pauly, L. Rodhe

IGC Proceedings (1977-2023)

A two-year field trial was performed on ley near Uppsala, Sweden, with the following treatments (3 plots/treatment): A, no manure or fertiliser; B, manure applied in Oct.; C, manure applied in Oct. followed by rolling plots in May; D, manure applied in May; E, mineral fertiliser only. Apart from cattle manure, plots allocated to treatments B, C and D received the same amount of mineral nutrients as treatment E. The objective of this experiment was to get an indication of how different times of manure application (before or after the growth period) affected forage yields and the quality of the …


The Effects Of Cellulase On Cell Wall Structure And The Rumen Digestion Of Alfalfa Silage, T. Ishida, A. Aisan, K. Tomiyama, T. Watanabe, H. Terui, E. No, K. Ataku Dec 2021

The Effects Of Cellulase On Cell Wall Structure And The Rumen Digestion Of Alfalfa Silage, T. Ishida, A. Aisan, K. Tomiyama, T. Watanabe, H. Terui, E. No, K. Ataku

IGC Proceedings (1977-2023)

First- and second-cut alfalfa (Medicago sativa) was ensiled with no additive, microbial (Lactobacillus casei) inoculant, cellulase derived from Acremonium celluloytics Y-94, co-addition of inoculant and cellulase, and formic acid. The resultant silages were digested in the rumen of a dairy cow. The alfalfa and the silages were then examined with scanning electron microscope (SEM) and their chemical characteristics analyzed to evaluate the effects of cellulase on the quality of alfalfa silage and its cell wall structure.

The addition of cellulase lend to both a greater loss of parenchymal tissue and decrease in digestibility during rumen degradation …


The Effect Of Cellulase On Cell Wall Structure And The Rumen Digestion Of Timothy Silage, A. Aniwaru, T. Ishida, T. Watanabe, K. Tomiyama, H. Terui, K. Ataku, L. E. Chase Dec 2021

The Effect Of Cellulase On Cell Wall Structure And The Rumen Digestion Of Timothy Silage, A. Aniwaru, T. Ishida, T. Watanabe, K. Tomiyama, H. Terui, K. Ataku, L. E. Chase

IGC Proceedings (1977-2023)

The objective of this study was to determine the effect of additives on the structure changes of related tissues during the ensiling process and the rumen digestion of timothy. In the first cut-timothy, the addition of LC+AC improved the fermentation qualities of the silage. Addition of cellulase resulted in significant decreases in NDF, ADF, cellulose, and hemicellulose content. SEM examination of the samples suggests that the degradation of parenchymal tissues was enhanced by the cellulase, but no significant differences were observed among the additives in the rumen digestion. The NDF and cellulose digestibility of the AC- and LC+AC-treated silages were …


Quality Of Ammoniated Brachiaria Decumbens Hay, L. O. Fernandes, Ricardo A. Reis, L. R. A. Rodrigues Dec 2021

Quality Of Ammoniated Brachiaria Decumbens Hay, L. O. Fernandes, Ricardo A. Reis, L. R. A. Rodrigues

IGC Proceedings (1977-2023)

The experiment was conducted at UNESP-Jaboticabal to evaluate the quality of Brachiaria decumbens hays harvested after seed ripening. The hays were submitted to the following treatments: control, anhydrous ammonia (3.0% NH3 in the DM), and urea (5.0% in the DM). The chemical composition, digestibility and the performance of steers were evaluated using a complete randomized block design with three treatments and six replications. The ammoniation either with NH3 or urea increased (P< 0.05) the CP content, and the IVDMD. The NH3 treatment reduced (P < 0.05) the contents of NDF and ADF, and the urea application reduced (P < 0.05) the contents of hemicellulose and lignin. The ammoniation did not affect (P > 0.05) the neutral detergent insoluble nitrogen, and acid detergent insoluble nitrogen values. Steers receiving Brachiaria hay plus soybean meal (1.08 kg DM.day), hay …


Ensiling Of Different Legumes Compared To Grass, S. Slottner, C. Rammer Dec 2021

Ensiling Of Different Legumes Compared To Grass, S. Slottner, C. Rammer

IGC Proceedings (1977-2023)

The objective of this study was to examine the ensiling characteristics of four different forage legumes: galega (Galega orientalis), lucerne (Medicago sativa), white clover (Trifolium repens) and red clover (Trifolium pratense), and compare these with perennial ryegrass (Lolium perenne), using different additives. The crops were mowed using a sickle bar mower and chopped using a precision chop harvester. The crops were ensiled either direct cut or wilted to 35-45% DM. Wilting took place on a barn drier. Forages were ensiled either untreated or with addition of formic acid, Promyr or …


Lactic Acid Bacteria Isolated From Forage Crops And Silage Fermentation, Yimin Cai, Ryuichi Uegaki, Y. Fujita Dec 2021

Lactic Acid Bacteria Isolated From Forage Crops And Silage Fermentation, Yimin Cai, Ryuichi Uegaki, Y. Fujita

IGC Proceedings (1977-2023)

Six strains, Lactobacillus plantarum CM 1, Lactobacillus rhamnosus CM 2, Pediococcus acidilactici CM 4 Enterococcus faecalis CM 5, Leuconostoc pseudomesenteroides CM 7 and Weissella paramesenteroides CM 8 isolated from forage crops were used as additives at 1.0x105 cfu g-1 of fresh matter to Italian ryegrass and alfalfa, and their effect on silage fermentation was studied. The two silage’s treated with strains CM 1, CM 2 and CM 4 were well preserved; had significantly lower pH values, butyric acid and ammonia N concentrations; and had significantly higher lactic acid content than did the respective control, strains CM 5, CM …


Fermentation And Cell Wall Degradation In Guineagrass And Italian Ryegrass Silages, Mitsuhiro Niimi, O. Kawamura Dec 2021

Fermentation And Cell Wall Degradation In Guineagrass And Italian Ryegrass Silages, Mitsuhiro Niimi, O. Kawamura

IGC Proceedings (1977-2023)

Guineagrass (Panicum maximum Jacq.) was ensiled at the room temperature and Italian ryegrass (Lolium multiflorum L.) was ensiled at the room temperature and at 30 under the laboratory conditions. As a result, the acetic acid silage was made from Guineagrass and the lactic acid silages were made from Italian ryegrass. The loss of cell wall components during ensiling was the most in hemicellulose followed by NDF, but those of cellulose and AD-lignin were slight. In the hemicellulosic monosaccharides, the loss of hexose (galactose and glucose) was relatively high and that of pentose (arabinose and xylose) was relatively low …


Evaluation Of Forage Sorghum Silages With The Addition Of Sorghum Grain, M. De León, E. Ustarroz, M. A. Brunetti, C. Boetto, M. Bulaschevich Dec 2021

Evaluation Of Forage Sorghum Silages With The Addition Of Sorghum Grain, M. De León, E. Ustarroz, M. A. Brunetti, C. Boetto, M. Bulaschevich

IGC Proceedings (1977-2023)

The aim of this experiment was to evaluate the effect of additional sorghum grain and stage of maturity of forage sorghum silage on the animal performance. Two feeding trials were conducted with forage sorghum silage made at different stage of plant maturity. In trial 1, early silage was made with the crop harvested in early bloom stage. Four diets based on different ratios of silage: sorghum grain were evaluated: 100% silage (ES); 80% silage: 20% dry grain (ES20D); 60% silage: 40% dry grain (ES40D) and 60% silage: 40% wet grain silage (ES40W). In trial 2, late silage was made with …


Influence Of Additive Aiv-2000 And Pre-Wilted Big Bale On Silage Quality, Animal Performance And Rumen Metabolism, Jonas Jatkauskas, V. Vrotniakienė Dec 2021

Influence Of Additive Aiv-2000 And Pre-Wilted Big Bale On Silage Quality, Animal Performance And Rumen Metabolism, Jonas Jatkauskas, V. Vrotniakienė

IGC Proceedings (1977-2023)

Silage treatment with AIV-2000 or making of silage big bales resulted in a higher level of lactic acid and organic matter digestibilities and reduced concentrations of butyric acid and ammonia-N. Feeding AIV-2000 treated and big bale silages increased weight gains of young fattening bulls by, respectively, 5.44 and 6.77% in comparison with the ordinary made silage. AIV-2000 treated and big bale silages affected microflora activity in the rumen. Infusoria count was higher by 13.5 and 30.34% (P < 0.05), VFA concentration increased by 0.39 and 8.45%, the pH value decreased by 0.05 and 0.1 unit, the content of total nitrogen was by 14.67 and 18.73 mg/100 ml, protein nitrogen by 14.12 and 16.63 mg/100 ml and non-protein nitrogen by 0.53 and 1.39 mg/100 ml higher, respectively for AIV-2000 and big bale groups in comparison with the control group.


Quality And Nutritive Value Of Mott Dwarf Elephantgrass Silage With Biological Additives, T. Clavero Dec 2021

Quality And Nutritive Value Of Mott Dwarf Elephantgrass Silage With Biological Additives, T. Clavero

IGC Proceedings (1977-2023)

This experiment was conducted to study the effects of cellulase enzymes and lactic acid bacteria on the fermentation characteristics, chemical composition and nutritive value of Pennisetum purpureum cv Mott silage. Five kinds of preparation were tested: sugar molasses (control); sugar molasses and cellulase enzymes; cellulase enzymes; concentrate of lactic acid bacteria and sugar molasses and concentrate of lactic acid bacteria. Significant differences (P< 0.05) were found in fermentation quality and chemical composition of control silage as compared to the biological additives treated silage. Addition of cellulase enzymes and lactic acid bacteria resulted in decrease of pH value, cell wall content and increased lactic acid concentration. The biological additives increased silage intake and daily live weight by growing steers.


Effects Of Different Additives On Silage Quality Of Napiergrass, Y. K. Cheng, C. S. Chen, P. W. Peng Dec 2021

Effects Of Different Additives On Silage Quality Of Napiergrass, Y. K. Cheng, C. S. Chen, P. W. Peng

IGC Proceedings (1977-2023)

Objectives of this experiment were to determine the effects of different additives on silage quality of napiergrass (Pennisetum purpureum). The cultivar of TLG2 with high water soluble carbohydrates was used to making silages added with or without 5 and 10% corn meal or wheat bran, and then treated with or without enzyme. Crude protein, acid detergent fiber, neutral detergent fiber, water soluble carbohydrates and volatile fatty acid contents of silage were determined to evaluate silage quality. From the results, it showed that var.TLG2 could be making good silages without any additives but the dry matter was low. Adding …


Sources Of Peanut Digging Losses And Strategies To Reduce Losses During Inversion, Loren Samenko Dec 2021

Sources Of Peanut Digging Losses And Strategies To Reduce Losses During Inversion, Loren Samenko

All Theses

Presented research was conducted at Clemson University’s Edisto Research and Education Center to quantify harvest related losses associated with the effects of peanut digger blade geometry, the effects of the peanut digger inversion assembly, and the effects of vine load on digging and strategies to address vine load. Three studies were performed to determine the potential losses incurred during the digging processes; various harvest metrics were analyzed to quantify the effects of the treatments. Five objectives guided the presented research. Objectives of the effects of peanut digger blade geometry study investigated the impact of blade geometry and blade aggression on …


Assessing Freezing Effect On Kiwifruit Cultivars And Mapping Suitable Areas For Growing The Crop In Eastern Texas, Lais De Oliveira Machado Dec 2021

Assessing Freezing Effect On Kiwifruit Cultivars And Mapping Suitable Areas For Growing The Crop In Eastern Texas, Lais De Oliveira Machado

Electronic Theses and Dissertations

Kiwifruit is a perennial vine originating from China where it has been grown for centuries. In the United States, green kiwifruit (Actinidia deliciosa) is primarily produced commercially in California. They are fuzzy, green fleshed and well known in the marketplace. Kiwifruit plants require low to moderate soil pH, adequate winter chilling and adequate precipitation to guarantee plant development and good fructification. Actinidia chinesis or golden kiwifruit are smooth skinned, feature golden flesh and are a more recent introduction into the global market. Kiwifruit crops have attributes that favor production in east Texas, including low pest problems, current long …


Climatic Factors Affecting Maize Grain Yield In Different Growing Areas Of The Philippines, Lakshman Kumara, Tonette Laude, Jose Hernandez, Pearl Sanchez, Moises Dorado, Jose Nestor Garcia, Gerardo Gauna, Pompe C. Sta. Cruz Dec 2021

Climatic Factors Affecting Maize Grain Yield In Different Growing Areas Of The Philippines, Lakshman Kumara, Tonette Laude, Jose Hernandez, Pearl Sanchez, Moises Dorado, Jose Nestor Garcia, Gerardo Gauna, Pompe C. Sta. Cruz

The Philippine Agricultural Scientist

Seasonal climate variation is one of the problems faced by Filipino maize farmers, due to varying climatic elements such as solar radiation, rainfall, relative humidity, and air temperature. This study determined the seasonal productivity of selected maize varieties in the major growing areas in the Philippines, and identified the yield-limiting climatic factors specific to location and growing season. Grain yield, covering two wet and dry seasons (2016-2018) from seven field trials (representing 3 climatic types) of the National Corn Testing (NCT) were used in the study. Climatic data (2016-2018) were gathered from the PAGASA weather station nearest to the trial …


Flowering Regulation Of Potted Bougainvillea Plants Under Five Water Treatments [Research Note], Kuan-Hung Lin, Jui-Mei Li, Chun-Wei Wu, Yu-Sen Chang Dec 2021

Flowering Regulation Of Potted Bougainvillea Plants Under Five Water Treatments [Research Note], Kuan-Hung Lin, Jui-Mei Li, Chun-Wei Wu, Yu-Sen Chang

The Philippine Agricultural Scientist

Bougainvillea (Bougainvillea buttiana) is a very popular evergreen landscape plant in the tropical and subtropical areas. The objective of this study was to investigate the growth, flowering, and physiological performance of bougainvillea ‘Taipei Red’ cultivar in response to water-stress conditions that can potentially be used to maximize the economic efficiency and benefits in the development and ACC potential of bougainvillea plants grown in controlled environments. Potted plants were subjected to five different levels of soil VWC: 60% (control), 40%, 20%, 1/3 of leaves visually observed to be drooping (equivalent to 18% VWC), and 2/3 of leaves drooping (15% …


First Detection Of Naturally Introgressed Bt Cry1ab In Asian Corn Borer [Ostrinia Furnacalis (Guenée)] - Resistant Traditional Maize (Silangan) In The Philippines, Merdelyn T. Caasi-Lit, Eureka Teresa C. Ocampo, Artemio Salazar, Jefferson Paril, Bryan Novio, Bernard Panabang, Angelyn Marta Marmeto Dec 2021

First Detection Of Naturally Introgressed Bt Cry1ab In Asian Corn Borer [Ostrinia Furnacalis (Guenée)] - Resistant Traditional Maize (Silangan) In The Philippines, Merdelyn T. Caasi-Lit, Eureka Teresa C. Ocampo, Artemio Salazar, Jefferson Paril, Bryan Novio, Bernard Panabang, Angelyn Marta Marmeto

The Philippine Agricultural Scientist

Resistance against insect pests is one of the most promising and highly favored characteristics of an economically important crop. In the Philippines, the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), is the most destructive insect pest of maize. The discovery of Bacillus thuringiensis and the Bt toxin, which led to the development of Bt corn, effectively controlled this pest. In this study, four traditional varieties of maize that showed resistance against ACB were tested for the presence of Bt Cry1Ab protein. Out of these four, a traditional variety from San Carlos City, Pangasinan, which was initially thought to have natural …


Epinasty Accompanies Potassium Nitrate-Induced Flower Bud Break In 'Carabao' Mango [Research Note], Ulysses Besas, Calixto Protacio Dec 2021

Epinasty Accompanies Potassium Nitrate-Induced Flower Bud Break In 'Carabao' Mango [Research Note], Ulysses Besas, Calixto Protacio

The Philippine Agricultural Scientist

The hypothesis that potassium nitrate application promotes epinasty in ‘Carabao’ mango through increased ethylene production was investigated. The degree of drooping, apical primordium growth as affected by shoot ethylene and levels after potassium nitrate spraying were monitored. Evidence presented established for the first time in ‘Carabao’ mango that epinasty occurred just before flower emergence, coinciding with visible bud break, and extended up to 18 days, marking floral anthesis. The possible reasons could be the higher levels of ethylene at 0.31% and earlier increase of ethylene in the shoot apex at four hours and apical primordium growth. Increased ethylene levels at …


Establishment Of The In Vitro Culture And Plant Regeneration Of Anubias Barteri Var. Nana 'Mini', Kuan-Hung Lin, Chih-Peng Kuo, Li-Ru Chen Dec 2021

Establishment Of The In Vitro Culture And Plant Regeneration Of Anubias Barteri Var. Nana 'Mini', Kuan-Hung Lin, Chih-Peng Kuo, Li-Ru Chen

The Philippine Agricultural Scientist

Anubias barteri is an ornamental aquatic plant of economic importance worldwide. Effective removal of contaminants has been a major problem for the in vitro propagation of A. barteri. Hydrogen peroxide (H2O2) was applied as a pre-disinfectant to treat rhizome bud explants of A. barteri var. nana ‘Mini’ followed by disinfection with mercuric chloride (HgCl2) to eliminate in vitro contamination. However, application of 0.1% HgCl2 for 5 min without pre-disinfecting with H2O2 significantly reduced the contamination rate to 44.4% compared to other combinations. Moreover, in vitro shoots of A. barteri …


American Burying Beetle, Plant Richness, And Soil Property Responses To Collapse Of Juniperus Virginiana Woodlands With Fire, Alison K. Ludwig Dec 2021

American Burying Beetle, Plant Richness, And Soil Property Responses To Collapse Of Juniperus Virginiana Woodlands With Fire, Alison K. Ludwig

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Grasslands are declining in the Great Plains due to land use changes, woody plant encroachment, and loss of historic fire cycles. Prescribed burn associations have utilized prescribed fire to collapse invading woodlands and allow the restoration of grasslands. This fire is considered “extreme” because it is capable of changing the structure and function of an ecosystem. Our study site is the Loess Canyons Experimental Landscape, a long-term, ecoregion-scale experiment to apply prescribed fire across the region to restore grasslands. The Nebraska Natural Legacy Project established the Loess Canyons ecoregion as a Biologically-Unique Landscape in 2005 with the state’s wildlife action …


Livestock Grazing Impacts On Crop And Soil Responses For Two Cropping Systems, Alyssa Kuhn Dec 2021

Livestock Grazing Impacts On Crop And Soil Responses For Two Cropping Systems, Alyssa Kuhn

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Diversified crop, forage, and livestock systems are assumed to be more sustainable and economically competitive than traditional cropping systems. Objectives of this study were to determine effects of integrating grazing livestock into corn (Zea mays)-soybean (Glycine max (L.) Merr.) (C-S) and corn-soybean-wheat (Triticum aestivum L.) (C-S-W) cropping systems on plant population, grain yield, soil nutrients and soil carbon dioxide (CO2) flux following winter grazing corn residue (both systems) and an oat (Avena sativa) cover crop (C-S-W only) planted after wheat. For the 2019 and 2020 production seasons, neither corn nor soybean plant …


A Method For Visualizing Water Flow Through Modified Root Zones, Dallas M. Williams Dec 2021

A Method For Visualizing Water Flow Through Modified Root Zones, Dallas M. Williams

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

As the number of impervious surfaces in urban environments increases, the ability of modified root zones to infiltrate water is becoming more important. Current methods of tracing water flow through soil profiles include excavating large pits in situ or analyzing soil cores in the laboratory with computed tomography or magnetic resonance imaging. While useful, these methods may not be suitable for urban settings or practical in every laboratory. We propose a new method that is less invasive, does not require extensive technical equipment and can reliably trace water movement through the soil profile in order to calculate flow rate based …


Sensitivity Of Soybean And Rice To Dicamba, Owen Wesley France Dec 2021

Sensitivity Of Soybean And Rice To Dicamba, Owen Wesley France

Graduate Theses and Dissertations

Although the integration of dicamba as a postemergence (POST) herbicide has proven useful in controlling many herbicide-resistant weeds, its damage to soybean at low rates, such as supplied by drift and volatility, has been well-documented. Injury to other crops, such as rice, from off-target movement of dicamba and other commonly used herbicides, such as glyphosate, may also occur. Practical options for mitigating injury and yield loss to soybean and other crops from dicamba off-target movement could prove beneficial if dicamba continues to be used during summer months. Experiments were conducted to determine the effects of multiple agricultural practices, including cultivar …


Recapture And Reuse Of Nitrogen And Phosphorus From Rendered Animal Materials To Enhance Nutrient Use Efficiency And Produce Quality In Agricultural Crop, Bhupinder Jatana Dec 2021

Recapture And Reuse Of Nitrogen And Phosphorus From Rendered Animal Materials To Enhance Nutrient Use Efficiency And Produce Quality In Agricultural Crop, Bhupinder Jatana

All Dissertations

The current fertilizer regime heavily relies on inorganic fertilizers to meet the crop nitrogen (N) and phosphorus (P) demand. However, the United States has a limited N production capacity, with 50% N demand met through imports. On the other hand, the nonrenewable natural reserves of P are being depleted at an unprecedented rate and are expected to be exhausted with in next 100 years. Additionally, high solubility/liability of the field applied inorganic fertilizers often results in lower nutrient use efficiency (NUE;

The MBM led to rapid N mineralization, with 35% of the applied N mineralized within the first five days …


How Do Cover Crops Change Soil Health In A No-Till System?, Aysha Kirsten Tapp Ross Dec 2021

How Do Cover Crops Change Soil Health In A No-Till System?, Aysha Kirsten Tapp Ross

Electronic Theses and Dissertations

Nutrient levels and aggregation measurements are currently the most accurate means to measure soil health. It has been suggested that bacterial and fungal communities may prove to be a more accurate measure of soil health. In this study soil microbe communities and nutrient levels were compared in rye cover cropped soils to measure for differences between treatments. Effects between the microbial communities and environmental measurements were also measured within those treatments to test for correlations between soil health measures and microbial communities. The plots were put in a biennial corn (Zea mays L.) and soybean (Glycine max …


Economic Potash Fertilizer Rate Recommendations, Kimberly B. Oliver Dec 2021

Economic Potash Fertilizer Rate Recommendations, Kimberly B. Oliver

Graduate Theses and Dissertations

This thesis is comprised of two studies that estimate profit-maximizing potassium (K) fertilizer application rates for various crops across different time periods. Estimation of profit-maximizing fertilizer-K rate (K*) for both studies considered the initial soil test level of K (STK) and yield response information, as traditional recommendations do, and added crop price and the cost of fertilizer. Profit maximum occurs where the marginal revenue from additional yield is equal to the marginal cost of applying an additional unit of fertilizer-K. The first study calculated K* for corn (Zea mays) and cotton (Gossypium hirsutum) and compared results to previous studies on …


Effects Of "Lemongrass Factor" On Galleria Mellonella Hemocytes, Jennifer C. Rice Dec 2021

Effects Of "Lemongrass Factor" On Galleria Mellonella Hemocytes, Jennifer C. Rice

Graduate Theses/Dissertations

The use of conventional chemical insecticides to control agricultural pest has become problematic as they may have a negative impact towards human health and the environment, resulting in a need to research alternative methods to insect pest control. Plant derived substances like essential oils have been used for generations as toxicants, repellants, and anti-feedants to control agricultural pest. More research is needed to understand how insect immune systems react to essential oils and if cellular immune responses of phagocytosis, encapsulation, and nodulation can be inhibited by such. Subjecting Galleria mellonella to various concentrations of “lemongrass factor” lets the researcher/scientist know …


Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher Dec 2021

Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher

Master's Theses

Effects of nitrogen management and cultivar on strawberry production under disease pressure

Kamille Garcia-Brucher

California strawberry growers face increasing regulatory pressures to manage nitrogen (N) applications in their production system. Standard practice in the California strawberry industry is to apply a synthetic pre-plant controlled release fertilizer (CRF) to ensure the crop has sufficient N during winter establishment. Some research from the UC Cooperative Extension suggests this practice is not efficient at delivering N to the crop since most of the N is released from CRF before strawberry crop N uptake is significant. Another concern for California strawberry growers is loss …


Comparing Organic And Conventional Yield Responses To Climate Variations, Joost Wilken Meyer Dec 2021

Comparing Organic And Conventional Yield Responses To Climate Variations, Joost Wilken Meyer

Graduate Theses and Dissertations

This thesis compares the responses of organic yields and conventional yields towards climate variations. To achieve this objective, weather variables such as growing season weather conditions (average temperature, precipitation, cloud cover, relative humidity, drought index), weather anomalies, the occurrence of severe or extreme droughts and excessive rainfalls, are combined with 23 data sets gathered from previous studies that compare organic and conventional yields from the same location and time periods. To narrow the scope, the thesis focuses on soybean, maize, and wheat production in Europe and North America. Study-level fixed-effects models are used to control for any time-invariant factors such …


Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston Dec 2021

Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston

Graduate Theses and Dissertations

Nutrient management in recirculating hydroponic systems requires the periodic replenishment of water and nutrients to the nutrient solution reservoir. Common nutrient management strategies, such as replenishing the reservoir with fresh solution and maintaining a constant solution electrical conductivity (EC), can lead to ion accumulation and nutrient imbalances since nutrients are taken up by roots and depleted from solution at different rates. To avoid nutritional disorders, commercial growers typically dump and replace the hydroponic solution periodically, which is wasteful and has an economic cost. A potential alternative is to specially formulate the nutrient replenishment solution to balance the supply of nutrients …


Precise Nitrogen Recommendations Improve Economic And Environmental Outcomes In Arkansas Rice Production, Cristin Roberts Dec 2021

Precise Nitrogen Recommendations Improve Economic And Environmental Outcomes In Arkansas Rice Production, Cristin Roberts

Graduate Theses and Dissertations

Soil testing has become an increasingly important tool in making agronomically efficient production management decisions. N-STaR is a N test used in rice production and is unique in its ability to selectively quantify soil organic-N compounds which are readily mineralizable for plant N uptake and contribute to growth and yield. This study uses historical (2002–2018) adoption rates of N-STaR, which is funded through Rice Checkoff funds, to calculate the total cost savings from N-STaR adoption. These cost savings alone would be the “typical” benefits used in a benefit-cost ratio of a public ally funded research program like N-STaR. However, we …