Browsing by Author "Ippolito, Jim, committee member"
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Item Open Access Intercropping alfalfa with select grass species for increased yield and quality under deficit irrigation(Colorado State University. Libraries, 2023) Doyle, Hunter, author; Brummer, Joe, advisor; Cabot, Perry, committee member; Ippolito, Jim, committee memberDrought and water scarcity have plagued the Western US for decades. As these issues become more prevalent, we must explore possibilities to utilize available water more efficiently. The objective of this study was to: Evaluate the ability of mixed and stripped intercropping alfalfa with grasses to increase yield and quality of the forage produced under deficit irrigation. Alfalfa (Medicago sativa) is the most common forage grown in the West and is known for its high-water use. Intercropping alfalfa with perennial grasses can potentially improve water use efficiency. Orchardgrass (Dactylis glomerata), meadow brome (Bromus biebersteinii), and tall fescue (Festuca arundinacea) were mixed on the same bed or strip intercropped on alternating beds with alfalfa under 100% and 60% ET irrigation regimes using subsurface drip irrigation. Three cuts occurred in 2021 and 2022, with deficit irrigation starting after cut one. Yield, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), neutral detergent fiber digestibility (NDFD), and relative feed value (RFV) were analyzed in this study. During year one, irrigation did not have a significant impact on yield due to high precipitation and the fact that alfalfa performs well under deficit irrigation. Quality was not affected by irrigation treatments throughout both years of this study. Planting treatments significantly impacted yield and all quality parameters throughout this study. In 2021, mixed intercropping treatments averaged 14,210 kg ha-1, stripped treatments averaged 12,285 kg ha-1, and alfalfa averaged 13,406 kg ha-1; significant differences were not present. All mixed treatments, tall fescue stripped, and meadow brome stripped yields were similar to alfalfa in 2021. In 2021, quality was generally only reduced in mixed intercropping treatments compared to alfalfa in the first cutting. The inclusion of grasses with alfalfa reduced crude protein content and increased neutral detergent fiber content during cutting one, overall reducing quality. In cuttings two and three, mixed intercropping did not generally reduce quality. Stripped treatments also reduced quality in cutting one but did not have a large effect on quality in subsequent cuttings. Relative feed value, a common parameter used among producers, was similar among all treatments for all cuttings in 2021. In 2022, deficit irrigation had a significant impact on yield in cuttings two and three. Yields due to deficit irrigation were reduced by 22% and 35% in cuttings two and three, respectively. Total yearly yields were reduced by 12.5% between irrigation treatments. Total yields in mixed intercropping treatments were significantly higher than the alfalfa monoculture, especially the tall fescue and orchardgrass. Meadow brome generally had a higher yield than alfalfa, though not always significant. Mixed treatments averaged 13,308 kg ha-1 and stripped treatments averaged 9,488 kg ha-1 compared to alfalfa at 10,758 kg ha-1. Similar to 2021, quality was only reduced in intercropping treatments during the first cutting. Crude protein and RFV decreased while NDF and ADF increased in intercropping treatments compared to alfalfa alone, resulting in reduced quality. In subsequent cuttings, quality was generally similar among intercropping treatments and alfalfa alone. Mixed intercropping demonstrated to be more productive throughout both years of this study compared to stripped intercropping. Advantages from intercropping were reduced in stripped treatments due to independent cultivation and limited species interactions. Grass species did not have as large of an effect on yield and quality compared to intercropping method. Tall fescue typically performed the best of the grasses, yet all grasses in mixed intercropping performed well compared to alfalfa. Mixed intercropping grass with alfalfa can lead to increased yields with minimal effects on forage quality compared to alfalfa alone. As severe drought continues in areas across the Western US, mixed intercropping could be an option for maintaining or improving yields while producing similar forage quality compared to alfalfa alone under deficit irrigation.Item Open Access Molybdenum exposure in drinking water vs feed affects copper apparent absorption differently in beef cattle consuming a high forage diet(Colorado State University. Libraries, 2020) Thorndyke, Meghan, author; Engle, Terry, advisor; Ahola, Jason K., committee member; Ippolito, Jim, committee memberTwelve Angus steers were utilized to investigate the influence of molybdenum (Mo) in drinking water or feed on apparent absorption and retention of copper (Cu) and Mo. Steers were fed a low-quality grass hay diet for 14 days. Steers were then housed in individual metabolism stalls for 5 days to determine dry matter intake (DMI). Steers were then blocked by body weight and DMI and randomly assigned within block to one of three treatments. Treatments consisted of: 1) control (no supplemental Mo); 2) 5.0 mg Mo/kg DM from sodium molybdate dihydrate (Mo-diet), and 3) 1.5 mg Mo/L from sodium molybdate dihydrate delivered in the drinking water (Mo-water). After the 5 day DMI determination period, total fecal and urine output was collected for 5 days. Dry matter intake, Cu and water intake, and DM digestibility were similar across treatments. As expected, Mo intake was greater (P < 0.05) in Mo-water and Mo-diet steers when compared to controls but similar between Mo-water and Mo-diet steers. Apparent absorption and retention of Cu (% of Cu intake) was greater (P < 0.05) in controls when compared to Mo-diet supplemented steers. Apparent absorption and retention of Cu (% of Cu intake) in steers in the Mo-water treatment did not differ from controls or those receiving the Mo-diet. Molybdenum-diet and Mo-water supplemented steers had similar apparent absorption and retention of Cu. Apparent absorption and retention of Mo (% of Mo intake) was greater in controls when compared to Mo supplemented steers. These data indicate that Mo consumed in water may impact Cu absorption and retention to a lesser extent than Mo supplemented in the diet.Item Open Access Phytoremediation and biofortification potential of Cannabis sativa L.(Colorado State University. Libraries, 2019) Stonehouse, Gavin C., author; Pilon-Smits, Elizabeth, advisor; Pilon, Marinus, committee member; Ippolito, Jim, committee memberSelenium (Se) is a micronutrient, but toxic at high levels. Both Se deficiency and toxicity are problems worldwide. I studied the potential of hemp (Cannabis sativa L.) for Se environmental cleanup (phytoremediation) and for accumulating elevated levels of this healthy micronutrient (Se biofortification). Hemp properties attractive for phytoremediation are fast growth, high biomass, hardiness and economic value. Furthermore, hemp produces highly nutritious seeds, of interest for Se biofortification. The first Chapter of this thesis reviews Cannabis sativa's history, biological attributes and applications, as well as the technologies of phytoremediation and biofortification, and plant Se metabolism. The second Chapter presents experimental data on two hemp studies. The first was a field survey of Se accumulation in hemp grown across Colorado, and in commercial hemp products. The second study involved controlled greenhouse experiments to study hemp Se tolerance, accumulation and metabolism. Hemp field surveys in four naturally seleniferous (Se-rich) agricultural areas in Colorado, U.S.A. found 15-25 µg Se/g in seed (intact or dehulled) and 5-10 µg Se/g dry weight in flowers and leaves. Hemp beer contained 42 µg Se/L. Considering the U. S. recommended daily allowance (RDA) of 55-75 ug Se, one bottle of hemp beer provides 25%, and 4 gram hemp seed (a half tablespoon) provides 100% of the RDA. In controlled greenhouse experiments, hemp was further characterized for Se tolerance, accumulation and Se speciation. Effects of Se on photosynthesis and cannabinoid and terpenoid levels were also analyzed. At the seedling level, hemp showed high selenate tolerance (up to 160 µM) and accumulation (up to 1,400 mg Se/kg shoot dry weight). Mature hemp was completely tolerant up to 40 µM selenate and accumulated up to 200 mg Se/kg DW in leaves, flowers and seeds. Seeds were found to contain free (water-extractable) selenomethionine and methyl-selenocysteine, superior forms for Se biofortification, reported to have anticarcinogenic properties for consumers. Hemp production of medicinal cannabidiol (CBD) and terpenoids was not affected by Se. Selenium enhanced potassium levels in seeds, and thus their nutritional value; other nutrient levels were unaffected. It can be concluded from these studies that hemp shows promise for Se phytoremediation and can produce Se-biofortified dietary products; Se does not affect levels of valuable secondary plant compounds, nor does it negatively affect nutritional quality of seeds. These findings are of significance in view of the widespread and rapidly expanding cultivation of hemp in seleniferous areas across the U.S.A. and Canada.Item Open Access Soil degradation and water scarcity: the importance of soil organic matter and reuse of non-traditional water sources within agricultural systems(Colorado State University. Libraries, 2023) Stokes, Sean, author; Borch, Thomas, advisor; Trivedi, Pankaj, committee member; Ippolito, Jim, committee member; Fonte, Steve, committee memberOur exponentially growing world will demand approximately 70% more agriculture production by 2050, yet according to the Food & Agriculture Organization of the UN, ~33% of land worldwide is experiencing soil degradation and by 2050, over 90% of soils could be degraded. Exacerbating problems with soil degradation are droughts that are becoming more common with a warming climate. According to the National Oceanic and Atmospheric Administration, ~60% of the USA experienced drought in 2022 and over 90% of the Western US is under drought conditions, including one of the largest agricultural regions in the world, California. Therefore, in order to address these urgent issues of soil degradation and water scarcity, agriculture needs to adapt to more sustainable management practices that emphasize the importance of maintaining soil health, specifically, soil organic matter (SOM), and implement treatment processes to utilize non-traditional water sources (i.e., wastewater from various sectors). This dissertation is a combination of two different research projects that focus on these topics. Two chapters are focused on soil degradation in agriculture in collaboration with an industry partner, Cutrale Citrus, and two chapters are focused on the reuse/treatment of non-traditional water sources in collaboration with the Department of Energy's National Alliance for Water Innovation (NAWI).Our scope within the NAWI project was to develop a baseline paper (i.e., a review) for this concept within agriculture, specifically the reuse of agricultural wastewater and the treatment of produced water (PW) for use as irrigation water. Since agricultural water quality has large regional variability, we focused on two agricultural regions, the Midwest and California. The Midwest has runoff primarily contaminated with nutrients that lead to eutrophication in the major water bodies of this region, while California has saline runoff that in some cases is too toxic to be released to the environment. California's agricultural runoff requires advanced treatment techniques while the Midwest could use existing tile drainage systems to capture runoff and re-apply it to cropland since the main contaminants are nutrients. The reuse of PW is more complicated since its often highly saline and contains other toxic organic compounds or metals. Kern County, CA has been reusing PW for over 20 years but only because their PW has low salinity, this allows them to implement low-cost treatments focused on dilution, but this reuse has been controversial. Our analysis showed there are many unknowns related to the toxicity of PW, so we also develop a path forward through the implementation of an "Adverse Outcomes Pathway" approach that could be utilized to minimize any risks associated with the reuse of this water for irrigation. The research focused on soil health utilizes soil from a citrus grove in SW Florida managed by Cutrale Citrus. The first study focused on why tree size varied between areas of the grove with identical management practices and trees of the same age. Based on these observations it was clear that soil health varied between these areas, so we endeavored to understand what components of the soil, including both physiochemical parameters and biological indicators, were showing significant differences between the productivity regions. The results showed that SOM concentrations, enzyme activity, and microbial diversity were the components of the soil that were significantly different between these areas. Additionally, these trees were all infected with Citrus Greening disease, so we developed a hypothesis based on how this phloem-limiting infection could also be impacting soil health or conversely, how soil health could impact the progression of this disease. Based on these results, the second study focused on how we could regenerate the SOM in this soil and improve soil health through the addition of different organic amendments (biochar and compost). A 400-day greenhouse study was conducted to look at changes to the SOM; we combined typical soil science analysis of SOM such as concentration and mineralization rate with molecular level analysis using high-resolution mass spectrometry (FT-ICR MS). Analysis of microbial diversity was also conducted but those results will not be finished in time to be included in the dissertation and will be included only in the published paper. The soils showed clear differences in molecular composition at both the start and finish of the study depending on which amendment was added. Overall, the compost soil showed an initial spike in activity followed by degradation and loss from the system while the biochar showed slower increases in activity and more stability in the soil. The molecular analysis clearly showed the shift of compost towards more oxygenated molecules and a decrease in the number of different chemical formula present, while the biochar soils had transformation occurring without much loss and contained molecules that were more reduced. Overall, this study showed how biochar is an effective amendment when considering the long-term impacts that one application could have compared to compost which has greater stimulation of the soil in the short term but quickly degrades and needs to be reapplied frequently. When considering the issues facing agriculture in the 21st century it is important to take an all-inclusive approach because agriculture is comprised of interconnected systems. For example, if soil health and SOM are not properly considered then that soil might have less ability to store and absorb water so more erosion or nutrient leaching might occur. Or conversely, if water of poor quality is applied to a field, then salts could build up and degrade the soil. However, if we continue to have devastating droughts in the Western US then we might need to consider reusing alternative water sources to irrigate our fields and we should begin to prepare for that possibility as our high-quality freshwater supplies dwindle.