A long-held practice is to mix agricultural soil with a soil amendment to improve growing conditions in crops. A common soil amendment is biosolids produced from both municipal and dairy wastewater due to the macro- and micronutrients within it. Both the agricultural and wastewater industries are participating in the Circular Economy concept (CEC). Two experiments explored using expended bioelectrochemical systems (BES) that treated either synthetic dairy wastewater (DWW) or synthetic municipal wastewater (SWW) as soil amendments to improve corn plant growth when treated with three different nutrient treatments: 100%- 50%- and 0% Hoagland Nutrient Solutions. Biochar and used terracotta clay were used as soil amendments too. Additionally, the DWW and SWW soil amendments are being invested to see if soil moisture can be retained during simulated drought conditions. The experiments took place in the late fall and winter of 2021 and summer of 2022 in Starkville, Mississippi.

Ruminant animals comprise the greatest proportion of herbivores around the world, provide essential ecosystem services and human consumable protein by consuming grass and human inedible dietary fiber. Herbivory pressure alters plant communities and species diversity, effectively making grazing animals ecosystem engineers in dynamic ecosystems. Development of advanced computer processing power coupled with biometric and ecosystem sensors may be employed in the internet of things framework to create an integrated information system designed to inform understanding of grazing system function and animal energy balance. Towards this end, I utilized Bos indicus / Bos taurus crossbred steers (n = 20) across two study sites each in consecutive calendar years and fitted them with GPS and accelerometer collar systems. Steers were grazed in improved grass pastures containing Tall Fescue (Festuca arundinacea) and Bermudagrass (Cyanodon dactylon). Forage samples were collected in a 20-m grid pattern at 35-day intervals to test nutritional composition, and NDVI maps were created using remotely sensed data collected using a UAV mounted camera system. In the first chapter, I utilize the movement ecology framework to investigate metabolic theory and animal behavior on energy budgets, then explore available technology to utilize in an integrative information system. In Chapter 2, I tested preprocessing and behavior collection methods used to train a machine learning randomforest classification model to predict animal behavior using triaxial accelerometers. Landscape functional scale and optimal sampling density is the primary focus of Chapter 3, where I explored the complex relationship between sampling regime, interpolation strategy, and landscape complexity, demonstrating that sampling density is a product of desired accuracy and landscape complexity. Finally, I focused on animal growth in Chapter 4, demonstrating the functionality of a walk-over-weigh system, and identified robust regression as the most accurate smoothing method to identify and remove spurious animal weights.

Med dagens transportteknik är det enkelt för stadsplanerare att importera exotiska träd från hela världen. Med importerade plantor finns dock risk att det följer med nya trädsjukdomar och skadegörare till länder där dessa sjukdomar ej funnits tidigare. När nya skadegörarna väl har etablerat sig på stadsträden är näst steg spridning till omgivande skogar. Förutom skador på skogsekosystem kan dessa skadegörare orsaka stora ekonomiska förluster. Syftet med studien var att identifiera möjliga risker för introducering av nya trädskadegörare till svenska skogar och jämföra hur stor andel importerat planteringsmaterial som används i olika delar av Sverige. I materialet från totalt sex städer upptäcktes brister i dokumentation av planterade träd, framför allt saknades information om planteringsmaterialetsursprungsland. Ett bättre registreringssystem behövs för att proaktivt kunna minska risker att främmande trädsjukdomar och skadegörare kan etablera sig i Sverige.

Denna studie undersökte skogsägares preferenser avseende hyggesfria metoder och faktorer som är viktiga i deras val av hyggesfria metoder. Genom att använda en webbaserad enkät inkom 84 svar från skogsägare. Plockhuggning identifierades som den mest önskvärda metoden följt av överhållen skärm. Ekonomi och biologisk mångfald var viktiga faktorer vid val av hyggesfri skötselmetod. Respondenterna önskade mer kunskap om olika metoder, ekonomiskt utfall samt påverkan på den biologiska mångfalden vid användning av hyggesfria skogsbruksmetoder. Brist på kunskap var en stor anledning till att tidigare inte ha brukat skogen med hyggesfria metoder.

Vid föryngring ger markberedning en bra förutsättning för plantan att överleva och växa, och med mindre risk för snytbaggeangrepp. Syftet med denna studie var att undersöka hur snytbaggeskydd och olika markberedningsmetoder långsiktigt påverkar stamantal, medelhöjd och volymproduktion hos gran (Picea abies). Markberedningsmetoderna som jämfördes var högläggning, fläckmarkberedning och inversmarkberedning. De jämfördes med att inte markbereda alls. Hälften av plantorna var behandlade mot snytbagge med permetrin, dessa var jämt fördelade i försöket. Studien genomfördes i en försöksyta 9284, vid SLU:s försökspark i Siljansfors, Mora kommun. Beståndet var 17 år när det mättes (16 år efter plantering) hösten 2018. Då mättes trädens höjd, diameter samt grönkronans höjd. Volym beräknades med volymfunktioner. Högläggning, inversmarkberedning, och fläckmarkberedning (i nu nämnd ordning) och snytbaggeskydd gynnade granplantornas volymtillväxt, gav flest stammar samt högst höjd. Att högläggning och inversmarkberedning var så framgångsrika i detta försök beror troligen på att marken i Siljansfors är näringsfattig och fuktig. Hög planteringspunkt ökar risken för en planta att torka. Permetrinbehandling hade en positiv effekt på volymen och stamantalet, dock var det ingen signifikant skillnad vad gäller höjden. Markberedning samt permetrinbehandling ger bestående långsiktiga resultat för produktionen. / In regenerations, soil preparation provides good conditions for plants to survive and grow, and reduces the risk of damage by pine weevil (Hylobius abietis). The aim of this study was to investigate the long-term effect of protection against pine weevil damage and the long-term effect of different soil scarification methods on the number of trees, tree height and the volume production of spruce (Picea abies). The soil preparation methods that were compared were mounding, patch scarification and the inverse method. These were compared as well as to, no soil preparation at all. Half of the plants were treated against pine weevil with permethrin. These were evenly distributed in the experiment. The study was conducted in the trial area 9284, at SLU's experimental park in Siljansfors, Mora municipality. The trees were 17 years old when measured (16 years after planting) in the autumn 2018. Then tree height, diameter and the height of the green crown was measured. Volume was calculated with volume functions. Mounding, the inverse method and patch scarification (in the order mentioned) and pine weevil protection benefited the volume production of the spruce trees, the numbers of trees and tree height. The fact that mounding and the inverse method was so successful in this experiment is probably due to that the soil in Siljansfors is nutrient-poor and moist. High planting points increases the risk of drought. Permethrin treatment had a positive effect on volume production and the number of plants, however, there was no significant difference regarding tree height. Soil preparation and permethrin treatment provide lasting long-term effects on production.

Piratebush (Buckleya distichophylla (Nutt.) Torr.) is a rare, hemiparasitic shrub with the only extant populations in western North Carolina, northeastern Tennessee, and southwestern Virginia. The preferred natural hosts of piratebush, Carolina and eastern hemlocks, have seen sharp declines over the last decade due to the invasive hemlock woolly adelgid. Virginia pine, another important host of piratebush, is also susceptible to disease, specifically Cronartium appalachianum, a rust fungus for which piratebush is the secondary host. This study described and analyzed current demographic parameters of three Tennessee piratebush populations. Additionally, spatial patterns of disease and demographic characters were analyzed. These data were compared to data from previous censuses to infer the impacts of diseases on piratebush and its host. All three populations were relatively stable in numbers and age structure over the past thirty years. Plant height and stems per shrub were similar among populations and stable over time. Seedlings represented 14%-19% of populations and non-flowering plants 33%-41% of populations. Two populations had an equal sex ratio and one population was male-biased. Disease prevalence was similar among populations but disease was more severe at Temple Ridge. The effects of hemlock decline were most acute at the Temple Ridge population where areas of high hemlock decline were associated with lower vigor piratebush individuals. Piratebush individuals near Virginia pines were more likely to be infected by C. appalachianum, and individuals infected by the rust fungus were more likely to have lower vigor. If hemlock decline is causing a piratebush host shift toward Virginia pine, piratebush populations may also decline because of potential enhanced infection by C. appalachianum. Treatment to prevent HWA infestation may be needed because of its effectiveness in improving the health of both hemlock and piratebush populations.

Agricultural system models integrate many different processes that cannot all be measured in field experiments and help quantify soil water dynamics, crop evapotranspiration, and crop growth with high temporal resolution. Understanding soil water dynamics and crop evapotranspiration is essential to improve agricultural management of field crops. For example, the interaction between nitrogen application rate and water dynamics is not sufficiently understood. In most cases, model simulations deviate from field measurements, especially when model input parameters are indirectly and unspecifically derived. The extent to which measured soil hydraulic property inputs decrease the discrepancy between measured and simulated soil water status is not well understood. Consequently, this study: (i) investigated thr use of measured soil hydraulic properties as Root Zone Water Quality Model (RZWQM2) inputs compared to indirectly derived inputs; (ii) explored the capability of calibrating measured soil hydraulic property input parameters for one crop and using them for other crops without further calibration; (iii) studied the effect of the nitrogen application rate on the behavior of soil water dynamics and crop evapotranspiration using RZWQM2 under different rainfall amounts. To evaluate the model in different field management conditions, a field experiment with soybean, corn, wheat, and fallow soil was conducted from 2015 – 2017 to collect field data to calibrate and validate the RZWQM2 model. The model presented a satisfactory response to using measured soil hydraulic property inputs and a satisfactory capability to quantify the effect of nitrogen rates on daily crop evapotranspiration, soil water dynamics, and crop growth. With sufficient measurements of soil hydraulic parameters, it was possible to build a RZWQM2 model that produced reasonable results even without calibration.

The biofuel market is dominated by ethanol and biodiesel derived from cellulosic and lipid-based biomass crops. This is largely due to the relatively low costs and reliability of production. At present, production of non-food plant-derived oils for biofuel production in the U.S. is minimal. A research team from the Commonwealth Scientific and Industrial Research Organization (CSIRO), an independent Australian federal government research institution, has developed an efficient transgenic system to engineer oil production in tobacco leaves. This novel system is comprised of multiple transgenes that direct the endogenous metabolic flux of oil precursors towards triacylglycerol (TAG) production. Additional genes were incorporated to store and protect the accumulated oil in vegetative tissues. Preliminary greenhouse tests by the CSIRO research group indicated an oil content of > 30% by dry weight (DW) in tobacco leaf lamina. Here we evaluated two transgenic lines against a non-transgenic control in 2017 and 2018 in greenhouse and field production systems. The 2017 pilot study showed that the high leaf-oil tobacco line was viable and will grow in the field in Kentucky. Chemical analyses revealed significantly higher oil content compared to the non-transgenic control despite several logistical setbacks. These promising discoveries prompted the deployment of additional transgenic line assessments and further data validation in 2018. Line evaluations in 2018 revealed that the LEC2:WRI1:DGAT:OLE transgenic line had the highest leaf oil content (≥ 19.3% DW-1) compared to both the WRI1:DGAT:OLE transgenic line (≤ 5.6% DW-1) and non-transgenic control (≤ 2.1% DW-1). The results of this research will contribute to the successful development of transgenic tobacco lines engineered to accumulate high concentrations of TAG in the leaves.

Water scarcity combined with an increasing world population is creating pressure to develop new methods for producing food using less water. Rice is a staple crop with a very high water demand. This study examined the success in maintaining yields under water-saving irrigation management, including alternate wetting and drying (AWD). A meta-analysis was conducted examining yields under various types of water-saving irrigation compared to control plots kept under continuous flooding. The results indicated that yields can indeed be maintained under AWD as long as the field water level during the dry cycles is not allowed to drop below -15 cm, or the soil water potential is not allowed to drop below -10 kPa. Yields can likewise be maintained using irrigation intervals of 2 days, but the variability increases. Midseason drainage was not found to affect yield, though non-flooded conditions when maintained throughout most of the crop season appeared to be detrimental to yields. Increasingly negative effects on yields were found when increasing the severity of AWD or the length of the drainage periods. Potential benefits and drawbacks of water-saving irrigation management with regards to greenhouse gas emissions, soil quality and nutrient losses were discussed to highlight the complexity of the challenges of saving water in rice production.

Healthy, natural pastures is very valuable for biodiversity in the form of both plants and animals. An efficient use of pastures helps to preserve biodiversity, but grazing animals needs to be de-wormed to keep them healthy and to prevent harmful parasites spread on the pasture. The awareness about the environmental impact of the frequent use of deworming agents is low among the public. Some people are unaware that the absorption in horses of anthelmintics is incomplete, which make the circumstances about enviromental effect important to investigate further. The scientific evidence in this area is limited and more studies and trials are needed to deepen the knowledge about the effects of anthelmintics in the environment. Our report includes a compilation of studies conducted on anthelmintics and equine parasites, as well as an experiment which was conducted at the University of Halmstad biogaslaboratory April 2014. Anthelmintics have been shown to have negative impact on the manure ecosystem and especially against manure living fauna. Deworming routines has changed over the years as the equine industry has developed. Nevertheless, there’s still a lack of concrete approach to deworming.