The aim of this thesis was to use long-term sewage sludge application to land to determine if sludge, particularly metal-rich sludge, alters the microbial community as indicated by substrate utilisation profiles (sups), using the Biolog ^TM method.  An additional aim was to assess Biolog^TM as a rapid method of monitoring soil health. Sludge rich in Cadmium altered microbial community profiles, but this was possibly due to differences in organic Carbon quality between sludges used in the trial.  Conditioning (incubation) of soils before analysis with Biolog^TM made these effects more apparent.  Storage of soil also altered microbial activity and community profiles, which were not restored by a conditioning period.  Both incubation and storage influenced the Biolog^TM response and can potentially affect available soil C. Therefore, the effects of organic matter application at high levels on the microbial community, were assessed without metals.  Low metals sludge altered microbial community function, although the trends were not consistent across soil types.  Biolog^TM was more sensitive to sludge treatment effects than total microbial biomass C. The microbial community responses to sludge and preparation disturbance were examined (using Biolog^TM and microbial PLFAs). A method to determine extractable carbohydrates was adapted for use in a microplate format, and was employed to assess the relationship between microbial community change and available soil C.  Changes in soil microbial community structure and function were not related to extractable carbohydrate C.  Biolog^TM and PLFA responded differently:  disturbance had a greater effect on Biolog response than either application of sewage sludge or the quality of soil C;  but PLFAs were more affected by long-term sewage sludge amendment, highlighting implications for the monitoring of waste-amended soils.

Traditional vineyard floor management in the eastern USA consists of mown resident vegetation in the aisle and herbicide bare driplines, promoting soil erosion and crusting, compaction, lowered water penetration, herbicide resistance, difficult weed management, increased plant parasitic nematode populations and decreased soil biodiversity for pest management. To investigate these issues, four novel vineyard floor management techniques and two N-fertilizer applications were investigated using nematode assemblages as a bioindicator of soil health. Main-plot groundcover treatments include: 1.) grower control, consisting of mown fescue (Festuca arundinacea) in the aisle with herbicide bare vine dripline, 2.) red fescue, creeping red fescue (Festuca rubra L.) established in both the aisle and vine dripline, 3.) successional, annually planted cereal rye (Secale cereale L.), spring oats (Avena sativa L.), and sorghum-sudan grass (Sorgum x drummondii) by planting them in succession with a no-till drill throughout the year, 4.) compost treatment consisted of a 2 to 1 mix of hardwood mulch and composted winery pomace applied across both the vineyard aisle and vine dripline. Split-plot nitrogen treatments include: 1.) no nitrogen fertility applied to grapevines, 2). 20 lb. N/ac applied to grapevine dripline at budbreak, bloom and veraison. The randomized complete block design with four main-plot treatments, two split-plot treatments and five blocks was established in 2013 and 2014 in a commercial mature Norton vineyard, planted in 2003, at 2.44 x 3.66 m spacing, in southern Illinois on a Hosmer silt-loam. The canonical analysis of principle components clearly revealed that compost and successional treatments were particularly effective at shifting nematode assemblages to higher populations of cp-5 nematodes to correlate with increases in soil respiration and organic matter, thus indicating establishment of a stable soil health structure both physically and ecologically. The results of the soil health analysis panel (soil respiration, water extracted organic carbon and water extracted macro-and micro-soil elements), consistently supported the interpretation of nematode community structure analysis. In fall 2015 the compost, red fescue and successional groundcovers combined with P and K soil fertility amendments increased water extractable K (WEK) in the aisle by 85%, 59% and 71%, respectively, compared to control; they similarly increased WEK in the aisle by 46%, 59% and 71%, respectively, in summer 2016. In the dripline WEK was increased 140%, 238% and 249%, respectively, by compost, red fescue and successional treatments that received no-N-prescription, compared to the control. The application of prescription-N increased WEK by 25% and 21%, respectively, in the compost and successional treatments that had a generous mulch layer. Soil P response to groundcover treatment clearly distinguished among each treatment the impact of nutrient turnover levels with water extracted P levels: successional > red fescue > compost > control, unique to each treatment. The water extracted mineral element levels detected with the soil health analysis were one-half to one-ninth the concentration extracted with the Mehlich-III test. Red fescue tripled the population of Pratylenchus spp. (236/100cc soil) in the dripline with prescription-N fertilization compared to no-N. Red fescue and successional treatments increased Helicotylenchus spp. populations by ~657% and ~172%, respectively, compared to compost (92/100cc soil) which closely resembled control response average in the dripline across 2015 and 2016. Prescription-N reduced Longidorus spp. by 78% compared to no-N treatment (23/100cc soil) in the dripline of fall 2015. Additionally, prescription-N added to the red fescue and successional treatments reduced Xiphinema spp. populations by 57% and 92%, respectively, compared to the control (52/100cc soil). Compost and successional groundcover treatments dramatically increased grapevine yield and crop size by 38% and 30%; and 29% and 38%, respectively, compared to grower control. The prescription N-fertilizer increased yield and crop size by 13% and 17%, respectively, compared to no-N. Compost and successional also increased Ravaz index by 33% and 60%, respectively, over control without reducing vine size which indicated their future vineyard sustainability.

Animal manures are land applied in agronomic systems to supply essential crop nutrients and decrease dependency on chemical fertilizers. Liquid manures are traditionally surface broadcast to fields and sometimes incorporated to reduce odor and nutrient losses; however, incorporation is incompatible with no-till agriculture. Subsurface manure injection is a no-till compatible alternative application method which addresses these concerns, but likely changes the dynamics of nutrient cycling. Comparison of the two application methods has yielded mixed results and warrants further research. Therefore, the objectives of this research were to contrast the surface broadcast and subsurface injection of dairy slurry on nitrogen and carbon cycling, crop yield, and biologic responses to proxy soil health. In a forced air-flow laboratory incubation, manure injection reduced ammonia volatilization by 87% and 98% in a sandy loam and clay loam soil, respectively. The increased ammoniacal nitrogen recovery resulted in increases of soil nitrate of 13% for the sandy loam and 26% for the clay loam after 40 days of incubation. Microbial measurements were inconclusive in the laboratory. In 7 site-years of field study, soil nitrate was greater in 7 of 25 measurements under manure injection and 30% higher under injection on average during the corn pre side-dress nitrate test (PSNT) time. Soil nitrate sampling methods were assessed for fields injected with manure; a standard random sampling method had a coefficient of variation (C.V.) of 28% and was as equally repeatable as utilizing an equi-spaced distribution of cores taken across an injection band, C.V. of 30%. Both biological responses, carbon mineralization (C-min) and substrate induced respiration (SIR), were not different between application methods; both were highly variable and C-min was especially intensive logistically. Corn yield showed no consistent response to application method, but probably was not nitrogen limited. In 2 years of field study conducted on a university research farm injection resulted in greater 0-15cm soil nitrate levels than surface broadcast 1 week after application and persisted for 9 additional weeks. In injected plots, nitrate was concentrated in the injection band; nitrate movement was significant only 10cm lateral to the injection band but overall distribution fit well to a second degree polynomial, especially 2 and 4 weeks after application, R2>0.80. Evidence of leaching was observed in one year after receiving considerable rainfall in weeks 1 and 2 after application. When corn grain yield was averaged year over year, injection was 26% greater than the no- manure control, and 15% greater than surface application. Both biological metrics, C-min and microbial biomass, were stratified by depth; C-min was concentrated within the manure band leading to greater mineralization under injected applications. Microbial biomass was significantly higher under injection at the 15-30cm depth. Overall biological response to manure application method was inconclusive, however manure injection is superior to surface application in terms of nitrogen recovery. / Doctor of Philosophy / Animal manures supply nutrients essential to crop growth (notably nitrogen and phosphorous); liquid manures (pigs and dairy cattle) are commonly applied by spraying them on soils before tillage. Where no-tillage is used as a conservation measure subsurface injection can be used as an alternative to leaving manure on the soil surface. The purpose of this research was to assess nutrient cycling, crop yield, and soil health impacts of surface applied and injected dairy manure applications. Manure injection greatly reduces a nitrogen loss pathway, and as a result supplies more plant available nitrogen to the crop. Methods of soil sampling fields using injection were compared and a recommended sampling method was defined. Transport of a form of nitrogen vulnerable to movement in the ground was found to only travel 10cm away from where manure was injected. Transport of this form of nitrogen below the injection area was observed after abundant rainfall. Crop yields were sometimes higher under injection however, yields are also determined by factors other than nitrogen. Soil health was not repeatably improved under one application method, but microbial activity was greater at shallower soil depths.

Master of Agribusiness / Department of Agricultural Economics / Jason S. Bergtold / Cover crops can be used as forage for cattle and other grazing animals. This research investigated the net returns of using cover crops for forage or grazing under four scenarios. These scenarios were: 1) a mixed crop and livestock producer who owns a herd of cattle and has both dry or pregnant cows and weaned calves available to graze corn stover and cover crops; 2) a crop farmer who purchases stocker cattle for the purpose of grazing the cover crop and corn stover; 3) a crop farmer who leases out a corn stover and cover crop field to a livestock producer (and who provides value-added services to the livestock producer for a fee); and 4) an integrated operation with crops and cattle where cover crops are not grown and hay is fed to cattle during the winter months. Each of these scenarios had different budgets, risks, and profit potentials. The research aimed to address the risks and profit potentials for each scenario. The stocking density was initially set at three cows and 31 steers for a period of 90 days, and alternatively, three cows and 25 steers for a period of 120 days. Two sets of cattle pricing data were used: the average historical prices from 1992 to 2011 and reported prices from a regional stockyard for the period of November 2016 to March 2017. The results showed that the initial stocking densities used for scenarios one and two were too low to provide profitable net returns regardless of pricing data used. Net returns for scenario three were also not profitable based on the services rendered and the management fee charged. Scenario four was profitable on one occasion. November steers with a 500 lb. average starting weight fed hay and concentrate for 120 days resulted in a positive net return of $375. A second analysis was done using stocking rates of 50, 75, or 100 steers to determine if increasing stocking density would result in a positive net return using only the 2016/2017 pricing data and only evaluating net returns on 2.0 and 2.5 lbs. of average daily gain. Positive net returns were achieved at various start weights and average daily gain rates at stocking rates of 75 and 100 animals. No positive net returns were realized at the stocking rate of 50 animals/100 acre field. The management fee charged for providing management services under scenario three was adjusted based on stocking densities to determine if a positive net return could be achieved at the set fee rate of $0.875/head/day. At that rate, no stocking rate resulted in a positive net return. Using the cost data, less the $900 field lease income, a breakeven pricing point for the management fee was determined for each stocking density and grazing duration within the scenario. Management of cost factors to achieve greater chances of profitability and additional research needs are discussed.

Most of the western United States faces increasing water shortages in the coming years, which will prove a major challenge for maintaining sustainable farms. Incorporating an alternative crop that is well adapted to the projected climate could be a successful approach to increasing the sustainability of farms in the region. Quinoa, Chenopodium quinoa Willd., may be an ideal alternative crop to meet the demands of the Intermountain West. Before widespread adoption of this novel crop can occur, best management strategies need to be documented. This paper provides research on cropping systems, irrigation rates, and weed competition with quinoa. Additionally, the impacts of prior cropping history and compost addition on soil health parameters are presented. Quinoa responded to compost addition in an organic cropping system trial where low soil phosphorous was a limiting nutrient. Cover crops, 70% hairy vetch (Vicia villosa Roth.) and 30% winter wheat (Triticum aestivum L.), provided sufficient nitrogen inputs for the following quinoa crop. In response to a line source irrigation trial, varieties showed optimal irrigation rate from 23- 42 cm of water for biomass accumulation, although no seed was produced by any variety. In a greenhouse weed trial, quinoa was less impacted by the presence of any other species, lambsquarters (Chenopodium album L.), red root pigweed (Amaranthus retroflexus) and green foxtail (Setaria viridis), suggesting a high competitive advantage. Finally, organically managed soil increased soil health indicators, including microbial biomass and resistance to stress, regardless of compost addition. In addition, compost increased soil health indicators in conventionally managed soil. Seed set across all field trials was hindered by peak summer temperatures above 32°C, a known temperature sensitivity threshold during flowering for the varieties tested. Therefore, further work to select adapted varieties for the region must be accomplished before widespread adoption is feasible. An integrated approach involving a locallyadapted novel crop and soil health protection promises to increase future farm sustainability.

No description available.

Soil quality and health indicators are necessary to monitor and improve the agricultural sustainability. This experiment was conducted at Mississippi State, MS between 2015 and 2016. Soil samples were taken to determine bulk density, enzymatic activity, and total C and N. Results indicated greater bulk density, total C and N, and enzymatic activity for inter-row position than for within the corn row which was disturbed by strip-tillage. Soil bulk density tended to increase with soil depth; however, total C and N and total microbial activity decreased with depth both years. Total soil C and N increased from 2015 to 2016. Enzymatic activity was greatest at corn planting and decreased up thru four weeks apparently due to total C and N decomposition. Total C and N were related to bulk density and enzymatic activity because increase in soil C and N decreased the bulk density and increased the enzymatic activity values.

No description available.

Healthy soils are essential for sustaining the world's ecosystems and maintaining human lifestyles. The adoption of biological, chemical, and physical analyses to assess soil health is a relatively new concept with a paucity of scientific work assessing how these metrics are affected by field management in urban systems Soil samples (n = 110) were collected from a diverse range of sports fields and, for comparative purposes, golf courses, farm fields, non-sport urban, undisturbed forest, and non-vegetated sandy soils. The samples were then analyzed using biological, chemical, and physical metrics to determine if there were significant differences between sport/golf venues and non-sport/golf soils. Soil health measurements included total organic carbon (TOC), organic matter (OM), permanganate oxidizable organic carbon (POxC), total inorganic carbon (TIC), potentially mineralizable nitrogen (PMN), carbon respiration (CO2), β-glucosidase (BG), autoclave citrate-extractable (ACE) protein, and aggregate stability (AS). All soils that supported vegetation had higher soil health test values than the non-vegetated sandy soils. In general, differences were either minimal or not detectable between sports field soils and other soils. Notably, golf venues demonstrated higher CO2 and BG than sport venues, while TOC and OM levels in sports fields and golf courses were similar to unmanaged, urban, and farm systems. In addition, ACE protein levels were notably higher in forests. The fertilized venues were generally higher for the less mobile nutrients with poor solubility (P, Zn, Fe, Mn, Cu) and lower in pH than the sand control. Somewhat surprisingly, the non-fertilized forest was generally equivalent to the fertilized venues in nutrients Sports fields had ample soil fertility and reasonable pH and EC, although they had excessively high soil P concentrations. Correlations between soil properties were performed and statistical differences were analyzed using Analysis of Variance and Tukey-Kramer mean separation. Biological and physical soil properties were highly correlated with each other, and overall, biological activity was similar across all land uses, including sports fields. In general, nutrient concentrations and EC were positively correlated, but tended to decline with increasing sand content. The data collected, and comparisons made, will add to scientific and community understanding of soil health as a function of land management.

Conventional farming practices and land-use conversions drive carbon out of soil and into the atmosphere, where it contributes to climate change. Biochar, a soil amendment produced by pyrolyzing organic feedstocks under low-oxygen conditions, is a promising tool to restore soil carbon and draw down atmospheric carbon dioxide. Biochar has received considerable attention from scientists, growers, and environmentalists in the last 20 years, but there is still a gap between academic research and practical recommendations on biochar production and application that are relevant to small-scale growers. Here I present the results from two complementary studies that demonstrate the utility of local-scale biochar systems and provide some recommendations for those looking to work with biochar. The first study sought to determine the impact of biochar amendments on soil carbon and nutrient retention on three working farms across a variety of soil types, cropping systems, and climates in the United States. The effect of biochar amendment depended on initial soil characteristics and the properties of the biochar applied. Biochar amendments increased soil carbon in all three sites and increased soil nitrogen at two of the three. In this study pyrolysis conditions appeared to be as important as local soils and climate influences on the efficacy of biochar treatments. The second study was a life cycle assessment using SimaPro software to quantify the carbon balance and global warming potential of biochar produced from three local feedstocks (softwood, hardwood, and hay) applied to pasture soils in Southwest Virginia. Feedstock type, pyrolysis gas yield, and transportation distance significantly contributed to variation in the carbon balance of each agro-ecosystem. Biochar made from softwood lumber scraps performed best, with the highest net carbon storage and lowest global warming potential, followed by biochar made from hardwood scraps. Hay biochar performed worst, with positive carbon emissions (i.e., more carbon released than stored over its life cycle) in most scenarios tested, mainly because of its low biochar yield and the carbon emissions associated with agronomic production and transportation. Together these studies demonstrate the potential of local biochar systems to improve both soil health and carbon sequestration, and reinforce how important it is to know the characteristics of the soil and the production history and properties of the biochar being applied in order to meet soil health and carbon sequestration goals. / Master of Science / Conventional farming practices break down organic material in the soil, which decreases the capacity of soils to sustain crop growth and contributes to climate change as the soil releases carbon dioxide and other greenhouse gasses into the atmosphere. Biochar, or charcoal that is deliberately incorporated into soil, is gaining popularity among farmers, gardeners, and climate scientists for its ability to improve soil health and draw carbon out of the atmosphere to create stable long-term pools of carbon underground. Unfortunately, much of the research on biochar does not translate easily into recommendations for growers and land-managers to make and use biochar. Here I discuss the results from two studies examining the effect of biochar on soil health and carbon sequestration on local scales. In the first experiment I analyzed soil samples shared by farmers in New Mexico, Minnesota and Virginia who applied locally-sourced biochar to their soils. I found that the initial characteristics of the soil and of the biochar affected how the biochar application changed agriculturally-relevant soil properties. In general, biochar improved soil carbon and nitrogen levels, had mixed effects on soil pH depending on the biochar's pH, and had no effect on electrical conductivity (a measure of soil salinity). The second study was a life cycle assessment that quantified and compared greenhouse gas emissions of three different types of biochar, from feedstock harvest to biochar application to soil. I found that the type of feedstock used to make biochar, the amount of gas emitted during the conversion process, and the distance the feedstocks and biochar were transported all played a role in the overall carbon balance of the life cycle. The biochar made from softwood scraps performed best from a carbon storage perspective, followed by biochar made from hardwood. These two biochars tended to return more carbon to the soil than they emitted over their life cycle. The biochar made from hay performed worst, and emitted more carbon than it stored in most of the scenarios I tested. Together these studies show the potential of local biochar systems to improve both soil health and carbon sequestration and reinforce how important it is to be familiar with the soil and the production history and properties of the biochar being applied in order to meet soil health and carbon sequestration goals.