Christine Charles
Title: The Impact of Early Season Drought on Host Millet Physiology and its Microbiome
Abstract: Diversified farming systems in which farmers intercrop millet with an indigenous shrub (Guiera senegalensis) have been shown to dramatically increase millet resistance to drought in Senegal in a system known as the Optimized Shrub Intercropping System (OSS). Such a localized agricultural solution is integral to resist weather pattern variations and drought seen through the Sahel that threaten food security and agricultural resilience. Several mechanisms underlying this system have been identified as important in assisting crops through growing-season drought periods including 1) the diverse microbial community conferred by the shrub and 2) the organic matter provided by coppiced shrub branches. Few studies have yet to explore the plant pathways and responses to these system dynamics. The primary objectives of the study will be to determine the influence of OSS cropping on soil microbial structure and function during drought and to determine linkages between isolated attributes of the OSS on millet’s phytochemistry and physiological responses in response to drought stress in pearl millet (Pennisetum glaucum). We will use a large number of different criteria to capture millet response to drought, soils with a history of OSS, and organic matter additions including CO2 exchange rate, leaf fluorescence, late embryogenesis abundant protein concentration (LEA), glutathione reductase concentration (GR), glycine betaine concentration (GB), nutrient content and allocation, soluble sugar content, biomass, and root morphology. Paired with soil extractable nutrient data and phospholipid fatty acid data (PLFA), our study intends to illuminate and lay the groundwork for the plant-system dynamics that occur with the OSS.
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Jiraporn Inthasan
Abstract: At this present, organic farming is one of the important systems in Thailand, to produce food safely using sustainable practices to reduce environmental impacts. One such practice is the use of bio-fertilizers reduce the rate of chemical fertilizer application that has been goal in Thailand since 2000. There is little information on the impacts of organic system and conventional systems on soil quality. Therefore, a study on biofertilizers for sweetcorn production was implemented in 2019 at Maejo University. The experiment had a randomized complete block design with 4 replications and 5 treatments as follows: 1) Control (uninoculated), 2) mycorrhizal inoculation, 3) free living bacterial inoculation, 4) K-solubilizing bacterial inoculation, and 5) mix of all 3 inoculants (2,3 &4) with compost fertilizer (6.25 Mg ha-1). After one year, soils were sampled (0-25 cm depth) and analyzed for enzyme activities (acid phosphatase, alkaline phosphatase, β-glucosidase, N-Acetyl-β-glucosaminidase and arylsulfatase) and microbial community structure (EL-FAME profiling). There was a significant (P<0.05) increase in the 5 soil enzyme activities for most of the inoculated treatments over the control. Total fungal and bacterial EL-FAME biomarkers were stimulated by the biofertilizer treatments. The largest impact on soil microbial properties occurred when compost was added to the mix of 3 inoculants indicating that this treatment had the biggest impact for improving soil quality.
Tvisha Martin
Title: The Use of Nematode Indexes and Enzyme Activities as Indicators of Soil Carbon and Nitrogen Cycling
Abstract: Mapping soil food webs through the use of soil biological indicators is imperative to optimize soil health within intensive farming practices. Thus far, farmers have yet to incorporate soil biological indicators as a method of assessing soil health on their farms. Primarily, two novel soil biological indicators that can serve as sensitive soil health measurements are nematode indices, and enzyme activity. Nematode indices can measure the structure of the soil food web (Structure Index), the method of organic matter decomposition (Channel Index), disturbance (Basal Index), rate of nutrient cycling (Enrichment Index), and soil food web succession (Maturity Index). In addition, enzyme activity can measure the phosphorus cycling, nitrogen cycling, sulfur cycling, and carbon cycling within a soil system. Nematode indexes, enzyme activities, permanganate oxidizable carbon, protein, and respiration were compared within two varying tillage intensities (no-till and chisel till) and two varying crop rotations (corn-alfalfa-alfalfa, and corn-soy) on a clay site and a sandy loam site during planting and harvest in 2020. Results indicate that soil health is improved within systems of greater perennially and decreased disturbance.
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Shao Xinghua
Title: Assessing Soil Health: Soil enzyme activities and microbial profiling as biomarkers of tillage disturbance and crop rotation at seven long-term US experimental sites
Abstract: Crop and soil management affects organic inputs and disturbance that ultimately affects soil health and its ability to deliver agro-ecosystem services. However, to guide management decisions that promote soil health, indicators are needed that are sensitive to management and that can be calibrated independent of soil type. Microbial properties hold potential to be sensitive to management but may be too variable temporally or across soil types to be calibrated, or too expensive for commercial adoption. Furthermore, an indicator ideally should correlate with crop productivity. To address this question, this study investigated soil chemical properties, enzyme activities, and microbial biomarkers for detecting soil management in relation to crop yield. Soils were collected from seven long-term experimental sites in Alabama (Auburn), Ohio (Wooster, Hoytville), Michigan (Kellog at Kalamazoo), Oregon (Adams, Pendleton), and California (Davis). Yield data was provided by the experimental stations managing the plots. Our results have shown that soil nutrient status did significantly differ across crop management systems, pH did not vary consistently with land-use. Crop rotation had little effect on microbial communities or enzyme activities. No-tillage resulted in significantly higher total nitrogen, total organic carbon, which was accompanied by higher β-glucosidase and arylsulfatase enzyme activities. Except for soils from Ohio (Wooster, Hoytwille), changes in β-glucosidase activity were significantly associated with changes in microbial community structure. Enzyme activities were higher on continuous grass sites than in cultivated fields in Michigan, however, enzyme activities in continuous grass field at California site did not show the same trend, probably because its soil total organic carbon was not significantly elevated under grass. Correlation analysis of enzyme activities and yield is underway and will be presented on this poster.
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Alice Snyder
Title: Biosolids application effects on soil carbon storage – A meta-analysis
Abstract: Many decades of research have investigated the effect of annual or semi-annual biosolid application on soil organic carbon (SOC) in agricultural and restoration settings. The aim of this meta-analysis is to evaluate how biosolids application treatments affect SOC levels compared to control treatments. After a thorough Scopus search, the following data was extracted from 84 papers: initial biosolids applied C amounts, study start and end year, study length, sampling depth, bulk density, soil texture and type, study location, and SOC levels after study completion for both biosolid and control treatment. Using the ‘excalc’ function within the ‘Meta-for’ R package, SOC results from the biosolids applied treatments were compared to their respective control treatments. Overall, there is a 62% increase in SOC when biosolids are applied to the soil.
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