Assessing and managing soil quality for urban agriculture in Ohio

Food, Agricultural, and Environmental Sciences (FAES): 3rd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)Urban agriculture (UA) is rapidly expanding in the majority of Ohio's cities and is widely recognized as a means of improving the ecological conditions, quality of life, and food security in urban areas. This project will apply the soil quality evaluation process to soils being used for specialty crop production in urban areas in Ohio with the goal of better understanding their soil properties and identifying appropriate management strategies. The project is focused around two major components: an experimental research site and a field study of production sites. The experimental site is located in a series of adjacent vacant urban lots in Youngstown OH where vacant houses were recently demolished and removed. The demolition process often leaves soils severely degraded and this experiment will document the soil's initial condition following demolition, as well as the ability for the soil to be improved for UA by applying organic matter. Experimental treatments focused on applying organic soil amendments produced from urban green wastes will be applied in a replicated, complete block experimental design, including the following treatments: 1) control, 2) leaf compost, 3) leaf compost + intensive cover cropping, 4) leaf compost + hardwood biochar. All plots are split plots comparing in ground cultivation with cultivation in 20cm raised beds. The experiment will be run for the 2011 and 2012 growing seasons. Data will be collected on vegetable crop yield and on soil physical, chemical and biological properties and analyzed through both hypothesis testing and soil quality indexing. Compaction is a primary constraint at the site with bulk density values of 1.79 g cm-3 for in ground plots and 1.55 g cm-3 for raised beds. Crop yield data from 2011 demonstrate strong treatment effects on both crop yield (p=0.002) and harvest index (p=0.008). Both compost amended and compost + biochar amended plots had significantly greater crop yields than control plots, while compost + biochar plots had the highest harvest index values. An additional study in 2012 will conduct soil quality assessment at urban market gardens in Ohio and provide producers with a soil quality report and management recommendations. Expected outcomes include improved knowledge and management of UA soils in the region.A one-year embargo was granted for this item

Permanganate Oxidizable Carbon Reflects a Processed Soil Fraction that is Sensitive to Management

Permanganate oxidizable C (POXC; i.e., active C) is a relatively new method that can quantify labile soil C rapidly and inexpensively. Despite limited reports of positive correlations with particulate organic C (POC), microbial biomass C (MBC), and other soil C fractions, little is known about what soil fractions POXC most closely reflects. We measured POXC across a wide range of soil types, ecosystems, and geographic areas (12 studies, 53 total sites, n = 1379) to: (i) determine the relationship between POXC and POC, MBC and soil organic C (SOC) fractions, and (ii) determine the relative sensitivity of POXC as a labile soil C metric across a range of environmental and management conditions. Permanganate oxidizable C was significantly related to POC, MBC, and SOC, and these relationships were strongest when data were analyzed by individual studies. Permanganate oxidizable C was more closely related to smaller-sized (53–250 μm) than larger POC fractions (250–2000 μm), and more closely related to heavier (\u3e1.7 g cm−3) than lighter POC fractions, indicating that it reflects a relatively processed pool of labile soil C. Compared with POC, MBC, or SOC, POXC demonstrated greater sensitivity to changes in management or environmental variation in 42% of the significant experimental factors examined across the 12 studies. Our analysis demonstrates the usefulness of POXC in quickly and inexpensively assessing changes in the labile soil C pool