How Does Your Garden Grow? Impact of Residuals-Based Amendments on Urban Soil Health, Vegetable Yield and Nutritional Density

This study combined field trials and a greenhouse study to measure the impacts of residuals-based soil amendments on soil health and vegetable yield and nutritional quality for three urban soils. Two biosolids based products and two food scrap-based materials were included. Amendment addition increased total C and N across all soils in the field trial. Reduced bulk density and increased infiltration rates were observed in two of the soils. Increases in permanganate oxidizable carbon (POX-C), a measure of biologically available C, were observed as a result of amendment addition. Plant yield in amended soils was similar to or less than fertilized controls for two soils. There was little to no yield in fertilized soil in the least productive soil. Organic amendment addition to this soil resulted in yields comparable to the highest measured yields in both the field and greenhouse trials. The greenhouse trial showed differences in amendment response with all amendments resulting in increased yield in the most disturbed soil in comparison to fertilizer addition. Plant nutritional quality varied by soil, amendment, crop and nutrient with no clear patterns. This study demonstrates the efficacy of residuals-based amendments for restoring health and productivity to disturbed urban soils