Comparison of Compost and Proprietary Soil Amendments for Vegetation Establishment

Status:  Active
Project Start Date:  05/14/2021


Vegetated roadsides occupy more than 24,000 acres of land in Minnesota. After construction is completed, roadsides are generally unvegetated and exposed to rainfall and subject to soil erosion; they are then typically covered with topsoil, fertilizer, turfgrass, and straw to establish plant growth. However, these establishment practices can be expensive due to the cost and hauling of materials and may pose environmental concerns because of the leaching potential of excess nutrients. While use of compost for roadside vegetation improvement has shown promise, its availability and quality are limited in certain parts of Minnesota (MN). Proprietary soil amendments may be less expensive or provide better turfgrass establishment conditions, however no guidelines are available to determine the mixing ratios for compost/proprietary amendments and poor soils. The overall goal of this project is to determine the optimum mixing ratios for both compost and proprietary products used as soil amendments to rapidly establish post-construction vegetation. This will be achieved through the completion of four objectives: (1) evaluate the vegetation establishment performance of the selected methods through greenhouse experiments; (2) evaluate field performance of test plots built in the MnROAD test facility; (3) analyze and compare the benefits of compost and amendments, and (4) develop guidelines and specifications for amendment use. The (1) greenhouse tests will be designed to determine the optimum mixing ratios. The (2) field testing will include full-scale test plot construction using the most promising mix designs. An excel-based tool (3) will be developed to select optimum mixing ratios. A (4) design guideline/specification for roadsides will be provided. The overall outcome of this research will provide guidance for the selection of compost and proprietary additives and optimized design for roadside vegetation establishment processes.

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