Organic Farming Research Foundation Awards Grant to Rodale Institute

The Organic Farming Research Foundation (OFRF) has awarded a $14,991 grant to Rodale Institute. Requested by Gladis Zinati, Rodale Institute Associate Research Scientist, this grant will fund the project “Field Evaluation of Designed Compost Extracts for Organic Weed Suppression” beginning May 1, 2016, and ending August 1, 2017.


There is a need for practical and cost-effective technology to reduce weed pressure for organic vegetable growers. The goal of of this project is to evaluate the impact of using designed compost extracts (DCE), as an alternative, to reduce weed pressure, soil degradation, and yield losses of field-grown organic cabbage crop and the germination-inhibitory compounds of DCE.

From 2013 to 2014, Rodale Institute conducted laboratory and greenhouse trials, funded by OFRF, which showed that chemically- and biologically-DCE with lower nitrate levels and greater nematode-to-protozoa ratios significantly reduced lambsquarter weed seed germination by 32% without affecting crop seed percent germination.

However, it is essential to assess the efficacy of using DCE on weed suppression, cost savings, and soil health when applied to field-grown vegetable crops as well as report on the germination-inhibitory substances (phenolic compounds and flavonoids) of DCE inhibiting weed seed germination.

Objectives of this project include; identifying and quantifying the phenolic acids and flavonoids in designed compost extracts to pinpoint the phytochemicals that are potentially involved in the suppression or enhancement of weed germination, demonstrating and evaluating the efficacy of field applications of the DCE at two rates on weed suppression, soil health and crop yield when compared to the grower’s standard method (hand-weeding and cultivation) for growing cabbage, identifying and quantifying the phenolic acids and flavonoids in soils samples that received DCE versus those treated without DCE, predicting yield losses in relation to weed density in various treatments, and publishing the results at Rodale’s Annual On-Farm Field Day, CSA field tours, and web articles.

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