The 2010 ASHS Annual Conference

Objective(s):
This workshop will review the scientific basis for alternative amendments including teas, humates, and microbial products in organic farming systems. Our working group desires to summarize advances in knowledge on the predominant mechanisms and modes of action of alternative amendments, review the role of cultural practices on amendment efficacy, and discuss their application in farming systems.

Organic and conventional farmers are increasingly utilizing a diversity of alternative amendments to improve plant health, growth and productivity.  Amendments are used to reduce the incidence of soilborne disease, improve the efficiency of nutrient cycling, and boost the plant’s natural defense system. The implementation of the National Organic Program’s Final Rule in 2002, the phase-out of methyl bromide, and a desire to reduce input costs are factors associated with the dramatic increase in the number of commercially-available alternative amendments. Typically these products can be grouped into four categories based on their function and/or activity area: 1) those that induce systemic acquired resistance in the plant; 2) those that act upon soilborne pests or, 3) on pests that reside on plant surfaces; and 4) those that enhance the plant’s growth and development. Unfortunately, it is often difficult to separate the “snake oils” from the products that do, in fact, provide benefits as described. Many farmers state positive results following the addition of compost and vermicomposts teas, microbial products, biopesticides and humates that are made on-farm or purchased from area suppliers. However, ingredients, processing, shipping, handling, and application strategies are variables that may affect the efficacy of alternative amendments. Additionally, ecological and biological conditions vary among sites, so results are not always consistent.  Scientific knowledge on the function and efficacy as well as cultural practices of these amendments is needed to facilitate the development of sustainable, biologically-based farming systems. The Organic Horticulture Working Group will host a panel discussion on the scientific basis of alternative amendments in cropping systems. Panelists will present and discuss topics including the modes of action of alternative amendments, the roles of specific compounds and organisms, and the effects of cultural practices on amendment efficacy.  Panelists will present information based on their own research and experience. The discussions will be focused on research methods to evaluate the efficacy of products that provide multiple ecosystem services, the role of state and federal laws and regulations on product use, and areas in need of additional research. Audience participation is encouraged.