Feed the Future
This project is part of the U.S. Government's global hunger and food security initiative.

Researching Agriculture Development: The “Green Fertilizer” Edition

This post was written by Marta Schneider, a senior at Knox College in Galesburg, Illinois and eIntern with the Bureau for Food Security Knowledge Management team. Marta was tasked with getting the scoop on green fertilizer, an important component to sustainable agriculture.

 Excessive use of chemical fertilizers and pesticides creates health hazards to consumers and increases farmers’ overhead costs. USAID projects in Bangladesh address these challenges by working with local organizations to produce and promote the use of organic compost and fertilizer. Photo by A. Ellicott/PRICE

 

When wandering through any store today, many Americans will stumble upon products that promise to be “green,” or contain that word somewhere in the product title. The use of this word implies that the use of the product will help the environment, even if that is not always the case. I personally view the term “green” as meaning that a product is made completely free of chemicals, with natural ingredients, and is fully biodegradable. I was recently in an environmental studies class that covered the very issue of trying to find sustainable products in a sea of “green” promises. Thus, when I came across the term “green fertilizer” in a chat box discussion during an Ag Sector Council webinar, I was skeptical of the idea and decided to do a little research.

I turned to my favorite search engine and typed in “green fertilizer.” The first few items that popped up were for-sale fertilizers that contained the word “green” in the title. As an eIntern with the Agrilinks Knowledge Management team, I have learned that when researching agriculture development, it is important to comb the footnotes and explore the work of multiple organizations. I left my favorite search engine in favor of ATTRA, The National Sustainable Agriculture Information Service, managed by the National Center for Appropriate Technology (NCAT) in cooperation with the United States Department of Agriculture's Rural Business-Cooperative Service. I found multiple well-researched ag-related publications including one titled “Overview of Cover Crops and Green Manures” which finally answered the question, what is green fertilizer?

Green fertilizer, more commonly known as green manure, is often associated with organic farming. The concept is simple; to take cover crops like clover or grass and to plow them in under the soil while they are “green” or “soon after flowering”. This practice can improve the nutrients found in the soil, help combat soil erosion, add nitrogen to the soil (when legumes are used), and reduce plant diseases and pests. Crops that become green fertilizer can serve a dual purpose as cover crops that protect rich topsoil. The “Overview of Cover Crops and Green Manures” by ATTRA discusses multiple types of green manure that can be used as fertilizer throughout different seasons. Some examples include legumes, such as alfalfa, clover, and soybeans and non-legumes such as ryegrass, buckwheat, and oats. The best choice depends on the type of soil and regional temperature.

The concept of green fertilizer is not a novel practice, but in times of climate change and environmental change it should not be forgotten. The greatest limitations for cover crops being used as green fertilizer is the likely increased need of water to sustain them and extra time buffer needed to plow them into the soil before planting a subsequent crop. Despite those limitations, the potential to reduce chemical fertilizers and pesticides that pose a risk to nutrients already in the soil and the environment at large is worth investigating. Green manure techniques may prove to be a useful soil management tool in smallholder farming systems, contributing to the natural resource management goals of sustainable agricultural development.

Do you commonly hear the terms “green fertilizer” and “green manure” used in the field? Is green fertilizer a sustainable consideration for agriculture development? Please share your thoughts and resources in the comments section below!

To learn more about fertilizer, check out some of these past Agrilinks events: