Brian Flanagan as a USAID-funded Modernizing Extension and Advisory Services (MEAS) project
In EDN 127, we mentioned that a number of MEAS (Modernizing Extension and Advisory Services) documents were being summarized and distilled for ECHO’s audience. An article on Farmer Engagement in Agriculture Extension was shared in EDN 128, and we want to continue to highlight these articles as good resources for extension work. Other ECHO summaries of MEAS docs can be found on ECHOcommunity.org.
Workshops are an often-used and effective tool that extension workers can use to teach new skills to groups of farmers. This document, drawn from the USAID/MEAS Technical Note on Presenting Workshops to Adults, explains how a workshop setting differs from that of a classroom/teaching setting, and how best to plan and conduct workshops to effectively transfer knowledge and skills to farmers.
Tim Motis, PhD
Some tropical crops contain cyanogenic glycosides, toxic substances that release hydrocyanic acid (HCN; also referred to as cyanide or prussic acid) when cells are crushed. Consuming these plants without cooking them can cause cyanide poisoning, with varying effects depending on cyanide levels and how long a person or animal has been eating that plant. Cassava roots and leaves contain cyanogenic glycosides, so people whose diets are heavily dependent on cassava are especially at risk. Traditional methods to process and detoxify cassava roots include fermentation, prolonged soaking and boiling. Chaya leaves also contain cyanogenic glycosides; it is best to cook chaya leaves before eating them, to boil off the HCN rather than ingesting it. ECHO has previously written about cyanide in food plants.
To determine if a plant is safe to consume, either by humans or livestock, a simple cyanide screening test is very helpful. At the 2014 ECHO International Agriculture Conference in Florida, Dr. Ray Smith provided ECHO with sample strips of Cyantesmo paper for screening plant material for HCN. A 2.5 cm (1 in.) strip of this paper is all that is needed to detect the presence of cyanide in a sample of plant material. Cyantesmo paper is available in a 5-m long roll for 49.50 US dollars from CTI Scientific (item 90604). One roll supplies enough 2.5-cm long paper strips for 200 tests. The paper does not have to be kept in a freezer, although Smith recommends that it be refrigerated.
Gene Fifer at Cornell University responds to Brad Ward’s article on permaculture in EDN 129 in "Potential Constraints to Sharing Permaculture Ideas."
Abram Bicksler, Director of ECHO’s Impact Center in Thailand, writes in response to the article about Inca nut in EDN 129 "Caution about Inca Nut."
Ben Fisher and ECHO staff
When trying to find affordable planting containers in the developing world, organizations and workers all over have promoted the use of a readily-available waste resource: tires. Over the years, many have asked whether or not tires contain harmful chemicals that could potentially be taken up by your crops. This article is written to communicate what we found from our search of literature on this topic.
Much of the literature on the subject pertains to tires that have been recycled into small particles. In comparison to the side wall of a tire container, the tire surface area in contact with growing media is much greater with small chunks of rubber. Much of the information available also pertains to toxins in the ash of burnt tires, or those leached from tire material subjected to strongly acidic solutions. Tire garden containers, of course, are not being converted to ash.
Furthermore, the media used to grow plants in tires is not nearly as acidic as the solutions often used to study contaminants in tire leachate.
Nevertheless, tires do contain trace amounts of four metals that are known to be toxic to humans. Most of the discussion below relates to metallic elements, but there is also brief discussion of organic contaminants. The article concludes with suggested practices to make tire gardening as safe as possible. This write-up is not meant to be exhaustive or definitive. Depending on feedback and what we learn going forward, we are open to follow-up articles.
ECHO’s Seed Bank has several new vegetable varieties, profiled below.