Notes to broadcasters on fertilizer trees

    | January 23, 2012

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    This story mentions several ways in which farmers can use trees to help their crops. Mixing trees and crops in this way is called agroforestry. Trees help crops in many ways. Some trees, especially leguminous trees such as Gliricidia sepium, add nitrogen and other nutrients to the soil through their roots and leaves. Many trees help keep moisture in the soil, and shade crops from the withering effects of direct sun. Others act as windbreaks. And of course, trees can directly provide farmers with products such as fruit, nuts, firewood, and timber for construction.

    For general resources on agroforestry, see:

    Agroforester’s Library:

    The Overstory: This non-academic, plain language agroforestry journal is no longer published, but 100 issues are freely available on-line at:

    FACTnet Fact Sheets on agroforestry species:

    This recent news article talks about Kenyan farmers using fertilizer trees:

    Farmers turn to ‘fertiliser tree’ to boost crop production (Business Daily, May 30, 2011)

    Here is an overview of the World Agroforestry Centre’s Evergreen agriculture program, which includes fertilizer trees among other projects:

    Farm Radio International has published many scripts on forestry and agroforestry. You can browse these scripts here:

    Here’s a script which shows how reforestation can bring rains back.

    Community Reforestation Brings Back the Rains in the Brong Ahafo Region of Ghana (Package 78, Script, July 2006).

    Here is a recent script which talks about the various benefits that trees offer farmers.

    Paying farmers for environmental services (Package 87, Script 5, April 2009).

    Two issues of Voices from 2005 talk about the benefits of agroforestry:

    Trees Hold Down the Soil and Keep Back the Desert (Voices No. 76, October 2005)

    Agroforestry in Africa (Voices No. 74, March 2005)

    Farm Radio Weekly has published a number of agroforestry stories. Here are a few:

    Ethiopia: Farmers group proves that planting trees can reduce temperatures (FRW 61, April 2009)

    Niger: Farmers plant trees to slow deserts’ advance (FRW 25, June 2008)

    Southern Africa: Tree is a ‘fertilizer factory’ in the field (FRW 82, September 2009)

    This FRW story talks about intercropping to improve fertility

    Malawi: Intercropping helps farmer Phiri buy ox-cart (FRW 143, January 2011)

    Do farmers in your area grow or keep trees in their fields, or on the perimeter of their fields? Ask farmers how having trees benefits their crops. Do particular species offer specific benefits?

    Ask farmers about ‘fertilizer trees.’ Do any farmers keep trees in the fields to boost soil fertility? Do they use particular tree species to shade their crops, to protect them from strong winds, or to retain soil on sloping fields?

    If farmers are skeptical about using trees in their fields, find out whether they have reasons for not choosing to grow trees. Have they had negative experience in the past, or are their opinions based on other farmers’ experiences? Or on hearsay?

    You could invite an agroforester, a representative from an NGO involved with agroforestry, or an extension agent to speak about how trees and crops can help each other. Invite farmers to phone in with their questions, complaints, comments, and problems. You could also feature a progressive farmer who uses trees in specific ways to help his or her crops.