Restoring the Soil - Canadian Foodgrains Bank

56Decision Tree GuideHowever, if fruit trees are used for shade, something must be done to providesoil fertility. Farmers who want to improve their coffee fields’ fertility can useperennial peanuts (Arachis pintoi) as a low-lying gm/cc, if they can get thecuttings. Perennial peanuts are a little difficult to get established, but once theyare established, they provide a cover less than 20 cm thick that will completelycontrol weeds and fix nitrogen for as long as it is in the ground. Choose S28 andgo to #5.If farmers cannot obtain perennial peanut cuttings, they will usually settle forjackbeans as an intercrop with their coffee. See S29, then go to #5. Also see thedescription of jackbeans in #29.58. Coconuts, oil palms or cacao. Select S26 (or S29 if perennial peanut cuttings arenot available) and go to #5.59. Gm/ccs for fruit trees. I have seen jackbeans, mucuna, perennial peanuts andCentrosema pubescens used as gm/ccs for fruit trees. I believe the perennial peanutis easily the best of these systems. See S26 then go to #5. Centrosema works wellas a perennial, but forms a mat of about 30-40 cm in depth; this means fruit thatdrops is often lost. As well, the Centrosema might become a cover for snakes. Ifextension workers and the farmers favor this system, go to S67 and then to #5.Jackbeans can be used, but have to be replanted every year or two. Go to S38,and then #5. Mucuna would have to be replanted every year in most climates,and would also have to be trimmed regularly around the trees. I consider mucunaas advantageous only where farmers have a serious problem with sun scorch (asthey do in Paraguay, where farmers are very happy with mucuna). In this case,use S37 and then go to #5.60. Much of the land is wasteland. See S77, which can be used with the normalannual mucuna, or the perennial species. In most situations, however, it wouldbe better to plow the soil and broadcast jackbean seeds on it, at a rate of approximately4 seeds/m 2 . If the soil is so infertile that even jackbeans will not grow on it(an extremely rare phenomenon), you might use a little animal manure to get thejackbean started.