Restoring the Soil - Canadian Foodgrains Bank

60Green Manure/Cover Crop Systemsshould therefore also teach the community to winnow the grain as Asians do their riceand other small grains.S10. Tomatoes/jackbeans. Jackbeans are intercropped in the rows between tomatoplants. They are usually planted at the same time as the tomatoes. When they begin toshade the tomatoes, they are pruned back to a height of about 30 to 40 cm, whichforces them to sprout more branches and grow laterally rather than vertically. Atmost one hundred farmers use this practice that was developed in Yucatan during the1980s.S11. Chili peppers/jackbeans. Jackbeans are managed in chili pepper fields in Yucatanthe same way as in the tomato fields in S10.GuatemalaS12. Maize/runner bean-1. In the Department of San Marcos, scarlet runner beansare intercropped very sparsely with maize. The runner beans produce a good deal oforganic matter. Since they are climbers, they can cause the maize to fall over towardthe end of the growing season. Therefore, farmers tend to plant it quite sparsely, usingas few as one or two seeds in each 3 m x 3 m sector. The runner bean is planted at thesame time as the maize. At least 3,000 to 5,000 farmers use this traditional system.This “problem” of the production of a massive amount of organic matter by the runnerbean could be a tremendous advantage in terms of soil fertility and productivity. Isuspect that if the runner bean and maize could be supported by a third, fast-growing,woody-stemmed plant (perhaps tephrosia?), the system could become one of the mostprofitable and sustainable highland maize-growing systems anywhere. This possibilityneeds to be researched.S13. Maize/runner bean-2. In the central highlands a variety of runner bean is intercroppedmuch more densely with maize (up to one seed for every 2 square metres)(Photo 19). Maize yields have been maintained for up to 20 years in many placeswith this system. Before the Europeans arrived, similar systems were apparently usedin virtually all the temperate or highland areas from New York State in the UnitedStates, south to Mexico, Guatemala, Honduras, Colombia, Ecuador, Peru, Bolivia andnorthern Chile. Hundreds of thousands of farmers, stretching from Mexico to Bolivia,use this system today.S14. Maize/mucuna-4. Mucuna is rotated with maize in the Cerro San Gil region,Department of Izabal (Photo 31). The maize is planted when the rains start in Mayor June, and mucuna is relay-cropped into the maize 30 to 40 days before the maize isharvested (Photo 32). Maize following mucuna, without chemical fertilizer, has producedup to 7.4 MT/ha on Brazilian experimental stations. 16 This is evidence of thepotential yields that can be achieved by rotating or relaying mucuna with maize. Thissystem is also used in Nicaragua and Brazil. In Paraguay some farmers wait to plant16Lathwell, op. cit.