Restoring the Soil - Canadian Foodgrains Bank

38Decision Tree Guide12. Altitude above sea level. At what range of altitudes do you work?a) If mostly below 1,500 m above sea level, go to #22.b) If mostly between 1,500 m and 3,000 m above sea level, go to #17.c) If mostly above 3,000 m above sea level, go to #13.13. Above 3,000 m. What is the main crop in the area? If it is maize, go to #14. If it ispotatoes, go to #15. If it is fruit trees, go to #16.14. Maize. Fava beans (also called “broadbeans”) and runner beans (sometimescalled “scarlet runner beans” because manyvarieties have bright orange-red flowers)can usually be intercropped with maize atthese altitudes (Photos 18 and 19). Bothproduce widely consumed and tasty ediblebeans. Fava beans can be eaten both greenand dry. The runner bean generally producesmore organic matter, and increasessoil fertility more, than do the fava beans.18. Mexico. In the Americas, fava beans are onlyproduced at high altitudes, but are produced at lowelevations in the Sudan and other parts of the Arabworld. In either case, they make a very valuableand tasty gm/cc for intercropping with maize,sorghum or millet. In fact, since the plants are erectand therefore will not pull down the sorghum ormillet, they might be one of the best intercrops forthese grains. However, I know of no one who hasever tried such a system.Farmers from central Honduras haveintercropped runner beans with theirmaize for 20 years without using chemicalfertilizer and without seeing any decreasein their soil’s productivity. Runner beansoften don’t grow well the first year in agiven field (presumably because of a lackof appropriate rhizobium), but shouldgrow very well after the first year. Theyalso have a tuber that sprouts each yearfor up to ten years after the first planting,thereby eliminating the cost of reseedingthem, but farmers say it is better to replantthem every fifth year.See information on the systems using bothfava beans and runner beans in S6, S12and S13. If you choose one of these, goto #5.19. Honduras. Scarlet runner beans have tremendouspotential for use in highland maize systems.Sometimes tephrosia will also have to be grownin the same field, to keep the weight of the runnerbean’s biomass from pulling down the maize stalks.Another possibility is sweet clover(Melilotus albus), used in areas wherepeople also raise cattle. Sweet clover is avery hardy perennial that will fertilize thesoil efficiently, and also provide fodder forcattle during the entire dry season. It is so