Restoring the Soil - Canadian Foodgrains Bank

Green Manure/Cover Crop Systems67BrazilEPAGRI, the agricultural development arm of the state government of Santa Catarinain Brazil, has introduced well over a hundred gm/cc systems, using over 70 gm/cc species,in the state. Many of these systems, and some others, have also been introducedinto huge areas of Parana, Rio Grande do Sul and other Brazilian states, to a sum totalof well over a million farmers. I have personally observed the handful of systems listedbelow, but they are only the tip of a very large iceberg.41. Brazil. Brazilian farmers use gm/ccs, amongother things, to be able to increase the organicmatter in their soils as rapidly as possible, so theycan begin using zero tillage within a year or two.Therefore, gm/ccs like this crotalaria, that wasintercropped with maize, are very popular, becausethey commonly produce a total biomass of wellover 80 t/ha (green weight).S44 to S46. Maize/crotalaria. At least threespecies of the genus Crotalaria are used asintercrops with maize in Santa CatarinaState (Photo 41). The crotalarias are generallyplanted at the same time as the maize.In Brazil, all of these systems includingthose using other intercrops such as forageturnips, jackbeans and oats (the latter notincluded here because they are not leguminous)are designed not so much to providenutrients to the soil as to produce largequantities of organic matter. Farmers usethe systems so they can increase their soilorganic matter content enough to move tozero tillage as quickly as possible. Over 25million ha of land in Brazil and Argentinaare now in zero tillage. 24S47. Fruit/mucuna. Mucuna is used as a cover crop under various species of fruit treesin Acre State. Perennial peanut would probably be a better choice of cover crop, toreduce the labor of cutting the mucuna out of the trees and of reseeding the mucunaeach year.S48. Onions/mucuna. Mucuna is used in a rotation for onion production in SantaCatarina. Hundreds of farmers use this system introduced by EPAGRI.S49. Various crops/common peas. For a number of different crops, peas are grown asa winter rotation crop in Santa Catarina, both as a gm/cc and as a cash crop.Hundreds, if not thousands, of farmers use this traditional system.24Brown, Lester R., World on the Edge, How to Prevent Environmental and Economic Collapse (New York: Earth PolicyInstitute, 2011), pp. 143-44.