Restoring the Soil - Canadian Foodgrains Bank

More documents

Recommendations

Info

2the best of my knowledge, only two of the gm/cc systems recommended in this bookare no longer being used.By and large, this book (except for the Annex) is written in such a way that anyonewith a basic understanding of the English language will be able to understand itscontent. However, I have included a few technical agricultural terms that many readersof English may not understand. I could have avoided using these terms, but theyare terms that anyone who works with gm/ccs will find useful. In each case, I haveexplained the word’s meaning the first time it is used in the text, and have included itin the small glossary at the end of the book. A list of the different species mentionedin the book is also included at the back of the book.
The Definition of Green Manure/Cover Crops31. The Definition Of Green Manure/Cover CropsWe need to distinguish the term “green manure/cover crops” (gm/ccs) from whatagronomists have traditionally called “green manures.” The basic idea of traditionalgreen manures is that they are plants grown in a field all by themselves (they aremonocropped) and then plowed into the soil (as one does with “manure”) when theyare in the flowering stage, while they are still “green”.But most gm/ccs are managed in an entirely different way. First, rather than alwaysbeing planted alone, gm/ccs are usually planted together with farmers’ traditionalcrops and at about the same time (intercropped), or they are planted among the traditionalcrops just before these crops are harvested (“relayed” into the traditional crops).Occasionally gm/cc species are even planted under tree crops. In these ways, farmerscan fertilize their soil without dedicating any extra land to growing the fertilizer.Second, gm/ccs are almost always cut down after they have produced seeds, ratherthan at flowering time. This is done because the farmers want to eat the seeds, sellthem, or feed them to their animals. And, finally, they typically save at least some ofthe seeds to plant the next year.Third, the gm/cc species are almost always cut down and left on top of the soil, ratherthan being plowed or dug into the soil. This saves the expense of plowing or diggingthem into the soil, and the organic matter on the surface protects the soil from the hottropical sun.While we are still using the basic “green manure” idea of using plants to fertilize thesoil, most of how we manage the gm/cc species today has been changed by smallholderfarmers as they developed better and better ways to use them.Smallholder farmers also want the chosen species to do a lot more than just fertilizetheir soils. One of the most important benefits smallholder farmers want is for thegm/ccs to control weeds. In fact, most farmers in the tropics are considerably moreinterested in controlling weeds than they are in improving their soil fertility. That iswhy we have joined the concept of “cover crops” (whose job is to control weeds) withthat of “green manures” (whose job is to fertilize the soil).Because the idea of gm/ccs has changed so completely in the last 35 years, it isimportant that we define exactly what we mean by gm/ccs. The following definition,used in this book, is the most commonly used definition today: a “green manure/covercrop” is a species of plant, usually a legume, whether it is a tree, a bush, a vine, acrawling plant or an algae, which is planted by farmers to maintain or improve theirsoil fertility or control weeds, even when they have many other reasons for growingthese plants.The two main objections to this definition by some agronomists is that systemsthat use trees to fertilize the soil (what some people call “agro-forestry systems”) are
Page 3: A timely and extremely valuable boo
Page 8 and 9: Restoring the SoiliiAcknowledgement
Page 10 and 11: Restoring the SoilivHow To Use This
Page 14 and 15: 4The Definition of Green Manure/Cov
Page 16 and 17: 6A Brief History of Green Manure/Co
Page 18 and 19: 8Existing Green Manure/Cover Croppi
Page 20 and 21: 10Existing Green Manure/Cover Cropp
Page 28 and 29: 18Improving Soils: The Basic RulesF
Page 30 and 31: 20Choosing The Right GM/CC Cropping
Page 38 and 39: 28Using The Decision Treewhich has
Page 40 and 41: 30Decision Tree7. Decision TreeIntr
Page 42 and 43: 32Decision Tree13.What isthe domina
Page 44 and 45: 34Decision Tree42.Are some ofthe fi
Page 46 and 47: 36Decision Tree Guidewho work in ag
Page 48 and 49: 38Decision Tree Guide12. Altitude a
Page 50 and 51: 40Decision Tree Guideleast a week o
Page 52 and 53: 42Decision Tree GuideLeucaena trees
Page 54 and 55: 44Decision Tree Guidegrow well and
Page 56 and 57: 46Decision Tree Guide25. Honduras.
Page 58 and 59: 48Decision Tree Guidec) Pigeon peas
Page 60 and 61: 50Decision Tree Guideeties should n
Page 62 and 63:
52Decision Tree Guidenot dry-season
Page 64 and 65:
54Decision Tree Guideat least once,
Page 66 and 67:
56Decision Tree GuideHowever, if fr
Page 68 and 69:
58Green Manure/Cover Crop Systems30
Page 70 and 71:
60Green Manure/Cover Crop Systemssh
Page 72 and 73:
62Green Manure/Cover Crop Systemsth
Page 74 and 75:
64Green Manure/Cover Crop SystemsS2
Page 76 and 77:
Page 78 and 79:
68Green Manure/Cover Crop SystemsAf
Page 80 and 81:
70Green Manure/Cover Crop Systemssp
Page 82 and 83:
72Green Manure/Cover Crop SystemsAs
Page 84 and 85:
Page 86 and 87:
Annex 1: Glossary of Agricultural T
Page 88 and 89:
Annex 2: The Evidence79Annex 2: The
Page 90 and 91:
Annex 2: The Evidence81The Amount o
Page 92 and 93:
Annex 2: The Evidence83this level o
Page 94 and 95:
Annex 2: The Evidence85content of a
Page 96 and 97:
Annex 3: List of Recommended Green
Page 98 and 99:
Annex 3: List of Recommended Green
Page 100 and 101:
Annex 4: Seed Sources for Green Man
Page 102 and 103:
Annex 4: Seed Sources for Green Man
Page 104:
Roland Bunch has worked in agricult
show all

Restoring the Soil - Canadian Foodgrains Bank

Create successful ePaper yourself

Delete template?

Save as template?