Most of us here are involved with helping the poor to become more self sufficient via agriculture. Green Manure Cover Crops (GMCC) are highly touted as a way for the poor to do better with their agricultural projects. We all agree with that. But, annual crops like Canavalia, Macuna, etc. are most often recommended and that is the problem….because they require large amounts of seeds which the poor seldom have. Even when money is no issue, I spent 2 years and could only find 50 lbs of Canavalia seed here in Honduras. I wanted 200 lbs but the best I could do was 50. From my many years here, I am very well connected with many seed sources in Honduras and neither money nor transportation is an issue and yet I could not buy 200 lbs of seed. So, there is no way the poor will be able to get the seeds.
I know some will say to find a few seeds and grow more but that takes a lot of time….maybe two years. And, then every year it needs to be done again. And when growing as seed, it is no longer a GMCC. So, unless one is in a location with good seed resources, it seems to me annuals are not the best choice. Just notice how many times on this list, folks are looking for those seeds. Bottom line: I think too many ag leaders are theorizing or extrapolating from their small plots in terms of what they recommend but, when dealing in hectors, it is a totally different story.
We are basically giving up of using or recommending annuals as GMCC. It is too expensive, too weather dependant, too labor intensive, too uncertain and just plain impossible for most poor families. Instead we are going exclusively with perennials. Many of the perennials are not legumes but that is the tradeoff we think is worth making.
In other posts here, I have written of Mombassa grass as being the nearly perfect cut and carry grass for livestock. We are going to begin using it a a big part of our GMCC plants. It grows thick and to about a meter tall each 35 days. That is a HUGE amount of green manure in a year. I doubt anything else compares. The great part of Mombassa is the seed is available globally and low cost. Plus, a little seed goes a long way when planting.
We have always used some legume trees for diversity but I think the mombassa will produce so much biomass in our plantain fields, lemon orchards, etc that the others will be relatively insignificant. Another good thing about mombassa is it can be walked or driven on without a problem plus it is easy to cut with a machete in our Chop and Drop system that we use on all our land. And it is very shade tolerant.
We share a lot of cuttings with the poor that serve as seed for growing many of our perennial GMCC. Mombassa is the same. It can be divided the same way that vetiver can but much, much quicker. Whereas vetiver needs about a year to form a large plant to divide, mombassa does so in about 2 months. And like vetiver, it is non-invasive. It doesn’t spread beyond a cluster size about the same size as a vetiver cluster.