It’s good to share thoughts with you, Nathan.
In response to your note about the people planting in ridges, we have stopped doing that in part because of the labor but also because raised beds exposes it to more evaporation. Secondly, because we try to never disturb the soil so as to not disturb the micro organisms that are working in the soil.
Observing farms here in Spain and Portugal I am noticing they do the opposite. That is, they plant in lowered beds instead of raised beds, claiming that it better conserves the moisture… which makes sense because of reduced surface exposure. We might try that at our farm school in Honduras when I get back there.
In terms of grasses, we mostly use vetiver on the contour lines to eliminate erosion and control the flow of water during the hurricane seasons. But for animal feed and for GMCC that are interplanted with our fruit trees, we use a lot of Mombasa grass. To be clear, the grass that grows with our fruit trees is not cut for animal feed. It is only used as GMCC. We’ve had it tested during the drought season and it only had about 10% protein, but also tested during the rainy season, when it has about 20% protein. As you know protein equals nitrogen. That is, the amount of protein is equal to the amount of nitrogen in a plant. I think that means the nitrogen provided is somewhat similar to legumes.
We cut it approximately each 20 to 30 days when it is about waist high. So, we are adding that much nitrogen to the soil as well as providing an abundant supply of organic matter…mulch that becomes compost. The tonnage per acre is mind boggling. We provide no other fertilizer other than the organic materials we collect and distribute within our irrigation system.
If it makes any difference, I find Mombasa grass almost impossible to kill and yet it’s not the least bit invasive. So for example, we have dug it up and totally eradicated it to build a building, but decided not to build the building. From the remaining roots, it totally regenerated within a few months so it was impossible to recognize that it had been recently totally uprooted. Uprooting provides excellent seed material for planting new areas…like vetiver. In that respect, it is just like vetiver. But it is probably 100 times more productive than vetiver. Producing about 30 tons per hector per year.
I know people who have been growing it for 25 years and at the end of the drought season they burn it. It comes back good as new. It’s an amazing grass. I think it originated in Africa.
We don’t use Mombasa where we grow corn and vegetables. There we use legumous trees. We also use legumous trees in our pastures and in our orchards.
Bottom line, we only use perennials for GMCC. That makes everything much more simple and much more economical.