Hi everybody. I'm fairly new to permaculture. I find it incredibly fascinating. I apologize if this is an ignorant question, but I couldn't find a definitive answer, as they tend to be mixed. The question is quite simple when is it that you are supposed to chop and drop legume plants? For example, I watch the youtube channel The Natural Farmer (which I like very much). In one of his videos on how he builds his soil, he talks about the growing and chopping of beans. He mentions that he doesn't chop the plant until the it produces a bean. He claims that the carbon is not stable until you do so. He starts talking about it at 7:20. I'm curious what others think. Do you practice this or do you chop and drop before that, like when the plant starts to flower or something like that?
I don't have an answer to your question, but I just wanted to say thank you for posting the video. His climate seems somewhat similar to mine, so I'm so glad to have discovered these videos. I'm now watching them one by one and learning a lot.
I think it depends. A lot of people will plant a nitrogen fixer and then chop it before it produces seed so they can plant a crop that will grow up and cover the area. But for bigger nitrogen fixing legume trees the person may chop at certain times depending on the management style of the tree. A lot of nitrogen fixing tree seedlings get hacked out of the way whenever they start shading something that is seen as more important at that time.
Just when the flowers start forming is the most beneficial time to cut it down. If it's an annual and you'd like it to be there next year, you might want to let it go to seed once. Some plants tolerate being hacked down multiple times better than others. Perennials might tolerate being cut down a couple times per year, but they will also eventually need to go to seed so they can repopulate.
"Turning the sand and rocks into food and pollinator habitat one compostable at a time." - Erica Daly
hau, Jon, as has been mentioned, perennials can be cut multiple times with out worry. This is also true of annuals but you must do the cuts early enough that the plants can recover and produce a seed crop before winter set in.
If it is beans then you can chop and drop twice, these are fairly fast growing plants and only need around three leaf sets to be able to continue growing after a chop session.
If it is clovers you can mow them down every six or seven weeks, they will thrive from this treatment and they will keep coming back.
In most cases, as long as you don't chop things right at ground level, they will continue putting forth new growth.
I leave six inches of most plants when I chop and drop, but I also do ground level chopping on the deep root vegies that I plant for deep soil humus (daikon radish, rape, etc.), these get cut off so they will die and decay.
The question really is not that simple. For starters, as others have pointed out, there are lots of different legumes with very different characteristics. There are different purposes and circumstances, too. I generally think of beans as a food crop that conveniently also fixes nitrogen, so I don't think n terms of chop and drop there. On the other hand, the vetch family make nice nitrogen producing cover crops that can suppress undesired volunteers and I have no problem chopping them back when I want nitrogen rich mulch.
Something to keep n mind, there are very few, if any, 'exact' recipes in permaculture. Everything is an integrated, cross-linked juggling act of sorts. Green manure crop A will be at its peak when it has certain characteristics, but if the crop you want to feed with it is out of synch with the green manure, better to chop and drop at less than peak nutrient value rather than wait for peak but miss the window when the target crop most needed the help.
When it comes to growing plants in a real world environment, not a laboratory, it is practically impossible to actually optimize the process. The list of variables is far too great.
Thanks for the helpful videos and tips. This will help me with my own food forest planning. @Tyler, Geoff Lawton is quickly becoming my new best friend . This article from the Permaculture Research Institute mentions the use of Pigeon Peas, which I will probably use extensively where I can. And @Duane, anyone who has the ability to grow moringa in their environment is lucky. That includes me. I have lots of plans for that tree...
10 Podcast Review of the book Just Enough by Azby Brown