calliandra
Well-Known Member
Yeah my reaction too!woa had no idea. i have never really cut open my legume nodules. im finishing up a new bed of legume peas though. when i till it ill have to check this out!
That streak in the garden, it was me hustling to pull a plant from the alfalfa bed, knife in hand haha
I actually just stumbled over this the other day in an online course I'm taking (about guess what ). This is the passage of the transcript of that lesson:
It's great to share this adventure - cheers!When we start looking at manure, we have to pay attention to the quality of the manure.
We have to pay attention to the quality of the legumes.
So, you go get a bale of lucerne. You've got lucerne hay. Is that going to be high nitrogen?
It's a legume.
But what do you have to look at to determine whether that legume is actually high nitrogen?
The growth form?
What determines whether we actually fix nitrogen in this plant or not?
The legume. Look at the nodules on the roots. So you've got to go back to the root system. You've got to pick up the nodules. You've got to cut them open. Are they red? If they're not red, this is not high nitrogen. If those nodules weren't functioning that plant material is actually now in which category? Yeah, might be there [greens]. If lucerne was cut while it was still green, it would be there.
But what if they didn't cut it until it was dry and brown? Then it's there [woody].
You know, the seed that the legume produced, the plant put a lot of its nitrogen into that seed.
So, if what you're actually getting is the legume straw and it wasn't actually fixing nitrogen, it's that (woody). Yeah, you've got to be looking. [...]
If that plant's actually fixing nitrogen, then any of the dead plant material is going to be in this category. C: N is usually 10:1, even when it's dry and brown. But if you weren't fixing nitrogen, then the stock material is going to be this. After the plant has translocated all the nitrogen out of the tissues of the rest of the plant and stuck it into the seed, the rest of that plant is now C: N ratio woody.
If we're dealing with trees; now that's a little bit different.
Yeah, and that's where this book [‘The On-Farm Composting Manual’, Cornell University Extension Service] gets to be really useful. When you're starting to separate out the different stages of growth, when you're looking
at a tree.
What if you've got a nitrogen-fixing tree - acacia? We're looking at loquat - nitrogen-fixing tree.
Well, where's the high C: N ratio material being produced in a nitrogen-fixing tree? In the leaf material, in
the roots. So, the green leafy stuff has this wide C: N ratio. The branches, the stems, the wood itself is here.
So, it may look like wood but it has a C: N ratio of 30 so you should count it as green stuff.
Isn't this fun?
Trying to figure out what you're actually dealing with.
And you know, the easier way to deal with of this is do the best you can to put in the different percentages and kind of give it a guesstimate. Put the pile together and now you monitor temperature.
-Elaine Ingham, Soil Food Web Course