[NWNR]

good info thanks

[G.O. Joe]

No till, like that's really important. The nitrogen is only mobile and available to something other than the legume's roots when the entire legume has been plowed under. Trap question. The legume has to be properly inoculated as well.

[Granger2]

Yes, the legume needs to be inoculated with the appropriate N fixing bacillus. But the N in the nodules on the legume roots are available even if you don't plow under the entire plant. Plowing the entire plant under will give you more N, as will cutting the above ground part of the plant and using it as a topdress/mulch which will decay into the medium. -granger

[G.O. Joe]

Originally Posted by Granger2

But the N in the nodules on the legume roots are available even if you don't plow under the entire plant

To the plant the nodules are on, yes. To other plants, no. The nitrogen is consumed by the plant as it is produced by the bacteria.

[Microbeman]

Originally Posted by G.O. Joe

To the plant the nodules are on, yes. To other plants, no. The nitrogen is consumed by the plant as it is produced by the bacteria.

For the predominance of N you are correct and chopping and dropping is the better way to provide N to adjacent plants. My experience over 30 years on a farm seemed to show that living red clover and alfalfa provide all necessary N to cohabitating Timothy, fescue, barley and many other non-legumes. This was hypothetical but evident.

Also observed outdoors was a similar transfer of N from red clover to cannabis.

My hypothetical explanation was microbial interaction - living soil. There is research that supports this idea. There have been fungal interconnections discovered inter-species where via AM fungi one plant species received nutrients from another which is mycorrhizal with the same AM fungal species.

Additionally endophytic bacteria and fungi seem to play a role in N transfer and uptake in the soil.

[G.O. Joe]

A lot of that is true but the same studies tracing isotope ratios show that simulated grazing conditions only transfer so much nitrogen to the non-legume and it's not much the first two years, however it happens. Yes my first post should not have been so black and white but I doubt that companion clover could meet all N needs and my personal experience with alfalfa, hairy vetch, and white clover in my (outdoor) gardens has not been impressive.

Apparently, grazing the legume causes some nodules to separate from the plant and what N is in the nodules becomes mobile. But most of the N that got fixed ends up in the above-ground part of the legume.

[Microbeman]

I believe that various studies have yielded differing results. I think there has been greater transfer of N when both species were inoculated with AM and there was no mesh between them but still it is an area of contention.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429567/

https://www.researchgate.net/profile...99060b2a3d.pdf

https://www.scielo.br/scielo.php?scri...41998000400011

My observations are anecdotal.