Nitrogen Fixing Clover Nodules

We have a lot of clover, which as Cotswold Seeds describe, are plants that fix nitrogen from the air in combination with Rhizobium bacteria living in root nodules. Since I’m going to use this for the high Nitrogen component instead of chicken crap I wanted to see if there were any active root nodules – after all if there were no bacteria or we had used nitrogen fertiliser there would be no nodules.

Clover root nodules
Clover root nodules

The good news is there are root nodules – so the clover is ready to fix nitrogen. The first  sample nodules have no red in them, even when dissected, which seems to mean they weren’t actually fixing nitrogen. This only starts when the soil temperature is above 8C. However, taking a second sample from the same patch showed better results.

opened nitrogen fixing root nodule
opened nitrogen fixing root nodule shows a distinct red colour

Looks like with these you have to open the nodules to see the red colour of leghemoglobin , they’re not particularly pink from the outside. Leghemoglobin transports the nitrogen to the plant from the nitrogen fixing bacteria.