Grow your own fertilizer - Mexican Sunflower (Tithonia Diversifolia)

General Fruit Growing
22

i think multiple things could be going on.

a quick back on the envelope calculation (if i did it correct) leads me to believe the amount of mulch they introduced has roughly 120 pounds of N in it. The content of N in wood is very low (i used 0.03%). But unlike “pure” or artificial fertilizing your not using a handful of it. But a truckload.

Combine that with more effective storage and better bio-availability from the humus rich layer. (less leaching more available)

And possible a stored amount of the fertilizer that has been given in the past years, but was taken up by the bacteria and soil life to grow rapidly to decompose the mulch. And is now being released.

Could explain quite a bit.

in short.
More N was imported due to N being in the mulch.
Fertilizer from past years was temporarily stored in the mulch
less leaching and better bioavailability from organic rich soil leads to less leaching/waste and thus buildup if “conventional” fertilizer regimes are used.

This is just conjecture from my part though. I have no proof that say that this is the case. there just idea’s that might be true or could explain what your experiencing.

23

Oscar, they didn’t say what the overall weight of the mulch was. At any rate it is impossible to calculate the amount of N being released by the original OM in the soil without testing it.

24

yea, they diden’t specify the mulch.

But i drew a rough estimate based on the volume while doing my “back of the envelope calculation”

there is a large error on such a calculation, but it gives you a feeling for things. And often is well within an order of magnitude precise.