I've been doing a lot of mulberry research lately and I found an interesting concept for mulberry that could possibly translate over into apples or other tree crops:
foliar application of nitrogen fixing bacteria. Since I can't remember much talk surrounding nitrogen fixing bacteria being an ingredient in foliar cocktails and, to be honest, I've never really heard much conversation on non-soil applications of n-fixing bacteria, I wanted to briefly post about it here.
According to this
paper, foliar application of what they are calling "biofertilizers," (nitrogen fixing bacteria) is great because:
1.) N is being fixed close to the place of assimilation
2.) Some strains of N fixing bacteria on the leaf surface are antagonistic to many plant pathogens
3.) There is enough food material for nitrogen fixing bacteria on the leaf surface in the form of leaf leachates and degrading cuticles
4.) When sprayed on leaves, the bacteria don't experience as much competition by other microflora as they do in the soil.
In mulberries, foliar sprays of nitrogen fixing bacteria have been shown to control powdery mildew and rust (they also are controlled via soil applications). And in a crazy Ukranian paper that won't let me link to it right now (and it's also written in Russian), the N fixing bacteria "Azospirillum" increased the leaf content of vitamins B1 and B2 - by 8%, niacin by 11% and vitamin E by 16%. Broadly, it also improved leaf quality with a 20% increase in calcium, 55% increase in manganese, 23% in zinc, 50% increase in copper and 46% iron. It also increased photosynthetic pigments (they only mention carotene) by 46%
Those increases seem crazy to me, but given how easy it is to purchase strains of Azotobacter and Azospirillum online, it may be worth adding it to our foliar cocktails to see what happens.
Edited 2 time(s). Last edit at 12/15/2020 11:29PM by Eliza Greenman.