Me, too! In particular because I am advising Vermont & other NE USA growers, & representing a couple product lines with protein hydrolysates as key parts of their formulations. The body of knowledge is growing, and results shown from manufacturer-sponsored University trials look good. (Of course, most won’t show ones in their dossiers that didn’t look good.) After a year of interacting with the manufacturers and reviewing as much ‘objective’ info as I can find – and after a year of seeing these products applied under several situations, I am getting much more comfortable with recommending them for different situations.

General scenarios:

A. Dry, soil applied products:

In soils regularly tilled, or on low-performing hay/sod/pasture even with strong organic matter, 1/4-1/2 of standard N rates from a good protein hydrolysate dry product (meant to be applied dry to soil) will give crop response at least as good as standard N rate from conventional N fertilizer (urea). Applications used: in-furrow at planting for annual, or broadcast on perennial crop.

B. Foliar products (powders or pre-liquified)

Between hay cuts or grazing events, as foliar-applied, I was impressed to see responses similar to conventional urea N in 2020 on a few hay applications. They were not each exactly same formulations, but the calculated amounts of actual nutrients was extremely low.

When used foliar, these are definitely all about plant biostimulation of higher photosynthesis = higher microbial activity & thus more soil nutrients are plant available and sustaining.

As dry soil applied, I think there’s both – and they are shown to dramatically increase over-all soil microbial populations rapidly and diversely, and crops plants respond quickly and depending (I guess) on the amount used, the effects are prolonged.

Websites of the 3 manufacturers of products I currently work with, as they offer various info & research & each has more than PH nitrogen for efficacy:

https://ferticellusa.com/ferticell-technology/

https://www.naturesafe.com/products/research

https://oceanorganics.com/agriculture/#agriculture-labels

Here’s a scientific article I just read, with a few more reads to digest it all:

Colla G, Hoagland L, Ruzzi M,

Cardarelli M, Bonini P, Canaguier R

and Rouphael Y (2017) Biostimulant

Action of Protein Hydrolysates:

Unraveling Their Effects on Plant

Physiology and Microbiome.

Front. Plant Sci. 8:2202.

doi: 10.3389/fpls.2017.02202