What does amino acid fertilizer do for plants?
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Amino acid fertilizers based on protein hydrolysates do three things. They supply organic nitrogen that plants take up directly as amino acids or peptides, which helps under stress when nitrate assimilation is impaired. Specific amino acids act as signals and stress protectants, such as proline as an osmolyte and tryptophan as the auxin precursor. And amino acids chelate micronutrients, improving their uptake.
What is protein hydrolysates and amino acids?
Protein hydrolysates are proteins broken into peptides and free amino acids by chemical or enzymatic hydrolysis. Source can be animal - collagen, leather, feather, blood - or plant, typically legume or cereal protein. Enzymatic hydrolysis of plant protein generally yields a better-defined product with a higher proportion of intact L-amino acids; harsh chemical hydrolysis can racemise amino acids into D-forms that plants cannot use, and can leave undesirable residues.
Source and process therefore matter considerably, and are frequently undisclosed.
What do protein hydrolysates and amino acids do?
Three contributions, in descending order of evidential strength. As a nitrogen source they supply organic nitrogen that can be taken up directly as amino acids or peptides, bypassing part of the energy cost of nitrate assimilation - useful under stress when that machinery is impaired.
As signaling and stress-protective agents, specific amino acids do specific jobs: proline and glycine betaine as osmolytes, glutamate in nitrogen metabolism signaling, tryptophan as the auxin precursor.
As chelators, amino acids complex micronutrient cations and improve their uptake and mobility, which is why amino-acid-chelated micronutrients are a product category in their own right.
Where does protein hydrolysates and amino acids appear in the range?
Note a data issue to resolve: the Vita Boost page currently carries two incompatible formulations, one listing gluconic acid with Ascophyllum and protein hydrolysate at NPK 1-0-5, the other citing 18% amino acids with citric acid and magnesium sulfate at 0-0-2.
What does protein hydrolysates and amino acids not do?
They are not a substitute for mineral nitrogen at field rates - the quantities applied are small. Uptake of intact peptides through leaf surfaces is limited, so foliar amino acid products deliver less than the label percentage suggests. And amino acid content alone says little: the profile and the L-form proportion determine whether it is useful.
Key takeaways
- Protein hydrolysates come from animal sources (collagen, leather, feather, blood) or plant sources (legume or cereal protein).
- Enzymatic hydrolysis of plant protein generally yields more intact L-amino acids than harsh chemical hydrolysis.
- Chemical hydrolysis can convert amino acids into D-forms that plants cannot use.
- They are not a substitute for mineral nitrogen at field rates.
- The amino acid profile and L-form proportion matter more than total amino acid content.
References
Frequently asked questions
What is the difference between animal and plant protein hydrolysates?
Animal hydrolysates come from collagen, leather, feather or blood, and plant hydrolysates typically from legume or cereal protein. Enzymatic hydrolysis of plant protein generally gives a better-defined product with more intact L-amino acids, while harsh chemical hydrolysis can convert amino acids into D-forms plants cannot use and can leave undesirable residues. Source and process are frequently undisclosed.
When should amino acids be applied?
The organic nitrogen route is most useful under stress, when the plant's nitrate assimilation machinery is impaired, because amino acids bypass part of that energy cost. They supplement rather than replace mineral nitrogen, since the quantities applied are small.
Do foliar amino acid sprays deliver the label percentage?
Not fully. Uptake of intact peptides through leaf surfaces is limited, so foliar amino acid products deliver less than the label percentage suggests.
Related reading
Products
No direct product mapping. Nothing in the Vegalab range declares protein hydrolysates and amino acids in its composition, so this page has no product link - the absence is deliberate, not an omission.