Many aspects of organic production remain poorly understood. Researchers from the University of California Cooperative Extension and UC Davis looked at the transformations of N that occur in the soil and organic amendments/fertilizers that ultimately produce plant available forms of N (nitrate and ammonium, a.k.a. mineral nitrogen).
Dissolved Organic Nitrogen (DON) in low molecular weight can be transported into microbial cells for direct assimilation. Once inside the microbial cell, enzymes decompose these DON compounds, and the N is used to make proteins and other components needed by the microbe. If the N from the DON exceeds the immediate need from the cell, the excess will be released back in the soil solution (mineralization). Microbial uptake of both DON and mineral N take place concurrently in the soils. However, microbes are constantly consuming and releasing N back to the soil where it’s consumed or taken up by the plant.
In the research referenced, the amount of N applied as a fertilizer ranged from 1.4 to 3.9 times the crop N uptake. However, counting only the fraction of organic fertilizer N assumed to be mineralized, N applications ranged from 0.4 to 1.9 times crop N uptake. The net amount of fertilizer N made available from the organic fertilizer was less than crop uptake in 6 out of 10 fields. This data would suggest that the organic crops were under fertilized, but tissue N evaluations at harvest indicated that only 1 in 20 fields might have been low in nitrogen. Clearly, the crops were getting their needs met from other sources of N like the mineralization of N by the microbes in the soil.
This study confirms the value of products like compost teas and fish hydrolysates can have on all kinds of crops. By increasing the microbial biology of the soil, the amount of N that’s available to the plant is greater than the sum of N applied. Not to mention, microbes are the building blocks for organic matter providing great holding capacity for water, Nitrogen and Phosphorus. The increase in microbial activity increases the plant’s root system providing greater capacity for nutrient access and improving the plants ability to battle stress including hot weather.
Andaman Ag sells many high quality products contributing to building healthy soils like MetaGrow compost teas and Pacific Gro, fish hydrolysate.