How Carbohydrates Work

In a purely technical sense, an organic chemical is any substance that contains carbon.   Therefore, a fertilizer supplier could sell you urea as an "organic" even though it is manmade.   Carbohydrates are organic compounds that contain carbon, hydrogen and oxygen, and carbohydrate chemical families include sugars, alchohols, starches and cellulose.   Table sugar is a disaccharide composed of the two simple sugars, glucose and fructose.   Regardless of the source, however, the literature agrees that the lack of a digestible carbon source is the single most limiting factor in the growth of microorganisms in the soil.

Several carbohydrate fertilizers use sugars as a base ingredient.   Great care needs to be taken with these sugar-based products because an overapplication will cause an explosion in microbial growth - which could lead to a temporary depletion of nitrogen and other minerals, potentially leading to sever chlorosis.

It has been shown that glucose and fructose can be absorbed through the leaves in small quantities in one to four hours.   As a result, such application would be giving your plants free photosynthates, as Beard's study indicated.

Numerous studies have shown the effects of adding glucose to soils.   Two researchers, for instance, used a combination of nitrogen and glucose to treat soil samples, and their study showed that nearly all the glucose had been used within the first 24 hours.   The nitrogen applied was also rapidly converted into biomass.   Although the nitrogen was lost to the plants temporarily, it was realesad slowly through the natural mineral cycling in the soil, which in effect, serves as a natural slow-release mechanism.   Another study suggest that the the addition of glucose rapidly reduces the available nitrogen supply in forest soils and can lead to denitrification under anaerobic conditions.

Another study showed similar effects with phosphorus.   This study used serval types of carbohydrates, and the researchers concluded that the more complex carbohydrate sources resulted in a great stabilization effect on soil phosphorus due to the production of humic and fluvic acids.