Maximum Yield USA March 2018 | Page 74

cycl chelation utrient molecules are often present in soil or grow media yet not available for root systems to absorb N and take them up. Enter chelation. The process is a tad technical, but it isn’t rocket science. Also, understand- ing nutrient mobility is key to advancing your crops from good to great when it comes to plant health and yield. After all, if the nutrients that the plant needs are in the soil and not available for uptake, symptoms of malnutri- tion will eventually show up. Most molecules in grow media or soil have negative charges. So too does the plant root wall. Plant nutrients, however, normally have a positive charge surrounding them. These opposite charges tend to bind the nutrients with the soil and not release them into the plant roots. Ever put the opposite poles of a magnet together and see how stuck they become? It’s kind of like that. (A quick note, nutrients in organic fertilizers are not yet in the ionic form. Thus, they do not have a negative nor positive charge, but neither are they plant available. Soil microbes are required to work on these nutrients and convert them.) 72 NUTRIENT MOBILITY IN PLANT MOBILITY IN SOIL Nitrogen Mobile Mobile as NO 3- Immobile as NH 4+ Phosphorus Somewhat mobile Immobile Potassium Very mobile Somewhat mobile Calcium Immobile Somewhat mobile Magnesium Somewhat mobile Immobile Sulfur Mobile Mobile Boron Immobile Very mobile Copper Immobile Immobile Iron Immobile Immobile Manganese Immobile Mobile Zinc Immobile Immobile Molybdenum Immobile Somewhat mobile Chlorine Mobile Mobile Cobalt Immobile Somewhat mobile Nickel Mobile Somewhat mobile grow cycle “ IT IS LIKE A BLANKET AROUND THE CHARGED NUTRIENT ELEMENT; IN EFFECT,, IT CREATES A NEUTRAL CHARGE. ” To a degree, the plant and the biology of the soil can once again make the nutrient available, but this is a limited feature. More often, precipitation occurs. For example, iron, a basic trace element, could react to ethyl alcohol, another element, and form insoluble ferric hydroxide. This change of form is called precipitation. We want as much as possible to prevent precipitation from happening in the first place. What would help the plant to absorb the nutrients would be to make the charge neutral. Enter the chelate, or coating, for the nutrient. It is like a blanket around the charged nutrient element; in effect, it creates a neutral charge, allowing for the binding or fixing of the nutrient at the plant root or pore. (Making the trace nutrient a complex by chelating it also prevents precipitation.) The nutrient is no longer attracted to the negative grow media molecules and is instead allowed, and encouraged, to exercise mobility. The natural process of diffusion causes nutrient to disperse throughout the soil. This repulsion is similar to what happens when you place two magnetic north poles together. Once bound with a nutrient, a chelate keeps it free and mobile until needed. Then, the chelate releases the nutrient for plant use. (The chelating agent itself does not actually provide plant nutrition, but rather makes the nutrition present more available.) Chelates work both outside and inside the plant. Outside and in the grow media, a chelate keeps a nutrient in reserve and prevents it bonding with other elements and precipitating. Then, once inside the plant, where some mineral nutrients might be prevented from mobility, the chelate helps the element move freely. As such, the chelated nutrient easily moves to areas of the plant that need it the most. If we look at the mobility chart, it is apparent just how important chelating nutrients can be for initial root uptake as well as transport throughout the plant.