Silicon as a Plant Nutrient

 

January is when the coldest weather generally occurs in winter. For agriculture, cold temperatures can be beneficial. Many insect and disease organisms are reduced due to the freezing and thawing. Slug and vole (field mice) populations often decline, especially if the snow is not too deep to insulate them from the cold. Another benefit occurs when microbes freeze, they split open and spill nutrients into the soil. Plant spring green-up is a natural benefit as long as these enriched nutrients do not leach away.

Two ways plants survive cold temperatures is by elevating certain nutrients in their cells like potassium (K) and silicon. These two nutrients allow plants to continue to grow longer in the fall, lowering the temperature at which they freeze. While K is a known essential element, very little is known about silicon until recently and its effect on plant growth.

Our soils are largely composed of silicon, sands (silicon oxide), and clays (aluminum-silicates plus many other elements). Silicate is the 2nd most common element in the soil, and in plants, it is often 7th. In some plants, there is more silicate (mono silicic acid) than nitrogen or potassium (K). It is not officially registered as a fertilizer or as an essential element and exists in many forms, never by itself. It’s very similar to carbon in its form and actions. It’s always combined with other elements.

Since the element silicon is so abundant, why should we be interested in what it does? Just like calcium, silicon and silicates are not always plant available as mono silicic acid. In the soil, it acts like a plant and nutrient bioregulator and anti-stress regulator. It relieves stress (heat, drought, cold stress, improves saline soil), reduces diseases, and improves growth and even yields. The plant-available form is most needed in the growing point of plants, but it is hard to move within the plant. Similar to carbon, it combines with everything and tends to turn to a gel or gum up the plant. The plant-available form of silicon is very rare in the soil since it combines easily with so many nutrients (aluminum, iron, manganese, phosphorus, etc.). The plant-available form is also microbe-available, improving soil health by increasing beneficial soil bacteria by 58% and beneficial fungi by 188% (mycorrhizae fungi increase by several hundredfold). The 3-D silicate soil matrix it forms makes many soil nutrients plant and microbe available.

A major plant function of plant-available forms of silicon is stronger plant cells. It gives cells rigidity so plants are less likely to lodge. Plants are stronger and bigger, with larger roots and stronger stalks. This nutrient causes the vascular system (the phloem and the xylem) to have larger, stronger pipes for moving nutrients around in the plant. Plants are healthier and can produce more fruit or grain, bigger and heavier. Fungal diseases are depressed, so fruit quality remains high longer. From a grain standpoint, test weights are higher (more nutrients) and the grain stays in good condition and can be stored longer.

Researchers have calculated the possible maximum yield losses due to plant stress. Possible yield losses may be as high as 82% of maximum possible yield in wheat, 69% in soybeans, and possibly 65% in corn. Put another way, due to the natural stress plants receive each year, farmers are not fully maximizing their crop yields. Recent research shows that the plant-available form of silicon may help these stresses greatly. Considerable yield increases are possible. For example, increases in crop yields of 38% on wheat, sweet corn 34%, tomatoes 31%, and rice 34%. Potatoes and strawberries have more blossoms and fruit, increased size and weight, higher nutrient value, and they are firmer and store longer. Most of the current research is on fruit and vegetables, but common agricultural crops (corn, wheat, soybeans) have shown similar results.

Overall, the use of foliar applications of plant-available silicates (5-6 ounces per acre) appears to be increasing in agriculture. Application rates and timing vary by crop. Benefits include higher yields and lower losses due to stress, faster growth including stems and root growth, and lower water and fertilizer needs for the same plant growth. Adequate plant silicate increases the nutrient content of grains, fruit, and vegetables and also increases plant chlorophyll. Silicates may not currently be classified as essential, but as our scientific knowledge expands and improves, it appears that maybe it is one of the forgotten nutrients and may have a much bigger plant effect than we currently realize.

For more information, read the book Silicon Solutions on my website.