Calcium silicate is a fertilizer that provides plants with both calcium and plant-available silicon. This dual-purpose material acts as a nutrient source for the plant and as an amendment to improve the soil environment. Its application introduces silicon that can be absorbed by the plant and calcium that supports various growth processes.
Improving Plant Vigor and Defense
Plants absorb silicon from the soil as silicic acid. Once absorbed, it is transported through the plant’s water-conducting tissues and deposited in cell walls, forming a silica layer. This strengthened cellular structure provides a barrier that can make it more difficult for fungal hyphae, such as those from powdery mildew or rust, to penetrate leaf surfaces.
The hardened plant tissues also serve as a deterrent to certain insect pests that feed by chewing or sucking on the plant. Research has shown that crops treated with silicon exhibit greater resistance to pests like thrips and aphids. The structural enhancement from silicon also reduces the risk of lodging, a condition where crop stems break or bend over.
Beyond physical defense, silicon helps plants cope with environmental stressors. It can reduce water loss by regulating the pores on leaves responsible for transpiration, which is particularly beneficial during periods of drought and high heat. The presence of silicon also assists in maintaining metabolic functions during stressful periods, allowing the plant to better manage challenges like salinity and extreme temperatures.
Calcium, the other component of this fertilizer, contributes to the structural integrity of cell walls and membranes. It plays a part in cellular signaling pathways that are involved in plant growth and responses to environmental stimuli.
Enhancing Soil Conditions
Calcium silicate applications can alter the chemical properties of soil, creating a more favorable environment for plant growth. One of its main functions is to act as a liming agent, as the silicate component of the fertilizer works to neutralize soil acidity and raise the overall pH of the soil. The effectiveness of calcium silicate in this role is comparable to that of standard agricultural lime, or calcium carbonate.
Raising the soil’s pH has secondary benefits for nutrient availability. In acidic soils, elements like aluminum and manganese can become highly soluble and reach levels that are toxic to plants. By increasing the pH, calcium silicate reduces the solubility of these elements and also improves the availability of other nutrients, such as phosphorus and molybdenum.
The silicate in the fertilizer can also bind with heavy metals present in the soil. This process, known as adsorption, reduces the amount of these potentially harmful elements that are taken up by the plant’s roots. This binding action helps to create a safer growing medium, particularly in soils that may have some level of contamination.
The application of calcium silicate can lead to more efficient use of other fertilizers. By improving the soil’s chemical balance and nutrient availability, plants are better able to absorb and utilize macronutrients like nitrogen, phosphorus, and potassium. This can enhance the effectiveness of a comprehensive fertilization program.
Practical Application Methods
The most common sources of calcium silicate for agricultural use are processed wollastonite, a naturally occurring mineral, and slag, a byproduct of the steel manufacturing industry. Both sources provide a form of silicon that becomes available to plants over time as the material breaks down in the soil. Wollastonite, for example, releases its nutrients over a one to two-year period.
Application rates of calcium silicate should be determined by soil testing. A soil analysis can identify the existing pH level and any deficiencies in calcium, allowing for a more precise application. The goal is to apply enough material to adjust the pH to a desired range.
The most common method of application is to broadcast the calcium silicate evenly over the soil surface before planting. After spreading, it should be incorporated into the soil through tilling or cultivation. This ensures that the material is well-distributed within the root zone.
Certain crops are known to accumulate high levels of silicon and tend to show a strong positive response to its application. These include rice, sugarcane, wheat, and various members of the cucurbit family, such as cucumbers and pumpkins. Turfgrass also benefits from calcium silicate, which contributes to stronger, more resilient blades of grass.