John Haguewood, Technical Manager for SMS Additive Solutions, offers his insights on how soil surfactants work to help golf course turf managers achieve optimal course conditions. SMS provides a comprehensive line of valuable additive solutions, including soil surfactants, spray adjuvants and wetting agents, all designed to help provide exceptional playing surfaces.
Q: What are soil surfactants?
A: Soil surfactants are products applied to soil to improve water penetration. High quality soil surfactants move water quickly off the surface and allow it to penetrate the soil, moving it into the root zone where nearby plant roots have access. Soil surfactants improve the ability of water to penetrate uniformly into the soil profile, this maximizes the efficiency of water applied. As water moves through the soil, so do the pesticides and/or nutrients that are carried in water, by applying soil surfactants we improve the efficiency of those products as well.
Q: How do soil surfactants help golf course turf?
A: Soil surfactants directly influence the performance of golf course turf, particularly when dealing with hydrophobic (water repellent) soils. Most golf courses or other fine turf is grown on sandy soils to combat compaction issues; however, over time, sandy soils become very hydrophobic. Putting greens can be nearly 100% sand with just a little organic matter, so high levels of hydrophobicity is often present. Therefore, golf course superintendents need soil surfactants to improve water penetration and create uniform soil moisture to provide the highest level of turf quality and playability.
Q: How do soil surfactants work?
A: Soil becomes hydrophobic and water repelling when organic coatings build up on soil particles, this tends to happen faster and to a stronger degree in sanding soils. The organic coatings originate mostly from decomposing organic matter including roots and shoots from the turf. The organic coatings are very hydrophobic, causing water to repel from its surface. Soil hydrophobicity is predominantly a surface issue in the top inch of the soil profile, causing water to run-off the surface and leaving behind localized dry spots, this is known as preferential flow (where water does not uniformly penetrate the soil). Soil surfactants act as a bridge between the organic coatings and water to help the water penetrate and be retained (to a certain degree) in the soil, creating a matrix flow (where water uniformly penetrates the soil).
Since soil surfactants improve water penetration, resulting in improved soil moisture uniformity, other inputs — such as fertilizer or pesticides — perform better. Depending on surfactant chemistry and application rate, soil surfactants will remain in the soil from a few weeks to a few months. They can be applied individually or with other products as a tank mix.