Midwest Factsheets

April 2010


The following recommendations are for the state of Indiana and may not apply to turf areas outside of Indiana.


Spring applied soil surfactants can improve seasonal soil moisture consistency

Cale A. Bigelow-Purdue Agronomy/Turfgrass Science

Turf managers constantly strive to produce consistent playing surfaces. Inconsistencies in soil moisture, sometimes called localized dry spot, particularly on sand-based rootzones, affect the ability to achieve consistency. A uniformly moist soil provides more consistent turf color, firmness and ultimately ball roll. Since, rainfall is never evenly distributed throughout the growing season and many irrigation systems are unable to consistently deliver a uniform distribution, some managers utilize soil surfactants/wetting agents to improve water penetration and retention.
There are generally two major thoughts on surfactant use, as a part of a seasonal program or simply as needed for “rescue treatments”. Since environmental conditions vary each year, the more predictable strategy is a seasonal program. To be most effective seasonal programs should be initiated in the spring prior to the onset of turf stress. This is because in the spring the soil is probably about as consistently well hydrated as it is ever going to be for the season. As the growing season progresses soils naturally become drier and substantial irregularities in soil moisture status may develop quickly. Furthermore, when coupled with clear, sunny and breezy days even more water can leave the soil resulting in irregular dry spots and in severe situations the development of water repellent soils. 

Inconsistencies in soil moisture as evidenced by irregular patches of turf may appear early in the growing season and create difficulty in achieving consistent playing conditions throughout the year. Initiating a seasonal soil surfactant program early in the spring prior to the onset of severe turf stress can help alleviate these problems. 

At this point a “rescue treatment” may become necessary to effectively rehydrate the soil.
Before selecting a surfactant there are many considerations, for example: What is your ultimate goal? Answering this is often not an easy and you may need to carefully analyze your cultural management strategies. For example, What exactly is your soil moisture management philosophy (e.g. keep things on the dry side? or sufficiently moist to promote growth and recovery?) How quickly do you need the product to react (e.g. alleviating existing localized dry spot=rescue treatments) How often do you want (or can you afford) to apply the product? How long do you intend the product to last (e.g. “season-long”/90-100 day products)? Realize the severity of soil hydrophobicity and soil organic matter content may affect the effectiveness of any surfactant.
Many manufacturers group their products based on what the product is intended to accomplish such as penetrate (improve infilitration), hydrate (retain moisture), correct/cure soil hydrophobicity or for spot treating small areas. For simplicity these classifications are helpful, however, some products are capable of one or more functions. The attached table is intended to be an initial guide to product selection. Understand there are numerous nuances and potential uses related to each product and a manufacturer’s representative may be helpful in selecting specific products for your situation.

Table 1. Potential use and sample product names of materials used for improving soil moisture in golf course turf.

Potential Use

Products*

Curative

Aquaduct, Affinity, Aqua-Aid, OARS, etc.

Seasonal program (also referred to as “monthly” products)

Revolution, Primer Select, Tri-Cure, Cascade Plus, Affinity, Aquifer etc.

Single application products
(also referred to as “season long” products)

Sixteen90, Capacity, Cascade Plus, Lesco Flo Ultra, PBS150, Conduit90, etc.

Large-area (e.g. fairway product), also includes products targeted toward native soil areas

Dispatch, Drench, Duplex, etc.

*Note: The mention of trade names, product names or proprietary information is purely made for convenience of the reader and does not imply an endorsement or constitute a guarantee by the author or Purdue University.

Application considerations: As a rule of thumb, all surfactants should be immediately watered into the soil to minimize any potential yellowing or plant injury. From our research experience there are exceptions with some products but frankly it is not worth the risk. Product application rate and prevailing weather conditions may also influence potential turf injury. When applied at high label rates or late in the day during warm periods of intense sunshine and low humidity may increase the potential for temporary turf discoloration.

Realize that there are MANY of soil surfactants on the market and that no single product is best for every situation. Grass species, cultivar (e.g. high shoot density bentgrasses), soil type, rootzone texture, organic matter content, growing environments, and management intensity all affect product performance. If consistency in soil moisture is your goal or if water repellency has been a chronic problem in the past then soil surfactants may be an effective management tool for your program. As a rule, beginning a seasonal program early in the growing season rather than later as a “rescue treatment” will improve your ability to manage soil moisture effectively. 

 

 

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Department of Agronomy, Turf Program
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Send corrections, suggestions, and comments to biehlj@purdue.edu