Q & A WITH PAMELA SHERRATT

How soon can we start an aeration program in spring ?

This will depend on the type of field and the rationale behind the aeration program .

Soil aeration , also known as soil cultivation , is primarily carried out on native soil fields to improve vertical air and water movement into the rootzone ( O 2 in ,

CO 2 out ), and alleviate soil compaction . Soil compaction ( bulk density ) is improved if soil is removed ( e . g ., during hollow core aerification ) or if the soil is heaved and fractured ( e . g ., vertidrain or shatter tine ).

The beneficial effects of aeration on soil compaction are greatly increased if coupled with a topdressing program aimed at improving the soil texture . Additional advantages of aeration include improved seed , pesticide and fertilizer placement ; dilution and increased degradation of thatch ; and promotion of root growth , leading to better water and nutrient uptake by turfgrass roots . On sand-based fields , the primary objective of aeration is to eliminate and dilute surface organic matter , supplemented by a sand topdressing regimen , while also realizing the aforementioned benefits .

It is important to acknowledge certain challenges associated with aeration . Some types of aeration equipment may cause substantial surface disturbance , potentially impacting play , and cause turf damage by uprooting crowns and desiccating roots . The extent of these drawbacks varies depending on the turf ’ s stress level and the degree of ground cover on the field . A densely covered field undergoing aeration on a mild day is less susceptible to adverse effects compared to a sparsely covered field under hot , windy conditions .

As a general guideline , aeration is most effective under conditions where the turf is not experiencing heat or drought stress , the soil is not frozen , and the soil moisture content is optimal , neither overly wet nor excessively dry .

Cool-season turfgrass species exhibit vigorous , healthy root growth in cool soils . Root development precedes shoot growth in spring and thrives in soil temperatures between 50 and 65 degrees F ( 10-18 ° C ). By this rationale , it should be okay to aerate in early spring if the grass has broken dormancy and is able to actively grow and recover from the task . Many facilities start their aeration programs in late March or early April and depending on local conditions and how early their playing season starts .

Most aeration programs include a monthly or bi-monthly aeration in spring and fall , with little or no aeration carried out in July and August .

Since the goal of surviving hot and dry summers depends on grasses having a robust root system , it ’ s imperative that all action is taken in spring to maximize roots leading into the playing season . Aeration plays a part in that by relieving soil compaction and opening vertical drainage channels , allowing for oxygen to enter the soil . Remember that grass roots grow in air spaces , not water . The improved soil conditions also allow fibrous roots to take up nitrogen fertilizer and water .

Avoid aerating when soil temperatures are above 80 degrees F ( 26 ° C ), because cool-season grasses have already lost a significant number of roots due to summer heat stress . Cool-season grasses will lose ~ 50 % of their root mass over the summer , and those roots do not grow back until the cooler fall weather arrives .

Attention must also be given to soil disturbance and weed encroachment . As previously stated , aeration operations cause soil disturbance . If the soil is disturbed , weed seeds in the soil bank might be brought up to the surface and spread .

Additionally , germination of some weed species could be triggered by the disturbance . It is best to avoid aeration during peak germination periods of prevalent and problematic weed species ; or use equipment that causes little disruption , such as pencil tines . For example , if Poa annua is a major concern , avoid major soil disturbance during its peak germination in the fall . If you are concerned about aerating in spring because of annual weeds like crabgrass , research has shown that you can apply a preemergence herbicide and then aerate - the aeration does not break the barrier . SFM

Pamela Sherratt Sports turf extension specialist The Ohio State University

Questions ? Send them to Pamela Sherratt at 202D Kottman Hall , 2001 Coffey Road , Columbus , OH 43210 or sherratt . 1 @ osu . edu

Or send your question to Dr . Grady Miller , North Carolina State University , Box 7620 , Raleigh , NC 27695-7620 , or grady _ miller @ ncsu . edu

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