Only apply what you need when fertilizing

By MINDY POEHL | Central Texas Edition

Dr. Jim McAfee, Extension turfgrass specialist, speaks about nutrient management programs for turfs. --  Photo by Mindy Poehl

Sept. 22, 2005 - Properly caring for turfs with a precise nutrient management program can help keep the environment healthy. On Tuesday, Sept. 13, the Central Texas Turf Workshop was held at the Hewitt VFW. Dr.  Jim McAfee, Extension turf specialist, was on hand to discuss nutrient management programs.

"Mismanagement has an adverse effect on water," McAfee said. "Nutrients will leach into waterways if you aren't careful. So, how do we stop that? Only apply what is needed."

For fertilizer, McAfee recommended to first recognize the turf species and then do a soil test.

"Only apply what you need," McAfee stated.

When fertilizing, McAfee said it is smart to have a buffer zone of 16 feet from waterways. 

"If fertilizer is on the sidewalk, waterways or streets, people do get fined," McAfee stressed. "Don't put anything on your grass if you know there will be rain showers coming. The chemicals will leach into waterways." 

For water, notice the environmental conditions around the turf. Shaded areas do not require as much water as non-shaded areas.

"The roots of mature trees and shrubs also need water, so you may have to water more in mature landscapes where the roots of many plants compete for water," explained McAfee.

If the soil is mainly clay, apply 1 to 1 1/2 inches of water to moisten the root zone to a 6-inch depth. Most sports fields are built out of sand, and sandy soil can be moistened to 6 inches by as little as 1/2 inch. 

Nitrogen is an important element in soil.

"You have to have that nitrogen, but excess nitrogen causes suppressed root growth," McAfee said. "Nitrogen is highly water soluble and easily leached. Excess nitrogen causes reduced cold tolerance, thatch accumulation and increased water use in turfs,"

Low nitrogen rates can cause sandburs, legumes and bluestem to grow. High nitrogen rates can cause chinch bugs, sod webworms, grubs, armyworms and mites.

Phosphorous is very important in seedlings, however, mature plants require little phosphorus.

"We are just now finding out that phosphorus does move in soils," said McAfee. "Excess phosphorus ties up other plant nutrients and leaches into waterways, causing algal blooms."