COLUMBUS, Ohio - A little composting can go a long way when establishing lawns in new urban developments.
Ohio State University researchers have found that by adding an inch of compost into the top soil, perennial ryegrass achieves nine times faster cover and Kentucky bluegrass five times faster cover than turfgrass seeded into noncomposted soil.
Ohio State plant pathologist Mike Boehm said the incorporation of compost into the soil improves lawn establishment following construction of new homes while practicing sound environmental management.
"When new homes are built, the topsoil, where all of the nutrients are located, is stripped away. So soils where newly seeded turfgrass is planted is depleted of nutrients, and is weakened and becomes more susceptible to diseases," said Boehm. "Homeowners compensate for this by putting down fertilizers and pesticides. Improving the soil with compost minimizes that heavy use of chemicals."
The Ohio State project analyzed the success of turfgrass establishment by placing composted sewage sludge on nutrient-poor, rocky back-filled clay soil - what a new homeowner would typically encounter. Half of the plots were seeded with compost mixed with the soil, while the other half were not, and the rate of turfgrass growth was then tracked over the course of a year.
"We found that the composted sewage sludge worked pretty well. Composted sewage sludge packs the biggest nutrient punch from a nitrogen and phosphorus aspect," said Boehm. "The plots with the compost had turfgrass that looked better, was denser and had better coverage."
Perennial ryegrass and Kentucky bluegrass had established themselves in composted soil within four weeks of planting compared to 10 weeks in noncomposted soil. Soils improved with compost also created better quality turfgrass than noncomposted soil. Significant quality differences were evident for composted perennial ryegrass plots within 14 weeks of seeding, while composted Kentucky bluegrass plots were producing better turfgrass quality by 39 weeks into the study. Boehm said the difference in establishment is due to a slower germination period for Kentucky bluegrass.
Boehm speculates that other composts, such as leaves, grass clippings and animal manure would have similar effects on turfgrass establishment, but encourages homeowners to familiarize themselves with composts before using them.
"Composts are all different. They have different nutrient values, physical characteristics and chemical compositions," said Boehm.
Researchers plan to take the study one step further and measure cost savings when compost is used. "There is a savings there, we just aren't sure how drastic those savings are," said Boehm. "Our goal is to develop a sustainable agriculture guide for homeowners that outlines what they'll need in terms of budget and resources based on the type of soil they have and what kind of turfgrass they want to establish."