If a school has an irrigation system , what would you recommend they set it to run for next summer ? Their soil is clay .

Q & A WITH PAMELA SHERRATT

Cool-season grasses generally need about one inch of water per week to replace what is lost through evapotranspiration ( ET ) during the growing season . While this is a general guideline , not all grasses require exactly this amount — as specific water needs vary depending on grass type and soil conditions . For sports fields , the soil type significantly affects water requirements . Clay soils retain moisture longer than sandy soils , but when dry can lead to runoff issues . Sandy soils , on the other hand , drain quickly and need more frequent watering .

Applying one inch of water all at once to a field is usually ineffective , as most of it will likely run off , particularly on slopes or compacted soil . To enhance absorption , water is typically applied in smaller increments to allow it to penetrate the soil . It is best applied very early in the morning to avoid those times of day that are hot and windy . Ground cover also affects water retention ; bare soil dries out faster than areas with a full , healthy stand of grass . Additionally , weather conditions can influence water loss , with fields drying out more quickly during hot , windy or sunny periods than in milder , cloudy weather . For that reason , adjusting watering schedules based on real-time ET data or soil moisture sensors can lead to more efficient water use . The summer and fall of 2024 brought prolonged heat and drought to many areas , leading to substantial soil water loss . Even decent rainfalls of 0.25-0.5 inches were not enough to replenish the soil water deficit , and compacted fields repelled the water , causing it to run off . Looking ahead to 2025 , sports fields should be prepared so they are ready to retain moisture more effectively , whether through rainfall or irrigation .

One of the best strategies for moisture retention is maintaining full turfgrass cover . With 100 % ground cover , soils can better retain moisture , which supports healthier rootzones and reduces surface runoff . Improving soil structure is also essential ; fields with reduced compaction are less likely to experience water runoff and can absorb water more effectively .

For fields without in-ground irrigation systems , now is an ideal time to consider portable options , such as rain trains , water cannons or large sprinklers . Portable equipment may not provide uniform coverage on large fields , but could be helpful for smaller areas . Assessing equipment costs , labor requirements and watering schedules will help meet field needs .

Rather than watering the entire field , concentrate on high-traffic areas where soil compaction and wear are most prevalent . To improve water retention in compacted soils , incorporate organic matter through aeration and topdressing . Adding quality organic material , such as screened compost or a soil : compost mix , can help build soil structure and improve water retention . If using sand or soil as topdressing , ensure it matches the field ’ s existing soil composition to avoid layering issues that can interfere with water movement . Consult your compost supplier for specific material characteristics — such as organic matter content , particle size , carbon-to-nitrogen ratio and pH — to ensure you ’ re adding quality material free from contaminants . Avoid using peat moss as a topdressing , as it lacks the bulk needed for soil structure ; instead , opt for a bulking agent such as wood chips .

Applying compost during aeration or as a ¼-inch topdressing layer across the field can also reduce fertilizer costs , as compost typically contains nitrogen and other nutrients beneficial to turfgrass . Be prepared for a growth surge in spring if compost with moderate nitrogen is used , as this may increase mowing frequency . 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

50 SportsField Management | December 2024 sportsfieldmanagementonline . com