Evaluating the impact of turf-care products on soil biological health

Golf courses require extensive use of inputs to meet the needs of playability and aesthetics. The impact of these inputs on soil biological health is largely unknown. Two field trials were conducted at a golf course in Georgia to evaluate short-term effects of wetting agents (Cascade Plus and Duplex [C+D], Revolution [Rev]), plant growth regulators (PrimoMaxx [PM] and Cutless [CL]), and a product called PlantHelper (PH) on soil biological health by measuring microbial abundance and function. Quantitative polymerase chain reaction was used to measure microbial abundance, which included total bacteria, total fungi, and ammonia-oxidizing prokaryotes. Soil respiration and enzyme assays were used as additional indicators of soil health. In bentgrass putting green, total bacteria and ammonia-oxidizing bacteria decreased in abundance in response to the wetting agents and PH, indicating their sensitivity to the products. Whereas C+D stimulated urease activity, Rev and PH caused a short-lived but immediate increase in respiration, indicating that they acted as labile carbon sources. In a bermudagrass fairway, PM was the only product that caused an increase in total bacteria abundance. PrimoMaxx and CL caused a delayed increase in respiration, suggesting that they may have affected the microorganisms indirectly through their impact on root growth and exudate production later. Although CL caused a decrease in urease activity, none of the products significantly affected phosphatase activity. Overall, the products did not seem to have a lasting impact on soil biological health, although long-term studies are needed to confirm these observations.