Shade and airflow restriction effects on creeping bentgrass golf greens

Creeping bentgrass (Agrostis stolonifera L.) golf greens are often shaded by trees and surrounded by shrubs or brush that restrict airflow. The objective of this study was to compare and independently evaluate turfgrass responses to light reduction and airflow restriction in 'L93' and 'SR1020' creeping bentgrass. Artificial structures (122 by 122 cm) were assembled from polyvinyl chloride (PVC), and covered with black, woven polyester shade cloth (80% light reduction) to provide treatment effects. Shade cloth was applied to the structures to reduce irradiance and allow airflow or reduce airflow and allow irradiance. Plots were rated monthly for canopy, soil, and air temperature, visual color, density, and disease, soil moisture, root mass, and root glucose and fructose. Canopy and soil temperatures were lower in shade than in airflow restriction and uncovered, unsurrounded control turf. Canopy temperature was higher in airflow restriction than control but soil temperatures did not differ. Both shade and airflow restriction had a negative effect on turf color in L93. Airflow restriction caused a greater reduction in mean color rating than shade in SR1020 but shade color did not differ from control. Turf density declined in both cultivars due to both airflow restriction and shade compared with control. Air restriction reduced density more than shade in SR1020 but not in L93. The severity of brown patch (caused by Rhizoctonia solani Kiihn) and dollar spot (caused by Sclerotinia homoeocarpa F.T. Bennett) in shade was less than in airflow restriction in both cultivars and less than control in SR1020. Soil moisture did not differ among treatments. Root mass was affected by both shade and airflow restriction in both cultivars and declined more rapidly in shade than in airflow restriction. Root glucose and fructose were not significantly affected by treatments.