Preliminary investigation of soil chemical and physical properties associated with type-I fairy ring symptoms in turfgrass

Fairy ring is a common disease of turfgrasses worldwide, and necrotic or severely injured turfgrass and soil water repellency are frequently observed in those turfgrass sites exhibiting type-I fairy ring symptoms. The objective of this research was to evaluate soil chemical and physical properties associated with type-I fairy ring symptoms in turfgrass. Soil samples were obtained from type-I fairy ring symptoms on two golf course fairways and one lawn area. Soil analysis from all the three locations revealed concentrations of ammonium-nitrogen, potassium, and sulphur were statistically higher in soil underlying necrotic or bare zones versus soil in healthy turfgrass zones. Soil electrical conductivity (EC) also was higher, while volumetric soil water content was consistently lower in necrotic zones versus soil under healthy turfgrass. Soil water repellency was considered moderate to severe in necrotic zones and mostly wettable to subcritical repellency in soil underlying healthy turfgrass. Soil pH, total nitrogen, magnesium, calcium, cation exchange capacity (CEC), and organic matter content (OM) levels were not consistently different among necrotic and healthy turfgrass zones. The necrotic zones of those type-I fairy ring areas in turfgrass were most likely associated with a combination of direct and indirect effects of the basidiomycete fungi on soil hydrophobicity and the accumulation of potentially phytotoxic compounds in the turfgrass root zone. Further research is needed to explore the interaction of basidiomycete fungi and the soil chemical and physical environment on turfgrass, and evaluate practices and strategies to control type-I fairy ring symptoms in turfgrass.