Sand Content of Sand‐Soil‐Peat Mixtures for Turfgrass

Abstract

AbstractSoils subjected to intensive foot‐traffic in areas used for sports usually require modification in order to maintain physical properties conducive to turfgrass growth. Commonly this is achieved by mixing soil with large quantities of sand and often some peat. Though present recommendations for quantity of sand are made using a great deal of experience, published supporting information is limited. The purpose of this research was to provide additional data.Seven sand‐soil‐peat mixtures were prepared giving a series that varied in sand contents from 75 to 97% by weight and in which organic matter remained essentially constant. A 35‐cm layer of sand‐soil‐peat mixture underlain by a gravel layer was placed in large pots and bentgrass (Agrostis palustris, Huds.) was established. Mixtures were watered as needed and were compacted daily for 53 days to simulate foot‐traffic, following which degree of compaction and infiltration rate were measured. Saturated hydraulic conductivities, variation in air‐filled pore volumes with water potential, and bulk densities of extracted core samples were also measured. Turfgrass yield and quality as well as root growth were evaluated.The data show that under the experimental conditions, sand‐soil‐peat mixtures having 87% or more sand by weight provided infiltration rates of 2.3 cm/hour or greater, and air‐filled porosities of 10% or greater at a soil water potential of −30 mbars. Sand‐soil‐peat mixtures with 87% sand gave as good turfgrass growth as those with greater amounts although the mixtures with > 90% sand supplied a greater safety margin for infiltration rate. Lower sand contents resulted in poorer grass yields, low infiltration rates and low drainable porosities.This minimum acceptable value of 87% sand by weight in a sand‐soil‐peat mixture was found using a predominantly medium sand, Nicollet loam soil and reed‐sedge peat. This value could vary with different sands and soils due to differing compaction characteristics and clay types.