SAND AND ORGANIC AMENDMENT INFLUENCES ON SOIL PHYSICAL-PROPERTIES RELATED TO TURF ESTABLISHMENT

Topsoil blending is a common practice in many metropolitan areas, get few scientific guidelines are available for design of general-use, law n-area soils. The objective of this study was to provide blending guid elines with focus on establishing a vigorous turfgrass ground cover. A Mahoning silt loam (fine, illitic, mesic Aeric Epiaqualf) and a Tioga loam (coarse-loamy, mixed, mesic Dystric Fluventic Eutrochrept) were each blended with a spent foundry sand and a peat humus to form 28 ind ividual soil mixes for each native soil. Soil properties and perennial ryegrass (Lolium perenne L.) growth were measured for each soil mix. Cation exchange capacity (CEC), bulk density, and plant available wate r exhibited changes due to soil mix that largely resulted from differe nces in mix organic matter (OM) content. Compression index, bubbling p ressure (H-b), air-filled porosity, and saturated hydraulic conductivi ty (K-sat) responded to both sand and ORI contents of the soil mixes. The pore distribution parameter, lambda, exhibited a response to sand and OM contents, but only at high levels of either component, principa l component analysis (PCA) of soil properties revealed that the first two principal components contained 85 to 88% of the total data variati on with correlations between compression index, H-b, air-filled porosi ty, K-sat, and lambda contained in the first component and correlation between CEC, bulk density, and available water contained in the secon d component. Regression of turf clipping yield vs. PCA factor scores a nd regression of factor scores vs. total sand and OM contents suggeste d that a high-quality, general-use soil for lawn establishment would c ontain about 65% sand and have an OM content of 8% by weight. The mult ivariate process of relating turf yield to soil physical properties, a s applied in this study, should provide more generalized mix formulati on guidelines than do recommendations based on relating turf yield to mix composition.