Harry A. J. Hoitink, Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio; Carol A. Musselman and Terry L. Moore, Research Assistants, Department of Plant Pathology, Ohio Agricultural Research and Development Center, The Ohio State University; Leona E. Horst, Research Assistant; Charles R. Krause, Adjunct Associate Professor, U.S. Department of Agriculture, Agricultural Research Service, Application Technology Research Unit, Wooster, Ohio; Randy A. Zondag, Ohio State University Extension, Chair and Extension Agent, Lake County, Painesville, Ohio; and Hannah Mathers, Assistant Professor, The Ohio State University, Department of Horticulture and Crop Science, Columbus, Ohio.
Composts evaluated in this work included:
All composts had been stabilized to a stability level suitable for incorporation into potting mixes. The composted manures were incorporated into potting mixes at a volumetric amendment rate of 5% and the composted biosolids at 6%. The types and quality of lime and fertilizers added varied with the location of the test and the crop, but all crops were treated with slow-release fertilizer. The pH of all mixes ranged from 5.3 to 6.0. The air-filled pore space after saturation and drainage exceeded 25% in 1-gallon containers.
All trials were arranged as a randomized complete block design with at least four blocks. The number of replicates used per block depended on plant availability and varied among but not within plant species. Plant growth was expressed as dry weight, plant canopy size, or on the basis of a salability rating scale. Disease severity was based on severity ratings scales, area under disease progress curves, or percent of plants killed or symptomless, depending upon the species or the disease. Data were analyzed by ANOVA, and means were separated by Fisher's least significant difference test.