Growth and Nutrient Status of Containerized Shrubs Grown in Composts Containing Waxed Corrugated Cardboard and Other Organic Wastes

Abstract

Four containerized deciduous ornamental shrubs, [silverleaf dogwood (Cornus alba L. `Argenteo-marginata'), red-osier dogwood (Comus sericea L.), ninebark (Physocarpus opulifolius L.), and deutzia (Deutzia gracilis L.)] were grown in 12 composts containing (by volume) spent mushroom substrate (50%), waxed corrugated cardboard (WCC; 0%, 25%, or 50%), and/or pulverized wood wastes (PWW; 50%, 25%, and 0%). Supplemental N as poultry manure and/or soybean wastes was added to some composts. Growth (shoot dry weight, average of two seasons) of all species was better or similar in most composts compared with two controls (100% pine bark and 80% pine bark: 15% peat: 5% sand). Deutzia grew best in 50% WCC composts and other species in 25% WCC composts. Porosity characteristics of the composts were acceptable for container growing (50% to 60% total; 25% to 30% aeration). Total soluble salts were initially high and potentially phytotoxic, particularly in the 50% WCC composts but were quickly leached and resulted in no injury to plants. There were no symptoms of nutrient deficiencies or toxicities in any of the species tested. Foliar nutrient (N, I P, K, Ca, Mg, Mn, Zn, and Fe) concentrations in all species were within normal ranges, except for low Mn and Fe concentrations in red-osier dogwood during the second season.