The use of a primary clarifier sludge as a container amendment.

摘要

Studies were conducted to evaluate the vegetative growth parameters of bedding plants (Zinnia elegans 'Thumbelina Mix', Petunia x hybrida 'Super Cascade Red', Vinca rosea 'Rosy Pink', and Salvia splendons 'Red Hot Sally'), poinsettias (Euphorbia pulcherrima 'Gutbier V-14 Glory'), and woody ornamentals (Rhododendron obtusum japonicum 'Coral Bell', Juniperus conferta, Euonymus japonica 'Aureo-Marginata', and Ilex crenata 'Compacta') as influenced by media consisting of varying proportions of pine bark, sharp sand, peat moss, and primary clarifier sludge (PCS), which is a by-product of hardboard manufacturing. Physical properties, such as total porosity, air space, water retention, particle size distribution and bulk density, and chemical properties, such as pH, electrical conductivity (EC), and cation exchange capacity (CEC), of each media blend was also determined.;Plant growth index and shoot dry weight was reduced with increasing levels of PCS similarly for each bedding plant species tested except growth index of V. rosea, which was not affected. The maximum reduction occurred where PCS was 50% or more of the total volume of the organic component of the media. Root dry weight of S. splendons and V. rosea was reduced with increasing proportions of PCS.;Plant growth index of I. crenata 'Compacta' and E. japonica was reduced with increasing levels of PCS. Maximum reduction was observed where PCS was 60% or more of the total volume of the organic component of the media. Shoot dry weight of R. obtusum japonicum was increased with increasing levels of PCS and decreased for J. conferta, I. crenata 'Compacta' and E. japonica. Root dry weight of all woody ornamentals was reduced with increasing levels of PCS.;Increasing the PCS percentage to 60% or more of the organic component of the media raised the pH above 6 and reduced the EC. The CEC was reduced to less than 6 meq./100 cc when 30% or more of the organic component of the media was PCS.;The bulk density of the media was decreased slightly with increasing levels of PCS. The percent water held increased at 30 to 60 cm tension when PCS was added to the media.