ISHS Acta Horticulturae 819: International Symposium on Growing Media 2007
USING A MINERAL AGGREGATE TO SUPPLY PHOSPHORUS AND POTASSIUM FOR CONTAINERIZED CROP PRODUCTION |
| Authors: | J.S. Owen, Jr., S.L. Warren, T.E. Bilderback, J.P. Albano |
| Keywords: | clay, nutrient, media, ornamental crop growth |
| Abstract:
There is a rising need for increased water and nutrient use efficiency in ornamental container production to maximize profits while minimizing environmental impact. Substrates containing industrial mineral aggregates (clay) can increase water use efficiency and reduce phosphate leaching while retaining maximum crop growth. In addition, these clays may be able to provide a labile source of plant available phosphorus (P) and potassium (K). A study was performed to determine if 9% (by vol.) palygorskite-bentonite industrial clay aggregate amended pine bark substrate could supply adequate P and K to maximize growth of Cotoneaster dammeri C.K. Schneid. ‘Skogholm’. Plants were top-dressed with single [nitrogen (N) only], incomplete (N and K only), or complete controlled release fertilizer (N, P, and K) and microirrigated cyclically to maintain a 0.25 leaching fraction. Dry mass of Skogholm cotoneaster was greatest when receiving the incomplete fertilizer (N and K) and least when only N was applied (P and K were absent). Foliar P concentration was not limiting in all treatments and greatest in plants receiving N only. In contrast, foliar K was limiting in Skogholm cotoneaster when receiving a fertilizer containing only N. Foliar K increased 46% when grown with a complete (N, P, and K) or incomplete fertilizer (N and K). Water extractable substrate K was unaffected by fertilizer treatment, however substrate extractable P decreased 55% when using single or incomplete fertilizer that contained no P. The clay amendment was able to supply adequate P to maximize growth when using an incomplete fertilizer (N and K). | |
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