Document Type

Article

Publication Date

1-1-2017

Abstract

Phosphorus (P) fertilizers with high water-solubility are often applied in excessive amounts to porous horticultural substrates to produce high-quality plants. As a result, high P losses during containerized plant production have presented an environmental challenge to responsible growers. Poultry litter ash (PLA), a byproduct of bioenergy production, contains P concentrations comparable to conventional P fertilizers but is characterized as having lower water-solubility. Therefore, a series of experiments were conducted to characterize effects of PLA on container-plant growth and P leaching. PLA was compared with superphosphate (SP), a highly water-soluble P source, in ratios of 0:100, 25:75, 50:50, 75:25, and 100:0 (SP:PLA) in the production of Lantana camara L. ‘New Gold’. In 2011, lantana fertilized with higher ratios of PLA exhibited slower growth with lower shoot and root biomasses compared with 100% SP-fertilized lantana. However, in 2012, differences in fertilizer treatments lessened, with 100% PLA-fertilized lantana exhibiting 14% less shoot biomass and no differences in root biomass compared with 100% SP-fertilized lantana. Measurement of shoot: root biomass, a common indicator of P deficiency, was not different between any P treatments in 2011 or 2012. This indicates root growth was most likely the driving factor in P-treatment effects on shoot biomass in each year of the experiment. During a post-production field trial, no differences in growth or biomass were observed between lantana previously fertilized with P, regardless of source. However, application of PLA as the single P source reduced dissolved reactive P (DRP) concentrations in leachate >90% and total P (TP) mass losses 69% compared with 100% SP-fertilized lantana during container production, with P treatments reducing DRP and TP losses as PLA ratios increased. Therefore, the benefit of P-loss reduction during container production achieved through PLA application may warrant the acceptance of slightly smaller plants or extending production cycles.

Publication Source (Journal or Book title)

HortScience

First Page

592

Last Page

597

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