Evaluation of fresh and aged clam processing wastes as agricultural liming agents for coastal vegetable production fields

Owen, J., S. LeBlanc, P. Toner and E. Fava.
Poster. Plant Canada 2006. Halifax, Nova Scotia, Aug 1-4, 2006.

Abstract
Clam processing in Atlantic Canada generates 4000 metric tons of clamshell wastes annually. Twenty-year stockpiles of shells must now be remediated to satisfy environmental regulations.

This study examined fresh and aged clamshells as agricultural liming agents for sandy, acidic, coastal vegetable production soils. Clamshell wastes fresh from processing and aged stockpiled shells were analysed for coliform bacteria, plant nutrients, calcium carbonate equivalent, and organic matter.

The shells met New Brunswick’s guidelines for wastes as soil additives. Clamshells were ground to three size fractions (<0.250 mm, 0.250 to 1.00 mm, 1.00 to 2.00 mm). These were mixed with two soils at four rates, and placed in a control-plus-factorial (commercial agricultural lime as control) pots experiment. During an eight-week incubation, soil water pH and electrical conductivity (EC) were monitored biweekly. At four and eight weeks, a soil extract germination test was conducted using watercress (Lepidium sativum L.), a species sensitive to water quality, as an indicator plant. The pH and EC data were used to develop prediction graphs of the soil reactions which can be used as a basis for guidelines for rates of land application for liming.

Clamshell amendment did not negatively affect germination of watercress seeds.

 

Source

PDF: CSHS Poster Halifax 2006.pdf

Posted October 2007