Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/4/2007
Publication Date: 6/14/2007
Citation: Novak, J.M., Szogi, A.A., Watts, D.W. 2007. Copper and zinc acumulation in sandy soils and constructed wetlands receiving pig manure effluent applications. In: Proceedings of the First International Scientific Symposium on Trace Elements in Animal Production Systems, June 14-15, 2007, Archamps, France. p. 7-8.
Technical Abstract: Over the past 20 years, North Carolina has experienced a substantial increase in pig populations from approximately 2.5 million to almost 10 million head. The majority (59%) of North Carolina’s entire pig population occurs in only four Coastal Plain counties that collectively comprise only 6% of North Carolina’s total land area. Localizing pig production operations into a small regional area of North Carolina has stirred concern about manure disposal and the soil’s long-term ability to assimilate nutrients. Pig manure effluent contains both plant macro-(N, P, etc.) and micro-(Cu, Zn, etc.) nutrients, so it is applied to fields containing row crops or perennial grasses. Crops require macronutrients in kg per tonne of crop yield; in contrast, much lower amounts of micronutrients are required (g per tonne of crop yield). Pig manure effluent applied to a North Carolina field after 10 years caused both Cu and Zn accumulation in topsoils. Soil Zn concentrations in this field after 10 years are beginning to reach a minimum Zn phytotoxic threshold level. If the Zn buildup reaches a critical threshold level, yields of Zn-sensitive crops may be reduced. As an alternative to land applying pig manure effluent, recent attention has focused on using vegetated constructed wetlands to treat or sequester nutrients. Constructed wetlands have been shown to be effective at reducing macronutrient concentrations in pig manure effluent, but its effect on micronutrient concentrations is not well known. This presentation will address how long-term pig manure effluent applications can cause the accumulation of Cu and Zn in sandy soils and will explore the influence of constructed wetlands to reduce Cu and Zn concentrations in effluent prior to land application.