Zinc from galvanized components, including support posts for solar panels, can move into the soil.[39] Zinc from building material stockpiles has been previously noted as a localized problem for peanut production in some North Carolina fields.[40] While it is difficult to predict in advance the degree to which this will occur, it is relatively simple to collect soil samples and monitor this situation in existing installations. Analysis of zinc is included in routine soil testing procedures used by the NC Department of Agriculture & Consumer Services Agronomic Services Division Laboratory. Awareness of zinc concentrations in the soil, and any spatial patterns noted with depth and distance from structures, should allow producers to determine if the field is adequate for desired crops as is. If zinc limitations exist, awareness of concentrations and spatial distribution patterns may indicate the potential for deep tillage, liming, or crop selection alternatives required for successful agricultural use.  Of the agronomic crops grown in NC, peanuts are the most sensitive crop to zinc toxicity. Based on information from the N.C. Department of Agriculture and Consumer Services, there is risk of toxicity to peanuts when the zinc availability index (Zn-AI) is 250 or higher, particularly in low-pH situations. Risk increases with increasing soil test levels, especially if pH management through a liming program is not followed. For most other crops, zinc toxicity does not become problematic until the Zn-AI index reaches 2,000-3,000.[41]

  1. ^ American Galvanizers Association.Hot-Dip Galvanized Steel’s ContributiontoZincLevels in the Soil Environment. 2013. Accessed August 2017. https://www.galvanizeit.org/uploads/publications/Galvanized_Steel_Contribution_Zinc_Soil_Environment.pdf
  2. ^ NC State Cooperative Extension Service.Zinc Discussion. July 2015. Accessed August 2017. https://peanut.ces.ncsu.edu/2015/07/zinc-discussion/.
  3. ^ David H. Hardy, M. Ray Tucker, Catherine Stokes.Understanding the Soil Test Report. North Carolina Department of Agriculture and Consumer Services Agronomic Division. October 2013. Accessed August 2017. http://www.ncagr.gov/agronomi/pdffiles/ustr.pdf.
NC State Credit