|Bilderback, T - North Carolina State University|
|Riley, E - North Carolina State University|
|Jackson, B - North Carolina State University|
|Kraus, H - North Carolina State University|
|Fonteno, W - North Carolina State University|
|Owen, J - Virginia Polytechnic Institution & State University|
|Fain, G - Auburn University|
Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2012
Publication Date: 11/1/2013
Citation: Bilderback, T.E., Riley, E.D., Jackson, B.E., Kraus, H.T., Fonteno, W.C., Owen, J.S., Altland, J.E., Fain, G.B. 2013. Strategies for developing sustainable substrates in nursery crop production. Acta Horticulturae. 1013:43-56.
Interpretive Summary: Pine bark is the primary component in potting mixes for container-grown nursery crops in North America. Regional availability of pine bark, increased transportation costs, and decreased availability due to reduced forest-industry activity has resulted in research for an alternatives to pine bark in container substrates. The objective of this manuscript is to provide a review of the work done so far in developing alternatives to pine bark. This includes a discussion on criteria for selecting potential alternatives, laboratory and field methods for evaluating alternatives, and case studies of the most commonly researched alternatives. Alternative materials discussed in detail include pine tree substrates, Douglas fir slash, commodity and biofuel crops, and consumer and agricultural waste resources.
Technical Abstract: A comprehensive literature search of industrial and agricultural byproducts to replace or extend existing soilless substrate components would produce a seemingly endless list of materials ranging from “garbage” to a plethora of manure-based composts that have been tested in both the laboratory and crop response studies throughout the world. Many of these alternatives have shown promise, but limiting factors for integration and use of the alternatives substrate components continue to include regional or national availability; transport costs; handling costs; lack of a uniform and consistent product; and guidelines for preparation and use of materials or impact on current crop production practices. If a product can overcome the above limitations, then researchers are tasked with documenting substrate physical or chemical characteristics. The objective in all studies is to maintain or increase growth of nursery crops and to extend the longevity and acceptable physical properties for long-term woody ornamental crops. Proof of results is determined using laboratory analyses and crop growth studies. Physiochemical properties are monitored over days, weeks and months to ensure stability. Particle size distribution and varying ratios of substrate components are manipulated to achieve optimal air-filled porosity and available water content. Soilless substrates are amended with lime, sulfur and nutrients or blended with other substrate components to provide optimal chemical characteristics. Additionally, substrates are evaluated under industry conditions to determine impact on water, nutrient and pest management to better understand the obstacles to commercial adoption.