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United States Department of Agriculture

Agricultural Research Service

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Research Project: Examining Nutrient Retention and Leaching Potential of Alternative Soiless Substrates Used for Container-Grown Crops

Location: Southern Horticultural Research

2013 Annual Report


1a.Objectives (from AD-416):
The objective of this cooperative research is to characterize and fully measure the retention and leaching potential of certain nutrients in various soilless substrates used for container-grown crops.


1b.Approach (from AD-416):
Using the cooperator's existing nutrient recovery system, nutrients (from various sources) will be applied to plants grown in various alternative soilless container substrates. The effluent and/or substrate at various depths will be collected and analyzed to determine the rate of nutrient retention and leaching.


3.Progress Report:

During the project period, ARS scientists modified an open-end nutrient/irrigation research system to meet the specific requirements for this project. The modified system is capable in delivering consistent and uniform irrigation amount to up to 144 containers arranged as a Completely Randomized Block Design (CRBD) on four benches in a research greenhouse. This design can have 2 to 6 treatments delivered through irrigation (i.e., irrigation amount, frequency, or nutrient treatments) to various potting media treatments.

After six small scale test-runs, a full size experiment is being planned to evaluate the water retention capacity and potential hydrogen/electrical conductivity (pH/EC) dynamics of an aged alternative potting medium (pole-mill ground) and its mixes with pine bark. Data collected from this study is expected to help ARS scientists understand the physical and chemical changes of these alternative potting mixes overtime, and provide background information for designing future studies with the inclusion of ornamental nursery crops. A proposal is being prepared on getting industry support from Louisiana Nursery and Landscape Association on alternative potting media research.

ARS scientists exchanged our experiences in nutrient research system designs with scientists at Southern Horticulture Research Lab. This retrospective learning process has benefited both of us and the future collaboration in this project.


Last Modified: 9/1/2014
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