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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF ALTERNATIVE SUBSTRATES FOR CONTAINER NURSERY CROPS

Location: Application Technology Research Unit

Project Number: 3607-21000-014-06
Project Type: Specific Cooperative Agreement

Start Date: Sep 22, 2008
End Date: Sep 21, 2013

Objective:
The objective of this research will be to screen and identify potential alternative substrates for use in nursery containers. Substrate materials regional to the midwest area (Kansas) will be collected and evaluated for suitability as substrate alternatives.

Approach:
Once materials are procured for testing, they will be evaluated three ways. First, plant bioassays will be used to observe the overall suitability of the materials for use as a substrate. Containers (6 in.) will be filled with the substrates and grown in a greenhouse with fast growing crops. Plants will be grown in a climate controlled greenhouse or nursery setting. Measured parameters will include plant growth, substrate nutrient capacity using the saturated media extraction procedure, plant nutrition using ICP analysis of foliage, and plant water use. Those that perform similar to traditional pine bark substrates will be evaluated further. Several iterations of the plant bioassay will be conducted to allow researchers to alter the substrates (particle size, for example) and optimize their potential for suitability. Once a suitable alternative substrate is identified, it will be studied more closely to understand how the material functions in a container environment. Further testing will include evaluation of the materials physical and chemical properties. Products will be measured for their porosity using NSCU porometers, particle size distribution, particle density, and moisture characteristic curves. This will provide a better understanding of the substrates hydrologic properties. Chemical analyses will include the substrates’ ability to buffer pH, provide macronutrients and micronutrients, and cation and anion exchange capacity.

Last Modified: 4/16/2014
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