2011 Annual Report
1a.Objectives (from AD-416)
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.
1b.Approach (from AD-416)
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.
We conducted 4 studies. These studies continued to focus primarily on Eastern Redcedar (Juniperus virginiana) as the local materials source, although we evaluated Osage Orange (Maclura pomifera) also. The first study was a late-Spring greenhouse-grown annuals project. We varied ratios of peat and 3/16-inch Redcedar (our smallest hammer mill screen size;) with a consistent 25% perlite in all treatments except 100% Redcedar. Three annual bedding plant crops were grown including Petunia (Petunia x hybrida ‘Suncatcher White’), New Guinea Impatiens (Impatiens hawkeri ‘Celebrette Lavender’) and Vinca (Catharanthus roseus ‘Pacifica Apricot XP’). The second study continued our outdoor crop evaluations. We evaluated 2 trees, 2 shrubs, and 2 perennials in substrates composed primarily of Redcedar processed to various screen sizes (3/4-, ½-, 3/8-, and 3/16-inch Redcedar) with a pine bark control treatment. Species tested included Baldcypress (Taxodium distichum), Redbud (Cercis canadensis), Crapemyrtle (Lagerstroemia indica ‘Arapaho’), Spirea (Spiraea japonica ‘Little Princess’), Maiden Grass (Miscanthus sinensis ‘Graziella’) and Black-eyed Susan (Rudbeckia fulgida var. fulgida). We concurrently conducted an identical study using these treatments and species with Osage Orange as the substrate rather than Redcedar (3rd study). The 4th study examined the effect of Redcedar as a propagation substrate using cuttings from Chrysanthemum (Chrysanthemum x morifolium ‘Abelle’), Ivy Geranium (Pelargonium ‘GerIV Colorcade Cherry Red’), Hibiscus (Hibiscus rosa-sinensis), Privet (Ligustrum x vicaryi ‘Golden vicary’) and Green Giant Arborvitae (Thuja ‘Green Giant’).
Additionally this year, the cooperator created a website to showcase the alternative substrate work funded by the Floral Nursery Research Initiative. The URL is www.SustainableSubstrates.com. Here you can find our researcher profiles, compilations of all of our written work (refereed, trade, etc.), slide sets, and links to upcoming learning opportunities.
This work applies directly under the ARS parent project plan Sub-objective 2A “Evaluate the use of regional agricultural/forest byproducts and synthetic materials for use as a substrate in nursery containers.”
The cooperator and the Authorized department officer's designated representative kept in touch via phone and email contact.