Effect of Container Depth on Taprooted Seedling Root Morphology and Post-Transplant Establishment Success

View the project final report

Commodities

• Nuts: chestnuts

Practices

• Crop Production: agroforestry, alley cropping, forest farming, forestry, nurseries, silvopasture

Taprooting perennials, by their nature, developed a survival strategy of sending a single primary root deep into the soil before shifting focus to robust lateral root growth. Nursery production of these perennials, by its inherent constraints, must artificially arrest taproot growth to produce a plantable sapling. Not doing so results in root-binding that is far worse for trees post-transplant success.

While concerted research has investigated the effect taproot pruning has on root morphology within containers, limited research has explored the effect that container depth and, by extension, taproot length/development has on the post-transplant establishment of saplings.

What is the ideal container depth that grows the highest quality nursery stock and encourages best initial vigor and survival? Is this the same across applications, whether agricultural or reforestation? The project is designed to investigate these questions using chestnuts grown from seed in containers of various depths, collecting data of initial seed weight, followed by survivorship, dry weight, taproot diameter at 4", taproot length, and caliper. Saplings will be transplanted to a test plot for a year of observation. Survivorship, tree height, caliper, and diameter at breast height will be recorded at the end of the year.

I will seek advisement primarily from Aaron Parker, a local nursery operator, and will also draw on the consultation of Caleb Goossens, MOFGA's Organic Crop & Conservation Specialist. Outreach will be conducted through written articles, online posts, and conference/event presentations.

This project seeks to determine the effects that nursery container depth has on taprooted seedling development in air-pruned nursery pots, and how these differences translate to post-transplant survivorship and initial vigor under contrasting management strategies that simulate real-life application.

In the first year, we will grow a total of 625 chestnuts from seed in air-pruned containers of equal diameter within five different soil depths (6", 9", 12", 15", and 30" - 125 seeds each). The collected results will provide nursery growers guidance on optimizing container production for taprooted seedlings.

In the second year, a random sample of 40 trees from each nursery group will be planted at 20' in-row spacing (32' between-row spacing) under the two contrasting management strategies detailed earlier in this application, for a total of ten experimental groups, and post-establishment data will be collected for a season. This aspect of the project seeks to draw out if/which root morphologies are better suited for particular applications (ex., agricultural vs. ecological restoration/forestry). Solid data on this will help inform purchasing decisions of nursery stock and propagation practices to improve project success rates.