Exploring the Economic and Environmental Sustainability of No-Till Organic Sweet Potato Production

Problem

Due to the efforts of Kansas State University, sweet potato production in Kansas has grown dramatically over the past few years and recently a group of growers have succeeded in getting October designated as “Sweet Potato Month” in the State of Kansas. Sweet potato production, especially organic sweet potato production commonly relies heavily upon tillage. Sweet potatoes are a relatively long season crop, and the ground is usually worked a number of times throughout the season to reduce weed pressure, which is detrimental to soil health.

In organic agriculture, two production systems both called no-till organic, are used to minimize tillage impact and control weeds. A “no-till” option based upon work at the Rodale Institute uses cover crops and mechanical rolling to terminate them and thus provide a deep mulch into which the economic crop is then planted. Calling this system no-till is a bit of a misnomer, as tillage is used to create the seedbed for the cover crop, but as it is widely called no-till I will also. The other system of no-till organic production uses a deep straw or hay mulch applied by hand or rolled across a field. This type of no-till is generally applicable only on smaller scales but it has been used on multi-acre production systems for a variety of vegetable crops. These techniques yield an additional risk for sweet potato production as sweet potatoes in this region are heavily impacted by vole damage, and voles also happen to find deep mulch to be an ideal habitat. This project is designed to address is to provide a detailed analysis of the economic viability of the two no-till organic systems, particularly as it relates to marketable yield and labor costs.

Solution

To provide an analysis of the viability of two no-till organic systems, this project will produce sweet potatoes in 3 different ways and record relevant data in regards to production costs as well as soil health. The basic experimental design will use a quarter acre of sweet potatoes grown for each of the next two growing seasons, and this total area will be divided into three trial plots, each to be managed using a different technique of organic sweet potato production.

The control will be the method that has historically been used on Buller Family Farm and is common throughout this region. That is placing sweet potato slips into raised beds, and controlling weeds with mechanical and hand cultivation.

The first experimental technique, I will refer to as no-till 1, is the no-till organic production espoused by the Rodale Institute. This involves terminating cover crops by rolling them, and using the remnant material as a deep mulch, into which plants are placed. Ron Morse of Virginia Tech has tailored these ideas to vegetable production, most notably in his development of the no-till planting aid. This is mechanical device that is made to cut planting furrows into the mulched bed, and is an economical tool to make planting faster and will be developed and used. The second experimental technique, no-till 2, uses a deep straw or hay mulch applied to the area to be gardened. This is often moved away from the planting area by hand, but in this experiment we will use the same no-till planting aid developed above to expedite this process.

In each of the trial plots three varieties of sweet potatoes will be grown, Beauregard, O’henry and Muraski to test for differences between varieties as well.

Yields and costs will be compared across the three systems.