Cover Story
Cover Crop Options that Provide Benefits for Tennessee Nurseries By Dr. Anthony Witcher 1 and Grayson DeLay 2 1Associate Professor and 2Graduate Masters Student, Tennessee State University, Otis L. Floyd Nursery Research Center
T
ennessee has over 19,000 acres in production of nursery crops with more than half of that total area planted with field-grown trees and shrubs that will be harvested as barerooted liners or dug as balled and burlapped (B&B) stock. Fertile and well-drained soils are critical for producing quality nursery stock. Yet in these systems, continuous cycles of nursery production with successive crop harvests leads to removal of topsoil and reduced soil quality. In many scenarios, once a new crop has been transplanted to the field, the soil surface can remain bare for several months until grasses and broadleaf weeds are able to establish in the nonproduction middle areas between rows. In this period, bare soil is susceptible to structural breakdown and soil erosion that are made worse during heavy rain events and windy conditions (Figure 1). Soil degradation and erosion also occurs in nursery middles subjected to
frequent tillage. The action of tilling will produce a shallow hardpan that limits water infiltration into the soil, making it more difficult for water to reach the crop root zone. Heavy equipment travelling through nursery middles for tillage and mowing also can degrade soil structure by compacting the soil leading to increased rainwater runoff and reduced water infiltration. Harvesting B&B crops removes large amounts of fertile topsoil from production areas, and it is cost- and labor-prohibitive to replace by importing new soil or organic material to the fields. Instead, producers can take advantage of implementing best management practices to their operation that will reduce soil degradation and improve soil properties, thereby maximizing the success of future crops. Cover crops are a versatile tool that can be used to reduce erosion and improve soil quality and cover crop options also can help restrict or suppress various crop pests.
FIGURE 1. Soil erosion resulting from heavy rainfall in a nursery field.
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tennessee greentimes WINTER 2023
