Intercropping for Pest Control in Organic Kale in Northern Florida

View the project final report

Commodities

• Vegetables: greens (leafy)

Practices

• Crop Production: intercropping
• Pest Management: integrated pest management
• Production Systems: organic agriculture

Intercropping has been a successful tool for farmers for thousands of years. Modern agricultural practices have diverted attention away from intercropping, but this has come at the price of sustainability. Reliance on monocultures supported by pesticides has led to reductions in pesticide efficacy, contributed to environmental pollution, and harmed human health. Intercropping can increase economic return for farmers through yield increases, and as a component of integrated pest management (IPM). However, successful implementation of intercropping can be highly context-dependent, depending on the specific crop, timing, and spacing arrangements (scale of inter-mixing of crops) suited to a particular region. This project seeks to evaluate intercropping as a tool for sustainable vegetable production on small organic farms in the Southeast. This project will address the question of how the efficacy of intercropping varies with the spatial scale of mixtures, and evaluate the use of a novel combination of kale (Brassica oleracea) and elephant garlic (Allium ampeloprasum). Previous work suggests that Allium species (onions, garlic, leeks) can be beneficial companion plants for many crops. Elephant garlic is well suited for intercropping with kale in the North Florida region, but its use has not yet been evaluated. Working with a small farm and an agricultural research station we will use organic practices to grow kale monocultures and dicultures with elephant garlic at different spatial scales of mixture. Insect pests, damage to plants and natural enemies will be surveyed; kale and garlic yield will be recorded, and net costs and benefits to farmers determined.

The objectives of this project are to evaluate intercropping as an economically viable and environmentally sustainable alternative to pesticide use and monocropping for pest suppression. The project will also examine differences in the benefits (pest suppression, yield) to farmers in using different scales of intermixing of kale and elephant garlic. We expect pest suppression to result from volatiles that repel herbivores or disrupt herbivore-searching behavior, as well as potentially increasing the diversity of natural enemies. We are testing different spatial scales of intermixing because, due to the short-range action of plant volatiles, it is possible that intercropping with elephant garlic will only be beneficial when the plants grow in close proximity.

This project is intended to engage local farmers practicing sustainable agriculture in the Tallahassee area. This project was developed in consultation with two local farms (Turkey Hill Farm, Full Earth Farm) that are both leaders in local sustainable agriculture and in the Red Hills Small Farm Alliance, a coalition of 60 farmers in north Florida and south Georgia that share an on-line farmers market delivering to the Tallahassee area. Both of these farms grow kale and elephant garlic, but they do not currently practice intercropping. In addition to working at a regional agricultural research station, we propose to leverage the planned expansion of a local small farm (Longview Farms) from beef and poultry production into growing vegetables for market, using some of their new vegetable beds for experiments at a second site. 

Our primary goals are to:

1) Evaluate whether plots of kale (Brassica oleracea, cultivar: Lacinto) intercropped with elephant garlic (Allium ampeloprasum) enhance biological control, insect diversity, and increase yield compared to kale monocultures. We will test three different spatial scales of intercropping.

2) Disseminate research to farmers and growers, and conduct science outreach to elementary school students.