Biofumigant Cover Cropping in Potatoes: Dale Gies
Dale Gies grows potatoes, wheat, and seed crops for vegetables and cover crops under irrigation near Moses Lake, Washington. In this publication, Gies discusses his experiences using a biofumigant cover crop to add organic matter and improve soil quality while successfully suppressing soilborne diseases and nematodes in potatoes.
This case study is part of the Farmer-to-Farmer Case Study project, which explores innovative approaches regional farmers are using that may increase their resilience in the face of a changing climate.
Information presented is based on growers’ experiences and expertise and should not be considered as university recommendations. Mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement. Grower quotes have been edited slightly for clarity, without changing the meaning.
Readers interested in other case studies in this series can access them at on the REACCH website, as well as in the WSU Extension Learning Library.
Average Annual Precipitation: 8 inches (irrigated cropping)
Cropping System: 2-year rotation of potatoes with winter or spring wheat, plus a biofumigant cover crop (mustard-arugula mix) in late summer after wheat harvest. Other crops grown on the farm include seed crops (mustard and arugula for cover crops, onion, carrot, and others) grown in rotation with wheat and vegetables.
Watch the companion video Mustard Cover Cropping in Potatoes, introducing Dale Gies and his cover cropping system.
Introduction
Dale Gies produces potatoes, wheat, and seed crops for vegetables and cover crops using irrigation from the Columbia Basin Project. He farms land his father started cultivating in 1952 just after the area was converted from native sagebrush. He hopes to one day pass the farm on to his two sons, who currently help in the operation.
With coarse sandy loam soils (Timmerman coarse sandy loam; NRCS 2013), low soil organic matter, and topsoil ranging from 12–36 inches in depth (averaging 18 inches), Gies does everything he can to prevent erosion and build soil quality. Using a reduced tillage system, he adds organic matter with a biofumigant mustard-arugula cover crop. This cover crop improves soil quality while successfully suppressing soilborne diseases and nematodes.
With this system, he has grown potatoes without chemical fumigation, despite his intensive two-year rotation. Conventional wisdom generally dictates a three-year or longer rotation for potatoes to produce a healthy crop, even with fumigation.
Gies also produces seed for vegetables and cover crops (Figure 1), and he consults with farmers around the world to help improve their disease suppression through rotations and biofumigant cover cropping.
