Eliminating Summer Fallow Reduces Winter Wheat Yields, but Not Necessarily System Profitability
Published in Crop Sci. 44:855–860 (2004). Copyright © Crop Science Society of America. Used by permission.
Summer fallow is commonly used to stabilize winter wheat (Triticum aestivum L.) production in the Central Great Plains, but summer fallow results in soil degradation, limits farm productivity and profitability, and stores soil water inefficiently. The objectives of this study were to quantify the production and economic consequences of replacing summer fallow with spring-planted crops on the subsequent winter wheat crop. A summer fallow treatment and five spring crop treatments [spring canola (Brassica napus L.), oat (Avena sativa L.) + pea (Pisum sativum L.) for forage, proso millet (Panicum miliaceum L.), dry bean (Phaseolus vulgaris L.), and corn (Zea mays L.)] were no-till seeded into sunflower (Helianthus annuus L.) residue in a randomized complete block design with five replications during 1999, 2000, and 2001. Winter wheat was planted in the fall following the spring crops. Five N fertilizer treatments (0, 22, 45, 67, and 90 kg N ha-1) were randomly assigned to each previous spring crop treatment in a split-plot treatment arrangement. The 3-yr mean wheat grain yield after summer fallow was 29% greater than following oat + pea for forage and 86% greater than following corn. The 3-yr mean annualized net return for the spring crop and subsequent winter wheat crop was $4.20, -$6.91, -$7.55, -$29.66, -$81.17, and -$94.88 ha-1 for oat + pea for forage, proso millet, summer fallow, dry bean, corn, and spring canola, respectively. Systems involving oat + pea for forage and proso millet are economically competitive with systems using summer fallow.