Eliminating Summer Fallow Reduces Winter Wheat Yields, but Not Necessarily System Profitability

Abstract

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.

Replacing Fallow with Continuous Cropping Reduces Crop Water Productivity of Semiarid Wheat

“…Thus, all components of the water‐limiting yield formation function (HI, TE, TF, and WU; Passioura, 1977) were reduced when fallow was eliminated in continuous cropping systems. These results are consistent with those of Lyon et al (2004, 2007), Nielsen and Vigil (2005), Saseendran et al (2004), Vigil and Nielsen (1998), Miller et al (2006), and Nielsen et al (2002). Our results also support prior findings that reductions in ASW and crop productivity increase with the duration of the fallow replacement crop (Vigil and Nielsen, 1998; Nielsen and Vigil, 2005; Lyon et al, 2004) and that these effects were exacerbated under drought conditions in the CHP (Nielsen et al, 2002; Nielsen and Vigil, 2005; Lyon et al, 2007), PNW (Miller and Holmes, 2005), and Mediterranean (López‐Bellido et al, 1996).…”

Choice of Summer Fallow Replacement Crops Impacts Subsequent Winter Wheat

“…The yield response to available soil water increased with increasing precipitation during May and June. Lyon et al (2004) studied the impact of replacing summer fallow with various spring-planted crops prior to winter wheat seeding. Oat (Avena sativa L.) and pea for forage or proso millet for grain were economically competitive with systems that included summer fallow, despite reducing winter wheat yields by 23% (450 kg ha 21 ) and 34% (690 kg ha 21 ) compared with wheat after fallow.…”

Do Interactions between Residue Management and Direct Seeding System Affect Wheat Stem Sawfly and Grain Yield?

“…Several studies report benefits when broad leaf crops such as pulses are integrated into a semiarid cropping system (Brandt, 1996; Miller and Holmes, 2005; Miller et al, 2002; Miller et al, 2003; Zentner et al, 2002). Other studies report a decline in winter wheat yield when fallow phases are removed, although overall system profitability is maintained or even improved (Lyon et al, 2004).…”