Yield and quality of hard red spring wheat cultivars following fallow and wheat

Continuous wheat (Triticum aestivum L. emend. Thell.) and other intensive cropping systems are replacing t he wheat-fallow (WF) system in the semiarid prairie region of Canada and the northern USA. However, most wheat cultivar recommendations are based on performance in a WF system. Our objective was to determine if cultivar ranking for grain yield, grain protein concentration, and kernel weight changed for hard red spring wheat in WF compared with continuous wheat (WW) systems. Ten cultivars were seeded on a Dark Brown Chernozem loam following fallow and wheat over 3 consecutive years at Dickinson, ND, USA. Fertilizer was applied for equivalent yields in both systems based on soil test results. More grain and heavier kernels were produced during the crop phase of the WF system than the WW system, in part because soil-water content was greater after fallow than wheat in 2 of 3 yr. Grain protein concentration was unaffected by cropping system. Grain yield, grain protein concentration, and kernel weight differed among cultivars. Interactions did not occur between cropping systems and cultivars for any grain parameter. Results of this study support the hypothesis that wheat cultivar ranking based on performance in a WF system can be extended to a WW system. Key words: Crop rotation, cropping systems, fallow, monoculture, wheat