|Impact of cover crop termination methods on diseases of wheat and lentil |
N. B. RANABHAT (1), M. E. BURROWS (1), Z. J. Miller (1), E. A. Lehnhoff (1), F. D. Menalled (1). (1) Montana State University, Bozeman, MT, U.S.A.
Crop rotation, cover cropping, and livestock integration may improve the sustainability of farming systems, but there is very little data on their effect on plant disease intensity. We investigated the impact of cover crop termination method on disease development in Bozeman, Mt. The experiment was began in 2013 with three systems of weed/cover crop management including sheep grazed organic (OG), organic tilled (OT) and conventional no-tillage (CNT). Each system (main plot) was split into five crop rotations (safflower/clover; clover; winter wheat; lentil; winter wheat). For two years, data were collected in the wheat and lentil phases of the rotations at three growth stages: tillering, flowering and matured. Incidence and severity of plant disease were recorded on 25 plants/subplot and subsets were chosen for identification of causal species. Management system did not impact disease incidence in wheat (<i>P</i>=0.38) in both years and in lentil in 2013 (<i>P</i>=0.9). CNT had lower disease incidence (<i>P</i><0.001) but OG and OT had similar disease incidence in lentil in 2014. The impact of management system on disease incidence depended on the crop phase and stage of wheat plants in 2014 (<i>P</i><0.001) and only with stages of wheat in 2013 (<i>P</i>=0.2). This result suggests that disease incidence depends on plant stages irrespective of management system thus cropping system diversification of including targeted sheep grazing will not contribute to increased disease intensity.