Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/21/2006
Publication Date: 12/1/2006
Citation: Strausbaugh, C.A., Windes, J.M. 2006. Influence of subsoiling and direct seeded cereals in southeastern Idaho. Canadian Journal of Plant Pathology. 28:596-608. Interpretive Summary: Small grain cereals are produced in both dryland (rain-fed) and irrigated, tillage-based production systems. To minimize crop inputs and reduce soil erosion from water and wind, growers have been encouraged to consider direct-seeded cereal production. Direct-seeded dryland fields in southeastern Idaho are normally planted annually to cereals. However, some areas are too dry to produce high quality malt barley and therefore are restricted to continuously cropped wheat. In high elevation areas, winterkill and snowmold fungi further restrict growers to spring cereal production. Under such limited cropping options in no-till systems, root diseases can increase and soil compaction can occur. In effort to address these concerns, we investigated the influence of shallow subsoil tillage on soilborne pathogen populations and soil parameters in direct-seeded cereals. Subsoiling had a tendency to increase soil moisture and organic matter, which is desirable. Subsoiling did not statistically influence the nematode populations but increased the fungal root rot disease severity (P = 0.07). Yield was increased by at least 8% at two locations the first year. Yield increases were not significant in the other two years when moisture was exceptionally limiting or abundant. Additional studies is warranted with subsoil tillage as this practice may be a way to increase yield and desirable soil parameters without compromising on the positive benefits associated with no-till cereal production. More information is needed to determine the impact on root disease.
Technical Abstract: The influence of shallow (20 cm deep) subsoil tillage on direct-seeded cereals was investigated for three years at two locations in southeastern Idaho. Fusarium culmorum was the primary fungus isolated from diffuse brown-black root lesions in the wetter location (Ririe), while F. semitectum, F. reticulatum, F. equiseti, and F. acuminatum were the dominate species isolated at the drier location (Arbon Valley). Subsoiling direct-seeded fields did not influence nematode populations but an increase (P = 0.07) in fungal root disease on seminal roots is a concern. The primary parasitic nematode found at both locations was Pratylenchus neglectus. Methyl bromide fumigation indicated that the biology of the system was yield limiting. Subsoiling had a tendency to increase soil moisture in the 61-90 cm zone, increase organic matter, and decrease nitrogen. Yield increased by 8% or more with subsoil tillage at both locations the first year. Yield increases were not significant in other years when moisture was exceptionally limiting or abundant. Subsoiling should be considered for direct-seeded cereals since most soil parameters were heading in a favorable direction, but fungal root rots may be a concern.