No-till or direct seeding can be described as seeding directly into the crop stubble from the previous season without use of tillage. A reduction in tillage can result in many benefits, including increased soil organic matter, increased water holding capacity, and reduced fuel costs. However, the effect of no-till and reduced tillage on crop root disease profiles is poorly understood. To study the effect of tillage on disease dynamics, soil samples were collected from commercial wheat fields representing a wide range of tillage strategies in fall 2016 and fall 2017. Because precipitation might affect soilborne diseases, wheat fields located across a diverse gradient of precipitation zones of the dryland Pacific Northwest were selected. Fusarium spp., Pythium spp., and Rhizoctonia spp. were quantified from soil samples using soil dilution plating and quantitative PCR (qPCR) assays. Results of dilution plating showed that the colony counts of Fusarium, Pythium, and Rhizoctonia at the genus level were negatively associated with tillage. However, the same patterns were not observed when specific causal agents of Fusarium, Pythium, and Rhizoctonia that are known to be pathogenic on wheat were quantified with qPCR. Furthermore, precipitation affected the population density of some fungal pathogens (F. culmorum, P. ultimum, and R. solani AG 8). Within the scope of inference of this study, results of this study indicate that the benefits of adopting reduced tillage likely outweigh potential risk for increased root disease.

免耕或直接播种可被描述为从上一个季节开始直接播种到作物秸秆中，而无需耕种。减少耕种可带来许多好处，包括增加土壤有机质，增加保水能力和降低燃料成本。但是，免耕和减少耕作对作物根部病害的影响知之甚少。为了研究耕作对疾病动态的影响，在2016年秋季和2017年秋季从代表商业耕作策略的小麦田中收集了土壤样品。由于降水可能影响土壤传播的疾病，因此麦田分布在不同的降水区中选择了西北太平洋的旱地。镰刀菌属，腐霉属和根瘤菌属 使用土壤稀释板和定量PCR（qPCR）分析从土壤样品中定量。稀释平板的结果表明，该属的镰刀菌，腐霉菌和根瘤菌菌落数与耕作呈负相关。但是，用qPCR对已知对小麦致病的镰刀菌，腐霉菌和支原体的特定病原体进行定量分析时，未观察到相同的模式。此外，沉淀的影响一些真菌病原体的人口密度（F.孢，P.霉，和水稻纹枯病菌AG 8）。在本研究的推论范围内，本研究的结果表明采用减少耕作的好处可能超过增加根部疾病的潜在风险。