|Larkin, Robert - Bob|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2005
Publication Date: 12/15/2005
Citation: Larkin, R.P., Honeycutt, C.W. 2004. Effects of different 3-yr cropping systems on soil microbial communities and soilborne disease of potato. Phytopathology. 96: 68-79 Interpretive Summary: Numerous financial and production constraints limit the potential of commercial potato production in the northeast, including high disease pressure, lack of profitable rotation crops, and high fertilizer and pesticide requirements. Crop rotations or multiple year cropping systems can be an effective means of disease control, nutrient input, and improving crop productivity without additional chemical inputs. Effective and profitable crop rotations are needed. Currently, several potential cropping systems are being evaluated for use in potato production systems in the northeast based on their profitability, sustainability, and beneficial attributes, such as soil fertility, disease reduction, and nutrient inputs. In this study, several different 3-yr cropping systems, including rotations with soybean, canola, barley, sweet corn, and green bean in various combinations, were found to have distinct effects on soil microbial communities. These effects were also related to reductions in the incidence and severity of Rhizoctonia disease of potato plants and tubers, and also in improved tuber quality. Overall, the soybean-canola, soybean-barley, and sweet corn-canola rotations were best, whereas barley-clover and sweet corn-soybean were not as effective. This information can be used by scientists, extension agents, and ultimately growers for the development of beneficial crop rotations and environmentally friendly approaches to disease control.
Technical Abstract: Eight different 3-yr cropping systems, consisting of soybean-canola, soybean-barley, sweet corn-canola, sweet corn-soybean, green bean-sweet corn, canola-sweet corn, barley-clover, and consecutive potato (nonrotation control) followed by potato as the third crop in all systems, were established in replicated field plots with two rotation entry points in Presque Isle, ME, 1998. The effects on soil microbial community characteristics and the development of soilborne diseases of potato were evaluated in 2000 and 2001. Soil bacterial populations and activity were highest following barley, canola, and sweet corn crops. Other characteristics of the soil microbial communities, including substrate utilization profiles (Biolog plates) and fatty acid methyl ester (FAME) profiles also demonstrated distinct differences among cropping systems. Incidence and severity of stem and stolon canker and black scurf of potato, caused by Rhizoctonia solani, were reduced for most rotations relative to the consecutive potato control. Potato crops following canola, barley, or sweet corn provided the lowest disease levels and best tuber quality.