Cumulative and residual effects of different potato cropping system management strategies on soilborne diseases and soil microbial communities over time

Abstract

Soilborne potato diseases and soil microbial community characteristics were evaluated over 8 years in different potato cropping systems designed to address specific management goals of soil conservation, soil improvement and disease suppression. Results were compared to a standard rotation and non‐rotation control in field trials in Maine. Standard rotation consisted of barley underseeded with red clover, followed by potato (2‐year). Soil‐conserving system (SC) featured an additional year of forage grass and reduced tillage (3‐year, barley/timothy–timothy–potato). Soil‐improving system (SI) added yearly compost amendments to SC, and the disease‐suppressive system (DS) featured crops with known disease‐suppressive capability (3‐year, mustard/rapeseed–sudangrass/rye–potato). Systems were established in 2004, evaluated with and without irrigation, and actively managed until 2010, with potato also planted in 2011 and 2012 to examine residual effects. All rotations reduced soilborne diseases black scurf and common scab, and increased yield after one rotation cycle (3 years), but diseases increased overall after two rotation cycles. DS maintained lower soilborne disease levels than all other rotations, as well as high yields, throughout the study. Cropping system effects became more pronounced after multiple cycles. SI system and irrigation both resulted in higher yields, but also higher levels of soilborne disease. Cropping system and irrigation effects were significant even after systems were no longer maintained. Soil microbial community data showed significant changes associated with cropping system, and differences increased over time. Cropping system strategy had significant and lasting effects on soil microbiology and soilborne diseases, and can be used to effectively enhance potato production.

Quantity and Nature of Water‐Extractable Organic Matter from Sandy Loam Soils with Potato Cropping Management

“…In addition, findings in this study can contribute to the overall goal of enhancing productivity and sustainability of the Maine potato industry. This work and other recent publications (Halloran et al, 2013;Larkin et al, 2016;Olanya et al, 2014Olanya et al, , 2016 on the same project will also be helpful to global potato production practices as this project is a continuation of one of the eight global case studies compiled in the book Sustainable Potato Production (He et al, 2012a).…”

“…At each irrigation event, 1.25 to 1.27 cm of water was applied. Total rainfall, number of irrigation events for the growing months, and 30-yr rainfall averages are available in Larkin et al (2016).…”

The soil microbial hydrolytic activity, content of nitrogen and organic carbon were enhanced by organic farming management using cover crops and composts in potato cultivation

“…The use of organic fertilisers such as manure, various mulches and green manure crops increase the organic carbon content and the microbial activity in the soil (van Vliet et al 2006;Larkin 2008;Larkin et al 2010;Mandic et al 2011;Bhagat et al 2016). In potato cultivation, activity of bacterial populations and soil microbes have been increased by using the green manure cover crops which have also had a positive effect on the tuber yield (Larkin et al 2017). In conventional potato farming system, soil is intensively managed during the growing period (e.g.…”

Use and Effects of Different Brassica and Other Rotation Crops on Soilborne Diseases and Yield of Potato †

“…It should be noted that these trials represent results based on a single year of a rotation crop grown prior to potato, and that to fully evaluate the more long-term effects of these rotation crops, additional testing over multiple rotation cycles is needed. In previous field studies, Brassica crops used as rotation or green manure crops reduced black scurf and common scab over multiple cropping cycles and years [26][27][28]. In other studies, two-year rotations with a variety of different crops (alfalfa, oats, vetch, lupine, buckwheat, and ryegrass) have all been observed to reduce the incidence and/or severity of some soilborne diseases, such as stem lesions of R. solani by as much as~50-80% relative to continuous potato [29,30].…”