Soil type-driven variable effects on cover- and rotation-crops, nematodes and soil food web in sugar beet fields reveal a roadmap for developing healthy soils

Abstract

Improving soil health and managing beneficial and harmful nematodes using cover crops such as oilseed radish and mustard integrated with maize and soybean as rotation crops are major priorities in US sugar beet production. Despite extensive research on effects of rotation- and cover-crops on soil health, variable outcomes remain a problem. Using sandy clay loam and loam fields with known SBCN infestation, we tested how two each of oilseed (‘Defender’ and ‘Tillage’), mustard (‘Pacific Gold’ and ‘Ida Gold’), sugar beet (‘B-18RR4N’ and ‘B-10RR34’) and soybean (‘92Y80’ and ‘92M91’), and a maize (‘P9910R’) variety affect nematode community and soil food web in the 2013 and 2014 growing seasons. Each treatment (crop) was replicated six times. Maize is a non-host and Defender and Pacific Gold are poor hosts for SBCN. Nematode community composition at intervals during growing seasons and soil physiochemical properties at the end of year 1 were measured. The crops had no effect on nematodes. Nematode abundance and community indices varied by sampling time, growing season and/or soil type. Principal component analysis showed that the crops distinctly separated by soil type and only a few nematode community indices and/or soil physiochemical parameters overlapped with crop. Soil food web analysis showed depleted and degraded conditions in the sandy loam soil and disturbed and approaching enrichment in the loam soil. The study suggests a roadmap to get to agrobiologically suitable soil conditions to meet industry priorities for healthy soils.