Soybean [Glycine max (L.) Merr.] seed treatment adoption has increased dramatically over the past decade in addition to the number of pesticide components within commercially available seed treatments. The study objectives were to evaluate the effects of multiple seed treatments and their individual pesticide components (fungicide, insecticide, and/or nematicide) on soybean plant stand and seed yield across diverse environments. Trials were conducted at 10 Wisconsin locations during the 2011 to 2013 growing seasons. Soybean seed treatments containing fungicide + insecticide + nematicide increased plant stands over the untreated control (UTC), fungicide only, and fungicide + insecticide seed treatments by an average of 10, 9, and 5.5%, respectively. During 2013, yield was increased by the fungicide only seed treatment pyraclostrobin + metalaxyl + fluxapyroxad; however, across all environments, no consistent yield increase was shown for fungicide only seed treatments. Fungicide + insecticide seed treatments increased yield over fungicide only seed treatments by 55 and 76 kg ha -1 during 2011-2012 and 2013, respectively, and were similar to fungicide + insecticide + nematicide seed treatments. However, fungicide + insecticide and fungicide + insecticide + nematicide seed treatments only increased yield over the UTC in 2013. These results suggest that though fungicide + insecticide and fungicide + insecticide + nematicide seed treatments consistently increased plant stand, yield increases were variable and contingent on unpredictable factors. Therefore, producers will need to weigh potential yield gains with biological (resistance management) and economic (return on investment [ROI] and risk mitigation) concerns before implementing seed treatment practices at the whole farm level.

Elevated soybean [Glycine max (L.) Merr.] prices have spurred interest in maximizing soybean seed yield and has led growers to increase the number of inputs in their production systems. However, little information exists about the effects of high‐input management on soybean yield and profitability. The purpose of this study was to investigate the effects of individual inputs, as well as combinations of inputs marketed to protect or increase soybean seed yield, yield components, and economic break‐even probabilities. Studies were established in nine states and three soybean growing regions (North, Central, and South) between 2012 and 2014. In each site‐year both individual inputs and combination high‐input (SOYA) management systems were tested. When averaged between 2012 and 2014, regional results showed no seed yield responses in the South region, but multiple inputs affected seed yield in the North region. In general, the combination SOYA inputs resulted in the greatest yield increases (up to 12%) compared to standard management, but Bayesian economic analysis indicated SOYA had low break‐even probabilities. Foliar insecticide had the greatest break‐even probabilities across all environments, although insect pressure was generally low across all site‐years. Soybean producers in North region are likely to realize a greater response from increased inputs, but producers across all regions should carefully evaluate adding inputs to their soybean management systems and ensure that they continue to follow the principles of integrated pest management.

Fusarium spp. are common fungal pathogens that infect a number of field and vegetable crops. Crop rotation, genetic resistance, and fungicides are the primary methods used for managing these pathogens; however, there is a lack of information regarding the interactions between these management strategies and how they impact Fusarium spp. population dynamics. Therefore, the objective of this research was to quantify the effect of crop rotation and management (i.e., variety selection and fungicide use) on F. graminearum, F. oxysporum, and F. virguliforme populations in the soil using real‐time quantitative polymerase chain reaction (qPCR). Soil samples were collected in 2011 and 2012 from a long‐term corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]–wheat (Triticum aestivum L.) rotation study near Arlington, WI, and populations for each species (spores g−1 of soil) were quantified from extracted soil DNA. Fusarium oxysporum was the most prevalent Fusarium sp. found. Crop rotation and management did not impact F. oxysporum populations nor F. virguliforme presence. A crop rotation by fungicide interaction was found for F. graminearum (P < 0.001), but this interaction was primarily affected by crop rotation. As expected, F. graminearum was found more often in plots with wheat as part of the rotation. This study found few interactions among crop rotation, variety selection, and fungicide use for controlling populations of three Fusarium spp. in the soil, and significant interactions or individual control methods were dependent on the species being examined.

Crop rotations involving corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are well‐known production systems across the Midwestern United States, but the addition of wheat (Triticum aestivum L.) in the rotation has received less attention. Additionally, the interactive effect of crop rotation with nitrogen (N) fertilizer and foliar fungicide application on yields for these three crops is not yet well understood. Data were collected in Wisconsin from a long‐term crop rotation experiment during 2013 to 2015 to measure corn (grain and silage), soybean, and wheat yield response to crop rotation frequency (seven rotations involving corn, soybean, and wheat), six levels of N, and foliar fungicide use. During the 3 yr of the experiment, minimal interactive effects were detected, which suggested that the examined management decisions can remain separate for growers in Wisconsin. Yearly crop rotation of corn and soybean increased corn grain yields in 2014 by 15 to 18% and soybean yields by 24 to 31% in 2015 compared with continuous cropping. No other crop rotation effect was observed. Fungicide use at the V5 growth stage for corn, at R3 for soybean, and at GS9 for wheat, increased wheat (7.4–16.8%) and soybean yield (3.6–5.4%) but not corn grain or silage yields. Nitrogen application was more beneficial for corn compared with wheat and soybean. The effect of N on soybean was similar across all rotations, and grain yields increased when N rate was higher than 100 kg ha−1. The data suggest that N rate recommendations should be based on crop needs, regardless the rotation system.

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Corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotations are common production systems across the midwestern United States. However, the interactive effect of crop rotation, tillage, and nematicide seed treatments on the yield of both crops in the rotation system is not well understood. Field trials were conducted in a long‐term crop rotation experiment during 2013 to 2015 to measure yield response of both corn and soybean to three factors: (i) tillage system (no‐till [NT] and conventional), (ii) crop rotation frequency (14 sequences involving corn and soybean), and (iii) three nematicide seed treatments (a control, abamectin/Pasteuria nishizawae, and Bacillus firmus). Rotations that involved consecutive years of soybean exhibited the greatest nematode populations in the soil, whereas, consecutive years of corn resulted in lower nematode populations. No significant differences in nematode populations were observed among the other examined management practices. Conventional tillage resulted in up to 18% greater corn and 10% greater soybean yield than NT. Yearly crop rotation increased corn yield by 20% and soybean yield by 22% compared with continuous cropping. Seed treatment nematicides had no effect on corn and soybean yield. The production system that involved yearly rotation of corn and soybean, regardless of tillage system and nematicide seed treatment, exhibited the greatest yield potential during the 3 yr of this study. Such rotation system using NT can be an attractive option for farmers in this region, since NT has reduced field operations and labor requirements.

Increased soybean [Glycine max (L.) Merr.] commodity prices in recent years have generated interest in high‐input systems to increase yield. The objective of this study was to evaluate the effects of current, high‐yielding cultivars under high‐ and low‐input systems on soybean yield and yield components. Research trials were conducted at 19 locations spanning nine states from 2012 to 2014. At each location, six high‐yielding cultivars were grown under three input systems: (i) standard practice (SP, current recommended practices), (ii) high‐input treatment consisting of a seed treatment fungicide, insecticide, nematistat, inoculant, and lipo‐chitooligosaccharide (LCO); soil‐applied N fertilizer; foliar LCO, fertilizer, antioxidant, fungicide and insecticide (SOYA), and (iii) SOYA minus foliar fungicide (SOYA‐FF). An individual site‐year yield analysis found only 3 of 53 (5.7%) site‐years examined had a significant cultivar × input system interaction, suggesting cultivar selection and input system decisions can remain independent. Across all site‐years, the SOYA and SOYA‐FF treatments yielded 231 (5.5%) and 147 kg ha–1 (3.5%) more than the SP, and input system differences were found among maturity groups. Yield component measurements (seeds m–2, seed mass, early‐season and final plant stand, pods plant–1, and seeds pod–1) indicated positive yield responses were due to increased seeds m–2 and seed mass. While both high‐input systems increased yield on average, grower return on investment (ROI) would be negative given today's commodity prices. These results further support the use of integrated pest management principles for making input decisions instead of using prophylactic applications to maximize soybean yield and profitability.

There is little peer‐reviewed information regarding prophylactic use of multiple inputs in soybean [Glycine max (L.) Merr.] production systems as a way to increase seed yield and profitability. Therefore, the objective of this study was to examine the effect of multiple inputs on soybean yield and quality in Wisconsin (WI). Two separate studies were established from 2011 to 2013. The inputs examined included: trait [first (RR1) and second (RR2Y) generation Roundup Ready traits], rhizobia inoculant, fungicide seed treatment, foliar fertilizer, foliar insecticide, and foliar fungicide. In the first experiment, main effects and up to three‐way interactions were evaluated; whereas in the second experiment, all inputs were combined in a high‐management (i.e., intensive) treatment. In the first experiment, soybean yield was not consistently increased due to the used inputs. Trait and foliar fungicide use were significant factors with variable effect on soybean seed yield in three and four of the nine location‐years, respectively. The foliar insecticide effect varied between traits in three location‐years. The (rhizobia inoculant + fungicide seed treatment) × foliar insecticide × foliar fungicide interaction was a significant factor in three of the nine location‐years. None of the examined factors significantly increased yield across all location–years. In the second experiment, high‐management, trait, and their interaction did not consistently increase soybean yield, nor improved seed quality characteristics. Overall, these results suggest that WI growers should continue to use university‐developed integrated pest management principles for making input decisions instead of relying on prophylactic input applications for maximizing soybean yield and profitability. No sole input or interaction consistently increased soybean yield across site‐years. Intensive management had inconsistent and minimal effect on soybean yield. Growers should not rely on prophylactic input applications to maximize soybean yield.