Within-field variation of mycotoxin contamination of winter wheat is related to indicators of soil moisture

Abstract

Humidity is an important determinant of the mycotoxin production (DON, ZEA) by Fusarium species in the grain ears. From a landscape perspective humidity is not evenly distributed across fields. The topographically-controlled redistribution of water within a single field rather leads to spatially heterogeneous soil water content and air humidity. Therefore we hypothesized that the spatial distribution of mycotoxins is related to these topographically-controlled factors. To test this hypothesis we studied the mycotoxin concentrations at contrasting topographic relief positions, i.e. hilltops and depressions characterized by soils of different soil moisture regimes, on ten winter wheat fields in 2006 and 2007. Maize was the preceding crop and minimum tillage was practiced in the fields. The different topographic positions were associated with moderate differences in DON and ZEA concentrations in 2006, but with significant differences in 2007, with six times higher median ZEA and two times higher median DON detected at depression sites compared to the hilltops. The depression sites correspond to a higher topographic wetness index as well as redoximorphic properties in soil profiles, which empirically supports our hypothesis at least for years showing wetter conditions in sensitive time windows for Fusarium infections.

Mycotoxins in the Environment: I. Production and Emission from an Agricultural Test Field

“…In addition, the absolute amount of mycotoxins at harvest differed from plot to plot, as well as in between both years. Although largely deliberately provoked by artificial Fusarium infection, such variability is similar to the one taking place under natural conditions . Within all subfields and in both years of investigation, DON was by far the compound which was quantified with the highest concentrations of up to 133 mg/kg dw , followed by NIV (<12 mg/kg dw ), ZON (<7.4 mg/kg dw ), 3-AcDON (<3.1 mg/kg dw ), and BEA (<2.2 mg/kg dw ).…”

“…Although largely deliberately provoked by artificial Fusarium infection, such variability is similar to the one taking place under natural conditions. 25 Within all subfields and in both years of investigation, DON was by far the compound which was quantified with the highest concentrations of up to 133 mg/ kg dw , followed by NIV (<12 mg/kg dw ), ZON (<7.4 mg/kg dw ), 3-AcDON (<3.1 mg/kg dw ), and BEA (<2.2 mg/kg dw ). Again, while such concentrations certainly are high, they are not completely beyond what can be observed in practice.…”

Impact of aggressiveness of Fusarium graminearum and F. culmorum isolates on yield parameters and mycotoxin production in wheat

“…There is general agreement that air humidity, soil moisture and weather conditions at and after anthesis have the most important influence on the severity of Fusarium infection, disease development and mycotoxin production (Del Ponte et al 2007;Müller et al 2011). In this study, we investigated the impact of fungal inoculations on crop quality parameters over 2 years that were fundamentally different in climate.…”