ARS | Publication request: Linking Microbial-Scale Findings to Farm-Scale Outcomes

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 24, 2001
Publication Date: October 1, 2001
Citation: JOHNSON, C.K., DRIJBER, R., WIENHOLD, B.J., WRIGHT, S.E., DORAN, J.W. LINKING MICROBIAL-SCALE FINDINGS TO FARM-SCALE OUTCOMES. AGRONOMY ABSTRACTS. CD ROM #203241. 2001.

Interpretive Summary: Electrical conductivity (EC) mapping was evaluated as a basis for integrating microbial-, field-, and farm-scale data. A 250-ha farm, in a winter wheat-corn-proso millet-fallow rotation, was separated into four zones (ranges) of EC for soil sampling and wheat yield appraisal. Soil samples were assessed for vesicular-arbuscular mycorrhizae (VAM) using C16:1(cis)11 fatty acid methyl ester biomarker (C16vam), immunoreactive total (IRT) glomalin, and wet aggregate stability (WAS) techniques; soil edaphic properties were measured; and geo-referenced wheat yield maps were taken. Concentrations of IRT glomalin, soil properties associated with yield potential, and wheat yields were different (P=0.05) among EC zones and negatively correlated with EC. Negative correlations between C16vam and EC were detectable in the fallow treatments only. The C16vam and WAS measures distinguished among cropping treatments (fallow < wheat < corn < millet). Zones of EC provide a point of reference through which data collected at multiple levels of scale can be related. Monitoring system parameters and profitability over time will allow linkage of microbial-scale processes to farm-scale ecological and economic outcomes.

Technical Abstract: Electrical conductivity (EC) mapping was evaluated as a basis for integrating microbial-, field-, and farm-scale data. A 250-ha farm, in a winter wheat-corn-proso millet-fallow rotation, was separated into four zones (ranges) of EC for soil sampling and wheat yield appraisal. Soil samples were assessed for vesicular-arbuscular mycorrhizae (VAM) using C16:1(cis)11 fatty acid methyl ester biomarker (C16vam), immunoreactive total (IRT) glomalin, and wet aggregate stability (WAS) techniques; soil edaphic properties were measured; and geo-referenced wheat yield maps were taken. Concentrations of IRT glomalin, soil properties associated with yield potential, and wheat yields were different (P=0.05) among EC zones and negatively correlated with EC. Negative correlations between C16vam and EC were detectable in the fallow treatments only. The C16vam and WAS measures distinguished among cropping treatments (fallow < wheat < corn < millet). Zones of EC provide a point of reference through which data collected at multiple levels of scale can be related. Monitoring system parameters and profitability over time will allow linkage of microbial-scale processes to farm-scale ecological and economic outcomes.