Maize and soybean root growth and distribution in the United States corn belt

When December 11, 2020, 12:20 PM - 1:10 PM

Where Zoom Online

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Quantitative root data are imperative to fully understand cropping systems and the interactions between soils, roots, crops and weather, but such data are not abundant. In attempt to close knowledge gaps of maize and soybean root growth, we carried out multiple field trials covering ten sites, four weather years (2016–2019), water management (rainfed, irrigated, and fields with subsurface tile-drainage), and N fertilizer rates (0 to 336 kg N ha-1) across Iowa. Results indicated that the environment (site-year) had a strong effect on both plant and root traits. Root to shoot ratios in maize ranged from 0.04 to 0.13 and in soybean from 0.09 to 0.26. Maize and soybean allocated about 75% of the total root mass and length in the top 60 cm soil profile, and it takes about 700 days to decompose 90% of the initial root mass. Root mass, length, and maximum depth were affected by the depth to water table, in contrast to what is known to restrict root growth in other states with well-drained soils like Pennsylvania (PA). In addition to root research efforts in Iowa, I will present preliminary results on maize and soybean yield components from a series of experiments in PA.  Using these data, it is feasible to detect low to high productivity zones across PA by using root depth, crop planting area and GIS techniques. The developed root and shoot information across both regions (Midwest and Mid-Atlantic) can assist crop model calibration and improvements, agronomic assessments and breeding efforts in these regions.