Soil water holding capacity mitigates maize production downside risk and volatility across the US Corn Belt: Time to invest in soil organic matter?

Authors: WILLIAMS, ALWYN - University Of Minnesota; HUNTER, MITCHELL - Pennsylvania State University; JORDAN, NICHOLAS - University Of Minnesota; KAMMERER, MELANIE - Pennsylvania State University; KANE, DANIEL - Yale University; SMITH, RICHARD - University Of New Hampshire; SNAPP, SIEGLINDE - Michigan State University; Davis, Adam

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2016
Publication Date: 8/25/2016
Citation: Williams, A., Hunter, M.C., Jordan, N.R., Kammerer, M., Kane, D.A., Smith, R.G., Snapp, S., Davis, A.S. 2016. Soil water holding capacity mitigates maize production downside risk and volatility across the US Corn Belt: Time to invest in soil organic matter?. PLoS One. 11(8):e0160974.

Interpretive Summary: Climate change models predict increases in extreme weather over the coming decades (e.g., rising summer temperatures, more intense droughts, and greater frequency of severe rainfall events), with negative consequences for agricultural productivity and yield stability. Expected changes in annual rainfall patterns and evapotranspirative demand are forecast to increase drought frequency in many regions, highlighting the importance of soil water supply to successful crop production. In response, some have advocated changes to agronomic management that improve soil attributes (e.g., increasing organic matter to increase soil water holding capacity, WHC), under the assumption that improvements in these attributes will help buffer crop yields against climate variability. To support regional climate adaptation strategies, we present a novel synthesis of extensive weather and soil data to quantify their joint impact on county-level maize yield stability from 2000-2014 in four states across the US Corn Belt (Illinois, Michigan, Minnesota and Pennsylvania). Yield stability is quantified as both ‘downside risk’ (minimum yield potential, MYP) and ‘volatility’ (temporal yield variability). High average daily maximum temperatures decreased yield stability while increasing precipitation increased stability. Soil water holding capacity reduced yield volatility directly and also increased MYP, thus constraining yield volatility. These soil attributes help buffer maize yields against variable weather. Within limits imposed by pedogenic processes, soils respond to agronomic management, highlighting regional opportunities for agricultural climate adaptation.

Technical Abstract: Protecting global food security from predicted declines in yield stability will be aided by improved understanding of how agricultural soil management may buffer yields against increased weather variability. To support regional climate adaptation strategies, we present a novel synthesis of extensive weather and soil data to quantify their joint impact on county-level maize yield stability from 2000-2014 in four states across the US Corn Belt (Illinois, Michigan, Minnesota and Pennsylvania). Yield stability is quantified as both ‘downside risk’ (minimum yield potential, MYP) and ‘volatility’ (temporal yield variability). High average daily maximum temperatures decreased yield stability while increasing precipitation increased stability. Soil water holding capacity reduced yield volatility directly and also increased MYP, thus constraining yield volatility. These soil attributes help buffer maize yields against variable weather. Within limits imposed by pedogenic processes, soils respond to agronomic management, highlighting regional opportunities for agricultural climate adaptation.