1a. Objectives (from AD-416):
We hypothesize that, relative to uniform management systems, precision zonal management systems change both physical and microbiological processes so as to substantially increase N- and water-use efficiency, improve soil C storage, and maintain high yield potential under more variable climate conditions. Our long-term goal is to understand the functional agroecology of precision zonal management systems that build upon current precision farming approaches (e.g. GPS guidance, variable rate fertilizer/agrochemical applications) to create highly resilient and sustainable field crop production systems. Our objective in this project is to advance understanding of physical processes and plant-soil microbial interactions that are the basis of functional differences between active-turnover and soil-building zones biology, and to examine the implications of these processes for resilience and adaptation to variable climates in cereal production systems.
1b. Approach (from AD-416):
To address our hypothesis, we will: 1) characterize microbial communities in -turnover and soil-building zones, using state-of-the-art molecular techniques, 2) assess key soil functional properties, including C cycling and storage, N- and water-use efficiency, and 3) quantify soil attributes that are functionally important to the resilience of high yield under variable climates, including water storage and infiltration, soil aggregation, organic matter dynamics, and pathogen suppression. We will utilize field-based, experiments in precision zonal-management cereal systems that use cover crops and carefully targeted tillage (e.g., ridge-till/cover-crop maize production systems). We will study both newly-initiated zonal systems, and more mature systems, over a range of soil and climatic conditions. We will integrate our findings in a decision tool to enable predictions of the functioning of precision zonal management systems under variable climates and plant/tillage/microbial interactions. To extend our detailed benchmark studies on research and ‘elite’ farms, we will further evaluate and refine zonal management via collaboration with farmers who are experimenting with transition to zonal management systems.
3. Progress Report:
This large, multi-state, multi-investigator project has required much organizational effort to perform field studies in a coordinated fashion over the five-year period of the project. The ARS scientist and cooperators meet annually at one of the participating sites, and coordinate through bi-weekly conference calls and emails. Data from the first season have been compiled and analysis begun; one article has already been submitted from these data. The second field season is underway, and both the establishment of agronomic treatments and data collection have been progressing very smoothly. The occurrence of extreme drought in 2012 and flooding in 2013 have already offered a challenging test of one of the central hypotheses of the study: that management of soil physical and biological properties through tillage and organic residue management can buffer cereal crop yields against highly variable weather events.