Our primary goal here is to answer the question (and title of the proposal): do soil health promoting practices make soybean production more climate resilient?

We will leverage the ISA-funded (FY 2022) precipitation exclusion, application systems (PEAS) to test specifically soybean physiological response to future climate scenarios. Climate models predict wetter springs (>15 %) and more variable summer precipitation that will include more droughty summers (NOAA National Climate Assessment, 2023). Our intent is to add 20% precipitation to ambient rainfall between months of April through June 21, and thereafter remove 50% precipitation until end of September. This will simulate a ’worse-case’ future precipitation (FP) scenario with wetter springs making it more difficult to get in the field, and drier summer mimicking soybean-limited soil moisture conditions that may occur more frequently in the future. We will have an ambient precipitation (AP) and FP sub-plots within a long-term (22 years), randomized, replicated trial crop rotation experiment – the Marsden Agricultural Diversity Experiment (MADE) – that has three rotations: corn-soybean plus synthetic N fertilizer (2-year), corn-soybeans-oat/redclover (3-year), and corns-soybean-oat/alfalfa-alfalfa plus composted cattle manure (4-year). Prior research from PI-McDaniel’s group, Soil Health Institute, and others have documented the many soil health benefits from the 4-year rotation compared to the 2-year. We will focus on comparing whether these increases in soil health translate to more climate resilience in 4-year rotation compared to the 2-year. In other words, does improving soil health buffer soybean yields against these changes in precipitation?

1. Determine if long-term adoption of soil health promoting practices (e.g., diversified crop rotations and manure) increase soybean resilience to drought.

2. Determine effects of future precipitation in Iowa - wetter springs drier summer - affects soils and crops more generally.

- Peer-reviewed publications
- Field days
- Extension/outreach presentations
- Contacts with farmers using similar practices

Springs are getting wetter and summer precipitation is more variable making growing soybeans more difficult for farmers.
Wetter springs reduce the days of operation and drier summers can hinder crop yields.

We're testing whether long-term management - in this case including small grains and forages plus animal manure as source of nutrients - can help buffer some of these changes.