Project ID

XP2016-19

Abstract

The goal of this project was to stimulate farmer consideration of “retiring” farmed potholes into land cover that both improves water quality and saves money. This was accomplished by measuring key pothole and plant production metrics, modeling pothole hydrology, plant productivity and profitability under alternative management (farmed vs. perennial cover), and informing stakeholders with outreach partners. Instrumentation and data collection for the 2016-18 seasons was completed at seven potholes, six of which are in conventionally farmed fields, the seventh is in the Conservation Reserve Program. Primary data collection was: depth of ponded water versus time (hourly) for mid-May through late October; water quality samples on days with sufficient ponding to collect a sample; and periodic measurements of crop canopy (leaf area index) and biomass (destructive samples). These data were used both to understand the behavior of these features with respect to hydrology and water quality, and to parameterize and assess the performance of hydrology and crop growth models. Stakeholder outreach allowed us to share our findings with a variety of audiences including farmers/producers and extension specialists.

Key Question

Does Increasing Landscape Diversity in Farmed Closed Depressions (Potholes) Increase Profitability and Ecosystem Services?

Findings

All of the potholes we monitored flooded multiple times during our monitoring. Subsurface drainage, even with surface inlets, reduced the likelihood and duration of flooding, but did not eliminate the risk of crop failure. Wet conditions, even without flooding, negatively impacts crop development and yield. The effect of excess-water stress can be simulated with a crop growth model with a drown-out function added. Standing water in the potholes has high nitrate concentration under early season “first flush” conditions, but is negligible thereafter. Concentrations of total phosphorus and dissolved reactive phosphorus were higher than expected, and increased over the course of inundation events. Farmed potholes may contribute to P export through tile drain systems, especially where there are surface inlets.

Principal Investigator(s)

Amy Kaleita

Co-Investigator(s)

Any VanLoocke; Michelle Soupir; Emily Heaton

Year of Grant Completion

2018

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