People that worked on this project
- Sam Zipper, graduate student
- Eric Booth, Assistant Scientist
- Evren Soylu, Post-doc
- Erin Gross, undergraduate student
- Taylor Pomije, undergraduate student
- Galen Bergguist, undergraduate student
- Hannah Friedrich, undergraduate student
- Allie Lobue, undergraduate student
Research topics
- Agroecosystems
- Corn
- Modeling
- Evapotranspiration
- Yield gaps
High-Resolution Mapping of EvapoTranspiration (HRMET)
Quantifying agricultural water use is challenging but necessary for the sustainable management of water resources. Remotely sensed methods are able to provide spatially continuous information, providing a tool to map patterns in evapotranspiration (ET). However, existing mapping approaches struggle in high-resolution approaches relevant to precision agriculture due to relatively homogeneous canopy conditions within an image. To address this challenge, Zipper and Loheide (2014) developed a new land surface energy balance model, HRMET, which is capable of mapping ET at ~meter-scale spatial resolution using thermal imagery and basic meteorological data. We collected measurements of two corn fields throughout the 2012 growing season, which was characterized by severe drought in south-central Wisconsin, and used these data to map drought sensitivity at high spatial resolution.
The HRMET code is freely available online at https://github.com/szipper/HRMET
For more information: Zipper SC, SP Loheide II (2014). Using evapotranspiration to assess drought sensitivity on a subfield scale with HRMET, a high resolution energy balance model. Agricultural & Forest Meteorology 197: 91-102. DOI: 10.1016/j.agrformet.2014.06.009.
Separating groundwater and soil texture effects on yield
Maximizing crop yield while minimizing environmental impacts is the key goal to sustainably closing yield gaps. To achieve this, it is necessary to understand the physical controls on yield, and how different controls interact at fine spatial scales. Using the same two cornfields as above, we carried out a multiyear field and modeling study of groundwater levels and soil textural properties to quantify the drivers of yield differences in both wet and dry conditions. Our results showed that shallow groundwater can provide a significant source of water to crops during drought, but also contribute to yield losses due to excess moisture in the root zone during wet periods. The magnitude and critical groundwater depths controlling these relationships responded to both soil texture (coarser soils had bigger potential effects, but needed shallowed groundwater to benefit) and weather conditions (for a given soil, the optimum water table depth was deeper in wetter years).
For more information: Zipper SC, ME Soylu, EG Booth, SP Loheide II (2015). Untangling the effects of shallow groundwater and soil texture as drivers of subfield-scale yield variability. Water Resources Research 51(8): 6338-6358. DOI: 10.1002/2015WR017522.
Booth EG, SC Zipper, CJ Kucharik, SP Loheide II (2016). Is groundwater recharge always serving us well? Water supply provisioning, crop production, and flood attenuation in conflict in the Yahara River Watershed, Wisconsin, USA. Ecosystem Services, 21, Part A: 153-165. DOI: 10.1016/j.ecoser.2016.08.007
Zipper SC, J Qiu, CJ Kucharik (2016). Drought effects on US maize and soybean production: Spatiotemporal patterns and historical changes. Environmental Research Letters, 11(9): 094021. DOI: 10.1088/1748-9326/11/9/094021
Conceptual model showing relationship between yield, water table depth (WTD), soil texture, and weather. (Figure 1 from Zipper et al., 2015, WRR)
Indirect Agricultural Response to Urbanization
Due to the influence of groundwater on crop yield (above), we hypothesized that local changes in land cover which change the quantity of groundwater recharge (e.g. urbanization) could have indirect effects on agricultural productivity elsewhere in a watershed by changing the contribution of shallow groundwater to crop water supplies. To explore this question, we developed MODFLOW-AgroIBIS, a new model which couples the MODFLOW three-dimensional saturated groundwater flow model with AgroIBIS-VSF, a dynamic vegetation/agroecosystem model with the soil physics of HYDRUS-1D. Using this model, we explored a variety of land cover scenarios and found that urbanization in upland areas can propagate through groundwater flow to both increase and decrease crop yield elsewhere on the landscape, depending on the pre-urbanization baseline groundwater levels. Urbanization in the lowland areas, however, had a negligible effect on yield elsewhere due to stabilizing ecohydrological feedbacks.
For more information: Zipper SC, ME Soylu, CJ Kucharik, SP Loheide II (2017). Indirect groundwater-mediated effects of urbanization on agroecosystem productivity: Introducing MODFLOW-AgroIBIS (MAGI), a complete critical zone model. Ecological Modelling, 359: 201-219. DOI: 10.1016/j.ecolmodel.2017.06.002
Media, news stories, and blog posts
- UW-Madison study looks at crop benefits of higher water tables. Wisc. Ag Connection (link).
- Soil texture determine how groundwater and rain impacts crops. AGU Eos (link).
- Soggy not always a bad thing. Agri-View (link).
- High water tables impact crop yields. Wisconsin State Farmer (link).
- High water tables can be a boon to crop yields. Yahara In Situ (link).
- Thermal imagery to precision ag: understanding crop water needs. Yahara In Situ (link).
- WSC project video: https://www.youtube.com/watch?v=8rioHIKzkX8
Publications
Zipper SC, SP Loheide II (2014). Using evapotranspiration to assess drought sensitivity on a subfield scale with HRMET, a high resolution energy balance model. Agricultural & Forest Meteorology 197: 91-102. DOI: 10.1016/j.agrformet.2014.06.009.
Zipper SC, ME Soylu, EG Booth, SP Loheide II (2015). Untangling the effects of shallow groundwater and soil texture as drivers of subfield-scale yield variability. Water Resources Research 51(8): 6338-6358. DOI: 10.1002/2015WR017522.
Booth EG, SC Zipper, CJ Kucharik, SP Loheide II (2016). Is groundwater recharge always serving us well? Water supply provisioning, crop production, and flood attenuation in conflict in the Yahara River Watershed, Wisconsin, USA. Ecosystem Services, 21, Part A: 153-165. DOI: 10.1016/j.ecoser.2016.08.007
Zipper SC, J Qiu, CJ Kucharik (2016). Drought effects on US maize and soybean production: Spatiotemporal patterns and historical changes. Environmental Research Letters, 11(9): 094021. DOI: 10.1088/1748-9326/11/9/094021
Zipper SC, ME Soylu, CJ Kucharik, SP Loheide II (2017). Indirect groundwater-mediated effects of urbanization on agroecosystem productivity: Introducing MODFLOW-AgroIBIS (MAGI), a complete critical zone model. Ecological Modelling, 359: 201-219. DOI: 10.1016/j.ecolmodel.2017.06.002