Feedbacks between irrigation and climate from field to regional scales in the Midwest US
Abstract
Irrigated land use is growing in the Midwest United States (US) and there is a need for actionable information to understand irrigation-induced climate change in this temperate, humid region. The Wisconsin Central Sands is a heavily irrigated area in the Midwest US where groundwater from an unconfined aquifer supports intensive production of potatoes, vegetables, and maize on coarse soils. Our goal was to quantify irrigation-induced climate change and better understand its underlying biophysical mechanisms in the Wisconsin Central Sands. At the regional scale, we used monthly groundwater withdrawals reported by tax parcel, a LANDSAT-derived land cover database (WISCLAND 2.0), USDA National Resource Conservation Service (NRCS SSURGO) soils data, and a 60-km transect of 28 temperature and relative humidity sensors operational for 31 months between 2014-2016. At the field scale, we installed 16 temperature and relative humidity sensors, three irrigation gauges, and a meteorological station on a single irrigated potato agroecosystem (26 ha). Field-scale irrigation events created a transient (~1-2 hour) reduction in temperature and increase in relative humidity. Regionally, we found that irrigated agriculture decreased maximum temperatures, increased minimum temperatures, thus decreasing the diurnal temperature range by an average of 3° C compared to surrounding rainfed agricultural lands and forests both during and outside of the growing season. Irrigated agriculture also decreased reference evapotranspiration and the vapor pressure deficit, but these impacts were most pronounced during the growing season. We demonstrate that combining field-scale and regional observations can provide a more mechanistic understanding of irrigation-induced climate changes important for weather forecasting, pest and disease ecology, regional planning, and agricultural extension efforts.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B23B..01N
- Keywords:
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- 0402 Agricultural systems;
- BIOGEOSCIENCES;
- 0495 Water/energy interactions;
- BIOGEOSCIENCES;
- 1842 Irrigation;
- HYDROLOGY;
- 1855 Remote sensing;
- HYDROLOGY