TY  - JOUR
T1  - Nonlinear groundwater influence on biophysical indicators of ecosystem services
JF  - Nature Sustainability
Y1  - 2019
A1  - Qiu, Jiangxiao
A1  - Zipper, Samuel C.
A1  - Motew, Melissa
A1  - Booth, Eric G.
A1  - Kucharik, Christopher J.
A1  - Loheide, Steven P.
AB  - Groundwater is a fundamental control on biophysical processes underpinning essential ecosystem services (ES). However, interactions and feedbacks among groundwater, climate and multiple ES remain less well understood. We investigated groundwater effects on a portfolio of food, water and biogeochemical ES indicators in an urbanizing agricultural watershed. Our results show that food production, water quality and quantity, and flood control are most sensitive to groundwater, with the strongest responses under wet and dry climate extremes. Climate mediates groundwater effects, such that several ES have synergies during dry climate, but trade-offs (groundwater increased some ES but declined others) under wet climate. There is substantial spatial heterogeneity in groundwater effects on ES, which is driven primarily by water table depth (WTD) and is also sensitive to soil texture and land cover. Most ES indicators respond nonlinearly to WTD when groundwater is within a critical depth (approximately 2.5 m) of land surface, indicating that small WTD changes can have disproportionately large effects on ES in shallow groundwater areas. Within this critical WTD, increasingly shallow groundwater leads to nonlinear increases in surface flood risk, sediment erosion and phosphorus yield; nonlinear decreases in drainage to the deep vadose zone and thus groundwater recharge; and bidirectional responses of crop and grass production, carbon storage and nitrate leaching. Our study illustrates the complex role of groundwater in affecting multiple ES and highlights that strategically managing groundwater may enhance ES resilience to climate extremes in shallow groundwater settings.
SN  - 2398-9629
UR  - https://doi.org/10.1038/s41893-019-0278-2
JO  - Nature Sustainability
ER  - 

TY  - JOUR
T1  - Nitrogen Fertilization Effects on Productivity and Nitrogen Loss in Three Grass-Based Perennial Bioenergy Cropping Systems
JF  - PLoS ONE
Y1  - 2016
A1  - Duran, Brianna E. L.
A1  - Duncan, David S.
A1  - Oates, Lawrence G.
A1  - Kucharik, Christopher J.
A1  - Jackson, Randall D.
AB  - <p>Nitrogen (N) fertilization can greatly improve plant productivity but needs to be carefully managed to avoid harmful environmental impacts. Nutrient management guidelines aimed at reducing harmful forms of N loss such as nitrous oxide (N<sub>2</sub>O) emissions and nitrate (NO<sub>3</sub><sup>-</sup>) leaching have been tailored for many cropping systems. The developing bioenergy industry is likely to make use of novel cropping systems, such as polycultures of perennial species, for which we have limited nutrient management experience. We studied how a switchgrass (<italic>Panicum virgatum</italic>) monoculture, a 5-species native grass mixture and an 18-species restored prairie responded to annual fertilizer applications of 56 kg N ha<sup>-1</sup> in a field-scale agronomic trial in south-central Wisconsin over a 2-year period. We observed greater fertilizer-induced N<sub>2</sub>O emissions and sub-rooting zone NO<sub>3</sub><sup>-</sup> concentrations in the switchgrass monoculture than in either polyculture. Fertilization increased aboveground net primary productivity in the polycultures, but not in the switchgrass monoculture. Switchgrass was generally more productive, while the two polycultures did not differ from each other in productivity or N loss. Our results highlight differences between polycultures and a switchgrass monoculture in responding to N fertilization.</p>
VL  - 11
UR  - http://dx.doi.org/10.1371%2Fjournal.pone.0151919
IS  - 3
ER  -