The Ogallala Aquifer, one of the largest freshwater aquifers in the world, supports 30% of U.S. crop and animal production, increases agricultural production by more than $12 billion annually, and impacts global food supplies. However, much of the Ogallala is rapidly declining and climate change will only compound this challenge.
We are collaborating with partners across Nebraska, Kansas, Oklahoma, New Mexico, and Texas, to develop practices, strategies and partnerships that optimize use of groundwater in the Ogallala Aquifer Region to sustain food production systems, rural communities and ecosystem services. Our research group will focus on the impact of soil management practices on ecosystem resilience and water use efficiency.
Dryland agriculture (i.e. non-irrigated crop production in arid and semi-arid regions) represents 44% of the global agricultural land area and more than 90% of wheat production in the United States. The spatial extent of dryland agriculture is anticipated to increase over time. In the Western U.S., large areas are experiencing reductions in available irrigation water due to climate change and the redirection of water to rapidly growing urban areas. Our long-term goal is to develop innovative cropping systems adapted to water-limited ecosystems that are resilient in the face of increased climatic variability. We are involved in several research projects designed to analyze the impacts of rotational diversity in dryland cropping systems on multiple ecosystem services.
- We are taking advantage of a cropping systems experiment established in 1985 and collaborations with the USDA-ARS Agricultural Systems Research Unit, to evaluate rotation legacy effects on soil properties that can influence susceptibility to wind erosion.
- In another project, we are integrating farmer interviews with on-farm soil sampling and spatial crop rotation analysis to evaluate the socioeconomic and political factors that influence farmer decision-making and adoption of diversified crop rotations and how rotations influence yield variability and soil physical properties.
- Integrating data from long-term cropping systems experiments, we are collaborating with the USDA-ARS Agricultural Systems Research Unit to intercompare agricultural systems models with a goal of improving their ability to simulate soil carbon and water dynamics under future climate scenarios.
We are collaborating with a diverse team of researchers, extension specialists, and producers across Colorado, Kansas and Nebraska to quantify the economic and soil quality trade-offs of different dryland cropping practices. In particular, we will be evaluating the potential of grazed forages and cover crop mixtures in different rotation scenarios. By rotating crops or integrating mixtures of grazed forage crops, farmers might reduce their long-term risk by improving the quality of their soil to the benefit all of the crops they plant. The challenge is in reducing short-term risk while managing the soil for longer-term benefits. Read more here.
Rhizosphere effects on carbon and nitrogen cycling
We are interested in understanding the mechanisms by which plant-soil-microbe interactions regulate nutrient cycling and applying this knowledge to improve nutrient use efficiency in agriculture. Research plots were nested within a cover crop research project in Pennsylvania to understand how rhizosphere dynamics influence carbon and nitrogen cycling. We are using stable isotope methods in a combination of greenhouse and field experiments to address the fundamental research question: Do plants mediate their own nitrogen supply through shifts in belowground carbon allocation? By integrating greenhouse and field experiments with modeling estimates, this research links rhizosphere carbon and nitrogen cycling mechanisms to their relative importance in agroecosystem and broader biogeochemical nutrient cycles.
Ecosystem services provided by cover crops
How beneficial are cover crops and what are the management constraints that limit their broader adoption? As a member of a multidisciplinary effort that involved postdocs, graduate students, and faculty, we sought to answer this question. Using quantitative models and semi-quantitative estimates, we estimated the temporal dynamics of 11 ecosystem services and two economic metrics when cover crops are introduced into a 3-year soybean–wheat–corn rotation in a typical Mid-Atlantic climate. We estimated that cover crops could increase 8 of 11 ecosystem services without negatively influencing crop yields. When we measure ecosystem services matters due to the episodic nature of some services and the time sensitivity of management windows. See the press release for more information.
We are collaborating on a field-based research project quantifying the ecosystem services provided by cover crops and cover crop mixtures within grain cropping systems in the Mid-Atlantic region. This research integrates ecological theories of biodiversity with real-world agronomic constraints and includes both research station and on-farm experiments. See the press release for more information: http://live.psu.edu/story/56088.
Managing organic cropping systems for multifunctionality
Other ongoing research is focused on understanding how to balance weed suppression, soil quality, beneficial arthropod conservation, and profitability in organic feed and forage cropping systems. In collaboration with a diverse team of scientists, This includes synthesizing the results from this 8-year cropping systems experiment using structural equation modeling and other multivariate statistical approaches. This research is funded by the USDA Risk Avoidance and Mitigation Program.
On-farm legume nitrogen fixation
Past research focused on the effects of soil fertility on legume nitrogen fixation. We utilized a management-induced fertility gradient across grain farm fields in the Finger Lakes region of New York to understand the relative importance of soil nitrogen availability and plant species interactions in regulating nitrogen fixation in annual and perennial legumes grown in mixtures and monocultures. This research was funded by USDA NRI, Land Institute Natural Systems Agriculture Graduate Fellowship, and small grants from the Cornell NSF IGERT in Biogeochemistry and Environmental Biocomplexity.
Agriculture’s impacts on global biogeochemical cycles
To link our field-scale research to broader social and economic contexts, we conducted an analysis of the role of international agricultural trade on global phosphorus flows as a postdoctoral scholar at McGill University in collaboration with Dr. Elena Bennett. This research highlighted the impact of increased global meat consumption and international trade on our ability to reduce nutrient losses from agricultural systems. Phosphorus presents a unique sustainability challenge because, unlike nitrogen, it is a non-renewable resource on any meaningful time scale for human management and mineable reserves are concentrated in a few geographic regions. A related collaborative project with colleagues from Brown University received some press.