By: Kathy Gehl Project Administrator/Extension eUpdate Editor, Kansas State University Department of Agronomy Research Staff; Peter Tomlinson, PhD Assistant Professor, Kansas State University Department of Agronomy
Midwestern row-crop agriculture is recognized as being highly productive, but is also cited for impairing surrounding ecosystems and impacting environmental quality. Water quality is a key metric utilized to characterize the health of an agricultural watershed. Therefore, it is important to know how new or alternative management practices impact water quality. With this in mind, the Kansas Agricultural Watershed (KAW) Field Laboratory was created in 2014 to study the effects of agricultural systems on water, sediment and nutrient losses. The goal of the KAW field lab is to evaluate and develop sustainable conservation practices that protect water quality, maintain yield and profitability and provide producers with flexible options for management of crops and nutrients.
The KAW Field Laboratory is a 22-acre site located in northeast Kansas. It consists of 18 small watersheds each roughly the size of a football field. A watershed is an area of land that drains all surface water to a common outlet (Fig. 1). Each watershed is equipped with a flume and automated instruments to measure runoff from natural rainfall and collect samples for water quality analysis. The site is also equipped with four automated rain gauges (Fig. 2).
Current Projects Current research at the KAW is focused on learning more about how water quality is impacted by methods of phosphorus fertilizer application and the integration of cover crops into a no-till corn – soybean production system. Phosphorus is essential for crop production, but when lost from fields it can cause problems in lakes and reservoirs. Cover crops are non-harvested crops grown for the protection and enrichment of the soil (Fig. 3 and 4). They can be beneficial to the environment and farmers in a variety of ways including reducing loss of soil by erosion, improving soil quality and suppressing weeds. Dr. Nathan Nelson, the project leader, said “toxic algae blooms in reservoirs are partially caused by phosphorus in runoff. We are developing best management practices (BMPs) that producers can implement to reduce runoff and phosphorus loss.” Understanding how management decisions affect runoff, phosphorus loss and soil health are overarching themes of this research (Fig. 5).
Project 1: Minimizing Phosphorus Loss with 4R Stewardship and Cover Crops
The goals of this project are to improve our understanding of how phosphorus fertilizer management and cover crops can help protect water quality and maximize nutrient use efficiency. The results are advancing 4R nutrient stewardship recommendations: applying the Right fertilizer source at the Right rate at the Right time and in the Right place. Specific research questions that the team is answering include:
How does phosphorus loss from fall surface-applied fertilizer compare to phosphorus loss from spring injected fertilizer, the current recommended BMP? Will cover crops reduce phosphorus losses and does this depend on the method and timing of phosphorus fertilizer application? What are the agronomic, environmental and economic effects of winter cover crops in a no-till corn-soybean production system?
Project 2: Protecting Surface Water with Healthy Soils and Cover Crops:
The goals of this project are to help us understand how improvements in soil health can influence water, sediment and nutrient losses. Dr. Nelson recently reported at the Agronomy department Field Day that, “total runoff has not changed but cover crops are reducing the peak runoff and extending the duration of runoff for most events compared to the no-till plots without cover crops.” The research team has also begun to quantify impacts of cover crop use on soil health parameters by measuring different physical, chemical and biological indices in the soil.
As part of this project, the KAW was expanded to include an on farm demonstration study with a co-operating producer where we are measuring many of the same parameters.
Staying up-to-date on the KAW
You can stay up-to-date on current research findings at the KAW by visiting the project website at http://www.k-state.edu/kaw/. The website includes additional information about the current projects as well as presentations and publications from the ongoing research.
The KAW field laboratory research team is led by Dr. Nathan Nelson, professor in the Agronomy department at Kansas State University. Other K-State team members include Drs. Kraig Roozeboom, Gerard Kluitenberg, Peter Tomlinson and DeAnn Presley from the Agronomy department and Dr. Jeff Williams from the Agriculture Economics department. Research at the KAW field lab is funded by the 4R Research fund, the USDA Natural Resource Conservation Service, the Kansas Soybean Commission, the Kansas Corn Commission and Kansas State University.