AgroPages-Researchers eye cover crops, fertilizer to boost water quality-Agricultural news

Steady rains that peppered much of Kansas in early December may have caused inconveniences for travelers and shoppers, but they were a blessing of sorts for Nathan Nelson.

Nelson, an associate professor of agronomy at Kansas State University, oversees the Kansas Agricultural Watershed field laboratory, an expansive project south of Manhattan to measure the effects of agricultural production systems on surface water.

The approximately 30 acres of research land is dissected into 18 field plots, each about the size of a football field. Researchers are learning more about what happens to phosphorus and nitrogen – two nutrients common to agricultural crop fertilizers – when rainwater snakes it way to local streams and rivers.

Kansas’ reservoirs have recently felt the pain of poor water quality, many due to chronic algal blooms. Over the last 15 years, city and state officials have increasingly been forced to close public waterways to recreation and fishing due to health concerns.

Nelson noted that poor water quality also affects nearby land values, and when cities pay more to clean up that water, it ultimately means a bump in the homeowner’s water bill. All of these issues affect the local economy.

The project that Nelson leads aims to do just that, so long as Mother Nature cooperates with rainfall that allows his research team to replicate field conditions. Currently, his team is testing corn and soybean fields in which fertilizer was applied in spring, fall or not at all; and with or without a cover crop planted after the main crop.

Cover crops are often planted as a winter crop to manage soil erosion and improve soil fertility. They may also help decrease weeds, pests and diseases in the field.

The early research also leaned favorably toward the value of cover crops as a best management practice to reduce phosphorus loss from broadcast-applied fertilizer.

Even so, data is sparse, and Nelson continues collecting data to determine long-term impacts of these practices. The research team also is working to determine the effects of tillage systems and rainfall events at different times of year, and how these findings vary across the state.