Can trees aid in nutrient management in the Lower Mississippi Alluvial Valley?

By: Vanessa Beeson

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Posted: 2/8/2021

Can trees aid in nutrient management in the Lower Mississippi Alluvial Valley? Photo By: Submitted

A first-generation forester from Myanmar is trying to help improve water quality in the Lower Mississippi Alluvial Valley.

The Lower Mississippi Alluvial Valley, or LMAV, consists of 25 million acres spanning seven states. This floodplain is responsible for draining 40 percent of the contingent United States. The LMAV is home to forested and wetland habitat critical to native and migrating wildlife and birds. The area is also home to some of the country's richest agricultural lands. Over the last several years, nutrients from agricultural production have degraded water quality in the region impacting the tributaries that flow into the Mississippi River and down to the Gulf of Mexico.

As part of his doctoral dissertation, Tu Ya Kyaw focuses on improving water quality in the LMAV. Kyaw, works under the direction of Dr. Heidi Renninger, assistant professor; Dr. Courtney Siegert, associate professor; and Dr. Randall Rousseau, extension and research professor, all in the Department of Forestry and scientists in the Forest and Wildlife Research Center.

The team has set up a plantation in Sidon consisting of short rotation woody crops (SRWCs) between agricultural fields and waterways in a riparian area in the Mississippi Delta of the LMAV. Another SRWCs plantation will be established in Satartia, which is also part of the Mississippi Delta. The project, which will conclude in 2022, will evaluate several genotypes of three tree species such as willow, eastern cottonwood, and sycamore to see if they help mitigate the nitrogen moving into the watershed. They planted 300 trees each of willow and cottonwood in June 2018, and open-pollinated sycamore families were planted during fall 2019. They will assess the ecosystem services the plants provide including their ability to remove nitrogen from the soil. Additionally, the team will evaluate the productivity of the trees, as potential revenue of woody biomass on lands adjacent to agriculture. The sites were selected because they are marginal lands where conventional agriculture is less profitable because of seasonal flooding and low water availability in the summer and fall. Researchers hope to identify species and genotypes that farmers can plant on lands like this as a potential source of extra income.

"If we plant trees between agricultural lands and the river, our hypothesis is that if the nutrients have to pass through our plantation, our trees will absorb the nutrients, diminishing runoff into the river. We are trying to remove the excess nitrogen from the system to improve water quality," Kyaw said.

Kyaw continued, "We hope to identify specific genotypes of these species that can achieve superior productivity on marginal lands in this region while also providing optimal water use and nitrogen efficiency."

Kyaw earned an undergraduate degree in forestry from the University of Forestry and Environmental Science in Myanmar in 2012. For the next four years, he worked for the Myanmar Forest Department as a range officer. After that, in 2016, Kyaw was one of ten candidates in the country selected by the Fulbright Foreign Student Scholarship Program to pursue a master's degree abroad. Kyaw chose to earn a master's in forest and natural resources management at the State University of New York College of Environmental Science and Forestry (SUNY ESF) in Syracuse, New York. After completing that degree, he came to MSU for his doctoral studies.

Kyaw said this particular project is exciting for two reasons—one because the study itself is unique and two because it gives him exposure to so many different areas of expertise.

"I will be excited to see which species and genotypes are best suited when it comes to excess nitrogen removal, water use efficiency and biomass production, the combination of which hasn't yet been researched extensively in the U.S.," Kyaw said. "This project is also professionally interesting to me because I get to learn about hydrology, chemistry, soils and plant physiology. Simultaneously, I am attempting to integrate hyperspectral remote sensing, spatial analysis and programming knowledge into the project. After this, I will have skills in a lot of different areas. At the end of the project, I can define myself as a computational ecologist."

This research is funded by the MSU Forest and Wildlife Research Center and is based upon work that is financially supported by the Agriculture and Food Research Initiative [#2018-67020-27934] from the U.S. Department of Agriculture's National Institute of Food and Agriculture.