Low external input sustainable agriculture: Winter flooding in rice fields increases bird use, fecal matter and soil health, reducing fertilizer requirements

Authors: FIRTH, ALEXANDA - Mississippi State University; BAKER, BETH - Mississippi State University; Brooks, John; Smith, Renotta; IGLAY, RAYMOND - Mississippi State University; DAVIS, BRIAN - Mississippi State University

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2020
Publication Date: 5/15/2020
Citation: Firth, A.G., Baker, B., Brooks, J.P., Smith, R.K., Iglay, R.B., Davis, B.J. 2020. Low external input sustainable agriculture: Winter flooding in rice fields increases bird use, fecal matter and soil health, reducing fertilizer requirements. Agriculture, Ecosystems and Environment. 300. https://doi.org/10.1016/j.agee.2020.106962.
DOI: https://doi.org/10.1016/j.agee.2020.106962

Interpretive Summary: Rice is a staple of food consumption across the world; as such, its production requires a large amount of land and sustainable production is necessary to further protect the environment as well as maintain productivity. The current study investigated sustainable rice production using annual flooding to create waterbird habitat as a benefit to soil quality compared with conventional production systems. Flooding occurs in the winter, thus allowing for waterbirds to establish habitats, thus depositing fecal matter as well as further the breakdown of rice stubble. Soil biological activity and group members were quantified as well as nutrient levels. Overall, numbers suggested that flooded fields, with greater waterbird activity, had higher levels of nutrients as well as biological activity. Some microbial groups indicated that fecal depositions were greater in flooded fields, while bird monitoring stations also indicated flooded fields were greater in bird activity. Results indicated that long term use of flooded fields has potential to reduce the need for nitrogen fertilization, by as much as 1/3, while potentially doubling soil organic matter.

Technical Abstract: Rice is the staple food for over half of the world’s population and is able to support more people per unit of land area as that of wheat or corn, because rice produces more food energy and protein per hectare than other cereal grains. Because the human population is estimated to reach 8.5 billion by 2030, major concerns about the sustainability of rice production practices have emerged because of the crop’s impact on water pollution and soil degradation. These circumstances create need to identify sustainable production practices that minimize environmental damage, but also maintain economic viability for producers. This study investigated a potentially sustainable rice production system in the Mississippi Alluvial Valley (MAV) that uses ecological principles to enhance environmental quality and economic gain at the field scale. It was hypothesized that the annual flooding of rice fields to create waterbird habitat would benefit soil health and subsequently water runoff, thereby providing dual agronomic and environmental benefits to the producer. Two rice farms that applied different management regimes during the winter were selected for study: those having conventional fallow and winter flooded fields. Soil microbial richness/activity and nutrient content were quantified and compared for a measure of overall soil health. Measured soil health variables linked flooded fields and high bird activity with more nutrient and microbial activity than those without. Results showed long term application of the unique system has the potential reduce nitrogen fertilizer inputs by as much as 1/3 and double soil organic carbon. Evidence from the investigation provided justification for future research, to develop a framework for other producers within the MAV to adopt similar management methods, ultimately improving the overall integrity of soil, water, and environmental quality as well as the farmer lifestyle.