Water quality and soil nutrient availability trade-offs associated with timing and duration of managed flooding for migratory waterbird habitat

Authors: Chatterjee, Amitava; Taylor, Jason; Read, Quentin; Moore, Matthew; Locke, Martin; HOEKSEMA, JASON - University Of Mississippi

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2025
Publication Date: 5/25/2025
Citation: Chatterjee, A., Taylor, J.M., Read, Q.D., Moore, M.T., Locke, M.A., Hoeksema, J.D. 2025. Water quality and soil nutrient availability trade-offs associated with timing and duration of managed flooding for migratory waterbird habitat. Soil Science Society of America Journal. https://doi.org/10.1002/saj2.70077.
DOI: https://doi.org/10.1002/saj2.70077

Interpretive Summary: In Mississippi, winter flooding of farmland to establish winter grounds for migrating birds is a common practice. However, the possible consequences of low oxygen level due to flooding on soil properties are not well known. Across three farms, the effects of five flood treatments (no flooding, passive rainfall capture, fall-, winter- and fall through winter flooding) on soil properties and enzyme activities were studied. Most soil properties, including pH, total soil carbon and nitrogen, and inorganic nitrogen, increased from pre-flooding to post-flooding time, but relative increases were not greatly influenced by flood treatments. Soil available phosphorus declined due to flooding compared to without flooding within the 0-5 cm soil depth. These results showed that besides available phosphorus, flooding did not make any major changes in soil properties. These results will be useful to promote the adoption of winter flooding in the Lower Mississippi River Basin. Findings could be of interest to growers and scientists managing winter flooding of farmland for migratory waterbird habitat.

Technical Abstract: In Mississippi, winter flooding of cropland to establish migratory waterfowl habitat is a common practice for enhancing agroecosystem properties. More recently the practice has been implemented during fall months to also provide habitat for threatened migratory shorebirds. However, the possible consequence of anoxic environment created by flooding to soil biogeochemical properties are not well known. Influences of fall and/or winter flooding on carbon (C), total and inorganic soil nitrogen (N), Mehlich 3- extractable nutrients including phosphorus (P) and exoenzyme activities including ß- glucosidase (BG) and ß-N-acetyl-glucosaminidase (NAG) were compared before (October) and after (February) flooding between five flood treatments distributed across three farms. Treatments included: (i) control or no flooding (CT), (ii) passive rainfall capture (P), (iii) fall (F)-, (iv) winter (W)- and (v) fall through winter (FW) flooding, which were all facilitated by pumping leftover irrigation water collected in tailwater recovery systems. Soil properties and enzyme activities were more influenced by soil sampling time than flooding management, and their interactions had little effect. Most soil properties including pH, total -soil C and -N, and inorganic N increased from pre-flooding to post-flooding time periods but relative increases were not greatly influenced by flood treatment. Interactions between flooding and sampling time had significant influences on Mehlich 3-P, -Mn and activities of BG and NAG enzymes within 0-5 cm depth. We observed a decrease in Mehlich 3-P in FW (P=0.007) which was significantly different from CT; all other treatments were not different than CT fields within 0-5 cm depth. Among enzymes, AS and NAG increased but FDA decreased after flooding but there were no significant interactions for these enzymes. NAG enzyme activities increased in P treatments which were significantly different from CT, but all other treatments had similar responses to CT fields for NAG. We can conclude that winter flooding did not induce significant transitions in soil properties and substrate distributions as evidenced by enzyme activities in the Lower Mississippi River Basin.