|Pezeshki, S reza|
Submitted to: Society of Wetland Scientists
Publication Type: Abstract only
Publication Acceptance Date: 4/1/2007
Publication Date: 6/10/2007
Citation: Pierce, S.C., Pezeshki, S., Moore, M.T. 2007. Ditch plant productivity under variable flooding: a study of rice cutgrass. Society of Wetland Scientists 28th Annual Meeting [abstract]. p 23. Interpretive Summary: Abstract only. Interpretive summary not required.
Technical Abstract: Vegetated drainages are an effective method for removal of pollutants associated with agricultural runoff. Leersia oryzoides, a plant common to agricultural ditches, may be particularly effective in remediation; however, the responses of L. oryzoides to flooding are undocumented. The objective of this study was to characterize the responses of L. oryzoides to various soil moisture regimes representative of agricultural ditches. Treatments included: a well-watered and well-drained control; a continuously saturated treatment; a pulse-flood treatment that was flooded for 48 hours once a week; and a partially flooded treatment in which the water-level was maintained at 15 cm below the soil surface and was flooded to the soil surface for 48 hours once a week. Leaf gas exchange and soil redox potential (Eh, mV) at 10 and 30 cm depths were measured periodically for eight weeks. At the termination of the experiment, root and shoot length, and biomass were recorded. L. oryzoides showed decreases in photosynthesis when Eh dropped below +350 mV. Flooding led to decreased aboveground:belowground biomass ratios, with continuously saturated treatment having higher aboveground biomass than control (p=0.022), while having shallower rhizome penetration depth (p=0.017). Root penetration, depth, longest shoot, and belowground biomass were not affected by flooding (p=0.858, p=0.459, p=0.431, respectively). Results indicated that management practices resulting in an altered hydroperiod in agricultural ditches would minimally affect productivity except in circumstances where soil oxygen is depleted for an extended period.