|Pezeshki, S reza|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/25/2007
Publication Date: 8/1/2007
Citation: Pierce, S.C., Pezeshki, S., Moore, M.T. 2007. Ditch plant response to variable flooding: a case study of leersia oryzoides (rice cutgrass). Journal of Soil and Water Conservation, 62(4):216-225. Interpretive Summary: Vegetation in agricultural drainage ditches act as filters for contaminants leaving the production landscape. These ditches have varying levels of water in them throughout the year, and little is known about the stress that may cause on the ditch vegetation. This study was designed to characterize the responses of a common grass found in ditches to soil moisture contents ranging from well-drained to saturated. No significant effect on plant productivity or root development was noted among the different soil moisture regimes, although biomass ratios were reduced in the flooded soils. This is important information when designing ditches for agricultural contaminant mitigation, especially those with unpredictable water regimes.
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 the remediation process; however, responses of L. oryzoides to flooding are undocumented. The objective of this study was to characterize responses of L. oryzoides to various soil moisture regimes representative of agricultural ditches, including four treatments ranging from well-drained to saturated. Over the eight weeks of the study, L. oryzoides showed decreases in photosynthesis only when Eh dropped below +350 mV. Although flooding reduced belowground:aboveground biomass ratios, overall productivity and root development was unaffected. Results indicated that management practices increasing retention time in agricultural ditches would not reduce productivity in L. oryzoides except in circumstances where soil oxygen was depleted for periods of several days to weeks.