Macronutrient (N, P, K) and Redoximorphic Metal (Fe, Mn) Allocation in Leersia oryzoides (Rice Cutgrass) Grown Under Different Flood Regimes

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, research characterizing responses of L. oryzoides to flooding are limited. Soil reduction resulting from flooding can change availability of nutrients to plants via changes in chemical species (e.g., increasing solubility of Fe). Additionally, plant metabolic stresses resulting from reduced soils can decrease nutrient uptake and translocation. The objective of this study was to characterize belowground and aboveground nutrient allocation of L. oryzoides subjected to various soil moisture regimes. Treatments included: a well-watered and well-drained control; a continuously saturated treatment; a 48-h pulse-flood treatment; and a partially flooded treatment in which water level was maintained at 15 cm below the soil surface and flooded to the soil surface for 48 h once a week. Soil redox potential (Eh, mV) was measured periodically over the course of the 8-week experiment. At experiment termination, concentrations of Kjeldahl nitrogen, phosphorus (P), potassium (K), iron (Fe), and manganese (Mn) were measured in plant tissues. All flooded treatments demonstrated moderately reduced soil conditions (Eh < 350 mV). Plant Kjeldahl nitrogen concentrations demonstrated no treatment effect, whereas P and K concentrations decreased in aboveground portions of the plant. Belowground concentrations of P, Mn, and Fe were significantly higher in flooded plants, likely due to the increased solubility of these nutrients resulting from the reductive decomposition of metalphosphate complexes in the soil and subsequent precipitation in the rhizosphere. These results indicate that wetland plants may indirectly affect P, Mn, and Fe concentrations in surface waters by altering local trends in soil oxidation-reduction chemistry.

Organic and Nitrogen Fertilization of Soil under ‘Syrah’ Grapevine: Effects on Soil Chemical Properties and Nitrate Concentration

“…Irrigation creates momentary conditions of aeration restriction and, especially in the deeper soil layers with greater water availability; the combination with organic matter makes the environment prone to reduction in Mn. Higher Mn uptake was observed by Pierce et al (2010) in Leersia oryzoides (L.) Sw plants, under partial and intermittent flooding.…”

Managing Artificially Drained Low-Gradient Agricultural Headwaters for Enhanced Ecosystem Functions

“…Two well-established examples are the release of oxygen [ 272 ] and organic carbon [ 339 , 340 ], which essentially create biogeochemical hotspots. These hotspots may immobilize phosphorus [ 335 , 341 , 342 ]; however, higher concentrations of organic phosphorus have been associated with plants [ 343 ]. Furthermore, as there is no major gaseous phase in the phosphorus cycle, these immobile forms remain in the system and may be released into the water column when plants senesce [ 197 , 343 ].…”

Intra- and interspecific ecophysiological responses to waterlogging stress in two contrasting waterlogging-tolerant arbor species

“…Waterlogging impedes gas exchange between the soil and atmosphere, leading to energy deficiency in plant roots and accumulation of toxic metabolites and reactive oxygen species (ROS) (Subbaiah and Sachs, 2003). In addition, waterlogging interferes with plant growth (Parad et al, 2013), reducing root activity (Li et al, 2022) and affecting the photosynthesis (Yordanova et al, 2005;Yordanova and Popova, 2007), uptake, and transport of mineral elements (Patrick et al, 1985;Pezeshki, 2001); nutrient distribution patterns (Smethurst et al, 2005;Pierce et al, 2010); and other physiological processes, thereby leading to plant death. Nevertheless, plants do not passively accept the damages caused by waterlogging stress.…”