Hydrology and species‐specific effects of Bacopa monnieri and Leersia oryzoides on soil and water chemistry

Abstract

In an 8-week greenhouse experiment, Bacopa monnieri (water hyssop) and Leersia oryzoides (rice cutgrass) were compared for nutrient assimilation as well as soil and water chemistry under variable flooding regimes using a nutrient solution rich in nitrogen (N) and phosphorus (P). Soil redox potential decreased in flooded treatments; however, mesocosms containing B. monnieri remained aerobic for much of the study, while flooded mesocosms containing L. oryzoides became moderately reduced. Soils containing L. oryzoides were higher in nitrogen. Generally, effluent concentrations of PO 4 3 were higher in B. monnieri mesocosms. B. monnieri immobilization of N and P was significantly less in below-ground tissues than L. oryzoides. P immobilization in L. oryzoides generally increased in response to flooding, while B. monnieri showed no detectable response. Results indicated that species-specific flood responses in plant nutrient status are due to differing interactions of B. monnieri and L. oryzoides with the soil environment. Additionally, L. oryzoides demonstrated greater P uptake than B. monnieri across treatments, resulting in decreased concentrations of PO 4 3 in effluent. Although N was also affected by flooding and species, generalizations on N allocation within the system are difficult to describe due to the changes in species of N in response to oxidation-reduction gradients and biotic assimilation.

The effect of competition on Bacopa monnieri zonation in an temporarily open/closed tropical estuary

“…This result does not corroborate our hypotheses, and we conclude that some abiotic condition is preventing the occurrence of B. monnieri in the freshwater zone. However, as B. monnieri can survive without salinity in other areas (Horník et al, 2008;Pierce et al, 2009;Rolon et al, 2012), we posit that this abiotic condition is not directly related to the absence of salt, but varies with it. Nonetheless, we noted that turfs in the non-saline zone were buried in organic matter.…”

The National Sedimentation Laboratory: 50 years of soil and water research in a changing agricultural environment

“…The five papers in this group present research on the spatial distribution of excess nutrients , and on environmentally-friendly conservation practices to reduce soil, nutrient and pesticide run-off to improve water quality (Lizotte et al, 2009;Pierce et al, 2009) and ecology (Smiley et al, 2009a, b). Shields et al (2009) highlight the problem of misplaced plant nutrients.…”

“…Concentrations of N in Hill streams do not exhibit seasonal patterns, but mean monthly P levels are correlated with mean monthly discharge. Pierce et al (2009) and Lizotte et al (2009) present research on best management practices (constructed wetlands and vegetated agricultural ditches) to reduce nutrient and pesticide concentrations in surface waters. Pierce et al (2009) compare nutrient allocation in two wetland plant species, Bacopa monnieri (water hyssop) and Leersia oryzoides (rice cutgrass), that are subjected to a range of water regimes ranging from drained to continuously flooded.…”

“…Pierce et al (2009) and Lizotte et al (2009) present research on best management practices (constructed wetlands and vegetated agricultural ditches) to reduce nutrient and pesticide concentrations in surface waters. Pierce et al (2009) compare nutrient allocation in two wetland plant species, Bacopa monnieri (water hyssop) and Leersia oryzoides (rice cutgrass), that are subjected to a range of water regimes ranging from drained to continuously flooded. Results indicated that species-specific flood responses in plant nutrient status are due to differing interactions of B. monnieri and L. oryzoides with the soil environment.…”

NUTRIENT AND GROWTH RESPONSES OFLEERSIA ORYZOIDES, RICE CUTGRASS, TO VARYING DEGREES OF SOIL SATURATION AND WATER NITROGEN CONCENTRATION

“…Recently, research has focused on the efficacy of aquatic and wetland plants to mitigate and diffuse agricultural runoff in primary agricultural drainage ditches to better manage and protect fresh water (Pierce et al, 2009;Pierce and Pezeshki, 2010). These plants diversify the homogenous agricultural landscape by trapping and removing nonpoint source pollutants, such as excess nutrients in the waterway through direct assimilation and immobilization (Kröger et al, 2007;Pierce et al, 2009).…”