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T. W. Robinson - One of the best experts on this subject based on the ideXlab platform.
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Minutes of the fifth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 3, 1951, at Phoenix, Arizona.
2014Co-Authors: T. W. RobinsonAbstract:Minutes of the fifth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 3, 1951, at Phoenix, Arizona.
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Minutes of the thirteenth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 1, 1953, at El Centro, California
2014Co-Authors: T. W. RobinsonAbstract:Minutes of the thirteenth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 1, 1953, at El Centro, California
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Minutes of the eleventh meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held June 16, 1953, at Carson City, Nevada.
2014Co-Authors: T. W. RobinsonAbstract:Minutes of the eleventh meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held June 16, 1953, at Carson City, Nevada.
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Minutes of the 54-1 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held Marc 2, 1954, at Sacramento, California.
2014Co-Authors: T. W. RobinsonAbstract:Minutes of the 54-1 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held Marc 2, 1954, at Sacramento, California.
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Minutes of the 56-3 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held September 16, 1956, at Denver, Colorado.
2014Co-Authors: T. W. RobinsonAbstract:Minutes of the 56-3 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held September 16, 1956, at Denver, Colorado.
Henry J. Cremer - One of the best experts on this subject based on the ideXlab platform.
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Minutes of the ninth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 2, 1952, at Riverside, California.
2014Co-Authors: Henry J. CremerAbstract:Minutes of the ninth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 2, 1952, at Riverside, California.
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Minutes of the twelfth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held September 2, 1953, at Granby, Colorado.
2014Co-Authors: Henry J. CremerAbstract:Minutes of the twelfth meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held September 2, 1953, at Granby, Colorado.
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Minutes of the 54-4 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 7, 1954, at Phoenix, Arizona.
2014Co-Authors: Henry J. CremerAbstract:Minutes of the 54-4 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held December 7, 1954, at Phoenix, Arizona.
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Minutes of the 55-1 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held March 23, 1955, at Berkeley, California.
2014Co-Authors: Henry J. CremerAbstract:Minutes of the 55-1 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held March 23, 1955, at Berkeley, California.
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Minutes of the 54-2 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held June 8, 1954, at Denver, Colorado.
2014Co-Authors: Henry J. CremerAbstract:Minutes of the 54-2 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held June 8, 1954, at Denver, Colorado.
David R. Steward - One of the best experts on this subject based on the ideXlab platform.
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Groundwater surface water interactions and the role of Phreatophytes in identifying recharge zones
Hydrology and Earth System Sciences, 2012Co-Authors: Trevor S. Ahring, David R. StewardAbstract:Groundwater and surface water interactions within riparian corridors impact the distribution of Phreatophytes that tap into groundwater stores. The changes in canopy area of Phreatophytes over time is related to changes in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine the location of trees with pre-development and post-development aerial photography over the Ogallala Aquifer in the central plains of the United States. It was found that once the depth to groundwater becomes greater than about 3 m, tree populations decrease as depth to water increases. This subsequently limited the extent of Phreatophytes to within 700 m of the river. It was also found that Phreatophytes have a higher likelihood of growing on hydrologic soil groups with higher saturated hydraulic conductivity. Phreatophytes exist along portions of the Arkansas River corridor where significant decreases in groundwater occurred as long as alluvium exists to create perched conditions where trees survive dry periods. Significant decreases (more that 50%) in canopy cover exists along river segments where groundwater declined by more than 10 m, indicating areas with good hydraulic connectivity between surface water and groundwater. Thus, interpretation of changes in phreatophyte distribution using historical and recent aerial photography is important in delineating zones of enhanced recharge where aquifers might be effectively recharged through diversion of surface water runoff.
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Groundwater surface water interactions through streambeds and the role of Phreatophytes in identifying important recharge zones
2012Co-Authors: Trevor S. Ahring, David R. StewardAbstract:Abstract. Groundwater and surface water interactions within riparian corridors impact the distribution of Phreatophytes that tap into groundwater stores. The changes in canopy area of Phreatophytes over time is related to changes in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine the location of trees with predevelopment and post-development aerial photography over the Ogallala Aquifer in the central plains of the United States. It was found that once the depth to groundwater becomes greater than about 3 m, tree populations decrease as depth to water increases. This subsequently limited the extent of Phreatophytes to within 700 m of the river. It was also found that Phreatophytes have a higher likelihood of growing on hydrologic soil groups with higher saturated hydraulic conductivity. Phreatophytes exist along portions of the Arkansas River corridor where significant decreases in groundwater occurred as long as alluvium exists to create perched conditions where trees survive dry periods. Significant decreases (more that 50%) in canopy cover exists along river segments where groundwater declined by more than 10 m, indicating areas with good hydraulic connectivity between surface water and groundwater. Thus, interpretation of changes in phreatophyte distribution using historical and recent aerial photophaphy is important in delineating zones of enhanced recharge where aquifers might be effectively recharged through diversion of surface water runoff.
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An analytic solution for groundwater uptake by Phreatophytes spanning spatial scales from plant to field to regional
Journal of Engineering Mathematics, 2008Co-Authors: David R. Steward, Trevor S. AhringAbstract:Phreatophytes are important to the overall hydrologic water budget, providing pathways from the uptake of groundwater with its nutrients and chemicals to subsequent discharge to the root zone through hydraulic lift and to the atmosphere through evapotranspiration. An analytic mathematical model is developed to model groundwater uptake by individual plants and fields of plant communities and the regional hydrology of communities of fields. This model incorporates new plant functions developed through aid of Wirtinger calculus. Existing methodology for area-sinks is extended to fields of Phreatophytes, and Bell polynomials are employed to extend existing numerical methods to calculate regional coefficients for area-sinks. This model is used to develop capture zones for individual Phreatophytes and it is shown that the functional form of groundwater uptake impacts capture zone topology, with groundwater being extracted from greater depths when root water uptake is focused about a taproot. While individual plants siphon groundwater from near the phreatic surface, it is shown that communities of Phreatophytes may tap groundwater from greater depths and lateral extent as capture zones pass beneath those of upgradient Phreatophytes. Thus, biogeochemical pathways moving chemical inputs from aquifer to ecosystems are influenced by both the distribution of groundwater root uptake and the proximity of neighboring Phreatophytes. This provides a computational platform to guide hypothesis testing and field instrumentation and interpretation of their data and to understand the function of Phreatophytes in water and nutrient uptake across plant to regional scales.
Curtis W. Bowser - One of the best experts on this subject based on the ideXlab platform.
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Minutes of the 60-1 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held March 10, 1960, at Glendora, California.
2014Co-Authors: Curtis W. BowserAbstract:Minutes of the 60-1 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held March 10, 1960, at Glendora, California.
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Minutes of the 60-3 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held August 17, 1960, at Boulder, Colorado.
2014Co-Authors: Curtis W. BowserAbstract:Minutes of the 60-3 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held August 17, 1960, at Boulder, Colorado.
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Minutes of the 60-2 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held June 18, 1960, at Winnemucca, Nevada.
2014Co-Authors: Curtis W. BowserAbstract:Minutes of the 60-2 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held June 18, 1960, at Winnemucca, Nevada.
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Minutes of the 60-4 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held November 29, 1960, at Las Vegas, Nevada.
2014Co-Authors: Curtis W. BowserAbstract:Minutes of the 60-4 meeting of the Pacific Southwest Inter-Agency Committee's Phreatophyte Subcommittee. Held November 29, 1960, at Las Vegas, Nevada.
Fanjiang Zeng - One of the best experts on this subject based on the ideXlab platform.
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nitrogen application mitigates drought induced metabolic changes in alhagi sparsifolia seedlings by regulating nutrient and biomass allocation patterns
Plant Physiology and Biochemistry, 2020Co-Authors: Zhihao Zhang, Akash Tariq, Fanjiang Zeng, Corina Graciano, Bo ZhangAbstract:Abstract Groundwater and its associated nutrients sustain the establishment and persistence of Phreatophytes. Rapid root elongation immediately after germination is vital for desert species to access deep water sources to avoid water-deficit stress. However, the growth strategy and responses to nutrients and water of young phreatophyte seedlings before their roots reach the water table are poorly understood, especially in the scenarios of nitrogen (N) deposition and drought. We investigated how simulated N deposition and drought affect the plasticity of Alhagi sparsifolia seedlings by multiple eco-physiological mechanisms. Seedlings were planted under drought-stressed or well-watered conditions and subjected to various levels of N addition (0, 3.0, 6.0, or 9.0 gN·m−2 yr−1). The amounts of N and water independently or interactively affected the photosynthetic traits, drought tolerance characteristics, morphological traits, biomass allocation strategy, and nutrient distribution patterns among the plant organs. Moreover, changes mediated by N addition at the leaf level reflected the drought acclimation of the seedlings, which may be related to biomass and nutrient partitioning between organs. The roots were found to be more sensitive to variation of the N:phosphorus (P) ratio, and greater proportions of biomass, N, and P were allocated to resource-acquiring organs (i.e., leaves and fine roots) than to other tissues. A. sparsifolia adopts numerous strategies to tolerate drought, and additional N input was crucial to enhance the growth of drought-stressed A. sparsifolia, which was mainly attributable to its positive impact on the N and P uptake capacity mediated by increased biomass allocation to the roots.
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Groundwater Depth Affects Phosphorus But Not Carbon and Nitrogen Concentrations of a Desert Phreatophyte in Northwest China.
Frontiers in plant science, 2018Co-Authors: Bo Zhang, Xiaopeng Gao, Muhammad Shareef, Huang Caibian, Liu Guojun, Dongwei Gui, Fanjiang ZengAbstract:Ecological stoichiometry is an important aspect in the analysis of the changes in ecological system composition, structure, and function and understanding of plant adaptation in habitats. Leaf carbon (C), nitrogen (N), and phosphorus (P) concentrations in desert Phreatophytes can be affected by different depths of groundwater through its effect on the adsorption and utilization of nutrient and plant biomass. We examined the biomass, soil organic C, available (mineral) N, and available P, and leaf C, N, and P concentrations of Alhagi sparsifolia grown at varying groundwater depths of 2.5, 4.5, and 11.0 m in 2015 and 2016 growing seasons in a desert-oasis ecotone in northwest China. The biomass of A. sparsifolia and the C, N, and P concentrations in soil and A. sparsifolia showed different responses to various groundwater depths. The leaf P concentration of A. sparsifolia was lower at 4.5 m than at 2.5 and 11.0 m likely because of a biomass dilution effect. By contrast, leaf C and N concentrations were generally unaffected by groundwater depth, thereby confirming that C and N accumulations in A. sparsifolia were predominantly determined by C fixation through the photosynthesis and biological fixation of atmospheric N2, respectively. Soil C, N, and P concentrations at 4.5 m were significantly lower than those at 11.0 m. Leaf P concentration was significantly and positively correlated with soil N concentration at all of the groundwater depths. The C:N and C:P mass ratios of A. sparsifolia at 4.5 m were higher than those at the other groundwater depths, suggesting a defensive life history strategy. Conversely, A. sparsifolia likely adopted a competitive strategy at 2.5 and 11.0 m as indicated by the low C:N and C:P mass ratios. To our knowledge, this study is the first to elucidate the variation in the C, N, and P stoichiometry of a desert phreatophyte at different groundwater depths in an arid ecosystem.
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Taklamakan Desert
2008Co-Authors: Frank M. Thomas, Fanjiang Zeng, Andrea Foetzki, Dirk Gries, Helge Bruelheide, Ximing ZhangAbstract:available online at www.jpe.oxfordjournals.org Regulation of the water status in three co-occurring Phreatophytes at the southern fringe of th