scholarly journals Partitioning daily evapotranspiration from a marsh wetland using stable isotopes in a semiarid region

2017 ◽  
Vol 49 (4) ◽  
pp. 1005-1015 ◽  
Author(s):  
Jing Zhang ◽  
Shichun Zhang ◽  
Wenguang Zhang ◽  
Bo Liu ◽  
Chao Gong ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Steady State ◽  
Wetland Management ◽  
Management Strategies ◽  
Theoretical Data ◽  
Early Morning ◽  
Semiarid Region ◽  
Hydrological Process ◽  
Leaf Transpiration ◽  
Vegetation Indexes

Abstract The hydrological process of evapotranspiration (ET) plays an important role in water circulation in wetlands, and understanding the contributions of wetland ET to local and regional water cycles can help in designing effective wetland management strategies. In this paper, a numerical model, vegetation indexes, and stable isotopes were integrated to partition ET in the Momoge Wetland to understand hydrological processes and calculate the contribution of wetland ET to local hydrological cycling. The results of the non-steady state (NSS) model indicated clear deviation of leaf water enrichment (δLb) from an isotopic steady state (ISS) for Phragmites australis, and the model accuracy improved particularly in the early morning and evening when air moisture was highest during the day. The isotopic mass balance showed that E and T contributed approximately 62% and 38% to ET, respectively. Using the estimated proportion of T to ET, in combination for the measured leaf transpiration, total ET was estimated at approximately 8.76 mm d−1. Additionally, the amount of ET clearly changed on an hourly scale, with most primarily occurring at approximately noon. Based on comparison among internationally important wetlands distributed in northeast China, the results in this study are reasonable and will provide theoretical data for wetland water resources management.

scholarly journals Morphometric analysis and prioritization of upper Benue River watershed, Northern Nigeria

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Caleb Akoji Odiji ◽  
Olaide Monsor Aderoju ◽  
Joseph Bisong Eta ◽  
Idris Shehu ◽  
Adama Mai-Bukar ◽  
...  
Keyword(s):  
Management Strategies ◽  
Decision Makers ◽  
Order System ◽  
Hydrological Process ◽  
Drainage Pattern ◽  
River Watershed ◽  
Digital Elevation ◽  
Hypsometric Integral ◽  
Cumulative Length ◽  
Elevation Model

AbstractThe upper Benue River watershed is undergoing remarkable modifications due to man-made and natural phenomena. Hence, an evaluation is required to understand the hydrological process of the watershed for planning and management strategies. This study aimed to assess the morphometric characteristics and prioritize the upper Benue River watershed. The boundary of the watershed and sub-watersheds, as well as stream networks, was extracted from the digital elevation model (DEM) coupled with hydrological and topographic maps. Twenty-eight morphometric parameters under three categories, i.e. linear, areal, and relief aspects were computed and mapped. Findings from the study revealed that the watershed is a seventh stream order system characterized by a dendritic drainage pattern. The result also showed that 4821 streams were extracted with a cumulative length of 30,232.84 km. The hypsometric integral of the watershed was estimated to be 0.22, indicating that it is in the old stage. In the prioritization of the watershed, the morphometric variables were utilized to calculate and classify the compound factor. The result showed that sub-watersheds 12, 16, 18, 24, 26, and 27 were ranked as very high priority for which conservation measures are required to mitigate the risk of flood and erosion. The outcome of this study can be used by decision-makers for sustainable watershed management and planning.

scholarly journals Effects of Irrigation and Fertilization on the Morphophysiological Traits of Populus sibirica Hort. Ex Tausch and Ulmus pumila L. in the Semiarid Steppe Region of Mongolia

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2407
Author(s):  
Ser-Oddamba Byambadorj ◽  
Byung Bae Park ◽  
Jonathan O. Hernandez ◽  
Enkhchimeg Tsedensodnom ◽  
Otgonsaikhan Byambasuren ◽  
...  
Keyword(s):  
Leaf Area ◽  
Nutrient Management ◽  
Sustainable Forest Management ◽  
Management Strategies ◽  
Semiarid Region ◽  
Leaf Biomass ◽  
Ulmus Pumila ◽  
Rainfall Events ◽  
Arid And Semiarid Ecosystems ◽  
Arid And Semiarid

Desertification is impeding the implementation of reforestation efforts in Mongolia. Many of these efforts have been unsuccessful due to a lack of technical knowledge on water and nutrient management strategies, limited financial support, and short-lived rainfall events. We investigated the effects of irrigation and fertilization on the morphophysiological traits of Populus sibirica Hort. Ex Tausch and Ulmus pumila L. and to suggest irrigation and fertilization strategies for reforestation. Different irrigation and fertilizer treatments were applied: no irrigation, 2 L h−1, 4 L h−1, and 8 L h−1 of water; no fertilizer, 2 L h−1 + NPK, 4 L h−1 + NPK, and 8 L h−1 + NPK; and no compost, 2 L h−1 + compost, 4 L h−1 + compost, and 8 L h−1 + compost. The leaf area (LA) and specific leaf area (SLA) of both species responded positively to 4 and 8 L h−1. Results also showed that the addition of either NPK or compost to 4 or 8 L h−1 irrigation resulted in a higher LA, SLA, and leaf biomass (LB). Total chlorophyll content decreased with irrigation in both species. The same pattern was detected when a higher amount of irrigation was combined with fertilizers. Lastly, we found that both diurnal and seasonal leaf water potential of plants grown in 4 or 8 L h−1 were significantly higher than those of plants grown in control plots. Therefore, 4 or 8 L h−1 with either NPK or compost has shown to be the optimal irrigation and fertilization strategy for the species in an arid and semiarid region of Mongolia. Results should provide us with a better understanding of tree responses to varying amounts of irrigation with or without fertilizer in pursuit of sustainable forest management in arid and semiarid ecosystems.

Investigation of soil water hydrological process in the permafrost active layer using stable isotopes

2020 ◽  
Vol 34 (12) ◽  
pp. 2810-2822
Author(s):  
Zongjie Li ◽  
Jinzhu Ma ◽  
Lingling Song ◽  
Juan Gui ◽  
Jian Xue ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Active Layer ◽  
Hydrological Process

Anthropogenically-induced recharge in a semiarid mountain front context

2020 ◽  
Author(s):  
Houssne Bouimouass ◽  
Younes Fakir ◽  
Sarah Tweed ◽  
Marc Leblanc
Keyword(s):  
Stable Isotopes ◽  
Hydrological Cycle ◽  
Stream Water ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Wet Season ◽  
Irrigation Area ◽  
Groundwater Fluctuation ◽  
Mountain Front ◽  
Irrigation Practices

<p>Mountain-fronts constitute important groundwater recharge areas in arid and semiarid regions. Mountain-front recharge processes are generally identified, in natural systems, as streamflow losses and subsurface inflow from the mountain block. However, another key recharge process is from irrigation practices; where mountain streamflow is distributed across the irrigated piedmont. In this study, coupled groundwater fluctuation measurements and stable isotopes (<sup>18</sup>O and <sup>2</sup>H) were used to identify and compare the natural mountain-front recharge to the anthropogenically-induced irrigation recharge. Within the High-Atlas mountain front of the Ourika basin, Tensift, Central Morocco, the groundwater fluctuation mapping from the dry to wet season showed that recharge from irrigation waters was higher than the recharge along the streambed. Irrigation practices in the region divert more than 65% of the stream water, thereby reducing the potential for stream recharge. Due to the traditional irrigation practices, upstream crops are preferentially irrigated with stream water over downstream areas. In downstream areas irrigation is only via stream water during large flood events and is otherwise supplemented by groundwater resources. These changes in water resources used for irrigation practices between upstream and downstream areas are reflected in the spatio-temporal evolution of the stable isotopes of groundwater. In the upstream irrigation area, the groundwater stable isotope values (d<sup>18</sup>O: -8.4 ‰ to -7.4 ‰) reflect recharge by the diverted stream water. In the downstream irrigation area, the groundwater isotope values are lower (d<sup>18</sup>O: -8.1 ‰ to -8.4 ‰) due to recharge with floods.</p><p>The results from this study particularly highlight that irrigation can deeply modify both the recharge processes and the water balance in the mountain front areas. Groundwater resources in such areas become reliant on the irrigation practices as an important source of recharge, and this anthropogenic modification of the hydrological cycle should be assessed and taken into consideration within climate change impacts and integrated water management strategies.</p>

scholarly journals Concentrations of OH and HO<sub>2</sub> radicals during NAMBLEX: measurements and steady state analysis

2005 ◽  
Vol 5 (6) ◽  
pp. 12403-12464 ◽  
Author(s):  
S. C. Smith ◽  
J. D. Lee ◽  
W. J. Bloss ◽  
G. P. Johnson ◽  
D. E. Heard
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Detection Limit ◽  
Diurnal Variation ◽  
Marine Boundary Layer ◽  
Chemical Conversion ◽  
Early Morning ◽  
Research Station ◽  
Solar Noon ◽  
Mean Concentration

Abstract. OH and HO2 concentrations were measured simultaneously at the Mace Head Atmospheric Research Station in the summer of 2002 during the NAMBLEX (North Atlantic Marine Boundary Layer EXperiment) field campaign. OH was measured by laser-induced fluorescence employing the FAGE (Fluorescence Assay by Gas Expansion) technique, with a mean daytime detection limit of 2.7×105 molecule cm−3 (5 min acquisition period; signal-to-noise ratio = 1). HO2 was detected as OH following its chemical conversion through addition of NO, with a mean detection limit of 4.4×106 molecule cm−3. The diurnal variation of OH was measured on 24 days, and that of HO2 on 17 days. The local solar noon OH concentrations ranged between (3–8)×106 molecule cm−3, with a 24 h mean concentration of 9.1×105 molecule cm−3. The local solar noon HO2 concentrations were (0.9–2.1)×108 molecule cm−3 (3.5–8.2 pptv), with a 24 h mean concentration of 4.2×107 molecule cm−3. HO2 radicals in the range (2–3)×107 molecule cm−3 were observed at night. During NAMBLEX, a comprehensive suite of supporting measurements enabled a detailed study of the behaviour of HOx radicals under primarily clean marine conditions. Case study periods highlight the typical radical levels observed under different conditions. Steady state expressions are used to calculate OH and HO2 concentrations and to evaluate the effect of different free-radical sources and sinks. The diurnally averaged calculated to measured OH ratio was 1.04±0.36, but the ratio displays a distinct diurnal variation, being less than 1 during the early morning and late afternoon/evening, and greater than 1 in the middle of the day. For HO2 there was an overprediction, with the agreement between calculated and measured concentrations improved by including reaction with measured IO and BrO radicals and uptake to aerosols. Increasing the concentration of IO radicals included in the calculations to above that measured by a DOAS instrument with an absorption path located mainly over the ocean, reflecting the domination of the inter-tidal region as an iodine source at Mace Head, led to further improvement. The results are compared with previous measurements at Mace Head, and elsewhere in the remote marine boundary layer.

scholarly journals Application strategies of saline water and nitrogen doses in mini watermelon cultivation

2020 ◽  
Vol 11 ◽  
pp. e3233
Author(s):  
Saulo Soares da Silva ◽  
Geovani Soares de Lima ◽  
Vera Lúcia Antunes de Lima ◽  
Hans Raj Gheyi ◽  
Lauriane Almeida dos Anjos Soares ◽  
...  
Keyword(s):  
Salt Stress ◽  
Saline Water ◽  
Management Strategies ◽  
Photochemical Efficiency ◽  
Northeastern Brazil ◽  
Limiting Factors ◽  
Semiarid Region ◽  
Saline Waters ◽  
Salinity Levels ◽  
High Level

Salt stress is highlighted as one of the limiting factors for the establishment of agriculture in the semiarid region of Northeastern Brazil. In this context, it is essential to look for new strategies aiming at minimizing the effects of salt stress on the crops. The present work aimed to evaluate the photochemical efficiency, photosynthetic pigments, and growth of the watermelon cv. Sugar Baby under different use strategies with saline waters and nitrogen fertilization. The experiment was conducted in a protected environment at the Center of Technology and Natural Resources of the Federal University of Campina Grande, municipality of Campina Grande, Paraíba. An experimental design in randomized blocks was adopted, arranged in a 6 x 2 factorial scheme, with six management strategies of water salinity and two nitrogen doses (corresponding to 50 and 100% of the recommendation), with five replications. Two salinity levels of the irrigation water were studied, one with low and another with a high level of electrical conductivity of the water (ECw = 0.8 and 3.2 dS m-1). The watermelon cv. Sugar Baby expressed higher sensitivity to salt stress in the flowering phase, with a decrease in the synthesis of chlorophyll b, chlorophyll total, and carotenoids. The 50% dose of N provided an increment in the initial fluorescence, stem diameter, and the number of leaves of the watermelon cv. Sugar Baby. The length of the main branch of the watermelon plants decreased with the salt stress applied in the fructification phase; however, the fertilization with 100% of N stimulated a higher growth when the irrigation with saline waters was performed at the vegetative and flowering phases.

scholarly journals Concentrations of OH and HO<sub>2</sub> radicals during NAMBLEX: measurements and steady state analysis

2006 ◽  
Vol 6 (5) ◽  
pp. 1435-1453 ◽  
Author(s):  
S. C. Smith ◽  
J. D. Lee ◽  
W. J. Bloss ◽  
G. P. Johnson ◽  
T. Ingham ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Detection Limit ◽  
Diurnal Variation ◽  
Marine Boundary Layer ◽  
Chemical Conversion ◽  
Early Morning ◽  
Research Station ◽  
Solar Noon ◽  
Mean Concentration

Abstract. OH and HO2 concentrations were measured simultaneously at the Mace Head Atmospheric Research Station in the summer of 2002 during the NAMBLEX (North Atlantic Marine Boundary Layer EXperiment) field campaign. OH was measured by laser-induced fluorescence employing the FAGE (Fluorescence Assay by Gas Expansion) technique, with a mean daytime detection limit of 2.7×105 molecule cm−3 (5 min acquisition period; signal-to-noise ratio = 1). HO2 was detected as OH following its chemical conversion through addition of NO, with a mean detection limit of 4.4×106 molecule cm−3. The diurnal variation of OH was measured on 24 days, and that of HO2 on 17 days. The local solar noon OH concentrations ranged between (3–8)×106 molecule cm−3, with a 24 h mean concentration of 9.1×105 molecule cm−3. The local solar noon HO2 concentrations were (0.9–2.1)×108 molecule cm−3 (3.5–8.2 pptv), with a 24 h mean concentration of 4.2×107 molecule cm−3 (1.6 pptv). HO2 radicals in the range (2–3)×107 molecule cm−3 were observed at night. During NAMBLEX, a comprehensive suite of supporting measurements enabled a detailed study of the behaviour of HOx radicals under primarily clean marine conditions. Steady state expressions are used to calculate OH and HO2 concentrations and to evaluate the effect of different free-radical sources and sinks. The diurnally averaged calculated to measured OH ratio was 1.04±0.36, but the ratio displays a distinct diurnal variation, being less than 1 during the early morning and late afternoon/evening, and greater than 1 in the middle of the day. For HO2 there was an overprediction, with the agreement between calculated and measured concentrations improved by including reaction with measured IO and BrO radicals and uptake to aerosols. Increasing the concentration of IO radicals included in the calculations to above that measured by a DOAS instrument with an absorption path located mainly over the ocean, reflecting the domination of the inter-tidal region as an iodine source at Mace Head, led to further improvement. The results are compared with previous measurements at Mace Head, and elsewhere in the remote marine boundary layer.

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