The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Christina Siebe - One of the best experts on this subject based on the ideXlab platform.
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changes in soil redox potential in response to Flood Irrigation with waste water in central mexico
European Journal of Soil Science, 2017Co-Authors: Lanca Gonzalezmendez, R Webste, Sabine Fiedle, Christina SiebeAbstract:Irrigation with untreated sewage water adds fresh organic matter to the soil. When it is applied by Flooding, as in the Mezquital Valley of Mexico, many of the pores in the soil become temporarily waterlogged and depleted of oxygen, and reduction generates nitrous oxide (N2O) and methane (CH4). We monitored the redox potential, Eh, in the soil at two sites in the Mezquital Valley to discover whether the short-term gaseous emissions matched the changes in Eh. One site is irrigated periodically by Flooding with waste water and has alfalfa, rye grass and maize grown in succession; the other site grows maize with water from summer rain only. Each electrode buried in the soil for the purpose produced sequences of measurements that were correlated in time. We modelled the correlation and took it into account to analyse the effects of the Irrigation by residual maximum likelihood (reml). After each Flooding, the redox potential under alfalfa and rye grass decreased by 150–200 mV from a norm of about 450 mV for 2 days, after which it returned to its norm. The short-term response to Flooding under maize was similar, but the redox potential did not recover completely; instead there was a decrease from one Irrigation event to another, in particular as a result of heavy rain in September that saturated the soil. The soil under rain-fed maize was slower to respond, partly, we believe, because infiltration into the less aggregated clay soil and drainage from it were also slow. Irrigation with untreated sewage water caused a sharp decrease in Eh lasting 1–2 days. It seems to have depleted the soil of oxygen, causing reduction in microhabitats rich in carbon and nitrogen and generation of N2O, which was captured in the closed chambers that we had installed. Highlights Land in the Mezquital Valley of Mexico emits much greenhouse gas when irrigated with sewage water. The soil's redox potential was monitored in situ as crops were irrigated or depended solely on rain. Each Irrigation caused a decrease in the soil's redox potential of 150–200 mV for 2 days. The decrease in redox potential corresponded in time with emission of nitrous oxide.
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short term emissions of co2 and n2o in response to periodic Flood Irrigation with waste water in the mezquital valley of mexico
Atmospheric Environment, 2015Co-Authors: Lanca Gonzalezmendez, R Webste, Sabine Fiedle, E Lozareyes, J M Hernandez, L G Ruizsuarez, Christina SiebeAbstract:Irrigation with waste water adds labile carbon and nitrogen compounds to the soil, and when applied by Flooding it rapidly changes the soil's atmosphere and redox potential. In the Mezquital Valley more than 90 000 ha is irrigated with waste water from Mexico City, and enhanced emissions of CO2 and N2O follow each Flooding. We measured the emissions of these two gases from a field irrigated periodically with waste water and under three crops, namely alfalfa, rye-grass and maize, using static chambers for 21 months. We also measured emissions from a field growing rain-fed maize before and shortly after two rain events. The data from repeated measurements from the same chambers are correlated in time, and so we modelled the ante-dependence and fitted the models by residual maximum likelihood (REML). The emissions of both CO2 and N2O increased rapidly in response to Flood Irrigation with peaks up to 448 mg C m−2 hour−1 for CO2 and 2.98 mg N m−2 hour−1 for N2O under maize. Emissions peaked in particular Irrigation events either as the infiltrating water replaced the gas from air-filled pores or several days after Irrigation as excess nitrogen and fresh sources of carbon were mineralized. Processes operating during the few days during and immediately after Irrigation seem to determine the dynamics of gaseous production in this agricultural ecosystem.
Wenzhi Zhao - One of the best experts on this subject based on the ideXlab platform.
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modeling soil water balance and Irrigation strategies in a Flood irrigated wheat maize rotation system a case in dry climate china
Agricultural Water Management, 2019Co-Authors: Hong Zhou, Wenzhi ZhaoAbstract:Demand for Irrigation water has been steadily increasing in arid regions where intensification of crop production is supported by Flood-Irrigation. An assessment of Irrigation performance, water productivity, and Irrigation schedules is critical to water conservation in dry climates. In this study, we conducted a field experiment to compare soil water balance in a Flood-irrigated wheat-maize rotation system during the growing season of 2015–2016. We then modeled the soil water balance and improved Irrigation strategies by coupling Hydrus-1D with the CROPWAT model, and using evapotranspiration calculated from climatic data. The calibrated Hydrus-1D model was used to simulate the temporal and spatial variation of evapotranspiration and deep percolation based on measured soil water distribution of soil profiles in the unsaturated zone. Results showed that using soil hydraulic parameters from inversion modeling can simulate soil water flow in multi-layer soil during a crop growing season. Simulation results indicated that about 36.6 and 40.6% (478.6 and 680.1 mm) of total water input in 2015 and 2016, respectively, was consumed by evapotranspiration. Furthermore, simulated deep percolation amounted for approximately 32.3 and 42.9% (403.9 and 696.6 mm) of the total amount of Irrigation water in 2015 and 2016, respectively. These results indicated that only a small proportion of Irrigation water was used by crops for transpiration. In addition, Irrigation performance indicators such as relative water supply, relative Irrigation supply, depleted fraction, and overall consumed ratio values indicated poor performance of Irrigation practices in the study area. Particularly, crop yields did not increase with increases in Irrigation water in Flood-irrigated fields during the last ten years. Results of the CROPWAT model indicated that combinations of a fixed Irrigation depth and timing, of 40 mm every 10 days, and 50 mm every 10 days were reasonable for wheat and maize, respectively, given the sandy soil in the study area. The improved Irrigation strategies will limit water Irrigation loss to 20% without significant effects on crop yields. This study provides an alternative approach for estimating deep percolation and crop water requirements supporting management efforts in water conservation in dry climates.
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a mathematical model for simulating water balances in cropped sandy soil with conventional Flood Irrigation applied
Agricultural Water Management, 2007Co-Authors: Ersi Kang, Rensheng Che, Wenzhi Zhao, Zhihui ZhangAbstract:In this paper, a model that integrates various complex model components for the purposes of water balance modeling throughout crop development in arid inland region under the conventional Flood Irrigation practiced is presented. These components are modules for calculating dynamic soil water content based Richard's equation, potential and actual evapotranspiration, and crop root water uptake. Soil water content in the active root zone and soil evaporation simulation obtained from the model were test using field data in 2003. The low values of MARE and high values of R2 and PE in the active root zone of soil profile as well as daily soil evaporation indicated that the soil water balance simulation model presented in the paper can be used with reliable accuracy to simulate the components of water balance in cropped sandy soil under the conventional Flood Irrigation condition in arid inland regions. The model simulation on components of water balance using observed field data in 2004 indicated that large quantities � about 43% of Irrigation water (amounting to 840 mm) � were consumed by deep percolation, only small (less than 41%) proportions of Irrigation water used by the plants for transpiration. The current Irrigation scheme is characterized by the unreasonable agricultural water management with the waste of water in the Irrigational system in this region. The impact of Irrigation scheduling on water balance presented in this paper showed that the reasonable Irrigation scheme with more frequent Irrigation and less amounts is more suitable for the Irrigation of spring wheat in Heihe River basin, northwest China. Therefore, to establish a decision-making system for agricultural Irrigation scheme and to utilize the limited water resources in this region have become an urgent problem that needs to be solved.
Raphael Abrahao - One of the best experts on this subject based on the ideXlab platform.
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nitrate contamination and its relationship with Flood Irrigation management
Journal of Hydrology, 2012Co-Authors: I Garciagarizabal, J Causape, Raphael AbrahaoAbstract:Summary Nitrate contamination is a significant unresolved environmental issue for agriculture in the 21st century, with longstanding challenges in its control and allocation to a specified territory. In order to address these challenges, real-world meticulous Irrigation area studies are required. The objective of this investigation is to analyze the evolution of nitrate contamination in relation to agronomic and management changes within a traditionally irrigated land. Specifically, the impact of changes in Irrigation allowance assignment, changes in Irrigation method from rotation to on-demand Flood Irrigation, and creation of water consumption accounts were analyzed. To this end, nitrogen monitoring and annual balances were carried out in a small irrigated hydrological basin (95 ha) located in Northeastern Spain throughout the years of 2001 and 2005–2008. The evolution of the nitrate contamination index was also analyzed, which relates the mass of nitrates exported to the fertilization necessities of a specific irrigated area. The results demonstrated that although changes in crop pattern caused a 33% reduction in the nitrogen required through fertilization, the fertilization rates applied are still double the necessities. Changes in Irrigation management decreased the mass of nitrates exported by half and the nitrate contamination index by 24%, but the nitrate levels present are still approximately double of those registered in modern Irrigation areas. The changes implemented by the Irrigation District in the Irrigation management were effective. However, this study confirms that a greater effort is still required to achieve adequate nitrogen fertilization matching the crop necessities.
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application of the Irrigation land environmental evaluation tool for Flood Irrigation management and evaluation of water use
Catena, 2011Co-Authors: I Garciagarizabal, J Causape, Raphael AbrahaoAbstract:Abstract Irrigated zones worldwide suffer from water deficits, making it necessary to analyze Irrigation management and to study alternatives to maximize adequate partitioning and distribution of Irrigation water. The objective of this study is to compare the water use efficiency before (2001) and after (2002–2008) implementation of a new Irrigation management plan in an area operating with traditional methods. To this end, annual water balances were carried out in a pilot basin (95 ha) in Northeast Spain during the period between 2001 and 2008. From these, the evolution of Irrigation quality (Net Hydric Needs, Irrigation Efficiency, and Water Deficit) was analyzed in climatically different years and after changes in Irrigation management (i. assignment of Irrigation allowances, ii. on-demand Flood Irrigation system, and iii. creation of water consumption accounts). The changes in Irrigation management contributed to a better adjustment between water consumption and net hydric needs of crops, translating into improved Irrigation efficiency and drainage reduction, although years with greater net hydric needs presented greater water deficits. Assignment of Irrigation allowances and billing according to the volume of Irrigation water consumed contributed to raising awareness of farmers about the value of water, especially in dry years. These facts, along with the flexibility in the time of Irrigation granted by an “on-demand” management, led to an optimization of Irrigation water applications to levels seldom exceeded by gravity Irrigation in such permeable soils.
I Garciagarizabal - One of the best experts on this subject based on the ideXlab platform.
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evaluation of alternatives for Flood Irrigation and water usage in spain under mediterranean climate
Catena, 2017Co-Authors: I Garciagarizabal, J Causape, D MerchaAbstract:Abstract Evaluation of water management has been progressively more necessary to determine the availability of water resources, especially in the Mediterranean environment where competition for these resources is maximum. This work evaluates the Irrigation management and evolution of hydric needs for the main crops implemented in the Ebro basin (Spain), through the monitoring of a pilot experimental basin between 1998 and 2012. This 15-year period comprehends changes in Irrigation implemented by the Irrigation District as well as climate and agronomic variabilities of the region. Changes in water management (implementation of an on-demand Irrigation system with annual water allowances and payment per surface and consumption, in opposition to an Irrigation system in shifts) and crops contributed to reduce Irrigation by 40% and drainage by 72%. This occurred due to better adjustments between the water volumes applied and the hydric needs of the crops, achieving Flood Irrigation efficiencies of 80%. However, small negative trends were detected in the water deficit evolution of corn and sunflower, which should be addressed and improved. Improvements in water management by farmers have enabled the increase of Irrigation efficiency up to values found in pressurized Irrigation systems, especially in initial stages of the Irrigation campaigns. However, specific water deficit episodes were detected that should be remediated.
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nitrate contamination and its relationship with Flood Irrigation management
Journal of Hydrology, 2012Co-Authors: I Garciagarizabal, J Causape, Raphael AbrahaoAbstract:Summary Nitrate contamination is a significant unresolved environmental issue for agriculture in the 21st century, with longstanding challenges in its control and allocation to a specified territory. In order to address these challenges, real-world meticulous Irrigation area studies are required. The objective of this investigation is to analyze the evolution of nitrate contamination in relation to agronomic and management changes within a traditionally irrigated land. Specifically, the impact of changes in Irrigation allowance assignment, changes in Irrigation method from rotation to on-demand Flood Irrigation, and creation of water consumption accounts were analyzed. To this end, nitrogen monitoring and annual balances were carried out in a small irrigated hydrological basin (95 ha) located in Northeastern Spain throughout the years of 2001 and 2005–2008. The evolution of the nitrate contamination index was also analyzed, which relates the mass of nitrates exported to the fertilization necessities of a specific irrigated area. The results demonstrated that although changes in crop pattern caused a 33% reduction in the nitrogen required through fertilization, the fertilization rates applied are still double the necessities. Changes in Irrigation management decreased the mass of nitrates exported by half and the nitrate contamination index by 24%, but the nitrate levels present are still approximately double of those registered in modern Irrigation areas. The changes implemented by the Irrigation District in the Irrigation management were effective. However, this study confirms that a greater effort is still required to achieve adequate nitrogen fertilization matching the crop necessities.
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application of the Irrigation land environmental evaluation tool for Flood Irrigation management and evaluation of water use
Catena, 2011Co-Authors: I Garciagarizabal, J Causape, Raphael AbrahaoAbstract:Abstract Irrigated zones worldwide suffer from water deficits, making it necessary to analyze Irrigation management and to study alternatives to maximize adequate partitioning and distribution of Irrigation water. The objective of this study is to compare the water use efficiency before (2001) and after (2002–2008) implementation of a new Irrigation management plan in an area operating with traditional methods. To this end, annual water balances were carried out in a pilot basin (95 ha) in Northeast Spain during the period between 2001 and 2008. From these, the evolution of Irrigation quality (Net Hydric Needs, Irrigation Efficiency, and Water Deficit) was analyzed in climatically different years and after changes in Irrigation management (i. assignment of Irrigation allowances, ii. on-demand Flood Irrigation system, and iii. creation of water consumption accounts). The changes in Irrigation management contributed to a better adjustment between water consumption and net hydric needs of crops, translating into improved Irrigation efficiency and drainage reduction, although years with greater net hydric needs presented greater water deficits. Assignment of Irrigation allowances and billing according to the volume of Irrigation water consumed contributed to raising awareness of farmers about the value of water, especially in dry years. These facts, along with the flexibility in the time of Irrigation granted by an “on-demand” management, led to an optimization of Irrigation water applications to levels seldom exceeded by gravity Irrigation in such permeable soils.
Zhihui Zhang - One of the best experts on this subject based on the ideXlab platform.
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a mathematical model for simulating water balances in cropped sandy soil with conventional Flood Irrigation applied
Agricultural Water Management, 2007Co-Authors: Ersi Kang, Rensheng Che, Wenzhi Zhao, Zhihui ZhangAbstract:In this paper, a model that integrates various complex model components for the purposes of water balance modeling throughout crop development in arid inland region under the conventional Flood Irrigation practiced is presented. These components are modules for calculating dynamic soil water content based Richard's equation, potential and actual evapotranspiration, and crop root water uptake. Soil water content in the active root zone and soil evaporation simulation obtained from the model were test using field data in 2003. The low values of MARE and high values of R2 and PE in the active root zone of soil profile as well as daily soil evaporation indicated that the soil water balance simulation model presented in the paper can be used with reliable accuracy to simulate the components of water balance in cropped sandy soil under the conventional Flood Irrigation condition in arid inland regions. The model simulation on components of water balance using observed field data in 2004 indicated that large quantities � about 43% of Irrigation water (amounting to 840 mm) � were consumed by deep percolation, only small (less than 41%) proportions of Irrigation water used by the plants for transpiration. The current Irrigation scheme is characterized by the unreasonable agricultural water management with the waste of water in the Irrigational system in this region. The impact of Irrigation scheduling on water balance presented in this paper showed that the reasonable Irrigation scheme with more frequent Irrigation and less amounts is more suitable for the Irrigation of spring wheat in Heihe River basin, northwest China. Therefore, to establish a decision-making system for agricultural Irrigation scheme and to utilize the limited water resources in this region have become an urgent problem that needs to be solved.