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Determination of crop and soil evaporation coefficients for estimating evapotranspiration in a paddy field

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International Journal of Agricultural and Biological Engineering 2017年第4期10卷 130-139页

作者： Yan Haofang Zhang Chuan Hiroki Oue Peng Guangjie ransford opoku darko Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China Institute of Agricultural Engineering Jiangsu UniversityZhenjiang 212013China United Graduate School of Agricultural Sciences Ehime University3-5-7 TarumiMatsuyama790-8566Japan Department of Water Management Delft University of TechnologyDelft2600GAthe Netherlands

Accurate estimation of evapotranspiration is important in efficient water management for improving water use *** order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agriculture Organization(FAO)method,pan evaporation was used instead of reference evapotranspiration calculated by the Penman-Monteith equation with detailed meteorological *** total crop coefficient and soil evaporation coefficient were determined using actual measured daytime evapotranspiration and evaporation by the Bowen ratio energy balance and lysimeter,respectively,in a rice paddy field in *** average evapotranspiration was 5.3 mm/d,4.4 mm/d,7.4 mm/d and 6.3 mm/d and crop coefficient was 0.79,1.18,1.01 and 0.86 for the initial stage,development stage,middle-season stage and late-season stage,*** evaporation was low and almost constant with an average value around 0.77 mm/d when the leaf area index(LAI)reached *** proposed average crop coefficients for different growing stages were applied to estimate daytime evapotranspiration and found suitable.A simple soil water evaporation coefficient model was developed using leaf area index for practical use and it was found that it could accurately estimate evaporation.

关键词： evapotranspiration evaporation paddy field lysimeter leaf area index(LAI) Bowen ratio energy balance

Overview of advances in improving uniformity and water use efficiency of sprinkler irrigation

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International Journal of Agricultural and Biological Engineering 2017年第2期10卷 1-15页

作者： ransford opoku darko Yuan Shouqi Liu Junping Yan Haofang Zhu Xingye Research Centre of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China Department of Agricultural Engineering University of Cape CoastCentral RegionCape CoastPMB Ghana

Water is the scarcest resource and the importance of the judicious use of water in the agricultural sector for sustaining agricultural growth and the retardation of environmental degradation needs no further *** successes of using sprinkler irrigation to develop new lands,point the way forward to a much greater role for the development of future land reclamation *** use efficiency through a proper improvement of water management techniques and other production factors are essential to boost on-farm *** factors affecting uniformity and water use efficiency in sprinkler irrigation have been outlined in this research,highlighting possible ways to improve such essential parameters in crop *** study emphasizes on an irrigation system that works adequately in applying water to stay within the root zone,making the water always available in sufficient quantities to meet the crop water *** suggests practical ways of managing irrigation systems within tolerable limits not neglecting the effects of wind which is a major contributing factor to non uniformity in sprinkler irrigation.

关键词： sprinkler irrigation uniformity water use efficiency crop yield

Optimization of movable irrigation system and performance assessment of distribution uniformity under varying conditions

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International Journal of Agricultural and Biological Engineering 2017年第1期10卷 72-79页

作者： Yuan Shouqi ransford opoku darko Zhu Xingye Liu Junping Tian Kun Research Centre of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China Department of Agricultural Engineering University of Cape CoastCentral RegionCape CoastPMB Ghana

The evaluation of the performance of distribution uniformity by linearly moved irrigation system(LMIS)should consider the impacts of non uniformity of the water on crop *** increasing pressures to improve water use efficiency,plant productivity and farm profitability,questions continue to be raised concerning the future direction of irrigated *** study therefore aimed at evaluating water distribution under LMIS newly designed by the National Research Centre of Fluid Machinery Engineering and Technology,Jiangsu University,*** article reports the real distribution of irrigation water under the LMIS with respect to sprinkler height above the ground surface as well as the consequence of different operating *** distribution coefficients used in the performance assessment were Christiansen’s coefficient of uniformity(CU),distribution uniformity(DU),scheduling coefficients(Sc)and the coefficient of variation(CV).The results showed that the mean CU ranged from 82.30%to 93.17%,and mean DU ranged from 70.39%to 88.44%.Also Sc values ranged from 1.13 to 1.42 with CV values ranging from 10.3%to 22.5%.The optimum method and results in this study can provide a reference to the operations for saving water and cost in the application of LMIS.

关键词： movable irrigation system sprinkler irrigation distribution uniformity coefficient of uniformity coefficient of variation scheduling coefficient

Hydraulic performance characteristics of impact sprinkler with a fixed water dispersion device

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International Journal of Agricultural and Biological Engineering 2018年第6期11卷 104-112页

作者： Zakaria Issaka Hong Li Yue Jiang Pan Tang Chao Chen ransford opoku darko Research Center of Fluid Machinery Engineering&Technology Jiangsu UniversityZhenjiang 212013JiangsuChina Department of Agricultural Engineering Tamale Technical UniversityNorthern RegionGhana Department of Agricultural Engineering University of Cape CoastCentral RegionGhana

One way to adapt to the trend towards low-energy and to improve the hydraulic performance of the impact sprinkler under a low pressure condition is by means of a fixed water dispersion device.A fixed dispersion device disperses jet flow from the nozzle *** shape of the tip,impact angle(θ),diameter(D),and depth in the jet flow(d)have significant influence on the hydraulic *** this study,the hydraulic performance characteristics of impact sprinkler as affected by the fixed water dispersion device were studied under indoor *** water distributions from the sprinkler were obtained by experiments for the fixed water dispersion *** was used to transform the radial data into net data,and the uniformities were simulated in a square layout from 1 to 2 times the range(R).The droplet size distributions from the fixed water dispersion devices were measured by a laser precipitation monitor(LPM).Results showed that the range increased with the increase of pressure,and the sprinkler with type C_(2) produced a rectangular-shaped water distribution pattern,while the range was maintained.A maximum uniformity of 71.56%,75.56%,77.23%,73.32%,78.88%and 86.67%was found for types A1,B1,C1,A2,B2,and C_(2),respectively under a pressure of 200 *** uniformity from the sprinkler using type C_(2) surpassed 80%,while type C1 fell *** sizes from type C_(2) was best,and the mean droplet diameter decreased with the increase of ***,type C_(2) can be selected for further optimization of the design features to improve the hydraulic performance of the impact sprinkler under low pressure conditions.

关键词： fixed water dispersion device impact sprinkler range water distribution uniformity droplet size

Irrigated agriculture for food self-sufficiency in the sub-Saharan African region

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International Journal of Agricultural and Biological Engineering 2020年第3期13卷 1-12页

作者： ransford opoku darko Junping Liu Shouqi Yuan Livingstone K.Sam-Amoah Haofang Yan Research Centre of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China Department of Agricultural Engineering University of Cape CoastCentral RegionCape CoastPMB Ghana

Increasing agricultural productivity in Africa will have important impacts not only on the agricultural sector but also can be a catalyst for industrialization through ***,therefore,has a crucial role in enhancing food security and reducing hunger in the *** countries in Africa consider water and irrigation management as a key factor in improving their food security and ensuring access to drinking-water for their ***,there is evidence from a number of places on the continent where the adoption of efficient irrigation systems has led to higher productivity among smallholder *** the appropriate interventions for the diverse agro-ecological zones of sub-Saharan Africa are known,adoption among smallholder farmers still remains a *** technology opens the vast untapped potential for farmers,investors,and entrepreneurs to improve the efficiency of food production and consumption in *** precision farming to an efficient food supply chain,technology could bring major economic,social,and environmental *** investment and involvement of the private sector is crucial for the up-scaling of irrigation ***,the sheer optimism across the startup ecosystem is that extreme hunger can be cured in Africa,in this generation,by significantly transforming the industry that employs most of its *** paper draws on lessons from past trends in the irrigation industry and emphasizes on novel directions to ensure that farmers,as well as other stakeholders reap the benefits associated with improved technologies.

关键词： food self-sufficiency irrigation development small-holder farms sub-Sahara Africa sustainability

Overview of modelling techniques for greenhouse microclimate environment and evapotranspiration

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International Journal of Agricultural and Biological Engineering 2021年第9期14卷 1-8页

作者： Haofang Yan Samuel Joe Acquah Jianyun Zhang Guoqing Wang Chuan Zhang ransford opoku darko State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing 210029China Research Centre of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013JiangsuChina Department of Water Resources Development School of Sustainable DevelopmentUniversity of Environment and Sustainable DevelopmentPMB SomanyaEastern RegionGhana Institute of Agricultural Engineering Equipment Jiangsu UniversityZhenjiang 212013JiangsuChina

Domestication of plants by man through greenhouse crop production has revolutionized agricultural farming systems *** the appropriate greenhouse technology together with the user-friendly evapotranspiration(ETc)model can optimize crop water *** greenhouse microclimate environment has nearly zero wind speed and low radiation,hence low transpiration due to high temperature and ***,matching the greenhouse microclimate with the appropriate ETc model will certainly optimize crop water use efficiency since water is becoming a scarce resource globally,more so in the greenhouse *** is one of the main reasons why the gap between the dissemination of various advanced ETc models and the application by the greenhouse crop producers’community needs to be *** likelihood or chances of rapidly disseminating and adopting advances in ETc estimating technology by a larger greenhouse crop producers community will increase if greenhouse ETc models become more user-friendly and *** contribution of the greenhouse system to increased and sustainable food production must come through improved disseminating,adopting and use of existing greenhouse ETc *** recommends a standard approach for the determination of crop water requirements utilizing the product of reference evapotranspiration(ET0)and crop coefficient(Kc)*** FAO approach can also be used in greenhouse cultivation ***,studies connecting greenhouse technologies and methodologies for measuring ET0 or ETc in greenhouses are not *** are also few studies undertaken that compared the performance of ET0 or ETc models under different categories of greenhouse *** this review,a link between greenhouse technology and ET0 model or ETc model,and how existing knowledge and methodologies in ET0 or ETc measurements can actually enhance the sustainability of greenhouse farming have been *** categories of greenhouses,equipment

关键词： greenhouse microclimate environment reference evapotranspiration models crop evapotranspiration overview

撒哈拉以南非洲地区农业灌溉实现粮食自给自足

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农业工程技术 2020年第33期40卷 84-84页

作者： ransford opoku darko 刘俊萍袁寿其 Livingstone K.Sam-Amoah 闫浩芳江苏大学流体机械工程技术研究中心海岸角大学农业工程系

提高非洲农业生产力不仅对农业部门产生重要影响,而且可以通过农业加工促进工业化发展。因此,灌溉在加强该区域粮食安全方面起到了关键作用。许多非洲国家认为水和灌溉管理是改善其粮食安全和确保其人民获得饮用水的关键因素,采用高效... 详细信息

提高非洲农业生产力不仅对农业部门产生重要影响,而且可以通过农业加工促进工业化发展。因此,灌溉在加强该区域粮食安全方面起到了关键作用。许多非洲国家认为水和灌溉管理是改善其粮食安全和确保其人民获得饮用水的关键因素,采用高效灌溉系统提高了小农户农场的生产力。虽然撒哈拉以南非洲不同农业生态区具有适当的干预措施,但在小农户农场中仍然是一个挑战。数字农业技术为农民、投资者和企业家打开了尚未开发的巨大潜力,以提高非洲粮食生产和消费的效率。从精确农业到高效的食品供应链,数字农业技术可以带来良好的经济、社会和环境效益。因此,增加小农户农场等私营部门的投资和发展灌溉技术至关重要。在这一代人中,通过改变农业产业模式等方式,非洲的粮食安全问题是可以解决的。该文借鉴了过去灌溉业发展趋势的经验教训,提出了新的方向,以确保农民和其他利益相关者从改进技术中获益。

关键词：粮食自给自足灌溉发展小农户农场撒哈拉以南非洲可持续性