Paper/Poster/Presentation Title

Integrated modelling within the soil-plant system in an irrigated semi-arid agroecosystem; Towards reduced Evapotranspiration losses

Presenter/Author Information

Douglas NyoleiFollow

Keywords

agroecosystems, soil moisture, water balance, energy balance, modelling, evapotranspiration

Start Date

25-6-2018 2:00 PM

End Date

25-6-2018 3:20 PM

Abstract

Most African agroecosystems in arid and semiarid areas have constantly reported low crop productivities due to water scarcities and low water productivities. Low water productivities have dominantly been linked to high soil moisture losses from direct evaporation and low irrigation efficiencies. For increased crop production with increased water productivities there is need to better understand the soil-plant water systems in an integrated manner. This can be achieved through improved integrated soil-plant water system modelling from a water and energy balance approach to provide better insight into the soil-plant system functioning thereby guide with soil moisture conservation and improvement in the practise of irrigation at field scale. In this study, we focused on field measurements and modelling within the soil-plant system in the midlands of Makanya catchment, a semi-arid agroecosystem with annual rainfall below 800m where irrigation is key to assured agricultural food production. The greatest challenge in the area is soil moisture with reported high moisture depletion rates, coupled with weak water sharing arrangements. We implemented this improved integrated modelling approach for improved understanding, quantification and prediction of ET especially the E and T separately, crop water use and water productivities. We, on one side, developed soil water and energy balance measuring systems based on validated low-cost soil temperature-moisture measurement to support with soil water modelling and ET estimation using RZWQM2 and AquaCrop Models and on the other side an ET validation system based on surface energy balance measurement and analysis system using a Bowen ratio energy balance (BREB) station

Stream and Session

Stream F: Systems identification approaches for complex environmental systems. Session F5: New and improved methods in Agricultural Systems Modelling.

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Jun 25th, 2:00 PM Jun 25th, 3:20 PM

Integrated modelling within the soil-plant system in an irrigated semi-arid agroecosystem; Towards reduced Evapotranspiration losses

Most African agroecosystems in arid and semiarid areas have constantly reported low crop productivities due to water scarcities and low water productivities. Low water productivities have dominantly been linked to high soil moisture losses from direct evaporation and low irrigation efficiencies. For increased crop production with increased water productivities there is need to better understand the soil-plant water systems in an integrated manner. This can be achieved through improved integrated soil-plant water system modelling from a water and energy balance approach to provide better insight into the soil-plant system functioning thereby guide with soil moisture conservation and improvement in the practise of irrigation at field scale. In this study, we focused on field measurements and modelling within the soil-plant system in the midlands of Makanya catchment, a semi-arid agroecosystem with annual rainfall below 800m where irrigation is key to assured agricultural food production. The greatest challenge in the area is soil moisture with reported high moisture depletion rates, coupled with weak water sharing arrangements. We implemented this improved integrated modelling approach for improved understanding, quantification and prediction of ET especially the E and T separately, crop water use and water productivities. We, on one side, developed soil water and energy balance measuring systems based on validated low-cost soil temperature-moisture measurement to support with soil water modelling and ET estimation using RZWQM2 and AquaCrop Models and on the other side an ET validation system based on surface energy balance measurement and analysis system using a Bowen ratio energy balance (BREB) station