scholarly journals Modelling of water and energy exchanges over a sparse olive orchard in semi-arid areas

2020 ◽  
Author(s):  
Wafa Chebbi ◽  
Vincent Rivalland ◽  
Pascal Fanise ◽  
Aaron Boone ◽  
Lionel Jarlan ◽  
...  
Keyword(s):  
Large Fraction ◽  
Soil Column ◽  
Olive Tree ◽  
Bare Soil ◽  
Modeling Tools ◽  
Olive Orchard ◽  
Vegetation Fraction ◽  
Tree Transpiration ◽  
Svat Model ◽  
Hydrological Functioning

Abstract. In the Mediterranean basin, olive orchards occupy a large fraction of agricultural lands due to its sustainability to harsh conditions, drought in particular. Since most modeling tools to simulate vegetation functioning are not meant to represent very sparse crops (i.e., rainfed olive trees have a vegetation fraction cover ranging from 2 to 15 %), computing the water needs and the vulnerability to drought of an olive orchard is a challenge. There is indeed a very high contribution of the bare soil signal to the total fluxes, and it is difficult to decipher the contribution of the tree from that of the entire surface. In this context, in an attempt to study the olive tree hydrological functioning at field scale (38 ha), an experimental site was setup and a Soil–Vegetation–Atmosphere (SVAT) model has been applied. To represent the orchard soil–plant–atmosphere interactions, a simulation with default settings was assessed using parameters derived from both the literature and ground measurements. In this default configuration, neither the predicted actual nor the potential transpiration could reach the observed transpiration acquired during the wet season (R2 = 0.67, the Root Mean Square Error (RMSE) = 5.63 mm week−1). We show that the model fails to reproduce the relevant leaf surface that transpires. To address this issue and to improve the estimate of the year-to-year variability of the olive tree transpiration, we propose guidance on how a SVAT model can be modified to more appropriately represent the hydrological functioning of a sparse orchard. Once the tree transpiration is accurately simulated (R2 = 0.93, RMSE = 1.62 mm week−1), we evaluated whether the fully coupled (single patch) or a fully uncoupled (two patch) system better reproduced the total fluxes and their components. Owing to the independent characteristics of the soil columns inherent in the assumption of the 2-patch version, the bare soil column shows a deficiency if the topsoil root extraction is not accounted for. We deduced that we cannot accurately reproduce the soil evaporation in this configuration. This study open perspectives for a better representation of water fluxes over sparse tree crops into both hydrological and SVAT models.

Analysing the combined effect of wetted area and irrigation volume on olive tree transpiration using a SPAC model with a multi-compartment soil solution

2017 ◽  
Vol 35 (5) ◽  
pp. 409-423 ◽  
Author(s):  
Omar García-Tejera ◽  
Álvaro López-Bernal ◽  
Francisco Orgaz ◽  
Luca Testi ◽  
Francisco J. Villalobos
Keyword(s):  
Soil Solution ◽  
Olive Tree ◽  
Combined Effect ◽  
Tree Transpiration ◽  
Wetted Area ◽  
Irrigation Volume

A physically-based soil surface model and its combination with numerical models for predicting bare-soil evaporation rates

2021 ◽  
Author(s):  
Xiaocheng Liu ◽  
Chenming Zhang ◽  
Yue Liu ◽  
David Lockington ◽  
Ling Li
Keyword(s):  
Numerical Model ◽  
Surface Resistance ◽  
Numerical Models ◽  
Soil Column ◽  
Soil Surface ◽  
Bare Soil ◽  
Water Vapor Transport ◽  
Surface Model ◽  
Vapor Flow ◽  
Physically Based

<p>Estimation of evaporation rates from soils is significant for environmental, hydrological, and agricultural purposes. Modeling of the soil surface resistance is essential to estimate the evaporation rates from bare soil. Empirical surface resistance models may cause large deviations when applied to different soils. A physically-based soil surface model is developed to calculate the surface resistance, which can consider evaporation on the soil surface when soil is fully saturated and the vapor flow below the soil surface after dry layer forming on the top. Furthermore, this physically-based expression of the surface resistance is added into a numerical model that considers the liquid water transport, water vapor transport, and heat transport during evaporation. The simulation results are in good agreement with the results from six soil column drying experiments.  This numerical model can be applied to predict or estimate the evaporation rate of different soil and saturation at different depths during evaporation.</p>

scholarly journals Detection of Bactrocera oleae (Diptera: Tephritidae) DNA in the gut of the soil species Pseudoophonus rufipes (Coleoptera: Carabidae)

2018 ◽  
Vol 16 (3) ◽  
pp. e1007
Author(s):  
Alice Albertini ◽  
Sónia A. P. Santos ◽  
Fátima Martins ◽  
José A. Pereira ◽  
Teresa Lino-Neto ◽  
...  
Keyword(s):  
Control Strategies ◽  
Cost Effective ◽  
Olive Tree ◽  
Carabid Beetles ◽  
Bactrocera Oleae ◽  
Negative Effects ◽  
Cytochrome Oxidase Subunit ◽  
Mtdna Sequences ◽  
Olive Orchard ◽  
Control Service

Pest control service provided by natural enemies of Bactrocera oleae, the key pest of the olive tree, is nowadays recognized as fundamental. B. oleae has developed resistance to common insecticides, and negative effects both on consumers’ health and non-target species are the major drawbacks of conventional control strategies. Carabid beetles are potential B. oleae pupae predators, but their predation on field still need to be assessed. We tested adult Pseudoophonus rufipes, a species known to be active in olive orchard when pest pupae are abundant in the soil, in order to detect B. oleae pupae consumption at different post feeding times for both male and female carabids. An already existing protocol was used for detecting B. oleae mtDNA sequences of the cytochrome oxidase subunit I gene in carabids’ gut, and its versatility improved. B. oleae mtDNA was detected up to 20 h after pupa ingestion with a high percentage of success, without significant differences between sexes and pair primers used. Prey DNA extraction was tested from both dissected and non-dissected carabids, obtaining comparable results. The trapping system used to collect carabids for molecular assays and the new elements introduced in the protocol represent cost-effective solutions that may be beneficial for future laboratory trials and, mostly, for the analysis of field-collected predators. Fostering the investigation of soil predators in olive orchard may increase the design of conservation control strategies against B. oleae.

scholarly journals Comparing high resolution WRF-VPRM simulations and two global CO<sub>2</sub> transport models with coastal tower measurements of CO<sub>2</sub>

2009 ◽  
Vol 6 (5) ◽  
pp. 807-817 ◽  
Author(s):  
R. Ahmadov ◽  
C. Gerbig ◽  
R. Kretschmer ◽  
S. Körner ◽  
C. Rödenbeck ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Fraction ◽  
Wrf Model ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Concentration Data ◽  
Modeling Tools ◽  
Global Models ◽  
Diurnal Variability ◽  
Resolution Model

Abstract. In order to better understand the effects that mesoscale transport has on atmospheric CO2 distributions, we have used the atmospheric WRF model coupled to the diagnostic biospheric model VPRM, which provides high resolution biospheric CO2 fluxes based on MODIS satellite indices. We have run WRF-VPRM for the period from 16 May to 15 June in 2005 covering the intensive period of the CERES experiment, using the CO2 fields from the global model LMDZ for initialization and lateral boundary conditions. The comparison of modeled CO2 concentration time series against observations at the Biscarosse tower and against output from two global models – LMDZ and TM3 – clearly reveals that WRF-VPRM can capture the measured CO2 signal much better than the global models with lower resolution. Also the diurnal variability of the atmospheric CO2 field caused by recirculation of nighttime respired CO2 is simulated by WRF-VRPM reasonably well. Analysis of the nighttime data indicates that with high resolution modeling tools such as WRF-VPRM a large fraction of the time periods that are impossible to utilize in global models, can be used quantitatively and may help to constrain respiratory fluxes. The paper concludes that we need to utilize a high-resolution model such as WRF-VPRM to use continental observations of CO2 concentration data with more spatial and temporal coverage and to link them to the global inversion models.

scholarly journals Can we use hourly CO<sub>2</sub> concentration data in inversions? Comparing high resolution WRF-VPRM simulations with coastal tower measurements of CO<sub>2</sub>

2008 ◽  
Vol 5 (6) ◽  
pp. 4745-4776 ◽  
Author(s):  
R. Ahmadov ◽  
C. Gerbig ◽  
R. Kretschmer ◽  
S. Körner ◽  
C. Rödenbeck ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Fraction ◽  
Wrf Model ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Concentration Data ◽  
Modeling Tools ◽  
Global Models ◽  
Diurnal Variability ◽  
Resolution Model

Abstract. In order to better understand the effects that mesoscale transport has on atmospheric CO2 distributions, we have used the WRF model coupled to the diagnostic biospheric model VPRM, which provides high-resolution biospheric CO2 fluxes based on MODIS satellite indices. We have run WRF-VPRM for the period from 16 May to 15 June in 2005 covering the intensive period of the CERES experiment, using the CO2 fields from the global model LMDZ for initialization and lateral boundary conditions. The comparison of modeled CO2 concentration time series against observations at the Biscarosse tower and against output from two global models – LMDZ and TM3 – clearly reveals that WRF-VPRM can capture the measured CO2 signal much better than the global models with lower resolution. Also the diurnal variability of the atmospheric CO2 field caused by recirculation of nighttime respired CO2 is simulated by WRF-VRPM reasonably well. Analysis of the nighttime data indicates that with high resolution modeling tools such as WRF-VPRM a large fraction of the time periods that are impossible to utilize in global models, can be used quantitatively and help constraining respiratory fluxes. The paper concludes that we need to utilize a high-resolution model such as WRF-VPRM to use continental observations of CO2 concentration data with more spatial and temporal coverage and to link them to the global inversion models.

scholarly journals Assimilation of surface soil moisture into a multilayer soil model: design and evaluation at local scale

2013 ◽  
Vol 10 (7) ◽  
pp. 9645-9688 ◽  
Author(s):  
M. Parrens ◽  
J.-F. Mahfouf ◽  
A. Barbu ◽  
J.-C. Calvet
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Surface Soil ◽  
Soil Column ◽  
Bare Soil ◽  
Surface Soil Moisture ◽  
Deep Soil ◽  
Background Error ◽  
Soil Layers ◽  
Diffusion Scheme

Abstract. Land surface models (LSM) have improved considerably in the last two decades. In this study, the ISBA LSM soil diffusion scheme is used (with 11 soil layers represented). A Simplified Extended Kalman Filter (SEKF) allows surface soil moisture (SSM) to be assimilated in the multi-layer LSM in order to constrain deep soil moisture. In parallel, the same simulations are performed using the ISBA LSM with 2 soil layers (a thin surface layer and a bulk reservoir). Simulations are performed over a 3 yr period (2003–2005) for a bare soil field in southwestern France, at the SMOSREX experimental site. Analyzed soil moisture values correlate better with soil moisture observations when the ISBA LSM soil diffusion scheme is used. The Kalman gain is greater from the surface to 45 cm than below this limit. For dry periods, corrections introduced by the assimilation scheme mainly affect the first 25 cm of soil whereas weaker corrections impact the total soil column for wet periods. Such seasonal corrections cannot be described by the two-layer ISBA LSM. Sensitivity studies performed with the multi-layer LSM show improved results when SSM (0–6 cm) is assimilated into the second layer (1–5 cm) than into the first layer (0–1 cm). The introduction of vertical correlations in the background error covariance matrix is also encouraging. Using a yearly CDF-matching scheme for bias correction instead of matching over the three years permits the seasonal variability of the soil moisture content to be better transcribed. An assimilation experiment has also been performed by forcing ISBA-DF with a local forcing setting precipitation to zero. This experiment shows the benefit of the SSM assimilation for correcting inaccurate atmospheric forcing.

scholarly journals Evapotranspiration partition using the multiple energy balance version of the ISBA-A-g<sub>s</sub> land surface model over two irrigated crops in a semi-arid Mediterranean region (Marrakech, Morocco)

2019 ◽  
Author(s):  
Ghizlane Aouade ◽  
Lionel Jarlan ◽  
Jamal Ezzahar ◽  
Salah Er-raki ◽  
Adrien Napoly ◽  
...  
Keyword(s):  
Energy Balance ◽  
Energy Budget ◽  
Bare Soil ◽  
Heat Fluxes ◽  
Olive Orchard ◽  
Dual Source ◽  
Irrigated Crops ◽  
Composite Energy ◽  
Convective Fluxes ◽  
Soil Patch

Abstract. The main objective of this work is to question the representation of the energy budget in surface–vegetation–atmosphere transfer (SVAT) models for the prediction of the convective fluxes in the case of irrigated crops with a complex structure (row) and under strong transient hydric regimes due to irrigation. To this objective, the Interaction Soil–Biosphere–Atmosphere (ISBA-A-gs) based on a composite energy budget (named hereafter ISBA-1P for 1 patch) is compared to the new multiple energy balance (MEB) version of ISBA using two representations of the canopy energy budget: a coupled approach (ISBA-MEB) where the vegetation layer is located above the soil and a patch representation corresponding to two-adjacent uncoupled source schemes (ISBA-2P for 2 patches). The evaluation is performed over a winter wheat field, taken as an example of homogeneous canopy and on a more complex open olive orchard. Continuous observations of evapotranspiration (ET) with Eddy covariance system, soil evaporation (E) and plant transpiration (Tr) with Sapflow and isotopic methods were used to evaluate the three representations. A preliminary sensitivity analyses showed a strong sensitivity to the parameters related to turbulence in the canopy introduced in the new ISBA-MEB version. The ability of the single and dual-source configuration to reproduce the composite soil-vegetation heat fluxes was very similar: the RMSE differences between ISBA-1P, -2P and -MEB did not exceed 10 W/m2 for the latent heat flux. These results showed that a composite energy balance on homogeneous covers is sufficient to reproduce the total convective fluxes. By contrast, differences were highlighted on the partition of ET. In particular, the ISBA-2P version showed an over-estimation of soil evaporation of about 20 % because of a direct exposition to incoming solar radiation and because there is no root extraction for the bare soil patch with regards to –MEB and -1P representations. By contrast, the dual source configurations including both the uncoupled (ISBA-2P) and the coupled (ISBA-MEB) representations outperformed the single source version (ISBA-1P) with slightly better results for ISBA-MEB in predicting both total heat fluxes and evapotranspiration partition over the moderately open canopy of the Olive orchard site. Concerning plant transpiration in particular, the coupled approach ISBA-MEB provides better results than ISBA-1P and, to a lesser extent ISBA-2P with RMSEs of 1.60, 0.90, 0.70 mm/day and R2 of 0.43, 0.69 and 0.70 for ISBA-1P, -2P and MEB respectively. In addition, it is shown that the acceptable predictions of composite convective fluxes by ISBA-2P for the Olive orchard are obtained for the wrong reasons as neither of the two patches is in agreement with the observations because of a bad spatial distribution of the roots and of a lack of incoming radiation screening for the bare soil patch. This work shows that composite convection fluxes predicted by the SURFEX platform as well as partition of evapotranspiration in a highly transient regime due to irrigation is improved for moderately open tree canopies by the new coupled dual-source ISBA-MEB model. It also points out the need for further local scale evaluation on different crops of various geometry (more open rainfed or denser intensive olive orchard) to provide adequate parameterization to global data base such as ECOCLIMAP-II in the view of a global application of the ISBA-MEB model.

Evaluating and modelling the hydrological and erosive behaviour of an olive orchard microcatchment under no-tillage with bare soil in Spain

2009 ◽  
Vol 34 (5) ◽  
pp. 738-751 ◽  
Author(s):  
E. V. Taguas ◽  
J. L. Ayuso ◽  
A. Peña ◽  
Y. Yuan ◽  
R. Pérez
Keyword(s):  
Bare Soil ◽  
No Tillage ◽  
Olive Orchard

scholarly journals A New Low-Cost Device Based on Thermal Infrared Sensors for Olive Tree Canopy Temperature Measurement and Water Status Monitoring

2020 ◽  
Vol 12 (4) ◽  
pp. 723 ◽  
Author(s):  
Miguel Noguera ◽  
Borja Millán ◽  
Juan José Pérez-Paredes ◽  
Juan Manuel Ponce ◽  
Arturo Aquino ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Low Cost ◽  
Canopy Temperature ◽  
Olive Tree ◽  
Thermal Infrared ◽  
Tree Canopy ◽  
Coefficient Of Determination ◽  
Crop Water ◽  
Olive Orchard

In recent years, many olive orchards, which are a major crop in the Mediterranean basin, have been converted into intensive or super high-density hedgerow systems. This configuration is more efficient in terms of yield per hectare, but at the same time the water requirements are higher than in traditional grove arrangements. Moreover, irrigation regulations have a high environmental (through water use optimization) impact and influence on crop quality and yield. The mapping of (spatio-temporal) variability with conventional water stress assessment methods is impractical due to time and labor constraints, which often involve staff training. To address this problem, this work presents the development of a new low-cost device based on a thermal infrared (IR) sensor for the measurement of olive tree canopy temperature and monitoring of water status. The performance of the developed device was compared to a commercial thermal camera. Furthermore, the proposed device was evaluated in a commercially managed olive orchard, where two different irrigation treatments were established: a full irrigation treatment (FI) and a regulated deficit irrigation (RDC), aimed at covering 100% and 50% of crop evapotranspiration (ETc), respectively. Predawn leaf water potential (ΨPD) and stomatal conductance (gs), two widely accepted indicators for crop water status, were regressed to the measured canopy temperature. The results were promising, reaching a coefficient of determination R2 ≥ 0.80. On the other hand, the crop water stress index (CWSI) was also calculated, resulting in a coefficient of determination R2 ≥ 0.79. The outcomes provided by the developed device support its suitability for fast, low-cost, and reliable estimation of an olive orchard’s water status, even suppressing the need for supervised acquisition of reference temperatures. The newly developed device can be used for water management, reducing water usage, and for overall improvements to olive orchard management.

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