Dear Marcus Hardie,

have you tried to use the SIMDualKc model? It has been used in orchard crops.

Bellow I'm sending two references about this model:

Rosa, R.D., Paredes, P., Rodrigues, G.C., Alves, I., Fernando, R.M., Pereira, L.S., Allen, R.G., 2012a. Implementing the dual crop coefficient approach in interactive software. 1. Background and computational strategy. Agricultural Water Management 103, 8-24.

Rosa, R.D., Paredes, P., Rodrigues, G.C., Fernando, R.M., Alves, I., Pereira, L.S., Allen, R.G., 2012b. Implementing the dual crop coefficient approach in interactive software: 2. Model testing. Agricultural Water Management 103, 62-77.

Dear Marcus

do you know SIMETAW model? Maybe it could be useful for you.

Let try to write to my colleague Donatella Spano ([email protected])

You could check into APEX. This model does allow several plants growing at the same time, thus allowing both fruits trees and ground cover in the alleyway. It is also very flexible in terms of management practices. It simulates leaf growth and leaf fall and you could add the pruning as a field operation.

Dear Marcus,

We simulate this with MODFLOW-FMP2 but this may be more thatn you want as we also can simulate the climate, surface water/groundwater irrigation, direct uptake, etc but we do split E and T as part of this simulation and this can be varied on any time interval that you specify. Here are some references on our integrated water software:

Schmid, W., Hanson, R.T., Maddock III, T.M., and Leake, S.A., 2006, User’s guide for the Farm Package (FMP1) for the U.S. Geological Survey’s modular three-dimensional finite-difference groundwater flow model, MODFLOW-2000: U.S. Geological Survey Techniques and Scientific Methods Report Book 6, Chapter A17, 127p. (http://pubs.usgs.gov/tm/2006/tm6A17/)

Schmid, Wolfgang, and Hanson R.T., 2009, The Farm Process Version 2 (FMP2) for MODFLOW-2005 - Modifications and Upgrades to FMP1: U.S. Geological Survey Techniques in Water Resources Investigations, Book 6, Chapter A32, 102p. (http://pubs.usgs.gov/tm/tm6a32/)

Hanson, R.T., Schmid, Wolfgang, Faunt, C.C., and Lockwood, B., 2010, Simulation and Analysis of Conjunctive Use with MODFLOW's Farm Process: Ground Water Vol. 48, No. 5, pp. 674 - 689. (DOI: 10.1111/j.1745-6584.2010.00730.x)

Hanson, R.T., and Schmid, Wolfgang, 2013, Economic Resilience through “One-Water” Management: U.S. Geological Survey Open-File Report OFR 2013-1175, 2p.

Let me know if you have interests in our newest version ([email protected])

Dear Marcus, we have a long experience simmulating Kcb from remote sensing data and Ke from top soil layer water balance. Our experience indicate that Kcb varies depending on canopy development, and the use of predictive models, based on tabulated values, doesn´t work adequatly. For aditional information please read:

Assessing satellite based basal crop coefficient for irrigated grapes. Campos et al. 2010. Agricultural and Water Management.

and

Remote sensing based soil water balance to estimate mediterranean dehesa evapotranspiration under water stress conditions. Campos et al. 2013. Journal of Hydrology.

Please contact me for additional information, [email protected]

Dear Marcus Hardie,

Yu can use the dual approach of FAO-56 model. we used it in orchard crops ( olives and citrus).

Bellow I'm sending you two references about this model:

-1. Er-Raki, S., Chehbouni, A., Boulet, G., Williams, D.G. 2010. Using the dual approach of FAO-56 for partitioning ET into soil and plant components for olive orchards in a semi-arid region. Agricultural Water Management. 97: 1769–1778.

-5. Er-Raki, S., Chehbouni, A., Guemouria, N., Ezzahar, J., Khabba, S., Boulet, G. and Hanich. L. 2009. Citrus orchard evapotranspiration: Comparison between eddy covariance measurements and the FAO 56 approach estimates. Plant Biosystems, 143 (1): 201-208.

I would suggest that you email Professor William Bauerle at Colorado State University (he is in the Department of Horticulture). Here are his two most current publications:

Barnard, D.M. and W.L. Bauerle. 2013. The implications of minimum stomatal conductance on modeling water flux in forest canopies. Journal of Geophysical Research: Biogeosciences, DOI 10.1002/jgrg.20112.

Bauerle, W.L., A.B. Daniels, and D.M. Barnard. 2013. Carbon and water flux responses to physiology by environment interactions: A sensitivity analysis of variation in climate on photosynthetic and stomatal parameters. Climate Dynamics, DOI 10.1007/s00382-013-1894-6.

His email is: bill.bauerle @ colostate.edu (please note unofficial empty spaces).

Tom

Dear Marcus,

I agree with Isabel Pôças, you should try SIMDualKc. We've been using it with orchards (peach, olive) with good results. It can be downloaded from:

http://ceer.isa.utl.pt/cms/

References for olive and peach ET modelling:

Pôças I, Paço TA, Cunha M, Silvestre J, Santos FL, Pereira LS (2013).Crop coefficients derived from METRIC and SIMDualKc models for discontinuous woody crops. A remote sensing application to a super intensive olive grove. 1st CIGR Inter-Regional Conference on Land and Water Challenges – Bari (Italy), 10-14 September, 2013.

Paço TA, Ferreira MI, Rosa R, Paredes P, Rodrigues G, Conceição N Pacheco C, Pereira LS (2012). The dual crop coefficient approach using a density factor to simulate the evapotranspiration of a peach orchard: SIMDualKc model vs. eddy covariance measurements. Irrigation Science, 30:115-126 (doi: 10.1007/s00271-011-0267-3).

Dear Marcus,

I also agree that straight tabular values from FAO or other sources are inadequate...we actually link our Integrated hydrologic models to the remotely sensed data so you get the advantages of both. So if you need to simulate larger areas this is a good way to go but if you just need a point estimate for a single field, then these other estimators may be more convenient and expedient.

How large is the orchard? Do you have access to satellites with thermal bands? If yes, you could use the energy balance models, such as SEBAL or METRIC or TSEB.

U can try to use remote sensing data, followed by energy balance model or any integrated model. It should work. Wil u pls share your feedback also.

Marcus,

I agree with Salah Er-Raki for using the FAO56 model. They have an official software model (CROPWAT) which is now v.8 (see attached link)

About HYDRUS, It is an excellent model for simulating water and solute flows in variably saturated porous media, but it is not a model for predicting ET.

http://www.fao.org/nr/water/infores_databases_cropwat.html

I also agree to use the FAO approach. This is implemented in MABIA. If you want to use it for water management purpose in a water resource system you should look for www.weap21.org. There is an option to use the MABIA dual Kc mehtod for the calculation of the catchment water balance. For reference evaporation you can either use class A pan measurements or the penman-montheith approach with different levels of data availability.

Dear Marcus,

If you are only looking for the splitted ET I am completely agree with the use of Allen dual aproach (FAO) because it works very well and it´s relatively simple. However, if you are looking for a deeper knowlwdge of your water balance (drainage, soil water content at different layers,...) I recomend you have a look for other complexer solutions as WAVE model, a physically based 1-D complex model that allows you introduce the daily ETo and the Kc (that you can calculate by Allen dual method).

Gabriel, J.L., Muñoz-Carpena, R., Quemada, M., 2012. The role of cover crops in irrigated systems: water balance, nitrate leaching and soil mineral nitrogen accumulation. Agric. Ecosyst. Environ. 155, 50–61.

Dear Marcus,

according to my experience there is no difference betzeen Hydrus and FAO 56-paper to calculate potential evapotranspiration but using Hydrus output files (T-level.out) gives you actual and potential Evaporation and Transpiration.

Dear Marcus,

What is the interval you want to use? Approaches have to be modified? Accurate modeling would involve also the plant spacing and exposed soil beyond LAI. Do yo have this set of data?

Learn more ET measurement and modeling skills at this ET symposium in Raleigh, NC, USA in April 2014.

http://www.asabe.org/meetings-events/2014/04/2014-evapotranspiration-challenges-in-measurement-and-modeling-from-leaf-to-the-landscape-scale-and-beyond.aspx

Dear Marcus

I've used FAO dual crop coefficient approach for estimating daily transpiraiton and evaporation under almond, citrus and now for grapvine as well. The estimated daily values were used in HYDRUS which worked perfectly well. The most important parameters in FAO 56 which I feel needs cautious attention are Ks, fc, fw and few. The density of the tree shade described in Allen et al. 2009 may be incorporated to further finetune results.

For hydrus, the FAO 56 dual crop method works perfectly well.

One approach is to calculate tree behavior on selected sites from meteorological and soil moisture data, another approach is let these calculations to do by trees and measure their results by simple, but very effective technology combining actual sap flow and changes of water storage. Trees (including different species, age, size, etc.) can control eventual irrigation procedure using specific algorithms working within diurnal periods of time. You are getting higher yield and less consumption of water this way. Look e.g. at papers by Nadezhdina et al. Jan

You can try SEBAL

I disagree. SEBAL can be very inaccurate and should not be used without ground truthing with land-based networks and use with an integrated hydrologic model. Studies have shown that SEBAL can be off by as much as 70%.

You can use CROPWAT and MODFLOW for this

I have simulated using my own model formulated in spreadsheet to model "Gange"basin during my masters research in IIT Roorkee. Latter I improved the same for my PhD research. I have uploaded my PhD thesis in RG for your reference pl go to this link

https://www.researchgate.net/publication/255909976_CONJUNCTIVE_USE_OF_SURFACE_AND_GROUNDWATER_TO_IMPROVE_FOOD_PRODUCTIVITY_IN_A_RESTRICTED_AREA_Degree_of_Doctor_of_Philosophy?ev=prf_pub

Thesis CONJUNCTIVE USE OF SURFACE AND GROUNDWATER TO IMPROVE FOOD P...

Dear Marcus:

I think that the best option is the dual approach of FAO-56 model. To obtain Kcb values you can use sap flow sensors.

See for example:

Poblete-Echeverria, C., and Ortega-Farias, S. (2013). Evaluation of single and dual crop coefficients over a drip-irrigated Merlot vineyard (Vitis vinifera L.) using combined measurements of sap flow sensors and an eddy covariance system. Australian Journal of Grape and Wine Research, 19 (2): 249–260.

The problem with these approaches is that they are not coupled and require considerable extra work. in the new MODFLOW-OWHM which includes the Farm Process all of this is internally coupled and linked to precipitation, applied water from surface water and from wells for irrigation and to direct uptake from groundwater in a dynamic scheme that is integral to the use and movement of water within this new integrated hydrologic version of MODFLOW. So these other methods are outdated and limit the simulation, analysis and testing that you can do.

Have you tried Shuttleworth and Wallace (1985) model to simulated evapotranspiration in the orchards? We found it helpful in calcating evapotarsanpiration for arid sprase apple orchard.