Dear colleagues,
We are looking for specific (or global) PTF functions (with good performance in sandy soils) to estimate hydraulic properties (field capacity, permanent wilting point, available water)
The "sandy soils" we are studying are from the classes sand, loamy sand, sandy loam.
The predictive parameters we are thinking to use are particle size (coarse sand, fine sand, silt, clay, organic carbon, bulk density, CEC, soil types and maybe others)
If someone has worked with this topic. I thank you in advance for your suggestions.
Regards from Brazil
Wenceslau Teixeira
Embrapa Solos
Hi Niels. Thank you very much for your recommendations. I hope to find or develop a good one. Cheers
Regards
Wenceslau
Dear collegues I thanks some suggestion for publications. I also do have found this publication for some sandy soil of Brazil. I may be of interested for people working with hydraulic properties in sandy soils.
Dear Dr. Teixeira,
If you do not know it already, the rosetta pedotransfer model may help you (Article ROSETTA: A computer program for estimating soil hydraulic pa...
). Rosetta allows you to estimates the van Genuchten water retention parameters based on soil textural properties and bulk density through an Artificial neural network. It is not a new model, but we have used it in Canada in sandy soil with reasonable success and accuracy.Best regards,
Jean-Pascal
Hi Jean, thank you for your message. I have used Rosetta to estimate initial values for Hydrus. But I have learned that the estimates (van Genuchten parameters) for clayey Ferralsols and Acrisols are not good. Probably because these soils are clayey but act as sand (in water transmission). Anyway - I do have a problem performing a lot of analyses using Rosetta and nowadays it only works in my PC (64 bits) inside Hydrus. Anyway, it is nice to know that it works for sandy soils in Canada. By the way - Canada do have a public database about soil water characteristics from its soils ?
Hi Dr. Teixeira, Yes, there is a National soil database holding soil water characteristics for many soils in Canada. There are also some provincial soil databases. They can be handy tools for modeling, depending on the intended scale.
Hi Jean-Pascal Matteau. It the National soil database for Canada open access? if yes I thanks in advance if you send the link. I'm interested to see the layout organization and access and the soil attributes because we are organizing a Rio de Janeiro state soil database where I wish to organize not only measured data but also data predicted from PTFs functions. Regards
Hi Wenceslau Geraldes Teixeira. Yes, the National Soil Database of Canada is open access. Here is the link to the various accessible databases :
https://sis.agr.gc.ca/cansis/nsdb/index.html.
The National pedon database (spatialized) and the soil name and profile data contain the highest number of soil properties. I think it may give you ideas on how a state soil database can be organized. Those databases are precious pieces of information and historical data. Combining measured and predicted values in them is a really interesting project.
Regards
Dear Plant Soil Available Water researchers. We developed a function to estimate plant-available water capacity, calibrated with soil moisture measured data of field capacity (10 kPa) minus soil moisture at permanent wilting point (1500 kPa). We used the simplex mixture statistical model to avoid abrupt changes in the textural classes.
It was published in Portuguese and if was a demand for the analyses of soil climate risk zoning that run and adapted version on the SARRA Models
Available at:
CIRAD. Système d'Analyse Régionale des Risques Agroclimatologiques Version H
(SARRA-H). Disponível em: https://sarra-h.teledetection.fr/SARRAH_BH.html.
https://sarra-h.teledetection.fr/ModeleSARRAH_En.html
We calibrated and validate this PSAW - PTF equation with Soil Brazilian Data.
Available in this Github repository
https://github.com/dvictori/ptf_zarc/blob/master/resultados/Preditos_triangulo_AD_m2.csv
I was wondering if someone has an interest in and measured data of sand, silt, and clay in combination to measured PSAW to test the accuracy of this equation outside Brazil?
What we intended is to go in a hierarchical system to predict PSAW using other information as bulk density (rarely available in soil surveys), fine sand, organic carbon, and some categorical parameters as soil types, clay mineralogy, soil color or structure parameter to evaluate how can increase the accuracy of the predictions. But before we want to learn a bit more about the grain size distribution and PASW
Cheers
Wenceslau
TEIXEIRA, Wenceslau Geraldes et al. Predição da água disponível no solo em função da granulometria para uso nas análises de risco no Zoneamento Agrícola de Risco Climático. Embrapa Solos-Boletim de Pesquisa e Desenvolvimento. 2021
https://www.researchgate.net/profile/Wenceslau-Teixeira/publication/350793394_Predicao_da_agua_disponivel_no_solo_em_funcao_da_granulometria_para_uso_nas_analises_de_risco_no_Zoneamento_Agricola_de_Risco_Climatico/links/6072c885a6fdcc5f7798c1fa/Predicao-da-agua-disponivel-no-solo-em-funcao-da-granulometria-para-uso-nas-analises-de-risco-no-Zoneamento-Agricola-de-Risco-Climatico.pdf
DRAPER N. R.; PUKELSHEIM F. K. Ordering of simplex designs for first-and second-degree mixture models. Journal of statistical planning and inference. v. 1, n. 2,79 p. 325-348, 1999.
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