For a project I'm looking at the cost and benefits of water retention in the soil versus water retention directly on the land. Is there a relation between soil water content and organic matter? If yes, what is that relation and what can be the minimum en maximum water content of a sandy and clay soil per ha or m3 of soil?
Jeroen:
Please use the latest version of the Soil Texture Triangle Hydraulic Properties Calculator which can be downloaded from the following website: http://hydrolab.arsusda.gov/soilwater/Index.htm. This calculator allows you to dial or choose organic matter content and then asks you to input %sand, %silt and %clay. It will calculate the hydraulic properies for you. I think this will a good beginning....
Good luck,
Noorallah
Jeroen:
Please use the latest version of the Soil Texture Triangle Hydraulic Properties Calculator which can be downloaded from the following website: http://hydrolab.arsusda.gov/soilwater/Index.htm. This calculator allows you to dial or choose organic matter content and then asks you to input %sand, %silt and %clay. It will calculate the hydraulic properies for you. I think this will a good beginning....
Good luck,
Noorallah
Thank you Noorallah, I will check that link out and see how usable this is for my project.
Greetings,
Jeroen
Thanks for your suggestion Khagendra, I'm already looking into that. What I really need and want to know are the (exact) effects, as described in numbers (like %, kg, m3/o.m% stuff like that). At the moment I already have a better understanding of that, but it is far from complete (enough) to make the cost-benefit analysis.
Jeroen,
There can be a correlation between organic matter and water content; however, the more direct relationship is between soil/sediment type and organic matter. In general, sandy soil/sediment contains less OM than silt or clay and this is related to the surface area. The higher surface area for a given sediment means more of the particles are coated with OM. Of course, this will change if the OM is particulate, such as plant material. Also, water content is related to soil/sediment type and this is also related to surface area and hydration. Clay can hold far more water than sand and would thus have a higher % moisture content compared to sand. I hope that helps.
Hi!
You can also predict soil hydraulic properties using the ROSETTA model developed by the USDA (United States Department of Agriculture). It's downloadable for free on their website: http://www.ars.usda.gov/services/docs.htm?docid=8953
I didn't mention the other numerical models which can estimate the hydraulic properties of your soil:
SoilPar http://www.sipeaa.it/ASP/ASP2/SOILPAR.asp
RETC http://www.pc-progress.com/en/Default.aspx?retc
Hi Mr BLOOM.
I'm afraid that OM can induces the inverse effect on soil water retention,
In certain cases OM can causes soil water repellency (hydrophobicity).
Organic matter is complex of chemical substances that has a great variability in their specific surface - SS(among many other properties that are related with water holding capacity). I.e humic substance (with large SS can hold water in dry range (> 1500 kPa) in the other hand some charcoal pieces (also called biochar) what it is also organic matter and can has large density of pores that can hold in the wet range (~ 200 kPa) ... I guess that will not be a easy answer ...
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