Something we are looking for is the difference between agricultural systems (industrial, organic) performances in providing ecosystems services to cities. I could not find a detailed literature about the different curve numbers according to changes in agriculture management. Anyway we know by other means that organic agriculture has a higher tax on organic matter which changes the water retention capacity, but I don´t know how this affects the curve number. Is there any reference that could help me with that?
Hi @jayamstel ,
That’s a great question. I’ve reached out to some of our science leads and will let you know as soon as I hear back!
Thanks for posting.
Doug
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Hi Jay,
I also did a quick lit search and did not find anything on impacts of OM to curve number. I have sent a note to a colleague who might know more, and will reply if or when I hear back.
One approach you might try, if you haven’t already, is to dig into the literature on saturated hydraulic conductivity (Ksat). There is plenty of information out there on the effect of OM on Ksat (e.g. here), and you should be able to find information specific to agricultural soils. (My own knowledge is limited in that regard).
Then, you could adjust the curve number (CN) for Ksat, using an approach such as in this paper. There might be some other approaches out there, as well.
Sorry I cannot be of more help, but this is an interesting question! I will let you know if I find any other information.
Regards,
Ben
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Another potential resource I came across is the SoilKsatDB, which could be helpful as it includes both Ksat and soil carbon data. I did not look into it carefully, but you may be able to use it find your area of interest, or locate some characteristic soils.
- Ben
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In case this is helpful, I did hear back from my colleague about OM and curve number. And while he didn’t not have a lot to add, he did provide this reference:
He also wrote the following:
> “However, organic agriculture doesn’t necessarily translate to large increases in SOM. As you might guess, there are lots of things to keep track of - and even if things are working in your favor, it will still take a long time to see measurable increases in SOM. Increased crop residue on the field surface will help to reduce runoff (if they are practicing no-till, for example). And there are established methods to adjust CN based on tillage practice. So if someone wanted to adjust CN based on no-till, there are existing studies available to back that up.”
None of this may be new information for you, but just wanted to pass it along in case it’s helpful.
Regards,
Ben
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Dear Ben,
Really thanks for providing me with adittional information. In fact, I didn´t realize that I could search for CN studies about no-till cropping, probably I´ll find something here in Brazil, as there a lot of studies about this pratice.
If I find something usefull I share here.
Thanks again for all the resources and references!
Jay van Amstel
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