Hello, I am working with vermicompost of agave bagasse with cow dung. I am tryng to measure the pH with 1:10 (w:v) with water, but the vermicompost absorbs all the water. Any recomendation??
For the pH determination, in your case particularly, you can use pH strips with detailed color coding. Some strips are color coded for just 1 to 12 but there are some strips available that has a representative color difference of pH 0.1 within each ten-fold increase (like 7.0, 7.1, 7.2, 7.3, 7.4.....and so on to 8.0 and likely) there you can compare your vermicompost pH more accurately corresponding to the color.
Alternatively, you can use automated pH probes (like testo 205 pH probe or any similar items) but first you need to dilute your vermicompost sample more. pH result will not change if it is not too much diluted. So go for 1:30 (1g of compost in 30ml of distilled water) and try to check the pH. Hopefully this will give you the result.
Perhaps treat it like a growing medium/potting mix. One "standard" method is the 1:1.5 volume extract. This is the basis for standard methods used in Australia (though originally from the Netherlands I believe). One easy to find reference can be found at https://www.ngia.com.au/Attachment?Action=Download&Attachment_id=1403 . If you can get a copy of the Australian Standard for potting mixes (AS 3743—2003) or Handreck, K.A. and Black, N.D. (2002) Growing Media for Ornamental Plants and Turf. UNSW Press these would be excellent sources of testing information.
I would try increasing the water addition until a slurry results and standardize your measurement based on that. The suggestion of using strips not so dependent of a more aqueous condition could be compared to give an idea of if the dilution changes the result. The Strip would not depend on have free water for solution but rather just enough to moisten by the wick action. Comparing both these options will be interesting. Most researchers want to have a slurry or solution but this may not be critical. Try these out and see what you get.
Possible by increasing the volume of of water we can get suspension but the problem if you dilute more the pH value is not the same i am very if you have formula to make equivalence of each dilution factors