Thread: Calculating Percents in Soil Sample

I am solving the following problem:

"A soil sample contains 10 grams of organic matter, 30 grams of water and weighs 90 grams. There is 60% of sand, 10 grams of silt (the rest of the mineral fraction is clay)."

I am to convert the sand percentage into grams. Mathematically, I know how to do this but I am unsure of what it is a percentage of. I am assuming I subtract the amount of water and organic matter from the overall weight (90 grams), which equals 50 grams. So is the sand 60% of 50 grams?

Originally Posted by soilquestions

I am solving the following problem:

"A soil sample contains 10 grams of organic matter, 30 grams of water and weighs 90 grams. There is 60% of sand, 10 grams of silt (the rest of the mineral fraction is clay)."

I am to convert the sand percentage into grams. Mathematically, I know how to do this but I am unsure of what it is a percentage of. I am assuming I subtract the amount of water and organic matter from the overall weight (90 grams), which equals 50 grams. So is the sand 60% of 50 grams?

Good question.

You will have to ask whoever posed the question as you can interpret it to be 60% of either 50 grams or 90 grams.

Your problem is not a mathematical problem it is the result of a poorly worded problem. The fault lies with whoever wrote the problem.

30/150 is 20%.

Apparently, if you are not totally at sea, the mass cooked off after drying is biomass?

But this is not like the first question, in the OP.