Another week in college and again looking back we have covered an enormous amount of ground. One of the areas I find most interesting is soil science and the composition of the soil, specifically my own soil. Earlier in the week I took a soil sample in to college the soil pH was around 6.5. This needs to be confirmed with a more accurate reading but it is unlikely to vary greatly.
I also got the opportunity to do a sieve analysis or a gradation test using three different size sieves. I dried out the sample in an oven and then gave it a grind and took a weighed amount and shook it through the sieve. The result gave me three figures for fine, medium and coarse which relates to clay, sand and silt. Using a triangular soil graph I added the percentages and came up with a result that would indicate a high level of clay.
This doesn’t surprise me as the soil is pretty heavy around here but it was great to get some kind of figure on it. According to this sample and method I have 62% Clay, 23% Silt and 14% Sand. We are going to do a moisture retention test and also an organic matter test but everything indicates I could improve my soil by increasing drainage and if I wanted to move my sand percentage up to around 28% I would need to add at least 5kg/m2.
So I intend to do a bit of an experiment on my new veg plot and work on improving the soil so I added some sand on a 12m x 8m patch. I decided to add some used coffee grounds which I have been collecting mixed in with the sand. As far as I can make out coffee grounds can supply phosphorus, potassium, magnesium and copper almost immediately and can act as a slow release nitrogen fertiliser. I am hoping that all this along with my usual addition of seaweed will increase both the fertility and the organic matter content of my soil.