Every year I get soil tests done as early as I can in the spring. This year I managed to sneak out late January during a warm snap when then soil was thawed enough to get down into the soil far enough to get a good sample.
I walk around the field and stick the tool on the left into the soil, pull it out and I have a 6 inch long tube of soil. I dump that sample in a clean bin and mix in 10-12 more sample all taken at different spots around the field. I want to try to get a good average of what the field looks like. This can be hard because I know where the good spots and the bad spots of the field is and finding an average of them all can be a little tricky. Once I have my mix I put a 2 cup sample of that and send it off to the lab.
I got my results back recently and have been going over the results. It always interesting to compare each year’s results with previous years to see how things have changed. Hopefully the soil gets better each year, but some years it doesn’t change much. So you can compare with me here are test results for 2015 and here are the results for 2016. Don’t worry, I have gotten them for 6 years now and I still don’t completely understand them.
The three numbers I look at each year that give me a pretty good gauge for how healthy things are in general are the PH. Humus, and CEC, all of which are toward the top. PH is probably pretty familiar to most people and we are in a healthy range. The Humus percentage is how much organic matter is in the soil. I’d love to be higher than 2.7%, but it is so hard hard. We have a generally sandy soil so while it has been slowly rising I need to keep adding compost and using cover crops to keep adding organic matter to the soil. The CEC ratio is a little more complex. It tells you how good the soil is at holding on to nutrients. Low CEC ratios (1-10) are sandier soils and nutrients have a tendency to leach away. While higher CEC ratios (11-50) are clay soils and the soil holds on to the nutrients more. This can mean that the soil may not be willing to share the nutrients with plants and you need to add a lot more nutrients to get your levels of shareable nutrients where they need to be. From 2015 to 2016 the increase in CEC was the biggest change I noticed. I am glad for the increase because I don’t mind the CEC being 7-9, this will give me a bit of a buffer to add some extra nutrients that will stay around in the soil for a while and be available throughout the season.
I also get recommendations for organic supplements to add to the field which are much more straight forward. Nothing is lacking too much, but I have been adding a little sulfur, copper, zinc, and boron each year to try to get those numbers up. I can get those supplements in bulk and spread them over the field in the spring. I also get compost and manure to add to the nitrogen and organic matter levels in the field.
If you think about it, so much produce (energy from the sun and soil) leaves the field each year I need to replace what was taken out. I wished I knew the total number of pounds of produced was harvested each year and compare that to how many pounds of soil nutrients I return to the soil. The soil is super complicated because thinking about adding what was taken also requires thinking about what the sun contributes, what the cover crops add, what the legumes are adding, and how much the little critters in the soil are working. Way too complicated for me, but it is still fascinating.