Soil testing my farm in Jackson County/southern Michigan
Soil testing my farm ( 75 acres, soil/corn/alfalfa with interspersed trees/woods and a swamp/wetlands) in Jackson County/southern Michigan: When is the best time of year to do the soil testing and send the soil samples to MSU for analysis? Second part of the question; how many soil samples from each of the five major fields comprising the farm should be taken
Thanks. D Peterson, md
Fall is generally the best time to sample as the annual crops are harvested and this gives you time to plan your fertility program for next year, incorporate lime or potassium. However, many people do soil sample in the spring before planting, and in the summer to troubleshoot plant growth problems.
There is a lot of good information at the MSU soil lab site, including sampling procedures.
Typically I recommend a soil sample for every 5 acres--if the field is very uniform then it could be more than 5 acres--perhaps a max of 20 acres.
If you suspect that a significant area of the field has difference soil type, then take a second sample so that you know how to fertilize each area. Each soil sample should consist of 15-20 subsamples, The typical sample depth for field soil is 8 inches. Discard the duff from ground level at the top of the sample.