Posted 2/20/2021 12:03 (#8846649 - in reply to #8846539) Subject: RE: Following your land grant University Recs
I dont do much manure but when I did I had a nutrient specialist to do the recs so I have no clue how his rec compared to umn. On the soil test side I do know a little more about the differences. For that there are basically 3 options, custom, university, or lab rec. University is the last option imho. It is the most generic as it has to "not be wrong" for Iowa to Canada. Which means it's not likely very right specifically to you either. It seems that alot of data is based on pretty out dated work or ideas. I would use univ as a starting point or to have them point you towards better specific information and then you adapt from there. I would not assume very much accuracy specifically to your situation unless their research was done on your field. Nutrient content in nature varies quite alot and you are correct that how much and when varies more too vs conv fert. I think you have to figure more conservatively for manure and expect less uniformity and less control. Do more individual tests of the manure pile and as close to application time the better and adjust as best you know how.