Posted 10/16/2020 07:18 (#8548337 - in reply to #8547439) Subject: RE: Soil grids
Seeing lots of debate over grids vs zones here, both have good and both have serious downfall. A square grid (composite of each square block is garbage), a site specific grid is accurate at each sample but loses accuracy to statistics between point the larger the grid size. Zones show a nice pattern you may be used to seeing in soil types or yield but that doesnt mean thats how your nutrients vary, all zones make a map without any nutrient data and then soil sample and apply nutrient data to it later. So you do not get any nutrient maps with a zone sample.
We have gone to Soil OPtix the last 4 years which gives the best of zones and grids. It uses site specific points (1 per 6 ac) placed based on the soil variability and the mapping gives us the rate of change for each layer INDEPENDANTLY as well as topography because where water flows makes a big difference. With this system we have a data point roughly every 10 ft fully stacked with soil test data. 40+ maps instead of 1 map like a zone system and I have never seen a field where more than a couple of those layers looked similar.
We did a 1/2 ac site specific grid to verify the data on multiple 160 ac fields and were amazed at how accurate the data was.
I attached a demo field if anyone wants to take a look, we do this western canada there may be providers that can come to your area but I dont know. We have set legends for the maps that we can so that a grower can compare all his fields on an even scale as well as to his friends. That is why there is an extra P map for this field because the P was very high that it was all at the top end of the scale.
That is another thing to always watch, legend can be adjusted to show lots of variability when there really isnt any, our sulphur maps can do this because S can vary so much the legend it set to put the full range of colours to whatever range is there, it can be 10 ppm or 300.