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Concordia, KS | You don't other than a soil test, no different than a grid sample. Needs to be done every 4 years or so. It's not perfect. If you work through zone sampling and the EC data, you can define zones and assign yield goals, work through a weighted average and get reasonable VR N recs.. The only way to measure how you are doing is through N use efficiency. Again, it's an educated guess. It works decent on some of th highly variable sands in the Republican River Valley. We have guys that fertilize for 200 bushel irrigated corn every year, raise 170 or 180 and are disappointed. 1.2 to 1.1 lbs of n per bushel. The sand drags field averages down so much that 170 or 180 is pretty typical. We take that Veris data, fertilize the poor sand for 75 and the good ground for 220 and hopefully end up with 170 or 180 averages and put a field average of 160 to 180 lbs N. 1 lb of N per bushel average. I get really scared to push more than that because we don't have that yield data for some guys, but we can at least add some N use effincy for them. Some of these soils have CEC's of 2 to 20. It works because of high variability. If we didn't have that, it would be much harder. | |
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Cost for Veris mapping? Does this sound right?
