|
SE Iowa | I was wondering what guys think of variable rate apps. I have not done any but the local elevator did do a field grid free for me a few years back just to show me a few things. I guess my question would be, if you have a nice 40 or 80 that lays good, is pattern tiled, only one or two soil types, and the grid shows certain areas need lime or 500 lbs of fertilizer and other areas show no need for lime and 150 lbs of fertilizer, how do you digest that? Say that field yielded a fairly consistent 225- 240bu/a. of corn. It removed x amount of N P and K per acre based on what those yields should remove, yet the gridding shows abnormal replacement numbers (some high, some low) for that field. After 40+ years of farming I think I know how much fertilizer my cropping methods remove. But I have a 95 acre farm that shows an off the wall need for fertilizer with every soil sample, even when that very flat farm went bust in a few extremely wet years, so little fertilizer was removed. I have over the years over applied on that farm but it never catches up to its needs, so to speak. I also have had two suppliers soil test the same ground one year and the results could not have been more different. I can see where a field I described above may yield more inconsistently in an adverse overlywet weather year where crop over the tile line may be double that of crop between the tile runs. But you can't spread variable rate if tile lines are on 40 ft centers. Fire away. | |
|
variable rate grids
