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NE Iowa | Jim, Greywolf, Paul, puma,
Thanks much for your 'conversation' on this topic - very enlightening to someone that hasn't had any formal training in agronomy, soils, nutrient uptake, etc.
We have always used crop removal rate of 150# K and 125# P for our typical yields of ~ 200 bu corn and ~ 60 bu beans.
Jim,
Like many on this board, I have had the chance to visit with you at various shows (most recently in Louisville) and always enjoy the conversation. Like you, I am an engineer, so am playing catch-up on this soil fertility game. I live in NE Iowa and help a certain company design tractors - seems we had a good conversation about my employer during our visit in Ky.
I agree with your sentiments about university broadcast P&K recommendation vs. actual plant uptake. What you stated was exactly what I was theorizing. The soil samples that showed the high P&K levels were taken in last year's corn row, which should be right where the strip was made in fall of 2006. We don't use RTK, so really don't know where this years strip will be in relation to that strip. To see what the profile looks like, Dad went out and took some more samples today. He repeated the in-row sample, but then also took 2 samples probing across the row a full 30". Will be interesting to see the results.
I like your comments regarding Nitrogen. After planting (like the same day), we surface apply ~ 90# of 32% in a stream directly on top of the row. Then when corn is 3' - 4' tall, or so, we put another ~30# on the ground near the base of each row. I have run some trials through the years to see if the sidedress is worth it - some years it is (when we have had lots of moisture after planting) and some years it isn't (normal or dry years). This year, I have a plot where I didn't put any on right after the planter, and another plot where I put 150# on right after the planter. Within these 2 plots, I also varied the sidedress. Should learn something in another month, or so.
Chris | |
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P&K + StripTill
