I've always wondered how strip till rationalized reduced fertilzer use. Maybe someone can explain to me...

Let's say for round numbers it takes 1# of P & 1# of K (I know these aren't right) to grow 1 bu of corn, regardless of tillage-row width-whatever. So, you either use it out of the soil & replace, or deplete the soil, or rob the crop if soil is deficient to some degree. So-if you grow 150 bu corn, you need to supply 150# of P & 150# of K PER ACRE somehow. But, how do we justify only fertilizing either 1/2 the acres (band) or 1/2 the amount needed by removal?

I'm guessing strip till is looking for good root growth and not just a Mohawk pattern, especially in higher population stands. I think it's been proven that roots grow downwards & sideways for many feet, not just inches. So-your plants roots will draw nutrients from outside the zone.

But still, you only need to use a reduced amount compared to someone that tills the entire 30" spread? I'm not talking about starter or N needs, I'm questioning P &K.

Why is that?