Low potash in corn tissue tests

Have started to try and find limiting factors on my farm for a few years by pulling more soil and tissue samples then normal. This year my potash levels were med to high on my soil test base sat k was 4.5% And higher. We put down 120 units of k2o this spring and going of last year test I sidedressed with another 40 units of k20 and tissue samples were good v1-v9. After that potash took a dive down into low. I understand that corn has super high need for potash at the time it crashed but has anyone had any luck with any other products to get past this high demand time. I’m not a big fan when it comes to foo foo dust and super high equivalent liquid fertilizers so everything I put down is actual by weight k2o plant food units. Thanks