I think you answered my question Pat - let me make sure..........please do not think I' m being a pain in the Arss but if I can use it I will.

If my soil test says K is " high" but the P & N are lacking - I' m likely to apply 11-52-0 (MAP) + 46-0-0 (Urea) and skip the K (for corn) - band it in at planting.

BUT.....

I do a tissue test and find out K is low in the plant - Do I then sidedress with 0-0-60 K (potash)?

Does the tissue test tell me HOW MUCH K to apply?

Does the test explain why its not being taken up while in the soil? - and how do I know that if I apply it - it will be beneficial to the plant ( or be available to the plant - eg. will the corn will take it in when it wouldn' t take it up in the soil (maybe its bound as a salt KSO2??)?

Ok - one last point- I assume that a crop plant like corn would have different N, P & K Requirements at different points in growth. - Like Wheat, & Oats - The nutrients in the stalk tend to migrate toward the seed as it develops. So I' d assume that tissue tests would vary at different growth stages of the plant. How do you know at what stage to do a tissue test - and do you subnit a full stalk for analysis?

Maybe I should have not used corn as an example - I could see where a more homgeneous plant like clover would be a better example - but still how do you know when to take a tissue sample - or does it not matter?

Thanks
Sorry I' m a pain - asking questions is how I learn.

Sean