Splitting applications across pre plant, side dress before hilling and fertigation is definitely the best approach if you have the equipment and time (from a general fertilization standpoint). Full disclosure – I’ve never grown a field of potatoes in my life, so I’m not familiar with their specific requirements, but something to consider is what you’re hoping to get out of short term acidification. ATS will help, but you might also be able to get around the P and micro uptake issues with foliar feeds and inoculating with phosphate solubilizing bacteria? Someone more familiar with high pH soils might be able to help more! But those are my quick thoughts.

Any way you can get the land owner to agree to an annual sulfur application to keep things moving in the right direction?