I purchased my first field this winter and I will be able to farm it this coming spring. It is in the platte river valley but about 3 miles from the river ( never flooded in 19). Im thinking of doing 1 acre grids just to know where I'm at. Ground was corn this year and plan on corn the next year as well. Ground is pivot irrigated. The plan is striptill this fall variable rate my dry and plant his spring. Will float on 32% pre and y drop later on. Can I do my only soil sampling? Is one acre too small? too costly? Where I buy a probe at? Will my phone work good enough for GPS.?