i would mix it 1:1 with peat ,then water it in ,check in a few days see what it is,the sulphate can be toxic if you over do it,reason i asked what was there ,was if it had clover the soil was acidic,being bare ,could indicate dumped salts on the spot,if there were trees there and they flurish the soil is nuetral,to alkaline the tree wont grow,just old myths some may say,but has worked many time gorrila growing in the forest for me,i look for a spot with clover and water source near on the south west side of a hill.anyway cant help but think your meter is wrong,that be my best guess,soil at 7.5 cut with peat and added vermiculite and or perlite to help with drainage,make hole a good size were the drainage will be away from the plant