The untended land will also lose its fertility. Victor Ludlow explains the measurements used in this verse:
The phrase “ten acres” is derived from the Hebrew phrase “ten yokes,” meaning the amount of land ten yoke of oxen can plough in a day. Ten acres or “yokes” would equal about five acres. A harvest of grapes from this much land would normally yield dozens of gallons of wine. For the cursed land of Israel, however, this large area produces only one “bath” or from four to eight gallons of wine. Similarly, a “homer” of seed (about six bushels, also called a “donkey’s load”) yields only ephah of harvest (four gallons or twenty two litres). The complete irony of the situation can be seen in this last comparison, since ten ephahs equal one homer. Isaiah is promising that the harvest will be only one-tenth of the original planting. Instead of the soil yielding thirty, sixty, or one hundred fold, it produces only a fraction of the seed originally planted. This is such a drastic contrast from what is expected that if a farmer wanted food for the next year, he would be better off not to plant at all.