Albert Barnes Commentary Job 31:8

"Then let me sow, and let another eat; Yea, let the produce of my field be rooted out." — Job 31:8 (ASV)

Then let me sow, and let another eat - This is the curse he calls down upon himself, if he had been guilty in this respect. He agreed to sow his fields and let others enjoy the harvest. The expression used here is common in the Scriptures to denote insecurity of property or calamity in general; see Leviticus 26:16: And ye shall sow your seed in vain, for your enemies shall eat it; compare Deuteronomy 28:30; Amos 9:13–14.

Yea, let my offspring be rooted out - Or, rather, Let what I plant be rooted up. So Umbreit, Noyes, Schultens, Rosenmuller, Herder, and Lee understand it. There is no evidence that he here alludes to his children, for the connection does not demand it, nor does the word used here require such an interpretation. The word צאצאים tse'ĕtsâ'iym – properly means shoots; that is, what springs out of anything – as the earth, or a tree – from יצא yâtsâ' – to go out, to go forth. It is applied to the productions of the earth in Isaiah 42:5; Isaiah 34:1, and to children or posterity, in Isaiah 22:24; Isaiah 61:9; Isaiah 65:23; Job 5:25; Job 21:8.

Here it evidently refers to the productions of the earth; and the idea is that if he had been guilty of dishonesty or fraud in his dealings, he wished that all that he had sown should be rooted up.