Farmers should be asking themselves two important questions as they finalize crop budgets for the 2016 growing season, according to Brian Hefty, an agronomist and co-host of AgPhd TV and radio shows.

The first is, "What is the yield-limiting factor on each acre of your land?" The second: "Is it profitable to eliminate that issue?"

And Hefty, who also farms with his brother in South Dakota, doesn’t let people cop out and blame the...