panel Good Yields for Oats in 1984! Again in 1985!

---> We resolved the yield issue for oats.

Fababeans: It turned out fababean yields had also been declining, likely also due to phytotoxicity. A change in tillage in 1984/5 (incorporating wheat residues by discing rather than rotovating ) improved those yields in 1985.

Wheat: Yields continued to decline, but with more sets of experiments we identifed the cause. Clover is incorporated just before wheat is planted in year III and also generates phytotoxins. The solution: incorporate clover earlier in the year, and cultivate several times before planting wheat (in early Sept.) to set back difficult perennial weeds (mostly Canada thistle) as well as to aerate the soil and stimulate breakdown of residues and phytotoxins.