The effect of chelating agents on the later break yields of Agaricus bisporus

It has been hypothesized that substances that accumulate during the mushroom cropping period are responsible for decreased yields as a mushroom crop ages. The objective of this study was to determine whether chelators added to compost substrate at spawning would affect the later break yield of Agaricus bisporus. Different types of chelators were used to determine if specific ions were involved. Supplemented compost receiving hypnum peat, IR120 (sodium saturated) cation exchange resin, ethyleneglycol tetra-acetic, and citric acid significantly increased later break yield. However, IR120 (hydrogen saturated) cation exchange resin, ethylenediamine tetra-acetic and sphagnum peat moss added to supplemented compost at spawning did not significantly increase yield in later breaks. These results suggest the accumulation of calcium or another cation may inhibit later break yields.