Bracts versus leaves. Limestone decreased N, Mg, Mn, Zn, and Cu but increased Ca level in the leaf-tissue. Limestone did not affect mineral content in the bract tissue. These results are an indication how the pH directly affects the minor element content of both leaves and bracts. It is not clear why the pH in the solution decreases.
Data are the mean of five sets of data.
The increase in EC is likely due to evaporation of water in the tanks and the solution picking up some residue in the troughs when irrigating. The normalized calcium concentrations did not change appreciable with recirculating but were generally lower with an increased bicarbonate level. Bicarbonate levels were generally not attained at the prescribed levels but also decreased between a fresh and a recirculated solution.