Effects of Lime and Boron on Brown‐heart, Leaf Tissue Calcium/Boron Ratios, and Boron Concentrations of Rutabaga

Abstract

Abstract A greenhouse study involving four levels of lime and six levels of B, and a field study at two locations involving three levels of lime and five levels of B were conducted on rutabaga ( Brassica napobrassica , Mill. var. ‘York’). Brown‐heart was more severe at high pH than at low pH under B deficiency conditions. The effect of lime on the appearance of B deficiency symptoms was a physiological effect in the plant rather than a chemical reaction in the soil. However, lime applications, generally decreased the B concentrations of leaf tissue. Calcium/B ratios in the leaf tissue were inversely related to the hot‐water‐soluble B content of the soil. Under field conditions, liming increased the Ca/B ratio of leaf tissue in most cases. Calcium/B ratios of 3,300 to 8,500 and B concentrations of 2 to 7 ppm in leaf tissue were associated with very severe brown‐heart condition. Leaf tissue Ca/B ratios of less than 400 and B concentrations greater than 40 ppm, when the roots began to enlarge were associated with roots free from brown‐heart.