Boron Tolerance of Snap Bean and Cowpea

Abstract

The effect of excess B in the soil solution on snap bean (Phaseolus vulgaris L.) and cowpea [Vigna unguiculata (L.) Walp.] was determined in large, outdoor sand tanks. Boron treatments were imposed by irrigation with culture solutions that contained 0.5, 1.0, 3.0, 6.0, 9.0, or 12.0 mg B/liter for snap bean; and 1.0, 2.0, 3.0, 4.0, 6.0, or 8.0 mg B/liter for cowpea. Relative pod yield of snap bean was reduced 12.1% and cowpea seed yield was reduced 11.5% with each unit (mg·liter⁻¹) increase in soil solution B (B_sw) >1.0 and 2.5 mg B/liter, respectively. Reduced yield of snap bean pods and cowpea seeds was attributed primarily to a reduction in pod number. Increasing B_sw significantly reduced plant size of both species.