Effect of defoliation on Virginia Bunch peanuts at Camden, N.S.W

Abstract

It is not at all usual to defoliate peanuts; however, the low harvest index (less than 0.34) and high vegetative yield (> 5 t ha-1) at Camden, N.S.W., suggested there might be foliage which could be harvested as forage. Accordingly, the ability of peanuts to sustain kernel yield after defoliation to 10 cm was examined using the cultivar Virginia Bunch at Camden. Defoliation up to early pod formation (10 weeks from sowing) caused no reduction in kernel yield, in contrast to later treatments where yield reductions of up to 40% were observed. The top dry matter so removed provides an additional useful forage product from the crop, with an in vitro dry matter digestibility of 79% and average nitrogen concentration of 2.4 g nitrogen/100 g at age 10 weeks. The reasons for the increased sensitivity to defoliation of older plants (> 10 weeks) are explored.