Agronomic studies on pigeon pea (Cajanus cajan (L.) Millsp.) III.* Responses to defoliation

Abstract

Two early-maturing and two late-maturing accessions of Cajanus cajan grown in the field for 161 days were defoliated to 90 cm 'stubbles' every 4,8,12 or 16 weeks over a period of 72 weeks. Evidence from total and seasonal dry matter and nitrogen yields, stand survival, and stubble yield at the termination of the experiment suggested that 8- and 12-week defoliation frequencies could be successfully integrated to incorporate cattle grazing and forage and seed production into a single management system. The late-maturing accessions were shown clearly to be better adapted to cutting, provided that basal green leaves always remained on the stubble. Defoliation of the accession UQ50 to reduce plant height to facilitate subsequent harvesting led to a reduced annual seed yield. The first seed crop was lost, as 'topping' removed the reproductive material.