Effect of Different Nitrogen Levels on Dry Matter Production, Canopy Structure and Light Transmission of Blackgram

The performance of blackgram (Vigna mungo L.) under various levels of nitrogen was evaluated at the Bangbandhu Sheikh Mujibur Rahman Agricultural University during March to June 2002. Two varieties of blackgram-BARI mash-3 and BINA mash-1 and six levels of nitrogen-0, 20, 40, 60, 80 and 100 kg N ha-1 were the treatment variables. Dry matter accumulation in different organs of plant was maximum with 80 kg N ha-1. The dry matter accumulation in different vegetative organs continued to increase until pod filling stage and then declined gradually. Contrary, the dry matter accumulation in reproductive organ increased up to maturity. Light Transmission Ratio (LTR) was decreased while Light Interception (LI) increased with the increasing level of nitrogen as well as with the plant ontogeny.