Physiological growth parameters, forage yield and nitrogen uptake of sorghum (Sorghum bicolor) as influenced with legume intercropping, harvesting time and nitrogen level

Abstract

A field experiment was conducted during the rainy (kharif) seasons of 1998 and 1999, to study the effect of in tercrops, harvesting times and levels of nitrogen on growth, yis13 and quality of forage sorghum [Sorghum bicolor (L.) Moench] under rainfed conditions. lntercropping of sorghum with cowpea [Vigna unguiculata (L.) Walp.] re corded significantly higher leaf area index, leaf: stem ratio, crop growth rate, relative growth rate, net assimilation rate, forage and crude protein yield and nitrogen uptake of sorghum compared to sorghum alone and its intercrop ping with clusterbean [Cyamopsis tetragonoloba (L.) Taub.] during both the years. Forage and crude protein yields and nitrogen uptake of sorghum were also significantly increased with harvesting at 75 days after sowing than har vesting at 45 days after sowing, but being statistically at par with harvesting at 60 days after sowing. However, sig nificantly higher leaf : stem ratio was recorded with harvesting at 45 days after sowing than harvesting at 60 and 75 days after sowing. Nitrogen application Q 80 kglha significantly increased the leaf area index, leaf : stem ratio, crop growth rate, relative growth rate, net assimilation rate, forage and crude protein yield and nitrogen uptake compared to the control and 40 kg Nlha during both the years.