Nitrogen management for production of sorghum (Sorghum bicolor) and cowpea (Vigna unguiculatd) forage under intercropping system

An experiment was conducted during the rainy (kbarif) season of 1998 and 1999 on nitrogen management in sorghum [Sorghum bicolor (L) Moench] and cowpea [Vigna unguiculata (L.) Walp.] intercropping system. The highest green and dry-forage yields were observed in sorghum + cowpea intercrop (4.2 row ratio) with 100 kg N/ha, which was on a par with its 75 kg N/ha treatment in respect of green forage yield. The highest benefit: cost ratio and land-equivalent ratio were recorded in sorghum + cowpea with 100 kg N/ha in 4:3 row proportion during the first season. However, these values were more with sorghum + cowpea with 100 kg N/ha in 4:2 row ratio during the second year.