Influence of irrigation and nitrogen on growth, yield and nutrient uptake by late-sown Brassica oilseeds

The field experiment conducted on Brassica oilseeds under late-sown conditi ons at IARI, New Delhi during 1992-93 and 1993-94 revealed that B. carinata A. Braun strain 'RK 8' produced 16.2 q seed, 83.2 q biomass and 597 kg oil per hectare, which were significantly higher than those of B. juncea (L.) Czernj. & Cosson var. 'Pusa Barani'. The former also removed 34, 36, 100 an d 116 % more N, P K and S than the latter. Irrigation at IW:CPE of 0.8 prod uced significantly higher seed (15.7 q), biomass (80.4 q) and oil (592 kg) yields per hectare as well as removed higher amount of nutrients compared w ith 0.4 ratio and unirrigated control. Nitrogen application significantly i ncreased the harvested biomass up to 120 kg/ha, but yield attributes, seed and oil yields as well as uptake of nutrients were increased only up to 80 kg/ha level. Oil in seed decreased due to irrigation and N application up t o 40 kg/ha. Response to applied nitrogen was quadratic in B. juncea but was linear in B. carinata.