Abstract
A field experiment was conducted during the winter seasons of 1994-1995 and 1995-1996 to study the effect of tillage and N management on winter sorghum [Sorghum bicolor (L.) Moench] under dryland conditions in Vertisols of Bijapur, Karnataka State, India. The grain, stover, total N uptake at harvest, and crude protein production increased from shallow tillage (7.5 cm) to deep tillage (30 cm) and N application up to 50 kg ha-1 compared to lower N rates. Among the different organic materials, i.e., farmyard manure (at 2.5 t ha-1), vermicompost (at 1.0 t ha-1), and Leucaena sp. loppings (at 2.5 t ha-1), application of Leucaena sp. loppings proved beneficial with greater sorghum production. Deep tillage compared to shallow tillage, produced greater grain (45%), stover (33%), total N uptake (79%), and crude protein production (80%) at harvest. Incorporation of Leucaena sp. loppings increased the sorghum grain yield, total N uptake, and crude protein production by 9 and 19% over vermicompost. Application of organic materials and 25 kg N ha-1 was beneficial with mild to severe drought at reproductive stages of crop growth during 1994-1995. During 1995-1996, when rainfall distribution was uniform, application of organic materials along with increase in N up to 50 kg ha-1 proved beneficial with greater N uptake, crude protein, and sorghum grain production. In the pooled data, application of 50 kg N ha-1 produced significantly greater grain yield (23%), stover yield (20%), total N uptake (63%), and crude protein production (64%) compared to the control. Deep tillage with application of Leucaena sp. loppings and 25 kg N ha-1 during drought years were beneficial, whereas further application of 25 kg N ha-1 at 30 days after sowing proved beneficial during normal rainfall situations.
