ALLELOPATHIC EFFECT OF Brassica BIOMASS TO CONTROL WEEDS AND YIELD OF WHEAT

Abstract

The experiment was conducted at the experimental field of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during the period from October 2007 to February 2008 to study the al]elopathic effect of Brassica biomass to control weeds and yield of wheat. The experiment consisted of two factors of which Factor A: 3 kinds of Brass/ca species viz. Si: Brass/ca campesiris. S 2: Brass/ca juncea and S 3 : Brc:ssica napus and Factor B: incorporation methods of Brass/ca biornass (5 levels) like: B 0: Control (no bioniass application); B 1 : Spreading above the ground; B 2 : Mixed with soil; B3 : Spreading in line and B 4: 50% spreading + 50% mixed with soil. At 30 days after sowing (DAS), the maximum numbers of weeds (25.53 n12 ) were found in the plot treated with Brass/ca funcea which was 44. 81°/a higher than Brass/ca campesiris. At 50 DAS. Bras's/ca juncea also showed the highest weed population (20.20 m 2). However, Brass/ca campes Iris resulted with the best effect on weed control showing the least number of weed population (14.07 rn 2 ). At 30 DAS, the lowest weed population (15.33 m 2 ) was seen by 133 while the highest (26,89 m 2 ) was found in the B2 . At 50 DAS, the highest (20.89 1112) weed population was found by B 2 whereas. B4 showed the lowest (13.11 m) population. S 1 B2 showed the lowest density of weeds (8.67n12 ) at 50 DAS which was significantly lower than S 2B0 (37.33n12 ) and S3B2 (40.00m 2 ) at 30 and 50 DAS respectively. Among the Brass/ca species, S 2 produced the highest grain yield (3.52 t ha d ) while the lowest (3.32 t ha d ) was obtained from S. The highest grain yield (3.54 t ha d ) was recorded from B 0 while the lowest (3.32 t ha ')was recorded from B2 . The S2 B1 had the highest grain yield (3.83 t ha") whereas the lowest (3.06 t ha") was recorded from S 3B1 . It is appeared from the above results that Brass/ca canzpeslris and B4 incorporation method was mostly effective in controlling weed. But yield was not affected by both species and incorporation methods