Response of Aqueous Extract of Botanical Herbicides on the Performance of Transplanted Rice during Boro Season

A field experiment was conducted in humid sub-tropics of West Bengal at the Instructional Farm, Jaguli of Bidhan Chandra Krishi Viswavidyalaya (BCKV), Nadia, India during 2016-17 to study some growth and yield parameters, also the economic advantages of various weed management treatments of summer transplanted paddy. The experiment was conducted with 8 treatments [T1- & T2 - Pre–emergence (PE) sole aqueous organic botanical extracts (AOBE) of Tectona grandis & Bambusa vulgaris respectively @ 100 mL/L water; T3 - PE sole synthetic organic chemical herbicides (SOCH) Pretilachlor 30.7 EC @ 500 g/ha;T4 – PE mixture of AOBE of Bambusa vulgaris & Tectona grandis @ 100 mL/L water; T5 – PE mixture of AOBE of Tectona grandis @ 100 mL/L water & SOCH Pretilachlor 30.7 EC @ 500 g/ha; T6 -PE mixture of AOBE Bambusa vulgaris of @ 100 mL/L water & SOCH Pretilachlor 30.7 EC @ 500 g/ha; T7 – Hand weeding (HW) at 25 & 45 days after transplanting (DAT) and T8 – Weedy check with three replications following randomised block design (RBD). The results revealed that the treatments T7 recorded the maximum biological yield (grain – 4.76 & straw 5.95 t/ha) and was statistically at par with the mixture of botanical and chemical treatments (T5 - 4.35 and 5.52 t/ha respectively) and T6 - 4.42 and 5.54 t/ha, respectively). The T6 recorded the highest benefit – cost ratio (BCR) value of 2.41 followed by T5 with 2.38. But in case of treatment T7, maximum cost of cultivation was incurred over all treatments due to higher expenditure on labour wages for that reason BCR was comparatively lower (2.02) and the lowest BCR was obtained against weedy check (T8) 1.85. Therefore, considering the crop growth, rice productivity, economics and farmers‟ easy availability the mixture treatments of AOBE Bamboosa vulgaris or Tectona grandis with SOCH Pretilachlor may be the best option and is an alternative to traditional HW treatment for increasing rice productivity through ecosafe weed management in transplanted paddy.