Studies on the effect of BecAno 500 SC (a pre-emergent herbicide) on soil borne fungi, nutritional status and weed control in tea soil

Abstract

A field as well as laboratory experiments were conducted at Bangladesh Tea Research Institute (BTRI) and the Department of Food Engineering and Tea Technology, Shahjalal University of Science and Technology to investigate the effect of BecAno 500 SC on microbial and nutritional status as well as pre-emergent control of weeds in tea soils. BecAno 500 SC had no effect on soil microbial populations, especially on fungi. Six types of soil fungi were isolated and these were Penicilliumsp., Pestalotia sp., Rhizopus sp., Trichoderma sp., Fusarium sp. and Macrophoma sp. After 15 days, fungal populations decreased at all concentrations when compared with the control (untreated soil), but increased after 30, 45 and 60 days. The results of this study showed that BecAno 500 SChad no effect on Trichoderma sp., Penicillium sp. and Macrophoma sp.  But, it had comparatively less effect on Fusarium sp. and Rhizopus sp. and also has a toxic effect on Pestalotia sp. In this experiment, the amount of soil nutrients such as N, P, K and P varied at different intervals. However, BecAno had no significant effect on soil nutrients. The present study also showed that, BecAno 500 SC@ 0.37 ml/L(T3) and 0.50 ml/L (T4) achieved 100% weed control after 1month from application and continued to show 90 to 100% control up to 2 months. The present study proves that BecAno 500 SC @ 0.50 ml/L (T4) suppressed weeds more effectively than @ 0.37 ml/L (T3) up to 60 days. But BecAno 500 SC@ 0.37ml/L (T3) had no effect on soil fungi and nutrients. It is concluded that BecAno 500 SC@ 0.37 ml/L (T3) could be used in tea soil for controlling the weeds.