Growth inhibition of some weeds and crop species by wood vinegar mixed with pre-emergence herbicides

Abstract

Weed control using herbicides is the most effective method. However, continuous using of herbicide may cause residue accumulation in the environment and the food chain. Reducing the rate of herbicide application may reduce its impact on the environment with the expense of its efficiency in weed controlling. Wood vinegar (a natural product from charcoal making) has been reported to increase efficiency of post-emergence herbicide. The objective of this study was to investigate the efficiency of wood vinegar mixed with pre-emergence herbicide on the growth of some weeds and crops. The experiment was conducted at the Weed Science Laboratory Faculty of Agriculture, Khon Kaen University, during January to March 2017. A Completely Randomized Design with 6 replications was used in the study. Four types of seeds were used: crowfoot grass; Dactyloctenium aegyptium (L.) P. Beauv), horse purslane; Trianthema portulacastrum, sorghum; Sorghum bicolor (L.) Moench and mungbean; Vigna radiata (L) Wilczek . There were 7 treatments including 1) pendimethalin + imazapic recommended rate, 2) pendimethalin + imazapic half recommended rate, 3) pendimethalin + imazapic half recommended rate + wood vinegar diluted 1: 50, 4) pendimethalin + imazapic half recommended rates + wood vinegar diluted 1: 500, 5) wood vinegar diluted 1: 50, 6) wood vinegar diluted 1: 500 and 7) water. The results indicated that the application of pre-emergence herbicide at half the recommended rate with diluted wood vinegar 1:50 and 1: 500 could inhibit growth of horse purslane and low dry matter accumulation of horse purslane and crowfoot grass but not significantly different from that of herbicide application at both rates. The experiment suggested that wood vinegar could stimulate seed germination of crop and weed species and increased herbicide efficiency. Therefore, special care should be taken when this pre-emergence herbicide mixed with wood vinegar are used in weed control in sorghum and mungbean to avoid the toxicity effect.