Effect of wood vinegar mixed with herbicide on weed control and yield of rice cv.KDML 105 under dry-direct seeded condition

Abstract

Herbicide using is an effective way to control weeds in dry-direct seeded rice production. Currently, the focus of rice production is to produce safe rice for consumers. Therefore, using wood vinegar (WV) in combinations with herbicides may reduce the amount of herbicide usage, encourage rice production and thus increase rice production security. The objective of this research was to assess the effects of herbicide usage at half of the recommended rate in combinations with WV on weed control efficiency and rice yield in dry-direct seeded rice condition. The experiment was conducted at KhonKaen University, during June to November 2012, using a randomized complete block design with four replications. The rice variety was KDML 105 and there were eleven treatments i.e. 1) oxadiazon at the rate 120 g(ai)/rai (recommended application rate), 2) oxadiazon at the rate 60 g(ai)/rai, 3) oxadiazon at the rate 60 g(ai)/rai+wood vinegar (WV)(1 ml in 500 ml water), 4) oxyfluorfen at the rate 28.2 g(ai)/rai (recommended application rate), 5) oxyfluorfen at the rate 14.1 g(ai)/rai, 6) oxyfluorfen at the rate 14.1 g(ai)/rai+WV, 7) butachlor+propanil at the rate 85.7 g(ai)/rai (recommended application rate), 8) butachlor+propanil at the rate 43.8 g(ai)/rai, 9) butachlor+propanil at the rate 43.8 g(ai)/rai+WV 10) hand weeding and 11) no weeding. The results revealed that WV increased weed control percentage (WCP) and weed control efficiency (WCE) of oxadiazon at the rate 60 g(ai)/rai or the haft recommended application rate, it also significantly increased rice seed yield over the oxadiazon1/2x treatment i.e. 358vs798 kg/rai. This indicates that WV had a beneficial effect by reducing the rate of oxadiazon application by half.