การพ่นปุ๋ยยูเรียสำหรับควบคุมการติดเมล็ดของข้าววัชพืช

Abstract

Study of urea foliar application for controlling seed setting of weedy rice seed was conducted at Phitsanulok and Lopburi Rice Research Center during 2009 - 2010. Three experiments were designed as RCB with 4 replications. Treatments of the first experiment consist of rates of urea between 0 - 5.0 kg/20 liters of water. Treatments of the second experiment consist of times of application which were 1) at panicle initiation stage 2) at the stage of immediate emergence of panicles from flag leaves 3) at the stage of half-emergence of panicles from flag leaves 4) at the stage of full-emergence of panicles from flag leaves, and 5) at milky stage. The third experiment was conducted in a farmer field with 6 treatments, consisting of rates of urea foliar application and herbicides wiping only on weedy rice panicles. The first three treatments were urea rates at 2.0, 2.5, 3.0 kg/20 liters of water. Another three treatments were herbicide wiping on weed panicles by using a glufosinate - ammonium mixture and glyphosate at the rate of 100 cc/liter of water and untreated as check. Results of this study showed that urea foliar application at 2.0 - 5.0 kg/20 liters of water could control weedy rice seed setting for 80 - 98 %. However, at the rate of 3.5 kg/20 liters and higher, urea could cause rice leaf damage. The most suitable time for urea foliar application was at the stage of full-emergence of panicles from flag leaves. The most suitable rate of urea was 3.0 kg/20 liters of water, which could equally control damage weedy rice seed setting comparing to the two herbicides. The urea foliar application technique can be effectively applied only when the weedy rice flowers before the cultivated rice. This technique can be an alternative method for controlling weedy rice seed setting instead of wiping weed panicles with herbicide technique.