Effects of Weeding Timing and the Numbers of Weeding Practice on Corn Yield

Abstract

Field experiments utilizing naturally occurring weed populations were conducted to study the effects of weeding timing and the numbers of weeding practice on yield of corn (Zea mays L. cv. Tainung No.1) in the experimental farm of Taiwan Agricultural Research Institute in the fall crop of 1992 and the spring crop of 1993. An adversed distribution of climatic factors during the growing seasons was shown. Corn yield was increased as weeding practices applied two times during the growing seasons of 1992 and 1993. Kernel yields were increased approximately 12 and 49% for Fall 1992 and Spring 1993, respectively. Weeding practice applied at 6 weeds attained the maximal increase of yield in one-weeding practices, an increase of 5% for the fall crop and 25% for the spring crop was recorded. It appeared that weights of ear and kernel per plant and 100-kernel weight were the yield components increased in two-weeding treatments in Fall 1992. In Spring 1993, ear length, weights of ear and kernel per plant, and 100-kernel weight were increased by weed removals except at one-weeding at 8 weeds after planting. Additionaily kernel number per plant was enhanced in two-weeding practice treatments in 1993.Weed control applied twice during the growing seasons improved the biological yield, harvest index and kernel yield, while only weeding at 6 weeks after planting in one weeding treatments increased these parameters in both seasons. It was also indicated that harvest index obtained from the fall crop was higher than that from the spring crop. The results suggested that weeding practices applied two times during the growing season significantly enhanced biological yield, yield components and harvest index and therefore kernel yield. Weeding at 6 weeks after planting is acceptable for both crop seasons on returns of considerable yield when considering the production cost by selecting one-weeding practice.