Determination of the critical period for weed control of sweet corn under tropical organic farming system

An understanding of the critical period of the crop for weed control (CPWC) is needed before making a decision on weed management. A field experiment to study a CPWC of sweet corn was carried out at the highland of Bengkulu Province, Indonesia from October 2015 to January 2016. The objective was to determine the CPWC of sweet corn under the tropical organic farming system. Weed infestations in the research plots including 14, 28, 42, 56, 70, and 84 days after planting (DAP) of weedy and weed-free periods were arranged in a completely randomized block design (CRBD) with three replications. Results showed that the plant height, leaf area, and yield of sweet corn descended and ascended due to the increase of weedy and weed-free periods, respectively. The biomass and yield losses due to weed competition during the growing season reached 49.5 and 54.7 %, respectively. The relative yield descended or ascended in logistic equation curves due to the increase of weedy or weed-free periods, respectively. Based on the acceptable yield loss (AYL) of 5 %, the CPWC of sweet corn under organic farming system was determined from 2 to 77 DAP, and with the AYL of 10 %, the CPWC was determined from 3 to 53 DAP.