Identification of Critical Weed Competition Period in Sugarcane (Saccharum officinarum L.) at Kessem Sugar Estate, Ethiopia

Sugarcane is a tall growing monocotyledonous crop that is cultivated throughout the tropical and subtropical regions of the world in a wide variety of soils and climates. The growth and productivities of sugarcane has been significantly affected by various constraints. Among reasons for low sugarcane yield and low sucrose recovery is weed infestation. It is a major limiting factor in the economic production of sugarcane yield. Therefore, field experiment on i d e n t i f i cation of critical weed competition period in sugarcane was conducted at Kessem Sugar estate during 2022/2023, to identify the starting time of weed control measures before they cause economic damage on sugarcane yield. The experiment was conducted with sugarcane variety C86/56, in RCBD design replicated three times. The treatments were either kept weed-free or weedy for different periods, viz., 0, 30, 60, 90, and 120 days after planting. The data on weed density, weed dry weight, yield components, quality parameters, sugarcane yield and estimated sugar were collected and analysed using Gensat statistical software 18 th edition and means were compared and separated by DMRT. The results showed that, weed density, weed dry weight, tiller number, cane height, cane girth, cane weight, millable cane number and cane yield were significantly (p≤ 0.01) affected by weed competition for different periods. However, sprouting percentage of buds on cane setts planted was not significantly different (P≤0.05) due to different weed competition periods. Similarly, the results showed estimated sugar yield, estimated recoverable sugar, pol and brix were highly significantly affected (p≤ 0.01) by treatments of weed competition for different periods. However, the purity percentage of juice was shows not significantly difference (p< 0.05) among different weed competition periods. Infestation of weeds for long season caused 88.96 % and 97.12 % sugarcane and sugar yield losses, respectively. The onset and end of critical periods of weed crop competition at the acceptable cane yield loss of 5% was found to be between 17 and 119 DAP. Therefore, to limit the impact of weeds on sugarcane and sugar yield, weed management measures should be implemented in sugarcane plantations during this important period