Periods of weed interference in raw and burned sugarcane

Abstract

The harvesting system in the cultivation of sugarcane influences the community of weeds. Particularly the time and duration of cohabitation period with sugarcane can hinder the development and production of culture. The objective of this work was to identify the interference periods of weeds in the culture of sugarcane in cane handling and raw cane burning. Os experiments in cane raw and burnt, they were conducted in July 2012 period to July 2013, in a randomized block design with eight replications, with two types of weed management (coexistence and control) and ten evaluation periods (0, 15, 30, 45, 60, 75, 90, 105, 120 and 145 days after sprouting). Were evaluated for weed, the phytosociological indices: relative density, relative frequency, relative dominance and relative importance. Based on result, it was estimated the period before interference, the total period of interference prevention and the critical period for prevention of weed interference in the culture of sugarcane, accepting up 2 and 5% reduction in productivity. The results showed that in a weed community with predominance of Senna obtusifolia, Spermacoce latifolia and Richardia brasiliensis, and accepting losses in productivity of up to 5%, a greater period prior to interference (PPI) for raw cane in compared to cane burned. The control measures, accepting 2% yield loss and 5%, should start before the 67 and 75 DAB and extend to 89 and 80 DAB, respectively, for cane raw, 48 and 72 DAB to DAB 142 and 103, respectively, for cane burning.