Sugarcane Root System Affected by Insecticide and Plant Growth Regulator

In Brazil the sugarcane crop is cultivated in about 10,0 million hectares, which 60% of plantations are concentrated in Sao Paulo state. Nowadays, the intense mechanization increases the soil compaction, consequently the sugarcane root system is affected. Some insecticides and plant growth regulator normally used in commercial field could help to improve the root characteristics in sugarcane crop. The objective of this research was to quantify the effect of Moddus^® (trinexapac) and Actara^® (thiametoxam) on the sugarcane root characteristics in three different field conditions. The trials were installed in three different soils, located at Colorado Mill (Miguelopolis city) and Maringa Mill (Araraquara city), both in Oxisoil and Noble Mill (Catanduva city) under Ultisol. Roots were sampled with probe, in two dates defined by the layers down to a depth of 1,0 m. The evaluations were done 30 (effect of trinexapac) and 180 (thiamethoxan) days after harvesting of the third ratoon, respectively December 2012 and April 2013. After washing, sieving and cleaning 2800 samples collected, the images of roots were analysed by Safira^®software in order to determine the diameter, area and volume. After that samples were dried to know the dry biomass. Results showed that the association of Moddus^® and Actara^® increased the dry biomass of roots, the area and root length, respectively in 2,3 Mg ha^-1, 60 m² and 8 m per trenches. It could be conclude that, the application of trinexapac associated with thiamethoxam improve the sugarcane root system, consequently the influence of water stress could be reduced as well as the nutrient uptake.