Operational evaluation of mechanical control of aquatic macrophytes submerged in the Jupia reservoir

摘要

This work aimed to study the harvest and discard of aquatic plants from different places and infestation in the Tiete/Parana River system. The operation was performed with equipment installed at an aquatic plant harvester, using GPS system with differential correction signal. The time spent to load and unload the harvester was determined by timing with a stop watch, and the distance between the collection final point to the discard point as well the displacement time were determined by timing and GPS. In some collections, polygons were marked to instruct the machine operator to work exclusively in the corresponding area. Data interpretation permitted to determine the collect time participation in relation to the operation total time, indicating a significant value from an operational point of view (70). Considering discard in areas infested with cattail, the mean total displacement was only 383 m, with 200.96s of mean time spent. Values of the harvester operational capacity oscillated between 0.23 and 1.60 ha h-1, indicating a mean value of 4.48 ha h-1 per day. The main limitation to the operational capacity was associated with the mean displacement velocity, intensifying in deeper and more infested areas. As for harvester displacement, there was great difficulty in orientation under normal operational conditions, making it impractical to maintain uniform spacing between the collect tracks. It was concluded that the operational evaluation indicated the unfeasibility of operating the machine without a GPS system allowing to guide the harvester throughout the control areas.