Design of a mechanical system for liquid fertilizers injection in ratoon cane

Abstract. Sugarcane is a semi-perennial crop which has a high vegetative production and a fast vegetative growth. After annual mechanized harvest of green cane, the restoration of extracted nutrients is commonly performed by applying fertilizers through furrows in both sides of the inter-rows or through surface application, due to existing mulching and roots. The last mentioned practice is not very efficient, especially when applying nitrogen fertilizers, due to ammonia volatilization and immobilization of N caused by the microorganisms. To fill the gap, a mechanical system was developed to enhance efficiency in nitrogen fertilizers application. It performs soil drilling with minimum mobilization, which allows liquid fertilizer injections in depth. The developed mechanism is composed by a rotating drum cam, a carriage and a spline shaft, a crank, a connecting rod and a sliding needle. To cancel the relative movement during soil drilling, the rotating drum cam sets the carriage and the punching mechanism in motion with alternate movements in the same direction and speed of the driving machine, which ensures vertical and equidistant perforations. The mechanical system was evaluated through Matlab simulation (kinematic analysis) and experimental testing conducted in a soil bin and sugarcane ratoon field. The following potential limitation factors for fluid injection through punching mechanism were observed: soil micro relief variations, time interval for fluid injection and soil penetration resistance. All in all, the mechanical process developed demanded low drilling power, as well as contributed to soil, trash and root preservation.