Liquid Fertilizer Spraying Performance Using A Knapsack Power Sprayer On Soybean Field

An effort for increasing soybean production can be conducted by applying liquid fertilizer on soybean cultivation field. The objective of this research was to determine liquid fertilizer spraying performance using knapsack power sprayer TASCO TF-900 on a soybean cultivation field. Performances test were conducted in the Laboratory of Spraying Test and on a soybean cultivation field to determine (1) effective spraying width, (2) droplets diameter, (3) droplets density, (4) effective spraying discharge rate, and (5) effective field capacity of spraying. The research was conducted using 2 methods: (1) one-nozzle spraying, and (2) four- nozzles spraying. Results of the research showed that at a constant pressure of 900 kPa effective spraying width using one-nozzle spraying and four-nozzles spraying were 0.62 m and 1.10 m. A bigger effective spraying width was resulted in a bigger average effective spraying discharge rate and average effective spraying field capacity of 4.52 l/min and 83.92 m2/min on forward walking speed range of 0.94 m/s up to 1.77 m/s. On the contrary, bigger effective spraying width was result in bigger droplets diameter of 502.73 μm and a smaller droplets density of 98.39 droplets/cm2, whereas smaller effective spraying width was resulted in a smaller droplets diameter of 367.09 μm and a bigger droplets density of 350.53 droplets/cm2. One-nozzle spraying method produced a better spraying quality than four-nozzles spraying method, although four-nozzles spraying was resulted in a bigger effective field capacity of spraying.