DESIGN AND DEVELOPMENT OF A COMBINE FERTILIZER APPLICATOR FOR DISPENSING INDIVIDUAL FERTILIZERS IN  SUGARCANE CULTIVATIONS 

Fertilizer application is an essential but, expensive management practice in sugarcane farming due to the scarcity of labor for manual application even in small-scale sugarcane farming. It is about 10 % of total costs of production in plant crop and nearly 20 % in ratoon crops. Thus, small-holder sugarcane fertilizer applicator will be a good solution to overcome such labor shortages. The broad objective of this research project was to design and construct a power tiller mounted combine fertilizer applicator for sugarcane cultivation. Specific  objectives of this study were to design an adjustable metering unit for the application of individual fertilizer ingredients uniformly as per the different fertilizer recommendations for  sugarcane cultivation and evaluate the performance of the new fertilizer applicator and compare it with the manual method. The fertilizer applicator was designed and fabricated in the Engineering workshop in Sugarcane Research Institute (SRI). Accuracy of fertilizer application rates, under different speed conditions, different furrow slopes and soil moisture levels were evaluated. Fertilizer dropping positions, field capacity, and uniformity coefficient were considered as  performance indicators. A cost comparison was performed against the manual method. The maximum power requirement for operating the new fertilizer applicator was around 8.95 kW (12 hp). Results showed that the variations in machine speed, furrow slope and soil moisture level did not affect the accuracy of the fertilizer dropping rates. The fertilizer dropping rate can be adjusted changing the cavity length of the fertilizer drum from 0 to 50  mm and the fertilizer dropping rate was changed 0.6 g/m in 1 mm range. However, fertilizer dropping start at the cavity length of 4.8 mm due to the varying physical properties of the  fertilizer and the many physical factors of the fertilizer applicator.  The average dropping position was 22 cm from the base of the sugarcane stool. The achievable field capacity of the machine was 0.484 ha/h. The uniformity of fertilizer application was 99 %. The result revealed that the 83 % labor saving and the cost of fertilizer application was reduced by 55% compared to the manual method.