RESUMEN
Higher risks involved in excess fertilizer application require precise placement of fertilizer in adequate amount in the root zone of the crop. The drawbacks of current fertilizer application techniques (band placement, pellet application, and ring basin method) include over-fertilization, soil acidity, nutritional imbalances, soil structure damage and an increase in bulk density. Development of a spot fertilizer applicator with precise fertilizer metering was planned to address the problem. The physical and mechanical properties of di-ammonium phosphate were determined. A new grooved belt type fertilizer metering mechanism was developed for orchard application using the fertilizer properties determined. The metering mechanism was equipped with a fertilizer box of 100 kg capacity. The torque requirement of metering mechanism was determined using torque transducer to select a DC motor. The maximum torque required was 4.5 N.m at 8 m.min-1 of metering belt speed. An automatic plant detection-based spot fertilizer applicator with developed fertilizer metering mechanism has potential to save about 20% fertilizer compared to band placement along with reduced labour requirement.
RESUMEN
A portable MSTD (mini solar tunnel dryer) was developed and evaluated in terms of drying rate, MR (moisture ratio) and drying efficiency for drying of pomegranate seeds. The drying characteristic curves were also determined for drying in MSTD and OSD (open sun drying). In order to study the drying behaviour of pomegranate seeds in OSD and MSTD, seven different models were fitted. The best prediction model was determined to estimate drying kinetics as criteria for evaluating the goodness-of-fit based on R2, SSE and RMSE. The Approximation of Diffusion model was adequate to describe the drying kinetics of pomegranate seeds in OSD and MSTD with R2 value of 0.99189 and 0.9943, respectively. The MSTD was 7% more efficient in drying of pomegranate seeds compared to OSD without affecting the quality of seeds. The dryer can be used by the farmers as an alternative to sun drying for on field drying of their product without compromising the quality.