M.Tech

Coleus (Solenostemon rotundifolius) commonly known as Chinese potato, is a major tuber crop of Kerala used for vegetable purpuse, raised purely as a rain fed crop from June to December. Manual harvesting of coleus is done by using spade, which is very tedious and time consuming, bruises and injuries. To overcome these problems and decreasing the cost of harvesting operation, a self propelled coleus harvester was modified and field tested. The developed coleus harvester was an attachment to a mini tiller, which consists of a prime mover, a digger, rotary blade, and driven wheels. As and when the tiller moves, digger pierced into the soil at a depth of 10-15 cm to digout the rhizomes that lie inside the soil. The uprooted coleus were then pushed out by means of the rotary splasher. The scattered coleus lying in the raised bed were collected easily and hence the harvesting becomes easier and faster. The rotary slasher are the rotating blades attached to the rear side of the tiller which was modified in such a way that they were removed and rubber flaps of 75 x 75 x 0.3 mm were fastened to the shank of the rotary blade. A set of larger wheels were designed and fabricated separately with diameter of 80 cm.
The performance of the modified coleus harvester was compared with respect to time, fuel consumption, capacity and percentage of damage of coleus separately with flat and angular tynes. The performance on time taken (s) to dig out coleus with 6- tyne and 10 - tyne flat and angular digger revealed that while using 6 - tynes, the time taken and fuel consumption (ml) were highest in beds of 70 x 30 cm, whereas minimum were in the bed size of 50 x 30 cm The capacity of coleus harvester with 6 -tyne and 10 - tyne flat and angular diggers were determined. It is noted that the uprooted was the highest in beds of 50 x 20 cm, whereas minimum weight uprooted was in the bed size of 50 x 40 cm when operated with 6 flat tynes. When 10 angular tynes were used, it is noted that the weight (kg) of coleus uprooted was the highest in beds of 70 x 30 cm and minimum weight uprooted was in the bed size of 50 x 20 cm. Thus the average capacity of the harvester was observed as 1069 kg.h -1.The percentage of damage of coleus observed was the highest in beds of 70 x 30 cm, whereas minimum was in the bed size of 70 x 40 cm while using 6 - tynes.
Performance analysis of a commercial harvester (TNAU ginger harvester) indicated that the vibrating mechanism provided was useful to obtain the coleus in clumps after harvest. In field operation it was not possible for uprooting coleus in the beds having more than 30 cm height.
The field capacity of the modified coleus harvester is 0.057 ha.h-1. At the present wage rate of Rs 500 per day, the total cost of operation by manual method is about Rs 31,250 per ha. Whereas harvesting by the harvester, the total cost of operation is Rs 7680 per ha. Hence the savings over conventional method is Rs 24,470 per ha. The field efficiency of the harvester was calculated as 95 %.
The performance of the machine was tested with two types of tynes - flat and angular with 6 - tyne and 10 - tynes. Time to harvest one bed of crop, fuel consumed for harvesting one bed, capacity of the harvester and percentage of damaged tubers were calculated. Among two types of flat tynes, the minimum time for harvesting one bed was achieved using 6 - tynes (21.66 min) and its fuel consumption was also less compared with 10 - of tynes. The average capacity of the machine was obtained as 1061 kg h-1.Percentage of damaged tubers was 5% corresponding to 6 - tynes. In the case of angular tynes, the shortest time for harvesting was achieved with 10 - tynes and the corresponding fuel consumption was 19 m1. The percentage of damaged tubers was 8% with 10 - tynes and was little high compared with 6 - tynes.