Mechanized sweet potato harvester for efficient post-production

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Sweet Potato is one of the most important food sources in the Philippines. Aside from its starchy tuberous roots, young leaves and shoots are also edible and a good source of dietary fiber, vitamin A, vitamin C, and vitamin B6. It is likewise appreciated as a source of antioxidants for neutralizing body toxins as by-products of metabolism. 

Photos from PHILROOTCROPS

Nowadays, the demand for sweet potato has dramatically increased with the realization of its potential for commercial applications. It is used as a raw material for manufacturing of flours, starch and pectin that are highly commercializable and exported to other Asian countries like of Japan, China and Korea. Its flour can be processed into products of fermentation such as soy sauce and alcohol. On the other hand, starch is also a material used in the manufacture of textiles or paper while dried sweet potato chips find in animal feed formulation.

With demand for sweet potato increasing, the government is now looking forward to improve the production of the sweet potato industry through research and development. One thing that needs to be improved is the traditional harvesting techniques and procedures that cause losses and poor crop quality.

Harvesting is one of the important parts of any farming ventures. It is when the labor and long time patience of farmers get to be paid off. In sweet potato production, harvesting can become the most critical part of the entire production and marketing operation as crop yield and quality can no longer be increased but they can be decreased, sometimes drastically by improper or inefficient harvesting practices.

Based on studies, certain cultural conditions, such as excess nitrogen, excess water, and poor soil aeration, can predispose tubers to damage. Traditionally however, most of the actual damage occurs when farmers plow or manually dig tubers during harvesting. Aside from being a laborious and very slow harvesting method, it bruises tubers and even breaks it into pieces. This decreases the crop value, if not spoil its marketability. In such instances, harvesting losses can reach 40-50 percent of the total harvest.

Preventing such damage has led the Philippine Root Crop Research and Training Center – Visayas State University (PhilRootcrops – VSU) to develop a tractor-drawn sweet potato harvester to increase the sweet potato harvest.

According to Alan B Loreto, agricultural engineer and professor at the Visayas State University (VSU) – proponent of the project, mechanization can improve the harvest operation thus enhancing productivity, efficiency and quality of sweet potato farming.

The PhilRootcrops has developed hand tools and animal-drawn implements for root crop farming. However, due to increased in area and volume of sweet potato production, these animal-drawn implements are no longer appropriate. Machine developed elsewhere for Irish potato will not work with sweet potato because of botanical differences between the two crops. The vegetative portion of the potato plant will senesce at maturity and does not interfere during harvest. On the other hand, sweet potato vines remain intact and actively growing even during maturity and poses a problem on harvesting (PRCRTC annual report). Indeed, creating a harvester specifically designed for sweet potato is needed.

The PhilRootcrops – designed sweet potato harvester has a customized vine cutter that effectively removes vines, leaving only the stalk close to the sweet potato roots to facilitate easier digging. It also has single-row digger – another feature of the machine that would allow farmers to harvest as fast as 1.08 hectare a day at the speed of 2 km per hour.

Researchers have estimated that this harvester could significantly reduce harvesting cost, which is about 13-25 percent of the total production cost.

The project is major effort of the government to improve the sweet potato industry in support to its banner program dubbed as FIELDS, which means (Fertilizer, Irrigation, Extension, Loans, Dryer and other post harvest facilities, Seeds and other genetic materials) – the overall framework development for agriculture and fisheries that has been adopted to ensure adequate, accessible, affordable and nutritious food for Filipinos.

The project was funded by the Department of Agriculture through the Bureau of Agricultural Research (DA-BAR).(Edmon B. Agron)

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The article is based on the project “Development of a Tractor-Drawn Sweet Potato Harvester” by Alan B. Loreto and Manolo B. Loreto of Philippine Root Crop Research and Training center, Visayas State University (PhilRootcrops-VSU), funded by the Bureau of Agricultural Research (BAR).

For more details, please contact: Allan B. Loreto, assistant professor, Philippine Root Crop Research and Training Center, Visayas State University Visayas State University, Baybay, Leyte or call him at tel.no. (053) 335-2601 mobile no. 0906-418-8440 or email at ablore2@yahoo.com