Exploiting sweet potato potential

Published Dec 17, 2012 12:18am

AS realisation increases about perils of overdependence on a few crops, there is a clear case for exploiting full potential of crops that have enough nutritional value, but are not used very widely. One of them is sweet potato.

In Pakistan, output of sweet potatoes has remained range-bound between 10,000 and 12000 tonnes since 2004 but agriculturists say the production could be doubled easily if a few needed steps are taken. “Back in early 1980s (in 1981 and 1982 to be specific) we were producing 20,000 tonnes of sweet potatoes,” recalls chairman of Pakistan Agri Forum Ibrahim Mughal. “We are capable of hitting that mark again and even surpassing it. But we need to take some real steps.”“Currently there are 870 million hungry people in the world that produces enough food for everyone”, to quote Graziano Da Silva, Director General of FAO. Feeding every hungry man is not possible if nations keep counting on rice, maize, wheat and potatoes for most of their caloric intake.

“You’ve to get used to eating what else you can eat, and there are plenty of things to eat on this planet,” according to a former chairman of Pakistan Agricultural Research Council. He adds: “growing more of alternative food crops is a must for countries like Pakistan where staple food crops are also a source of foreign exchange earnings.”

Agriculturists recall that sweet potato output had risen to 20,000 tonnes in early 1980s after seeds of some new varieties were introduced in the country. That was done after the production of this nutritious vegetable had remained range-bound between 9000 and 15000 tonnes throughout the 1970s. A repeat exercise is required.

Sweet potatoes are grown over an estimated area of only 2000 acres or so which is less than 0.5 per cent of the total area under cultivation of all vegetables, according to the Ministry of National Food Security and Research. Currently the average production comes to 5-6 tonnes per acre.

Progressive growers say, better varieties of sweet potatoes can double the per-acre yield. In the year 2011, average yield of sweet potato in the United States was recorded at 10.4 tonnes per acre.

Extensive research is being done on developing higher-yielding varieties of sweet potatoes in countries where the crop is grown on a large scale. Local agro scientists can benefit from contemporary research and introduce higher yielding varieties in our own country. Ibrahim Mughal says all research should focus on four basic areas: how to increase per-acre yield, how to ensure cultivation of sweeter varieties, how to enhance nutritive value and how to boost the content of fibres.

China accounts for a little over 75 per cent of global output of sweet potatoes which has remained a little over 100 million tonnes for last few years. Other major producers include Uganda, Nigeria, Indonesia, Tanzania, Vietnam, India, Japan and the US. “In all these countries and also in Bangladesh and New Zealand, experts are trying to come up with new varieties with higher per acre yield and higher nutritional value,” says Malik Sakhawat of Farmers Association of Pakistan (FAP).

“But we hardly hear about any research going on sweet potatoes in our country.” There are some 400 varieties of sweet potatoes the world over and at least 25-30 of them are doing very well. “Maybe we can join hands with countries like India, Japan and the US.”

Whereas introduction of improved varieties may take time, the current yield can be increased significantly if growers are guided properly. A latest FAP handout advised sweet potato growers to “use 180-200kg of slips for cultivation on one acre. (Sweet potatoes are grown from small plants called slips.) Bury the slips 18-20 centimetres beneath the soil. Space down the burrows at 1.75 metre and place the slips at a distance of 26-30 centimetres on burrows. Watering is required twice or thrice a week in the initial stage but later on at intervals of 15-20 days.”

Agriculturists associated with cultivation of sweet potatoes say production of sweet potatoes during this season (November 2012-February 2013) is expected to remain at around 12,000 tonnes level of last year.

They say in Khyber Pakhtunkhwa no less than 10,000 tonnes of these nutritious potatoes are expected to be produced during this season. The remaining 2000 tonnes are likely to come from the rest of the country. KP produces about 85 per cent of sweet potatoes and bulk of the remaining 15 per cent comes from Punjab and Azad Jammu and Kashmir. Combined share of Sindh and Balochistan is estimated around two to three per cent.

Value-added food product business is picking up fast with companies coming up with more and more brands of byproducts of wheat flour, maize, rice and potatoes.

Sweet potatoes have the potential to join the list. From frozen cubes and slices to hygienically preserved crushed sweet potatoes to doughnuts and pies there is a vast list of the ways in which one can use them. In countries like Japan one can see sweet potato breads to sweet potato puffs and fries. Food companies in Pakistan can also produce these items both for local consumption as well as for exports.

Just consider the big gap between the prices of raw and baked or boiled sweet potatoes. The price differential is income for very poor people like pushcart vendors.

In Karachi’s vegetable markets raw sweet potato is selling for Rs50-60 per kg but when these are baked or boiled and sold on the city streets, one kg fetches as much as Rs120-Rs180.—Mohiuddin Aazim


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