Bhutan starts growing potatoes on air

Considered as one of the major breakthrough in agricultural research and innovation, aeroponics is the latest discovery that could open a world of opportunities for potato growers in the country.

Aeroponics is in essence a method of growing plants in air or moist environment in a closed or semi-closed environment without the use of soil or an aggregate medium. Traditionally, potato is grown mainly under rain-fed conditions.

The National Potato Program and the National Seed Centre started an aeroponics unit in April, 2012, a part of its initiatives to revamp the formal seed potato production system to produce potato mini-tuber.

The World Bank through the Decentralized Rural Development Project (DRDP) funded this activity. In aeroponics, there is precise and timely supply of nutrients given with the help of timer-controlled sprays through a nebulizer system, the plant roots receive the nutrients and grow.

The nutrient solution is supplied from a nutrient tank by a pressure pump which flows back into the tank and is re-used.

Aeroponics was initially used in the production of mainly vegetable crops and is a relatively new technique especially for seed potato.

This new technique is perhaps a panacea for diverse problems faced in potato cultivation, ranging from poor seed quality, low production yields and lack of quality planting materials, to name a few. Mostly cultivated in high altitude areas between 1,500 and 3,000 meters above sea level, potato is one of the most important cash crops in Bhutan.

Aeroponics versus conventional system,

Aeroponics has the potential to make seed potato production more efficient.

This technique can lower costs by eliminating some generations of multiplication compared to the conventional method. Moreover, this method is considered safe.

This new, innovative technique is going to change the traditional method of growing potatoes increase yield and benefit Bhutanese Farmers.

Otazu reports that through the conventional system, eight mini-tubers per plant are obtained while through the aeroponics technique, a yield of 30 to 50 tubers per plant can be obtained.

The cost of growing a tuber using aeroponics is about one-quarter the cost of a conventionally grown tuber.

The Huancayo aeroponic facility of the International Potato Centre (CIP) yielded about 100 tubers per plant. It was also found that the aeroponic seeds yielded the same as that of conventional seed tubers.

Aeroponics system provides precise plant nutrient requirements for the crop, thereby reducing fertilizer requirements and minimizing the excessive fertilizer residues moving into the subterranean water table (Nichols, 2005).

Thus an Aeroponics system has the potential to increase income.

Potential for business venture

Aeroponics has a number of potential attributes to make seed potato production more efficient. The technique also has very low requirement in terms of space as the mini-tubers are multiplied in greenhouses.

Moreover, the mini-tuber production is also around ten times more than the conventional system. The technique needs lesser number of generations of seed potato multiplication in the field, thus lowering costs.

Furthermore, aeroponics system offers the opportunity to determine the precise fertilizer requirements for the crop, reduce fertilizer use, and reduces the risk of excessive fertilizer uses.

Considering the advantages aeroponics has over the conventional method, the technology could provide an agro-business enterprise to both farmers and the business community.

In China the technology has been taken up by farmers successfully. The International Potato Centre is also promoting this technology to the farmers in the Andes and the tropical regions of Africa.

This facility is the first of its kind in the country and has a very good potential for rapid multiplication of seed potatoes. However, there is need to invest in manpower since aeroponics operations need knowledge, skills and dedication.

Based on the experiences, private businesses interested in seed potatoes, can also be encouraged to take up aeroponics technique to produce seed potatoes. Plantlets being hardened before transferring to the facility reduce cost of production of quality seed potatoes to make it more accessible to growers.

A better seed production system

Aeroponics is introduced as an option for rapid seed multiplication method in order to revamp the formal seed potato production system in the country. The mini-tubers produced will be planted in the field at seed farms in Phobjikha and Bumthang for one generation and then will be transferred to the Seed Grower Groups’ field for one or two generations before packaging as seed potatoes.

This will reduce the number of generations of multiplication thereby reducing the cost of production of seed.

The aeroponics facility consists of a cultivation box, which is lined with black plastic covers and covered by high density Styrofoam lids. Inside the cultivation box, rows of nebulizers are fitted on pipes which are connected to the nutrient solution tank. A submersible pump that is controlled by a timer pumps the nutrient solution from the tank.

The nutrient solution flows into the cultivation box in the form of a mist through the nebulizers and flows back into the tank.

Potato mini-tuber production starts with the multiplication in vitro plantlets from meristematic tissue in the tissue culture laboratory.

After a period of one month, the plantlets are transferred to the screen house for rooting and hardening. In the screen house, the plantlets are planted in a vermiculite medium providing small quantities of nutrients (NPK). This process is called weaning which takes about one and half month for the plantlets to get ready to be transplanted in the aeroponic unit. The potato plantlets are transplanted in aeroponic unit when they attain a height about 10 -15 cm.

In the aeroponic unit, the hardened and rooted plantlets are planted in small holes (30-45 mm diameter) made on the Styrofoam lids of the growth chambers with the roots hanging inside the box.

The lowest leaf of the plant should be cut off every two weeks for the next two months. This allows the plants to push deep down into the growth chamber to promote stolen development. The plants are planted at distances of 10 cm (plant-plant) and 15 cm (row to row).

The harvested mini-tubers are dried under shade for 1- 2 weeks and is stored in the cold store at National Post Harvest Centre, Paro. According to records maintained by the Department of Agriculture, Wangduephodrang, Bumthang, and Chukha dzongkhags followed by Trashigang and Paro are major potato producing areas in the country.