Director General of International Maize and Wheat Improvement Centre (CIMMYT) Dr Masa Iwanaga made the observation in an exclusive interview with The Daily Star in Dhaka.

Iwanaga said, "Bangladesh has got more acute problem of agricultural sustainability than any other countries. You have to intensify the production by reaping more from per unit of fast-depleting land resources but again, without compromising the soil fertility, which means long-term sustainability."

He warned that over-exploitation of soil fertility might poses a serious threat to farm sustainability in Bangladesh and stressed replenishing the fertility level with organic materials instead of applying too much of chemical fertilisers.

Crop diversification is a fitting solution to the problem of agricultural sustainability in Bangladesh, the expert noted.

The agrarian economy of Bangladesh badly needs more international assistance for the farm sector. So, the Planning Commission should put agricultural projects top on agendas while seeking aids from bilateral or multilateral donors, he thought.

Iwanaga, who previously served in important capacities in Centro International de Agricultura Tropical and International Potato Centre, was speaking to The Daily Star on Thursday at CIMMYT's regional office in Dhaka at the end of his four-day official visit to Bangladesh.

Headquartered in Mexico, the CIMMYT is one of the 16 apex centres of agricultural research run by the Washington-based Consultative Group on International Agricultural Research (CGIAR). Other commonly known CGIAR centres include International Rice Research Institute (IRRI), International Food Policy and Research Institute (IFPRI) and International Potato Centre (CIP).

"Bangladesh is unique in the world in terms of population density. The number of small-hold farmers is too many here for obvious reasons of land fragmentation and poverty. The situation will worsen if per unit yield is not enhanced keeping the farming sustainable at the same time," he observed.

Iwanaga suggested that Bangladeshi farmers should go for cash crops like potato instead of cereals only.

Referring to the dietary pattern of the Bangladeshis and Japanese, Iwanaga, who is from Japan, said, "In 1951, Japan was one of the poorest countries in Asia. The Japanese used to consume 130 kilograms of rice per person per year. Today we're one of the most buoyant economies in the world and an average Japanese eats only 65 kilogram of rice a year."

He pointed out that Bangladeshis consume 150 kilogram of rice per person per year.

Iwanaga, also a former deputy director general of the Rome-based International Plant Genetic Resources Institute (IPGRI), noted that with the rise in people's income-level, dietary pattern too changes leading people to have more balanced diet, lessening dependence on rice. Dietary diversification also helps people get nutritionally fit and enhance their ability to work, he added.

Bangladesh should follow the path Japan did a few decades ago -- developing agro-based industries to raise people's income-level, he felt.

Meanwhile, addressing the CIMMYT staffs in Dhaka, Iwanaga said, "Success should not be measured by sheer rise in acreage of one particular crop or the other; rather it should be measured in terms of improvement in the livelihood of resource-poor people."

About his meeting with Agriculture Minister MK Anwar, he said, the minister's call for incorporating farmers' traditional wisdom into scientists' endeavours touched his heart.

During his stay in Dhaka, Iwanaga also visited Bangladesh Agricultural Research Institute at Joydevpur, Wheat Research Centre in Dinajpur, USAID office in Dhaka and Brac's maize fields in Bogra. He also held talks with Executive Chairman of Bangladesh Agriculture Research Council (BARC) Dr Nurul Alam.