Excessive rice cultivation puts soil fertility at risk

Southern Institute for Agricultural Science and Technology director Bui Chi Buu spoke with the newspaper Nong thon Ngay nay (Countryside Today) about plans to expand the area under rice cultivation.

We do not know the exact area of rice cultivation in the Mekong Delta, but right now there are about 2.6 crops a year. Though agricultural land in the delta is fertile, it is dangerous to overexploit the land. Farmers in other countries are afraid of cultivating three crops of rice a year, as the soil’s fertility is gradually reduced. I am not opposed to autumn-winter crops, but we should be aware of the cost of growing the crops. I think the Ministry of Agriculture and Rural Development already carefully considered this before the expansion of the autumn-winter crops by 100,000ha. However, provinces outside the delta must now consider the specific production conditions in their localities.

The whole delta grows about 2.6 crops each year. In other countries, farmers plant three crops that are not rice to avoid insect problems. Cultivated soil will use polyphenol to ensure the soil maintains its nutrients throughout the three successive crops. Farmers will have to invest a great deal of money and time before having a highly productive yield.

The number of crops planted each year in the Mekong Delta still needs to be determined. To do so, we must have an accurate number of cultivated land in the region. As far as I know, there are very few places capable of planting two crops of rice and one cereal crop in the current 500,000ha of cultivated land. Most of the rest grow three crops of rice each year.

The existing coefficient is already high in the delta; it may be raised, but it risks exploiting the soil. The delta has rich land, but it is not inexhaustible. The soil needs alluvium left by floods. In my opinion, the slogan ‘Living along with flood’ remains valuable.

I think they do not. It is possible to grow rice at any time. In the southern province of Tien Giang, for instance, many localities grow seven crops of rice in two years. However, as I already said, rice grows slowly if the soil does not have time to become fertile again.

We must alternate one cereal crop between two crops of rice. If we grow rice uninterruptedly, ploughing the soil then becomes mandatory. I want to remind localities that the Ministry of Agriculture and Rural Development only dictates the principle of expanding rice cultivation areas. Each of the localities need specific planning to lower the risks. They should not harvest too late, harvest time should be no later than November 15 this year. — VNS

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