Havana, September 26 (Xinhua-RHC) -- Some three-quarters of Cuba's 6.6 million hectares of arable land is affected by soil erosion, the Cuban News Agency reported Thursday.

The main reasons for the loss of topsoil are excessive mineral fertilization, burning the fields, failure to rotate crops, indiscriminate logging and inadequate reforestation, said Dr. Olegario Muniz Ugarte, president of the Cuban Soil Science Society.

Aggravating the problem are the lack of conservation of natural forest land that protects rivers and reservoirs, and the excessive exploitation of natural wells and other water sources, Muniz added. And he noted that a national program to improve soil quality is underway.

The Agriculture Ministry is implementing a strategy to mitigate soil erosion, including reforestation, planting living fences for livestock, integrated crop management, the selection of more drought-resistant clones and the practice of polyculture, or planting multiple crops over a single area.

Cuba imports 80 percent of its food necessities at a cost of nearly two billion U.S. dollars a year, a heavy burden for its economy.