Agricultural Drought in Vietnam

Abstract

Vietnam is located between 8°22'N and 23°22'N latitude and between 102°10'E and 109°21'E longtitude. The country has a geographical area > 333,000 km2 and a coastline > 3000 km long. Vietnam is situated in the typhoon center of the East Sea (Bien Dong), which is one of the five largest typhoon centers of the world, and it has a complicated topography ranging from narrow, low plains to steep, high mountains. Floods occur with high frequency, and drought occurs with medium frequency in Vietnam. If monthly rainfall is less than 50 mm, drought is considered to have occurred during the month. The climate of Vietnam is strongly influenced by mountainous terrain and by the northeast and southeast monsoons. The rainfall season, which usually begins in May–June and ends in November–December, accounts for about 75–85% of the total annual rainfall. The period from November– December to April–May is usually dry and is prone to droughts. Vietnam has been divided into seven agricultural regions: (1) north mountain and midland region, (2) northern delta region (Red River delta), (3) north-central region, (4) south-central region, (5) central highland region (Taynguyen platour), (6) southeast region, and (7) southern delta region (Mekong River delta). The rainfall distribution is uneven due to complex terrain conditions. While some places (in the north mountain, central, and central highland regions) receive 3000–4000 mm of rainfall annually, other places (such as Phanthiet and Phanrang of the south-central region) receive only 750–800 mm in a year. Rice and maize are the major crops in Vietnam, whose regional distributions are given in table 27.1. Table 27.2 shows rice area lost due to droughts during 1980–99 in different regions of Vietnam. The north mountain and midland region is not prone to droughts. Only moderate droughts occur at some places in this region. Droughts rarely occur for consecutive years, except the droughts that occurred during the summer season of 1988 and 1989. The northeast part of this region is more prone to drought than the rest of the region.