Abstracts for the 6th International GAME Conf.

3-5 December 2004

Kyoto Japan

Seasonal change of evapotranspiration and crop coefficient in a rain fed paddy field, cassava plantation and teak plantation in Thailand

Pedram ATTAROD (1), Daisuke KOMORI (1), Kazushi HAYASHI (3), Masatoshi AOKI (4), Tomoyasu ISHIDA (4), Kazunari FUKUMURA (4), Samakkee BOONYAWAT (4), Panya POLSON (8)

The evapotranspiration (ET) is an essential factor to estimate crop water use efficiency. It is also one of the factors in soil water storage and water resource in a region. Since researches on the evapotranspiration in the tropical region are relatively scarce, this study is to compare the trend of ET among three measurement sites in Thailand that are a rain fed paddy rice field, cassava plantation and teak plantation. Bowen Ratio Energy Balance technique (BREB), which is one of the accurate ways of measuring evapotranspiration, was applied in this investigation to measure the actual ET and heat flux between ground surface and atmosphere. Penman-Monteith equation was used in order to create crop coefficients. Measurement was carried out during 1999-2003 in the paddy rice field, 1999-2002 in the teak plantation and 2002-2003 in the cassava plantation. Results showed that the amount of daytime actual ET during the rainy season at the paddy rice field and the cassava plantation varied between 1 and 7 mm but at teak forest varied between 2 and 6 mm. The average amount of daytime ET in the teak forest in the dry season was 3.2 mm, that was higher than those of the paddy field and the cassava plantation, and the potential evapotranspiration rate (ET0) of the teak forest was lower than two other sites. It can be suggested that teak forest has potential of water saving for evaporation during the dry season. In the rainy season, the Kc factor for the teak plantation reached peaks of approximately 1.3. The maximum Kc for the rain fed paddy rice field and cassava were 1.1 and 1.2 respectively. In the rainy season, LE/Rn ratio in the cassava plantation and paddy rice field was 70% but in teak plantation was about 76%.

Submittal Information

Name : Date :
    Pedram ATTAROD
    06-Aug-04-16:38:54
Organization : Theme :
    Tokyo University of Agriculture and Technology(TUAT)
    Theme 5
Address : Presentation :
    Faculty of Agriculture, Tokyo University of Agriculture and Technology,Fuchu, Tokyo,183-8509
    Poster or oral
Country : Abstract ID :
    Japan
    T5PA06Aug04163854
Phone : Fax :
    042-367-5727
    042-367-6078
E-mail :
    attarod@cc.tuat.ac.jp