El Niño, the ocean-atmosphere phenomenon that does so much to shape the course of the world’s weather, is now giving officials in Thailand particular cause for concern. The Meteorological Department in Bangkok has announced that the cool, dry season has lasted an unusually long time, beyond its normal November to January range. The worry is that El Niño will eventually deliver a superheated hot season, usually February to April. Whilst the effects won’t be as severe as those of the catastrophic 1997/98 El Niño (see animation), there will likely be an impact on agriculture in Thailand and beyond.
The worry for Thailand is that the latex output from rubber trees (a major export commodity) is very dependent on rainfall. Drought means lowered production and that could hit the natural rubber industry hard. Efforts are already underway to defend against such a drought, with the Thai government promising $6.9 million to the endeavour. Water storage in reservoirs and cloud-seeding projects are expected to help to provide constant water supplies to farmers.
Read on below for an interesting abstract from a 1998 paper, Studies on the relationship between yield and meteorological parameters of para rubber tree. Lots more abstracts on rubber trees and farming and forestry in Thailand are also available to CAB Direct subscribers (Search terms: rubber industry, rubber plants, Thailand, weather patterns, climate, temperature, rain and cloud seeding).
Studies on the relationship between yield and meteorological parameters of para rubber tree (Hevea brasiliensis).
Rao,-P-S; Saraswathyamma,-C-K; Sethuraj,-M-R
Rubber Research Institute of India, Rubber Board, Kottayam 686009, Kerala, India.
Agricultural-and-Forest-Meteorology. 1998; 90(3): 235-245
The relationship between latex yield of natural Hevea trees and climatic variables was investigated. Under humid tropical rain fed conditions in India, the latex yields of Hevea (clone RRII 105) were between 19.8 and 90.5 g per tree per tap. The highest temperature experienced during 1, 7 or 30 days prior to tapping explained about 32, 42 and 64%, respectively, of the day-to-day variability in latex yields. Multiple regression models to estimate latex yield on a tapping day, with different antecedent weather conditions were developed. Weekly weather conditions associated with best yields were: maximum temperature of 30.4 degrees C, minimum temperature of 22.8 degrees , 5.9 h sunshine and 72 mm of rain. Any deviation from these meteorological conditions for up to a period of 6 months may significantly influence latex production. In general, highest temperature, sunshine duration, vapour pressure deficit and pan evaporation showed significant negative correlations with yield, irrespective of the time period considered. A significant positive association was observed between rainfall for >1 month and latex yield.