The office secretary-general Chantanon Wannakejohn said production of economic crops, such as rice, tapioca, pineapple, palm oil, mangosteen and rambutan dropped due to drought.
"The Covid-19 outbreak also caused a fall in demand for aquatic produce and wood," he said.
"However, the demand for meat and dairy increased, especially in China and Japan."
He expected the country's agricultural GDP this year to drop by between 2.4 and 3.4 per cent, adding that the office would be closely monitoring the weather, outbreak of plant diseases and pests, Covid-19’s impact abroad, and conflict among countries.
The third quarter saw rising domestic and international demand push up the price of rice, maize, tapioca, pineapple, rubber, oil palm, durian, mangosteen, rambutan, pork, white-leg (vannamei) shrimp, tilapia and catfish compared to the same period last year, reported office deputy secretary-general Tatsanee Muangkaew.
"Meanwhile, the price of longan, chicken, egg and raw milk dropped due to increases in production," she said.
She added that the export of Thai agricultural products from July to August this year totalled Bt205.01 billion, down 8.97 per cent from the same period last year.
"The export value of rice, maize, sugar, rubber, pineapple, durian, mangosteen, rambutan, shrimp and squid dropped year on year, while the export value of tapioca, palm oil, longan, pork and fish rose," she added.