A field observation was undertaken to investigate factors affecting flowering stage of cashew nut tree at the cashew plantations in Ranong province, Thailand and Champasak, Lao People’s Democratic Republic (Lao PDR). Soil moisture, soil pH, total nitrogen (in soil and leaves), and temperature were monitored. Results showed that soil moisture at Ranong Province and Lao PDR was 23.8-24.3% and 29.9-32.5%, respectively. Soil pH at Ranong Province was high in acidity and ranged from 4.7-5.0, such values did not differ from the soil pH at Lao PDR (4.4 to 5.0). Nitrogen contents of the soil and leaves at the observation sites were evaluated. Although, nitrogen content in soil at Ranong Province (1.82 to 2.26%) was higher than the soil in Lao PDR (3.06-3.62%), total nitrogen in leaves at Ranong Province (9.84-11.89%) was lower than those of leaves at Lao PDR (12.63 to 17.45%). Moreover, the temperature on December, 2012 in Ranong Province ranged between 32-35ºC which was higher than the temperature in Lao PDR (19.9 to 23.7ºC).
Keywords: field observation, cashew nut tree, flowering stage