OCCURENCE AND DURATION OF DAILY MINIMUM TEMPERATURES INJURIOUS TO FECUNDATION OF RICE FLOWERS IN SANTA MARIA, RS. III: OCCURENCE PROBABIUTIES OF THE DURATION WITH LOW TEMPERATURES

[摘要] Using daily minimum, maximum and at 21:00 hours temperatures observed during December, January, February and March registred in the main weather station located in Santa Maria, RS, the probabilities of occuring the maximum number of hours with air temperatures ≤ 10, 11 , 12, 13, 14, 15, 16 and 17,0°C was determined as well as the sequency of consecutive days with at least on hour with air temperatures ≤ 15, 16 and 17,0°C. These probabilities were obtained for every decade of December, January, February and March.The results indicated that the risks of occuring temperatures considered as damaging to fecundation of rice flowers is much lower in the 2° and 3° decades of February. Therefore seeding or cultivar choice should be done in such a way that flowering occurs during the second and third decade of February.

[学科分类] 农业科学（综合）

[关键词] rice;cold;risk;occurence probability