Onset of the growing season and dry periods in Tabasco, Mexico

Abstract

In rainfed agriculture, information about dates for the onset of rainy periods is used to plan activities inherent to exploitation, and even determines the success or failure of crops. The results are partially reflected after planting (germination) and at harvesting time. Dry periods are another very important factor to the agricultural cycle, causing poor germination, stunted growth, deficient development and considerable reductions in yield. Therefore, an analysis was performed at the onset of the growing season in Tabasco in order to identify different levels of probabilities for the dates for the beginning of this period. The frequency of 7-day dry periods was also studied (defined by a threshold of 1 mm) using daily rainfall and evaporation information from 18 weather stations in the state. A relationship was found between the average start of the growing season with the latitude and average annual rainfall. This was corroborated by a linear regression analysis, in which values for r2 of 0.6884 and 0.8112 were found for each case. The earliest dates for the beginning of the growing season relate to low probabilities for the onset of the rainy season; Tabasco has three regions in which the beginning of the growing season (80%) is distinctly affected by the occurrence of 7-day dry periods.