TECHNICAL PROPOSAL FOR MODIFICATION OF MAIZE SOWING DATE IN THE FUERTE-MAYO REGION, SONORA, MEXICO

Maize is the second most important crop in southern Sonora, Mexico, so it is an asset for the economy of the region, and it is highly relevant for the fall-winter crop pattern. The Fuerte-Mayo region is conducive for maize high grain yield potential; however, farmers used to establish the crop in a period of high frost occurrence. Therefore, the objective of this work was adjust the sowing date in order to optimize grain yield per hectare and escape the frost and heat risks. Experiments were established in the Fuerte-Mayo region which is located in the southwestern part of Sonora, during the crop season 2016-2017. Five commercial fields sown on different dates and in different areas of the region were selected for a follow up of the different phenological stages. Climatic information was taken close to the crop, by placing digital sensors within three of the fields; also, temperature data was taken from the automated weather stations from Module 01 and Zapata which belong to the weather network of the National Water Commission (CONAGUA), from October to June during the years 2015 to 2017, in order to identify months with high probability of frost and heat risks. Based on the temperature recorded by the digital sensors and the development of maize in those fields, three climatic zones were detected for avoiding the possible frost and heat risks: from November 15 to December 15 for early hybrids in a cold zone (central and northwest of the region), intermediate hybrids in the intermediate zone (central and east), and late hybrids in the warm zone (southeast and west). From November 15 to 30 for intermediate hybrids in the cold zone, and late hybrids in the intermediate zone, and from November 15 to December 31 for early hybrids in the intermediate and warm zones, and intermediate hybrids in the warm zone.