July 31, 2001

Mild Monsoon Over Mexico Central Plains

Summary:
Generally good growing conditions prevailed across southern Mexico until the second week of July 2001, when precipitation dropped off dramatically, stressing dryland production areas.  Surface and subsurface moisture has not been abundant this season (see soil moisture maps below), and dryland fields will begin to show serious moisture stress if precipitation does not resume shortly.  

Mild Temperatures Mitigate Effects of the Dryness:
Mild temperatures in the southern states of Mexico, where summer grain production is concentrated, have aided crop development into July.  The monsoon is usually longest and most consistent in this region, benefiting crop development.  However, early-season precipitation was sporadic, rather than the daily rainfall pattern of a strong, beneficial monsoon.  Fields in northern Veracruz, Tlaxcala, Puebla, Hiladgo, Queretaro, Guanajuato, Michoacan and Colima are among the states in the most immediate danger.  

Satellite Imagery:
In the AVHRR Vegetation Index composites below, note that plant vigor, as indicated by the intensity of the color red, is not as strong in 2001 as in the prior 2 years.  The disparity is most evident along the coastlines and within the contours of the mountains.

Water Resource Competition:
Mexico 's growing population is competing with agriculture for water resources across the central plateau, also known as the nation's "cornbelt" or "breadbasket".  Expanding residential centers and the demands for more food has begun to stress even the most productive agricultural areas.  Laguna Cuitzeo, in north Michoacan state at the border with Guanajuato state, relies upon the annual monsoon and tropical storms to recharge reservoir levels.  With less frequent tropical storms in recent years, reservoir reserves have been diminished at the same time that irrigation demands are increasing.  A September 1999 Landsat scene shows Laguna Cuitzeo after the very late arrival of the 1999 monsoon (mid-July rather than May), and the extensive agricultural activities surrounding it.  A June 2001 Landsat scene shows Laguna Cuitzeo to be holding slightly more water than in September 1999, but 3 months of growing season irrigation releases have yet to occur.  

For more information, contact Ron White with the Production Estimates and Crop Assessment Division on (202) 690-0137.