October 15, 2001

Mexico:  Summer Crops Enter Dry-Down Phase; 
Reservoirs Thirsty for Fall Rains

Summary:

Summer crops in Mexico's Central Plateau, the foremost corn and sorghum production region, have matured and entered the dry-down phase.  The early-season pattern of sporadic precipitation improved in July, in time for a full development cycle. Even so, production has fallen  short of Mexico's early-season expectations.  Earlier, the Mexican government had projected corn production at 15.3 million tons from a harvested area of  7.6 million hectares.  Sorghum  production was projected  at 4.1 million tons from a harvested area of 1.2 million hectares.  Production and area expectations have since been scaled back to approximately 15.3 million tons and 7.3 million hectares for corn, and 3.5 million tons and 0.9 million hectares tons for sorghum.  Additionally, the Central Plateau reservoir levels are just above fifty percent of capacity, and could benefit from a recharge that can come from tropical storms.  

Images: 
 Map of Mexico

Vegetative Development:
AVHRR Composite VIN Map 1-15 August 1999 
AVHRR Composite VIN Map 1-15 August 2000
AVHRR Composite VIN Map 1-15 October 1999
AVHRR Composite VIN Map 1-15 October 2000
AVHRR Composite VIN Map 1-15 September 20001

USDA estimates Mexican total grains (barley, corn, millet, oats, milled rice, sorghum, and wheat) production is 29.0 million tons in 2001/02 , 2 percent above than the 5-year average of 28.5 million.  Estimated area of 10.7 million hectares is 1 percent below the 5-year average of 10.78 million hectares.  The annual monsoon season (May-October) is usually longest and most consistent across the southern half of Mexico, but the 2001 season was mild through mid-July.  Concern over soil moisture eased somewhat with increased rainfall activity during the latter part of July in Bajio, prompting enhanced vegetative vigor.  

Although rainfall totals remain below normal in many areas, overall soil moisture has been sufficient to support crop development.  Natural dry down, rather than the application of chemicals to speed reduction of plant moisture content, is popular in Mexico, as the mild climate permits producers to leave crops in the fields for several weeks after maturity. The risk of damage by strong winds and very heavy rainfall from tropical storms does exist as dry-down coincides with the latter part of the tropical storm season.  In most years, natural dry down is successfully practiced.  Among the areas where dry-down has begun are the corn and sorghum fields found along the principal highways #45 and #17a & #17b in Guanajuato state.

Images:  World Meteorological Organization Precipitation Data, May 1 through October 10, 2001).

Guanajuato in Guanajuato state
Guadalajara in Jalisco state
Morelia in Michoacan state

Reservoir Levels Continue To Be Low Despite Recent Rains 

NOAA defines the hurricane season for the North American eastern seaboard generally as the period between June 1st and November 30, and historical records indicate that August through October is the period when most of the major storms develop. At least one official Mexican government agency fixes May 15th as the start of the season.  The Pacific coastline of North America has a similar window of storm development. The 2001 season has been very unusual in that no hurricanes were reported in the Atlantic prior to September, with only six tropical storms to date.  During the month of September, four hurricanes developed in the Atlantic, having no impact upon Mexico. The Pacific sector saw three hurricanes form during the same period, with limited impact upon Mexico.  

Ample time remains in 2001 for Mexican reservoirs to be replenished by the usual deluges from tropical storms and hurricanes. In late September, Hurricane Juliette made a small contribution in reducing the deficit (AVHRR from September 24).  Hurricane Juliette's rainfall fell over a narrow time period as she slowly meandered into the Gulf of California causing localized flooding in several places, however its impact (9/28/01,  10/01/01) was minimal over agricultural interests beyond the western shoreline.  Tropical storm Lorena also formed off of Mexico's Pacific coast in early October, came ashore over north Nayarit state, and dissipated over Guanajuato state.  Soon thereafter Hurricane Iris crossed the southern Yucatan Pennisula via Belize and dropped copious amounts of rainfall on Guatemala, but lacked tropical storm intensity by the time it reached the southern state of Chiapas.  Tropical storm Manuel also formed off the Pacific coast of Mexico, moved west and thus far it has not veered off toward land like Lorena and Juliette.  Overall, the reservoir levels continue to be low despite all of the recent tropical storm activity. 

At the start of the current hurricane season, NOAA had forecast an average number of hurricanes for 2001. NOAA considers an average hurricane season to be one in which 2 or fewer hurricanes make landfall on the United States and at least one makes landfall in the Caribbean Islands. The expectation of Mexican officials was that as many as five hurricanes would originate in the Atlantic, and as many as nine in the Pacific.

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