Dryland Agriculture in Mexico and the U.S. Southern Great Plains

Northern Mexico and the U.S. southern Great Plains contain extensive dryland production regions. The climate of the southern Great Plains and northern Mexico is a product of complex weather systems that integrate the effects of cold polar air masses interacting with moist air streams flowing from the Gulf of Mexico or the Pacific Ocean. Precipitation is the most important climate factor governing dryland crop production in northern Mexico. Evaporation is a process that integrates the effects of solar irradiance, temperature, and wind to transport water vapor from the soil, which, like precipitation, varies primarily along an east to west transect. Annual precipitation varies little spatially from north to south throughout much of the southern Great Plains region and often results in similar cropping practices. Tillage practices are commonly used throughout the region to optimize soil water storage during fallow periods for subsequent crop production by reducing water losses to weeds, evaporation, or runoff.