Dryland agriculture in north america

Abstract

Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges.