Management of extensive farming systems for drought-prone environments in North America and Australia. New directions for a diverse planet

The dryland cropping areas of North America and Australia share many common features, including crops, soil properties, farm size, and most importantly high variability in rainfall. Farmers in both regions have achieved extraordinary levels in productivity by adopting technologies and farming practices that maximize water and nutrient (nitrogen) availability for crop production and that minimize the cost and risk associated with cropping. When soil fertility is non-limiting, crop yield and water supply follow a linear model. Similarly, nitrogen and other macronutrients are proportional to crop growth and, hence, the crop water supply. This paper discusses the role of water supply on crop yield and describes how farmers, managing extensive dryland properties in North America and Australia, utilize improved tillage, residue management, plant arrangement (row spacing and plant population) to optimize the crop water supply and fertility to minimize production risk. Media summary Managing crops in drought-prone environments of USA and Australia requires farmers to pay careful attention to the crop water supply. Their first option is irrigation. If sufficient water is available at reasonable cost and appropriate quality attention is focused on maximizing conveyance and applicatio