Increasing World Average Yields of Cereal Crops: It's All About Water

Abstract Food demand of the growing and increasingly affluent world population may necessitate additional food grains production by the year 2100 by 1 billion Mg and meat production by 200 million Mg. However, of the 3 billion Mg food grains produced globally, ∼30% are wasted through postharvest losses in developing countries and an inefficient supply chain system in developed nations. Rather than increasing the area under production, an appropriate strategy is to reduce food waste and enhance productivity of drylands through adoption of an efficient irrigation system or use of conservation agriculture based on no-till, residue mulch, cover cropping, and integrated nutrient management. Grain yield (GY) is affected by the product of four factors: evapotranspiration (ET), transpiration: ET ratio (T/ET), 1/TR, and the harvest index (HI) [GY = ET × 1/TR × HI]. TR or transpiration ratio is the kg of water required to produce 1 kg of the aboveground biomass. The most impact determinant of GY is ET. Thus, conserving water in the root zone is essential to improving agronomic productivity of dryland agriculture. By narrowing the yield gap and conserving water in the root zone, it is technically feasible to produce the cereals needed to meet the global demand by the year 2100 on 0.5 billion ha of cropland. However, the importance of judicious governance for translating science of water management into action cannot be overemphasized. After all, it's all about water. Its judicious management is critical to enhance ET, improve GY, and advance food and nutritional security.