Increasing Soybean Yields: Brazil's Challenges.

Average soybean yield has increased over recent decades in many areas of the world, but a plateau seems to have been reached in some situations, Brazil being a typical case. Agronomic challenges for high yielding soybean systems are related to (i) early seeding and short maturity cultivars, (ii) biological N fixation ineffiency, (iii) broadcast application of P, (iv) soybean cultivation on sandy soils, and (v) early desiccation for an early harvest. High soybean yields in Brazil are common in regions where the agronomic practices are used correctly. Nevertheless, we consider that yields between 3.6 to 4.0 t/ha are likely 75 to 85% of attainable yield, and therefore some important questions are raised. How far are we from maximum yield? How much of the complex set of interactions between the cropping system and the production environment is understood? Ecological intensification of the cropping system represents a huge advantage for regions of the world where two or more crops can be grown in a season, but it is highly dependent on a fast operational system to crop vast areas in a short time. It seems that in some cases agronomic practices hold a second place priority in favor of the overall scale of production.