Submitted to: Fluid Fertilizer Foundation Symposium Proceedings
Publication Type: Review Article
Publication Acceptance Date: February 22, 2000
Publication Date: N/A
Technical Abstract: Producers strive for higher yields in order to maximize their return from land and in this quest often assume that the soil is a reservoir that is to be filled with various inputs. However, there has been little attention paid to the efficiency at which these inputs are used relative to crop biomass or yield production. The challenges that need to be addressed are complex because they require that we begin to understand the interactions among water, light, nutrients, soil types, crop genetics, and agronomic practices. These are not simple interactions nor are there simple experiments that can be conducted that easily define these characteristics. For example, we have found that water use varied within a field by a factor of two and within a soil type by 50% due to nitrogen management. From research completed in 1999 we found that corn yield is determined at three critical points: early in the growing season when potential ear size is being developed, at tasseling when the number of fertile ovules is being set, and in the early grain-filling period during the physiological efficiency of the crop. Understanding these processes has allowed us to examine the response across a field with a more quantitative measure of crop response. The role of the soil in providing an optimum environment is critical to high yields. Biological activity within the soil, a well-developed soil profile with no restricting layers, high soil water availability, and rapid exploration of the soil profile by the developing crop are factors that are linked to the most efficient crop production systems.