Laj Ahuja's Multidemensional Inspiration for Agricultural Systems Modeling.

Environmental factors in the plant environment vary in all four dimensions. Laj Ahuja has spent a career working to quantify the effects of these factors on plant growth, development and yield as well as on environmental quality. His research was often devoted to finding quantitative approaches to explain soil related processes and predict or estimate soil responses to environmental phenomena.  He has always emphasized the importance of using and developing system models to use this knowledge to integrate the varied environmental factors that affect the soil-plant environment. Because the plant canopy and roots are mult-dimensional they can have a large impact on vertical and lateral water and heat movement in soil under row crops. The spatial variation in water and heat fluxes around the plant can affect solute transport, and water and temperature dependent soil processes. The objective of this work is to present research and model applications to understand and manage two-dimensional processes in the plant environment and their effects on growth and development.  We will discuss field research and the development of a mechanistic model for corn growth and development mated to a two dimensional finite element model of water and heat movement and solute transport. We will show how the model can be used to investigate the interaction of management practices and the two dimensional environment of the plant on plant growth and soil nutrient movement.