Light, Water and Temperature Dynamics in Row and Interrow Zones in Maize.

The soil corridor concept is a research approach to maximize the capture of light and water to obtain optimum crop yields under row crop management. Water movement and heat transport in soil under row crops varies both vertically and laterally. This is partially due to the presence and spatial distribution of the plant canopy and roots. The spatial variation in water and heat fluxes around the plant can affect solute transport, and water and temperature dependent soil processes. Physically-based crop/soil models can be used to make management decisions in row crops that optimize the 2-D distribution of inputs of light and water to crop production. The objective of the research presented here is to model root activity and soil infiltration in and around a corn plant with contrasting canopy development. Data were collected from two plots planted to maize, one in a no nitrate treatment and one in a high nitrate treatment. In each plot, a total of 24 soil moisture probes were placed beneath and between corn plants and at depths of 20, 40, and 60 cm. Thermocouples were also placed at each location. The maize simulation model, MAIZSIM, was used to simulate water movement and heat transport. This is a mechanistic model of maize growth and development model that uses, 2DSOIL, a two dimensional finite element model to simulate soil processes. Temperature and water dynamics varied with spatial location and canopy development. The model simulated surface water contents better than subsurface water contents. Canopy interception of rainfall and radiation need to be accounted for in order to modify boundary conditions for heat transfer and infiltration of water. The spatial and temporal distribution of soil moisture as a function of nitrogen plant stress is discussed. Along with data from an evapotranspiration sensor located in the field, water uptake in the corn plants is evaluated.