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United States Department of Agriculture

Agricultural Research Service

Research Project: MECHANISTIC PROCESS-LEVEL CROP SIMULATION MODELS FOR ASSESSMENT OF AGRICULTURAL SYSTEMS

Location: Crop Systems & Global Change

Title: Modeling temperature responses of leaf growth, development, and biomass in maize with MAIZSIM

Authors
item Kim, Soo-Hyung -
item Yang, Yang -
item Timlin, Dennis
item Fleisher, David
item Dathe, Annette -
item Reddy, Vangimalla
item Staver, Kenneth -

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 22, 2012
Publication Date: August 9, 2012
Citation: Kim, S., Yang, Y., Timlin, D.J., Fleisher, D.H., Dathe, A., Reddy, V., Staver, K. 2012. Modeling temperature responses of leaf growth, development, and biomass in maize with MAIZSIM. Agronomy Journal. 104:1523-1537.

Interpretive Summary: There is a need for decision support and assessment tools including crop simulation models for estimation of yield and biomass, and management of nutrients and water usage by agricultural crops under existing and future climatic conditions. Among the variables simulated by crop growth models, green leaf area plays a critical role for crop growth and development. Current crop simulation models use summation of daily temperatures as an input variable to estimate green leaf area. This method, however does not account for the negative effects of high temperature on leaf growth. We developed an improved method that takes into account the effects of high temperatures on leaf growth. These equations were implemented in a simulation model for corn called MAIZSIM. The model was calibrated with data from outdoor sunlit growth chambers. The model estimated leaf area, leaf addition rate and biomass well. These results suggest that the use of a more realistic representation for temperature response in crop models can reduce the need for parameterization. These results will be of interest to policy makers, agricultural managers and researchers interested in simulating effects of temperature on the leaf area and yield of a corn crop.

Technical Abstract: Changing climate, growing costs of agricultural inputs, and social and environmental demands are challenges facing agriculture in the 21st century. There is a need for decision support and assessment tools including crop simulation models for estimation of yield and biomass, and management of nutrients and water usage by agricultural crops under existing and future climatic conditions. Among the variables simulated by crop growth models, green leaf area plays a critical role for crop growth and development. Leaf area determines the fraction of incident photosynthetically active radiation (PAR) intercepted by crop canopy and ultimately dry matter production. A majority of simulation models in use today use the thermal time concept of accumulated growing degree days (GDD) with a base temperature. The disadvantage of the GDD concept, however is that it is a linear scale. The metabolic responses of plants to temperature are not necessarily linear, even during the increasing phase, and have an optimum rate after which the rates decline steeply. In this study we used a beta function to represent the response of leaf initiation, addition and expansion rates to temperature in the maize model MAIZSIM. Equations for leaf expansion based on GDD were reformulated and reparameterized to utilize rates based on current temperatures. The parameters for the equations were fit using data from outdoor sunlit growth chambers. The model, MAIZSIM, was then used to simulate maize growth and development at two field sites for three years of data. No further calibration was performed. The model estimated leaf area, leaf addition rate and biomass well. These results suggest that the use of a more realistic representation for temperature response in crop models can reduce the need for parameterization.

Last Modified: 8/29/2014