ittle research has been performed on the physical effects of soil on corn (Zea mays L.) root systems. The purpose of this study was to develop and test a root growth model for corn that aids in understanding the pattern of root development and the response of root growth to environmental factors.
A simulation model of radicle root growth in corn was developed using daily temperature, oxygen concentration, penetration resistance, and matric potential as inputs. The outputs of the model are the position of the root tip and the growth pathway of the radicle root. The model was partially validated using experimental data which had not been used in its derivation.
Additional data for validation of the simulation model was developed in a greenhouse experiment. A randomized complete block design was used with three levels of temperature, two levels of matric potential, and two levels of compaction. Corn root length and growth direction were measured after 7 to 22 days of growth. Root growth directions were steeper than predicted for low temperature (12.5(DEGREES)C) treatments. However, reasonable agreement was found for the first 10 cm of root for medium (23.5(DEGREES)C) and high (32.2(DEGREES)C) temperature treatments. The model overestimated root length for the wet, compacted and dry, non-compacted high temperature treatments.
The validation work required a conversion of oxygen diffusion rate to oxygen concentration. Methods were developed to accomplish this conversion.
An independent study of root growth was designed to evaluate temperature interactions with penetration resistance and matric potential. A factorial design with three temperature regimes, three levels of matric potential, and five levels of bulk density was established to evaluate radicle root growth. A comparison of a regression model derived from this data (R('2) = 0.88) and the simulation model showed that the regression model gave a higher growth rate than the simulation model.
ittle research has been performed on the physical effects of soil on corn (Zea mays L.) root systems. The purpose of this study was to develop and test a root growth model for corn that aids in understanding the pattern of root development and the response of root growth to environmental factors.A simulation model of radicle root growth in corn was developed using daily temperature, oxygen concentration, penetration resistance, and matric potential as inputs. The outputs of the model are the position of the root tip and the growth pathway of the radicle root. The model was partially validated using experimental data which had not been used in its derivation.Additional data for validation of the simulation model was developed in a greenhouse experiment. A randomized complete block design was used with three levels of temperature, two levels of matric potential, and two levels of compaction. Corn root length and growth direction were measured after 7 to 22 days of growth. Root growth directions were steeper than predicted for low temperature (12.5(DEGREES)C) treatments. However, reasonable agreement was found for the first 10 cm of root for medium (23.5(DEGREES)C) and high (32.2(DEGREES)C) temperature treatments. The model overestimated root length for the wet, compacted and dry, non-compacted high temperature treatments.The validation work required a conversion of oxygen diffusion rate to oxygen concentration. Methods were developed to accomplish this conversion.An independent study of root growth was designed to evaluate temperature interactions with penetration resistance and matric potential. A factorial design with three temperature regimes, three levels of matric potential, and five levels of bulk density was established to evaluate radicle root growth. A comparison of a regression model derived from this data (R('2) = 0.88) and the simulation model showed that the regression model gave a higher growth rate than the simulation model.
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