Event Title

Improving Root Zone Performance Physical and Numerical Modeling of a Layered Plant-growth Medium

Presenter Information

Robert Heinse

Location

ECC 216

Event Website

http://water.usu.edu/

Start Date

4-5-2007 5:50 PM

End Date

4-5-2007 5:55 PM

Description

Growing media in greenhouses and nurseries are selected based on gas exchange, control of the liquid phase and nutrient holding capability. In an effort to maintain favorable aeration and to avoid nutrient/salinity buildup, irrigated and free draining root zones operate under suboptimal water and nutrient use efficiencies. A novel layered plantgrowth medium was designed to improve the efficiency of water and nutrient application and promote more uniform root density compared to conventional containerized plant growth media. Our objectives were to (1) design and model an optimized root zone system using layered media, (2) instrument the root zone to monitor the water content distribution and track nutrient release and transport, and (3) compare the layered media system to conventional, non-layered plant growth media. The root-zone system is comprised of layered Ottawa sand, where watering is achieved by maintaining a shallow saturated layer at the bottom of the column and allowing capillarity to draw water upward. Coarser particle sizes form the bottom layers with finer particles sizes forming the layers above. The depth of each layer was chosen to optimize water content based on the wetting water retention curves retaining saturation between 50 and 85 percent. The saturation distribution was verified by dual-probe heat-pulse sensors, while the nutrient concentration was sensed by in-situ electrical conductivity measurements. Hydrus-1D was used to model the dynamic response of nutrient transport and root water uptake during diurnal cycling of transpiration. This design should provide a more optimal rootzone environment than conventional potting soils by maintaining a uniform water content profile and on-demand water supply.

This document is currently not available here.

Share

COinS
 
Apr 5th, 5:50 PM Apr 5th, 5:55 PM

Improving Root Zone Performance Physical and Numerical Modeling of a Layered Plant-growth Medium

ECC 216

Growing media in greenhouses and nurseries are selected based on gas exchange, control of the liquid phase and nutrient holding capability. In an effort to maintain favorable aeration and to avoid nutrient/salinity buildup, irrigated and free draining root zones operate under suboptimal water and nutrient use efficiencies. A novel layered plantgrowth medium was designed to improve the efficiency of water and nutrient application and promote more uniform root density compared to conventional containerized plant growth media. Our objectives were to (1) design and model an optimized root zone system using layered media, (2) instrument the root zone to monitor the water content distribution and track nutrient release and transport, and (3) compare the layered media system to conventional, non-layered plant growth media. The root-zone system is comprised of layered Ottawa sand, where watering is achieved by maintaining a shallow saturated layer at the bottom of the column and allowing capillarity to draw water upward. Coarser particle sizes form the bottom layers with finer particles sizes forming the layers above. The depth of each layer was chosen to optimize water content based on the wetting water retention curves retaining saturation between 50 and 85 percent. The saturation distribution was verified by dual-probe heat-pulse sensors, while the nutrient concentration was sensed by in-situ electrical conductivity measurements. Hydrus-1D was used to model the dynamic response of nutrient transport and root water uptake during diurnal cycling of transpiration. This design should provide a more optimal rootzone environment than conventional potting soils by maintaining a uniform water content profile and on-demand water supply.

https://digitalcommons.usu.edu/runoff/2007/AllPosters/15