S06 - Session P16 - Substrate stratification can improve resource efficiency in container crop production

Authors: Jeb Fields *

As the world transitions to more sustainable agriculture, we are seeing a shift of many crop systems to soilless culture. Furthermore, demand for both food and ornamental crops continues to increase due to rising population, increased interest, and other global factors. All this, while natural resources are becoming more limited and availability is becoming increasingly scarce. Thus, we must seek new production practices that allow more sustainable and efficient use of natural materials. An emerging growing media management practice, recently described as substrate stratification, involves the layering of individual media materials (components or composites) within a container system. These stratified substrates provide opportunity to manipulate the hydraulics and chemical retention within a container system. In theory, utilizing coarse materials with high gravitational porosity in the bottom of the container, and fine or fibrous materials on the top half redistributes the air:water equilibrium within the system, resulting in a more uniform hydraulic gradient. By this, we can effectively support added water and nutrient retention in the upper half of the container without reducing air space to deleterious levels. In practice, we can engineer individual strata for specific physiochemical properties to design a new container system. To date, multiple research projects have identified the potential of stratified substrate systems to increase resource efficiency, reduce crop stresses, and provide cost-effective options for growers. All while producing similar or superior crops with reduced water & fertilizer. Moreover, utilizing high-cost, performance growing media in the upper, initial establishment strata, and low-cost growing media in the lower strata has the potential to reduce media costs significantly, while reducing reliance upon individual media components. Finally, the redistribution of water ate equilibrium within the container coupled with the modification of the physical nature of the soilless substrate system has shown the proficiency for controlling root morphology and architecture. Overall, this research is in its initial stages; however, there exists a good opportunity for high intensity, precision production practices to be developed in concert with soilless substrate stratification for improved production sustainability and efficiency.