Construction and Evaluation of a Device for Injecting Air into the Deep Soil and Modeling its Parameters

In urban environments, root growth is limited because of limitation of soil and some problems the plants are faced with, for example soil compaction. The aim of this study was to build and evaluate a device that could improve the existing deficiencies for tree roots by increasing soil porosity and permeability through air injection. After construction of the machine, weighing 240 kg, equipped with a 7.5 HP engine and maximum injection pressure of 12 bar, the effects of machine operation and some important physical properties of soil such as porosity and infiltration were investigated. Multiple linear regression was used to investigate the relationship between the independent variables of the device including air pressure at 3 levels (4, 8 and 12 bars) and depth at 2 levels (30 and 60 cm) and the dependent variable of porosity. The results showed a significant regression model among the variables. Also, the regression model estimation error was 1.75%. Based on the results, the system can be reliably designed and manufactured to inject air into the soil to increase porosity.