Experimental investigation of a digital electromechanical system to measure soil bulk density in a silty clay soil under different solarisation practices

A digital electromechanical system (DES) is an innovative system for in situ measurement of soil dry bulk density (pb) based on microwave drying of automatically collected core samples. This paper determines the effectiveness of DES for measuring soil pb in a silty clay soil under solarisation conditions. The experimental design consisted of 2 by 2 m plots arranged in a split-plot design with systematic plot arrangement, and three replicates were made. Three different treatments were used, namely, the tillage system, mulching system (the plastic type used x fertiliser added) and soil depth. The parameters investigated included soil pb, moisture content(µ) and evaporated soil moisture (EMC), which were all measured using DES. Results demonstrated that pb could be accurately measured using DES under different experimental conditions, and the accuracy was affected by the three different treatments studied. Although accurate results were obtained with DES, the highest systematic error was found for plots with single sheet transparent cover x without fertiliser under mouldboard plough followed by a spring disk system. EMC was strongly dependent on the mulching, tillage systems, and soil depth, which were directly related to the initialµ and the water holding capacity of the soil, having a significant role in determining the mean microwave drying time. The results indicated that pb changed with tillage system and mulching type and increased with soil depth. Thus, it is recommended to use the innovative DES to measure pb and µ under solarisation practice with different tillage systems and mulching types and for different soil depths.