Study On Key Technology Of Soil Water Flux Determinator

Soil water flux is an essential parameter in analyzing runoff, infiltration, and chemical transport. Soil scientists, environmental scientists and agriculture experts all want to know soil water flux density in some special location, however, they find it is difficult to determine by simulation method. Therefore, seeking for one direct method of measurement seems more attractive. To overcome these problems, using the combined method of theoretical analysis and laboratory test, the paper designs a real time monitoring system, which named soil water flux determinator.Paper proposed the design plan of soil water flux determinator based on the heat pulse techniques, and set up the real time monitoring system in laboratory. Soil water flux determinator uses CR800 as the core of the real time monitoring system, which controls peripheral circuits of system to switch measurement channels in turn and generate heat pulse. At the same time, it measures the voltage variety of the temperature sensors to monitor the whole process of heat pulse transmission in soil. Some specific values are recorded which can be downloaded by PC for analysis and calculate the real time soil water flux.Paper results are as follows:(1)Developed a rational design step of soil water flux determinator, through studying and analyzing the Domestic and international heat-pulse theory.(2)Proposed to the design plan, explained the reason for choosing CR800 as the control unit, and presented the select criterion on temperature sensors.(3)According to the design plan, designed the signal measurement unit and the heat-pulse control unit circuit, and completed circuit board debugging in laboratory conditions. In terms of software, wrote a great quantity of related procedures to restore the measurement data automatically.(4)Integrated the hardware and software, successfully completed the installation and test of experimental device, developed a detailed experimental procedures, and analyzed a large number of experimental data. The results show that this soil water flux determinator can work credibly, which has high practical value for soil thermal properties study.