Research On Estimation Method Of Litter Decomposition Degree Based On Impedance Analysis

Litter is an important component of the productivity of forest ecosystems,and its decomposition rate and degree of decomposition play an important role in regulating the climate,material circulation,and energy flow of forest ecosystems.Therefore,in the context of global climate warming,quickly and accurately obtaining the decomposition degree of litter is of great significance for studying the role of litter in the carbon cycle and the earth's carbon balance.The decomposition process of the forest litter layer is relatively complicated,which is affected by factors such as the nature of litter,temperature,moisture,soil microorganisms and animals.It has the characteristics of slow decomposition rate and many conditions.Traditional methods for measuring the degree of decomposition of litter mainly include mesh bag method,miniaturization experiment method,current estimation method and isotope method,which have the disadvantages of long measurement period,susceptibility to external conditions and large errors.Therefore,this paper proposes a rapid estimation method for the decomposition degree of litter based on impedance analysis.This paper designs a composite sensor suitable for measuring litter,including the multi-channel impedance measurement part based on AD5933 and the moisture measurement part based on standing wave ratio method.Complete the design of the software and hardware of the measurement system,use the multiplexed measurement probe structure,and design and integrate the impedance circuit and the moisture circuit step by step to achieve the functions of collecting,storing,processing and communicating litter data.Carry out experiments and analysis on the performance of the composite sensor,perform sensor calibration experiments,stability experiments,error experiments,and comparison experiments.Through experimental verification,the linear fitting coefficient of the measurement system is above 0.98,and the measurement accuracy error is within ± 3%.The measurement system is used to detect and analyze the semi-decomposed layer,total decomposed layerand mixed litter between the semi-decomposed layer and the fully decomposed layer in different forests to realize the decomposition degree of litter by measuring the impedance and water content judgment.Compared with the DT9205 A high-precision resistance tester and the German TDR moisture sensor,the absolute error of the measurement system developed in this paper for litter impedance and moisture measurement is smaller,and it has more advantages in terms of measurement cost,more convenient use,and wisdom Forestry microenvironment monitoring provides an effective means.