Unilateral nuclear magnetic resonance sensor and nuclear magnetic resonance method for measuring soil moisture

Abstract

The invention relates to a unilateral nuclear magnetic resonance sensor and nuclear magnetic resonance method for measuring soil moisture. The device comprises a housing, a magnet module arranged in the housing, and a radio-frequency coil arranged on the upper surface of the housing, wherein the magnet module is used for generating a static main magnetic field B0; and the radio-frequency coil is used for generating a radio-frequency magnetic field B1 vertical to the static main magnetic field B0, achieving excitation of a soil sample and receiving an echo signal generated by the sample. Hydrogen protons in the soil moisture are directly excited, and an electromagnetic echo released in a relaxation process is detected, so that the nuclear magnetic resonance technology is not affected by the salinity of the soil, the single measurement time is short and the sample is not damaged.

Description

technical field [0001] The invention relates to a non-destructive measurement of superficial soil moisture measurement device and a single-side nuclear magnetic resonance method. Background technique [0002] At present, my country is facing major challenges such as shortage of soil resources, serious ecological environment pollution, and relative shortage of agricultural water resources. Soil moisture is an important factor affecting the growth of crops, and its content and form are the controlling factors of many chemical, physical and biological processes in the soil. Therefore, in terms of agriculture and environmental protection, the significance of soil moisture detection is as follows: (1) Timely and accurate soil moisture detection is of great significance for evaluating the degree of drought and wet damage, optimizing the use of limited water resources, and ensuring crop yields (2) Soil water storage and soil water movement characteristics affect the movement and t...

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Problems solved by technology

Among them, the appearance and touch method is more subjective and requires a certain amount of experience accumulation; the drying and weighing method is currently recognized as the most accurate and classic method, but it takes a long time and cannot achieve non-destructive measurement of the same soil; the measurement of tension measurement method The range is greatly affected by the soil quality and the measurement speed is not fast enough; the neutron diffusion method is difficult to measure the moisture content of shallow soil, which is expensive and easy to cause radiation hazards; the time domain reflectometry is easily affected by temperature, bulk density and soil quality. Measure the moisture content of long-distance soil; the frequency domain reflection method is greatly affected by soil containing silt, sand and clay; the standing wave rate method is easily affected by soil salinity, and the measurement accuracy is not high enough; the traditional nuclear magnetic resonance method Most of them are closed measurement methods, which are not suitable for field measurement

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