Vertical soil profiling using a galvanic contact resistivity scanning approach.

Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function.

[Development of a portable SOM detector based on NIR diffuse reflection].

A portable soil organic matter detector based on near infrared diffuse reflectance was developed. The detector uses a microprocessor 89S52 as the micro controller unit (MCU) and consists of an optical system and a control system. The optical system includes an 850 nm near-infrared LED lamp-house, a lamp-house driving-circuit, a Y type optical fiber, a probe, and a photoelectric sensor.

[Application of wavelet packet analysis in estimating soil parameters based on NIR spectra].

Using the method of wavelet analysis, the NIR spectra of soil samples were decomposed and reconstructed, and higher precision PLS models were established to estimate soil parameter (TN, SOM). One hundred fifty soil samples were collected from a winter wheat field and the NIR spectra of all samples were measured. Firstly, experiment statistic features were analyzed aiming at all soil samples, and the system clustering was carried out for TN and SOM respectively.

[Estimation of soil organic matter and soil total nitrogen based on NIR spectroscopy and BP neural network].

Estimation models of soil organic matter (SOM) and soil total nitrogen (TN) were established based on NIR spectroscopy and BP neural network A total of 150 soil samples were collected from the tested farm, and the NIR spectra of all soil samples were measured. First, data pretreatment was performed for each sample with the method of locally weighted scatter plot smooth filtering. Then the box plot analysis for the measured SOM data and TN data were conducted separately and the information about the shape, location, and distribution of the target data was obtained.

[Development of soil-organic-matter fast-determination instrument based on spectroscopy].

An instrument used to measure the content of soil organic matter was developed based on spectroscopy. The instrument consists of an optical unit and an electronic unit. The optical unit is used to collect the reflecting light from soil surface and change the filtered light into the electrical signal.