Soil Visible - Near-infrared Spectral Response Measurement And Analysis System Testing And Research,

The rapid development of precision agriculture makes most croppers have a desire to apply a fertilizable prescription to soil, the precondition of which is to measure accurately soil composition and nutrients. But the traditional procedures for measuring soil properties are complex, expensive and time-consuming. So, a fast and convenient soil analytical technique is needed for soil quality assessment and precision soil management. This paper introduces mainly the structures and the functions of the instrument for analyzing rapidly soil composition based on optical spectral measuring techniques. This measuring system can be used to measure soil spectral properties with a response range from 400 to 2500nm. At the same time, the paper describes measuring principles on soil composition and the measuring precision demands for the system. On the basis of these, we studies the reflective spectrum of soil organic matter and soil water, and evaluates primarily the repeatability and stability of the system in the practical measuring. 1,Four soil samples are selected ,which are equal in organic matter content and different in water content, and their reflective spectrum curves from wavelength of 1000nm to 2500nm are analyzed. The result found that soil water has absorption peaks at the wavelength of 1450nm and 1940nm, which is agree with Yoshio Kano'conclusion [22]. This indicates that the system is available for the correlative soil research in the future. 2,Using the system, the reflective spectrum of 8 soil samples in the range of the wavelength of 400nm to 1100nm are measured, which is collected from different sites, and their reflective curves are gained. The correlative analysis between the organic matter content and reflective spectrum of these soil indicates that soil organic content has strong correlation with soil reflective spectrum at the wavelength of 560nm to 690nm, especially at 664nm, these results are agree with formers'conclusion. The system has been used and tested repeatedly, and proved to be stable and convenient. In conclusion, the study establishes some physical base for the fast and convenient measuring of soil properties. At the same time, it provides some meaningful theoretical basis and experimental data for the further improvements of the system in the future.