Browsing by Subject "on-line measurement"

Timing has a significant influence on grain yield. Determining factors for sowing time are moisture and temperature. Automatic sowing depth control would at least theoretically increase the chance for the seed to get sown in optimal moisture. Depth control during sowing requires technology suitable for on-line measurement of soil moisture content. Acquisition of soil moisture by Near Infrared reflectance (NIR) - seems promising for on-line measurements. NIR moisture measurements of a material do not require contact between the NIR-sensor and the measured material. NIR-measurements of material moisture content are based on the relationship between the absorbed and reflected radiation, sent to the material from a light source and measured by the NIR-sensor. The main goals of the study were to determine the suitability of Visilab IRMA 7D-moisuremeter for in field on-line soil moisture measurements and to consider the applicability of the moisture meter for automatic sowing depth control. To achieve the goals of the study the moisture meter was calibrated for three different soil types. Moisture measurements were carried out indoors in stable conditions to determine the dispersion and step response of the moisture meter. Also the impact of the angle between the measured surface on the moisture meter was examined. To achieve the main goal of the study a tractor operated implement was built to carry out the infield on-line moisture measurements of soil moisture content. In addition a test field was established in order to complete the measurements. According to the results of this study the Visilab IRMA 7D-moisture meter is fast enough and the dispersion is small enough for infield on-line soil moisture measurements. Long measuring distance and large beam of light requires a large and fresh area on the measured surface. Any soil should not run over on the area of the light beam during moisture measurements to achieve accurate results. A smaller area beam and shorter measuring distance would provide better potential for usage in infield on-line soil moisture measurements, by reducing sensitivity to external disturbance. The goal of the study was to perform more infield measurements to more specifically determine the suitability of the moisture meter. The measurements were not however performed due to the heavy rainfall during the autumn. The measurements which were carried out aimed more for the development of the implement.