Razvoj sistema za poziciono merenje mehaničkog otpora zemljišta / Development of a soil mechanical resistance measuring system with global positioning

Achievements of modern crop production have led to the "impoverishment and physical contamination" of soil which are manifested by the constant decrease in soil fertility. Likewise, there is an evident increase in total and specific soil mechanical resistance of tillage which are reflected in higher energy consumption and lower quality of tillage. The only way to increase the total soil crop productivity in an environmentally sustainable way, is to maximize the effectiveness of production practices. Crop production by the principles of the Precision agriculture is a breakthrough compared to conventional production. Prior to application of Precision agriculture it is necessary to establish a reliable system for collecting a large number of spatially oriented data in the field. Measuring the soil tillage resistance with each obtained data spatially located, we can improve and simplify the process of collecting field information for the purposes of scientific research or Precision agriculture. If the model is successfully defined, based on depending on the resistance and characteristics of soil, the number of required samples can be significantly reduced. In this thesis the development process of the original measurement system intended to measure the soil tillage resistance (resistance to treatment) during tillage operation with machines II or III category with the geographic location of each measurement is presented. The system was developed in the following stages. At first, mechanical frame was designed and built and after that it was equipped by dynamometers and acquisition equipment of high accuracy. The measuring system was subject of multiple testing in the laboratory and field. The result of laboratory tests is calibration characteristic of measuring system. Field tests were conducted to determine the functionality and reliability of mechanical constructions from the aspect of reconnecting, carrying and working with different machines. Also, validity of the measured draft resistance data was checked comparing it with the models which can predict the resistence according to the valid standards. Comparative studies involving the various machines and different soil conditions were also carried out. The final part of the development process is measuring the soil resistence and soil physical parameters using the GPS positioning technology and GIS geostatistical analysis technology for the purpose of mapping.The results obtained during the years of the development process which included a large number of tests clearly show that the obtained a new, completely original and functional solutionmeasuring device as well as the whole system. System characteristics achieved pre-set goals such as ease handling, robustness, high accuracy measurements, mobility, universatility of application for the various machines and applicability for precision agricultural production. During exploatation, some minor failures have been identified, and therefore proper recommendations have been given in order to improve present device.