Investigation of the interactions between tomatoes and handling devices in mechanized processes

Tomatoes are a major vegetable crop worldwide. Production costs for large due to high harvesting costs and difficult mechanization. An increase in labour productivity, the profitability of production, the increase in production and the decrease in cost is possible through the introduction of mechanization of production processes, the most important of which is harvesting [19]. It absorbs over 50% of total costs [5, 10]. Mechanized harvesting reduces labour costs 10 times, and according to Bakulev [1], the profitability of production reaches 200%. Research by the University of California [18] indicates that the price of mechanically harvested tomatoes is $9.84/t, and for hand-harvested tomatoes -$17.19/t. Depending on the qualifications of the workers, mechanization saves from 70 to 440 man-hours per hectare. The mechanization of harvesting also has a biological side [6]. The short period of harvesting allows to control the ripening. Thus, the degree of de-esterification of the pectin content beyond the desired can be avoided. A lot of research has been done to create a robot that picks tomatoes but it is still only in the research field. A practically implemented mechanization of the process is achieved with a tomato harvester that harvests the entire crop at once. Due to the large losses due to damage to the fruit and leakage of juice, this method also needs improvement. In the present study, dependencies have been derived that make it possible to determine the parameters of the handling devices in the tomato harvester in order to obtain a better result from the mechanized harvesting of tomatoes

Distribution of microbial abundance in long-term copper contaminated soils from Topolnitsa-Pirdop valley, Southern Bulgaria

This study presents the distribution of bacterial and fungal abundances in long-term copper (Cu) contaminated soils in Topolnitsa-Pirdop valley – a highly industrialized zone with a number of mines and processing plants for copper and other non-ferrous metals. The bacterial (16S rRNA gene copies) and fungal (ITS rRNA gene copies) were estimated using quantitative PCR technique in five topsoils, differently Cu contaminated (ranging from 28.05 to 198.9 mg kg-1). Bacterial abundance varied in a range of 1.68 × 1011 to 3.24 × 101116S rRNA genes, whereas fungi amounted from 1.95 × 108 to 6.71 × 108 ITS rRNA genes. Fungal and bacterial abundances were significantly (fungi) and insignificantly (bacteria) influenced by Cu contamination. The fungal/bacterial ratio related negatively with soil Cu, which shifted microbial communities’ structure towards bacterial dominance. Since the ratio between bacteria and fungi are vital in explaining many soil functions, the calculated changes in this ratio indicated deterioration in soil quality, being of primary importance for plant production