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  • Author: Agnieszka Szparaga x
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Abstract

Modified generalized logistic functions (also known as Koya-Goshu functions) were used for mathematical description of germination. These functions constitute natural modification of traditionally used Richards' function for description of plants germination that introduces a non-linear time increase in exponent and an element related to time shift. Curves were adjusted to experimental data based on minimization of the square sum of difference between experimental data and a mathematical model (the smallest squares method). Results of simulation research show that the determined parameters of curves (e.g., values of the growth parameter, time shift or upper limit of population) describing the number of seedlings as a time function stay compliant to interpretation with regard to biology of the investigated processes. Based on the research, it was stated that for control and application of plant extracts to soil, Koyu-Gosha model has better adjustment to experimental data in comparison to the generalized logistic model.

Abstract

The objective of the paper was to show various options of using by author an automated stand with computer image analysis for control of plant germination on the example of cauliflower Brassica oleracea L. ‘Pionier” variety. The developed system consisted of a mobile platform equipped with the acquisition and image processing system based on Raspberry PL processor. Germination of cauliflower seeds was the object of observation, which in one case were sown to soil after dressing them with plant extracts (sweet flag Acorus calamus L., great burdock roots Arctium lappa L.). In the other case, undressed seeds were sown in the place of previous application of the above-mentioned extracts. The use of a robot for monitoring plant germination enabled the automated analysis of the investigated material with higher frequency than it has been possible so far. Simultaneously, higher germination was reported when seeds were treated with macerates and extracts from great burdock roots.

Abstract

The paper analyzes the efficiency of material and energy expenditure in 679 farms with agricultural production as the main source of income for the years 2013-2015. Six groups of farms were identified according to usable agricultural area (UAA). The aim of the work was to determine the impact of UAA of farms on their material and energy expenditure efficiency. It was found that the area of UAA determines the farms’ material and energy expenditure efficiency. It was observed that small farms with UAA of 5 to 10 ha are characterized by the highest material and energy expenditure efficiency. It was proven that the material and energy expenditure efficiency in “Small” farms with UAA (<= 5ha) and “Very large”, with UAA (> 50ha) differs significantly from the efficiency determined for other farm groups. Material and energy expenditures were used the least efficiently in the farms with the smallest UAA.

Abstract

The paper presents kinetics of osmotic dehydration of plums in relation to the treatment time and concentration of sucrose solution. The main aim of the study was polyoptimisation of the preservation process, namely selection of optimal parameters of osmotic dehydration processes including changes in selected quality indicators. Defining of optimal conditions of the entire course of preservation may influence limitation of consumption of preserving substances (osmotic substances) and reduction of the energy demand. Based on the research which was carried out, it was found that parameters of osmotic dehydration had a significant impact on mass transfer coefficients and physico-chemical indicators of fruit - along with the increase of concentration of osmotic solution and extension of the time of the process, the increase of the investigated sizes was observed. In the second part of the paper, optimization of the fruit preservation process was performed. The idea of the objective function consisted in minimization of the difference between the expected values of criteria and the values obtained from the experimental results. For the defined scalar optimization criterion an explicit relation between quality and cost of the product was showed.

Abstract

The research material was prune plums (Prunus domestica L.), subjected to osmotic pre-treatment, with variable process time parameters and osmotic solution concentration. Plums thus fixed were frozen and stored for 6 months. At even (monthly) intervals, the product was defrosted by the vacuum-steam method, using the s-p-p chamber, until the thermocouple indicated a temperature of 4ºC in the sample’s thermal center. In order to study the kinetics of phenomena occurring during the defrosting process, the chamber was equipped with a measuring system to enable measurement and recording of temperature changes in time in the geometric center of the sample, as well as the temperature on the sample surface. The conducted tests proved that the time of vacuum-steam defrosting of fruit depended on the amount of water contained in it. In plums dehydrated in 45-65% sucrose solutions, duration of the defrosting process was shortened already after three months of frozen storage. After 6 months of storage, defrosting of these fruits was twice as fast as that of control samples.

Abstract

The study assesses the impact of the economic size of farms on the efficiency of their material and energy expenditure, based on 679 farms from the Lubelskie Voivodeship. The analysis was made for the years 2013-2015 and the farms were divided into six economic size classes. 5 indexes for the efficiency of material, energy and material-energy expenditures were calculated for all farms. The aim of the work was to select a group of farms with the highest efficiency of energy and material expenditure. It was found that economically small farms managed this expenditure most effectively, as evidenced by the highest values of 4 out of 5 analyzed indexes. Very small and medium-small farms demonstrated the highest efficiency of material expenditure. In contrast, energy expenditure was most efficiently used by medium-small farms. The farms that were the largest economically were characterized by the highest efficiency index of material and energy expenditure, calculated as the ratio of total production to the expenditure.