Volumen 21 (2017): Edición 3 (September 2017)

The paper presents research results which aimed at evaluation of the change in the sodding degree and selected strength parameters of sod used with varied intensity; additionally sod was modified through administration of biopreparation. Measurements were taken on two types of sod. The first one was formed from perennial rye grass, the second one from orchard grass. It was proved that the use of the investigated facilities resulted in reduction of sodding, which was related to the sod forming species. No impact of biopreparation use on the sodding degree was proved. Intensive use affected the increase of the value of the analysed strength parameters; at low soil moisture (5.0-5.5%) considerable compaction in the surface layer of soil was reported.

Decisions concerning investments in farm tractors is a significant problem of modern agricultural production. Ensuring efficient performance of agrotechnical treatments and a rational level of use of tractors in the aspect of exploitation costs are a derivative of the power equipment level in a farm. The paper presents studies carried out in 31 selected farms, which run production on the total acreage of 937 ha of agricultural land (AL) and exploit 70 tractors. Analysis covered information on: area of farms, number and power of used tractors, investments in technical equipment concerning purchase of farm tractors and a production profile. In the investigated farms at the average per 100 ha of the agricultural land area there was 7.47 tractors, 90% of respondents actively used subsidies available from the EU structural funds. A high energy equipment level was determined in particular in farm with a smaller acreage. Over 87% of farm used more than one tractor and the age of the third each did not exceed six years.

The objective of the paper was intensification of the process of threshing and grain separation by a rasp-bar threshing mechanism of a combine harvester with a differentiate concave; substantiation of a regular-style design and differentiate concave parameters as well as threshing and separating mechanism operation modes. Theoretical research has been conducted based on laws of motion, experimental investigation – in accordance with methods devised on the basis of conventional methodologies. Standard computing methods as well as Microsoft Excel and Mathcad application packages have been used for processing experimental data. Measuring and recording equipment has been used in the research process. Experimental investigation has been carried out on specially devised experimental assemblies. The research has enabled: to substantiate the design-manufacturing process of the threshing and separating mechanism with a differentiate concave; to establish analytical dependencies to determine the area of typical influence zones of a threshing drum and concave on threshing mass; to ascertain the regularity of stem deformation under the influence of different forces regulated by changing the distance between concave transverse slats; to figure out the regression equation enabling finding optimal process variables for a threshing and separating mechanism with a differentiate concave. The scientific novelty of the engineering solutions is confirmed by a patent of the Republic of Belarus for the utility model № 6335 « Tresking mechanism». The results of theoretical and experimental research have been used in developing design documentation for the production of a differentiate concave for combine harvesters PA «Gomselmash».

The paper presents the issue of modelling reliability of microclimate. It is very important to conduct the risk analysis in poultry farms in order to indicate the most dangerous elements of the discussed system in the aspect of maintaining usefulness. The main objective of the paper was to carry out the risk analysis for the system that maintains microclimate in a poultry farm. It was assumed in the paper that the ventilation system influences maintaining microclimate in a henhouse. Simultaneously, the most effective methods of risk reduction are indicated and a rational assessment of the safety level is made. Studies carried out in the paper enabled identification of the risk analysis approach which the best reflects the issue of maintaining technical equipment devices in operation. With the use of the matrix, the indicator and probabilistic approach, the exploitation risk related to the occurrence of previously defined failures of the henhouse ventilation system was assessed. Based on the results of analysis, a conclusion could have been made that concurrent results were obtained with the use of the matrix and probabilistic approaches. In these cases, for all failures the highest and the lowest exploitation risks of occurrence of certain failures in the ventilation system in a henhouse were the same.

The objective of the paper was to determine the impact of the value of the oil pressing pressure with the cold pressing method in a screw press on the pressing course and performance. Varied values of pressure were obtained through the use of three replaceable attachments of the pressing unit with a varied diameter of the outlet conduit (ф₁=2 mm, ф₂=4 mm and ф₃=6 mm). The soya oil pressing process performance was determined in relation to the applied attachment and the soya cultivar. Seeds of 7 Polish non-genetically modified soya cultivars constituted research material. It was proved that both variable pressure values and the used soya cultivars have impact on the pressing performance. Based on the analysis of the obtained research results it was proved that varied technical parameters and soya cultivars influence both the process performance and the remaining parameters and pressing conditions.

A single-factor field experiment concerned calculation of fuel consumption, time expenditure of the working time of machines, and winter wheat yield size in three technologies of soil cultivation. Fuel consumption in the tillage and non-tillage technology was comparable and amounted approximately to 31 l·ha⁻¹, but the highest consumption was generated by basic soil cultivation (tillage or heavy cultivation cultivator). Fuel consumption in the strip cultivation technology was the lowest and it was 23.0 l·ha⁻¹. Non-tillage cultivation allowed reduction of the time necessary to carry out the wheat cultivation technology by 28.8% (in comparison to tillage cultivation). On the other hand, strip cultivation allowed reduction of the total time of machines operation by 48.5 % (in comparison to tillage cultivation). The yield of winter wheat cultivated in the non-tillage technology was at the average by 4% better than the one cultivated in tillage cultivation. The highest yield of seed (7.63 t·ha⁻¹) was obtained in the strip cultivation technology (by 6.7% in comparison to tillage cultivation).

The paper presents a recommendation on how to use waste heat of post-treatment water in the balneological institute in Lądek Zdrój health resort. This heat may be used in stenothermal fish big scale breeding. The presented innovative solution of a technological breeding line of African sharptooth catfish (Clarias gariepinus) has not been carried out in practice yet and except for ecological values, it may soon bring real profits. The presented calculations show that the analysed technology may bring a real return of the incurred investment expenditures after approx. 6.5 years from the moment the production was launched. The calculated internal return rate is 14.25% and considerably exceeds the border rate (4%). As it was shown, there is an additional possibility of improvement of this profitability through the use of funding as a part of the Operational Programme Fisheries and Sea 2014-2020. Then, at the funding of investment in the amount of 50% of qualified costs IRR will increase to 25.03%. The period of capital return will decrease to approximately 3.5 years.

The paper presents a change in physical properties of loose, dust fodder additives (aluminosilicate) after mixing them with oil or glycerine. Additives where mixed in a blade mixer with the same mixing time for all samples, which was 1 minute. Tests with oil or glycerine were carried out in the following amounts: 5%, 10%. For mixtures of additives with oil or glycerine a selected group of physical properties was determined. Method of determination of physical properties was the same for all samples i.e. the same additives − without oil and glycerine as well as mixtures with their participation. Obtained research results and their analysis unanimously indicate that adding any amount of oil or glycerine for additives improves selected physical properties of mixtures.

The paper presents the impact of feed mixtures for poultry on their kinetic strength determined with Holmen's method. Research material came from a production line and 9 pelleted feed mixtures for poultry with diameter of 3.2 mm were accepted for the research. Feed was prepared, pelleted and cooled with the use of the same devices and their exploitation settings were comparable with regard to the investigated feed pellet. The obtained research results proved that kinetic strength of the investigated feed pellets was statistically significant in relation to the composition of the feed mixture. Relations of kinetic strength of pellets to the composition of the feed mixtures were determined with the multiple regression method. From the determined models the highest utilitarian value may occur in case of a model with four explanatory variables: corn (x₁), wheat (x₂), soya meal (x₄) and fat (x₅).

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.