International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In order to determine the influence of different rates of irrigation and fertilization on the growth, yield, and some yield-related characteristics of three genotypes of tomatoes, research was carried out at IVCM – Plovdiv in an unheated steel-glass greenhouse of the “Venlo” type. The experiment was carried out with three modes of irrigation: optimal – 100%, reduced – 75%, and increased – 125%, using water-saving irrigation technologies and three modes of fertilization – optimal – 100%, reduced – 75%, and increased fertilization – 150%. The amount of watering and irrigation norms, the number of waterings for the growing season of greenhouse tomatoes were determined based on soil type, and climatic conditions in the region of Plovdiv. An optimal or high irrigation rate combined with reduced or optimal fertilization leads to maximum yields in all three tomato varieties. A specific reaction of the variety was observed – in “Hayet” and “Pink rock ”varieties, maximum yields (14.1 t/ha and 8.8 t/ha) were obtained in the variants with 100%/75%, while in the “Malduo” variety, the highest yield was obtained (8.6 t/ha) in the variant with 125%/100%, irrigation/fertilizer rate. In the three studied varieties of tomatoes, the lowest yield was reported when the irrigation rate was reduced by 25%, which shows that the reduction of the irrigation rate by 25% is within the limits of the critical, while the reduction of the fertilizer rate by 25% is permissible.

Increasing the efficiency of machine usage for transport services in agricultural holdings can be achieved by creating stocks of aggregates and units in company warehouses based on a predetermined gamma-percentage of available resources.
This study proposes a methodical approach to determine the 80% of gamma-percentage resource for forklift elements, considering both known and unknown distribution laws for their resources. It includes truncated and repeatedly truncated samples.
The results obtained from this study can be utilized for planning purposes and establishing stock levels to ensure the operational readiness of Bulgarian forklifts.

The necessity of using the apparatus of mathematical statistics to obtain high reliability of the results of the evaluation of thereliability indicators of agricultural machinery in comparative tests is justified.
Two models of plant protection machines have been tested and the main numerical characteristics of the indicator production till failure of the failure-free feature have been obtained.
The application of the Student’s criterion for proving the statistical significance of the difference in the tested reliability indicator is justified.

The types of machine reliability tests and the applicability of the test plans are discussed. On this basis, a methodology for experimental testing of the reliability of the machines is proposed and the interrelation of the elements of the methodology is shown.

In order to establish the irrigation regime of pepper variety “Gold Medal”, grown in plastic unheated greenhouses in the Chelopechene experimental field, Sofia district, irrigation options were tested from fully satisfying the water needs of the crop /100% irrigation rate/ to irrigation with 20% and with a 30% increase in irrigation rates. A water-saving irrigation technology is used. The highest yield of 4879 kg/dka was obtained when using 130% irrigation rate, followed by the variant with 120% irrigation rate – 4460 kg/dka on average for the research period. The yield in the variant irrigated by class “A” evaporation pan, approaches the yield obtained in the variant with 100% implementation of the irrigation rate.

To determine the evapotranspiration of the pepper, variety “Golden Medal” grown in plastic unheated greenhouses in an experimental test field in Chelopechene, Sofia region, irrigation options were tested from fully satisfying the crop’s water needs to 20% and 30% increased irrigation of irrigation rates and a variant irrigated with 100% irrigation rate. An environmentally friendly and watersaving irrigation technique was used. The evapotranspiration of the culture and the evaporation from a free water surface were experimentally determined. Based on the calculated values of evapotranspiration and evaporation from a free water surface (evaporation) determined by a class “A” evaporation pan, the values of the biological coefficient of the culture in unheated plastic greenhouses were calculated, and the average for the vegetation period of pepper is 1.35.

This is a review of the groups of factors influencing the quality of the main and pre-sowing tillage of the soil for growing tomatoes – soil-climatic, technological.
The paper performs an analysis of the a priori information and from the conducted experimental researches the connection between the separate factors and the quality for performing the basic and pre-sowing treatment of the soil for growing tomatoes was established.

Irrigation plays a key role in growing vegetable crops. The efficiency of irrigation is expressed in obtaining optimal yields in terms of quantity and quality. The use of water resources should be water and energy saving in order to reduce the costs of vegetable production and to be environmentally friendly. The main criteria for assessing the effectiveness of irrigation are the total and additional net incomes. In order to meet the set requirements for irrigation, the best effect is obtained by applying drip irrigation. When growing tomatoes, the value of the irrigation system is redeemed in the first year for areas over 5 dka, for areas below 5 dka it takes 2 years. Drip irrigation of tomatoes has shown that the frequency and size of irrigation rates affect the weight, diameter and length of the fruit, their number and hardness.

Evapotranspiration of strawberry, remontant variety “Polka” (field production) was established in a three-year field experiment (2011-2013) drip irrigation on leached cinnamon forest soil in the area of the village of Chelopechene, Sofia region. Various irrigation regimes have been tested – from full satisfaction of the daily needs of the crop from water to irrigation with reduced by 20% and 40% irrigation rates.
On average for the research period the size of the total evapotranspiration for the vegetation period of strawberry is 240 mm, as its main part is formed by the irrigation norm – 58%, and the rest of the precipitation – 42%. The average daily values vary by ten days, with the highest values reaching the first and second ten days of June (harvest period). Values of the biophysical coefficient Z necessary for determining the design irrigation regime and forecasting the time for irrigation of the crop have been determined.

The type of supply voltage of the coil to achieve maximum induction and uniformity of the magnetic field in the magnetic chamber, where the processed material is determinate. The experimentally obtained dependence curves B=f(U) can be used to optimize the regime parameters when processing various agricultural materials in a magnetic field.

The aim of the study was to establish the influence of the irrigation regime on the yields of tomatoes and green beans, irrigated by sprinkling in open areas.
In order to achieve the set goal on a leached cinnamon forest soil in the area of the Sofia irrigation system (experimental field Chelopechene (IHM) now ISSAPP “N. Pushkarov”) a field experiment was carried out with tomatoes of Balkan variety and green bean variety “N ikos” , grown at varying degrees of satisfaction of their water needs. The maximum evapotranspiration was determined by compensatory lysimeters,as in options 3 and 4 it was reduced by 20 and 40%, and in option 1 it was increased by 20%. compared to the version with 100% ETM.
Two of the years in which the field experiments were conducted in terms of the amount of precipitation are very dry with a security of 88.7% and 86.7%, and one year is an average with a security of 51.0%. The high temperatures during these years, combined with the lack of rainfall have predetermined the need for irrigation of vegetable crops.
According to the amount of precipitation during the vegetation period of tomatoes, on average for the study period 8 irrigations with irrigation rate of 373 mm were realized in variant (120% ETM), and in green beans for the same variant 6 irrigations with irrigation norm 300 were realized. mm.
The highest total and additional yield is obtained with irrigation with 120% ETM in both crops 7800 kg / dka. (tomatoes) and ETM 240 kg / (green beans) on average for the study period.
It was found that the reduction of the irrigation rate leads to a corresponding reduction, but not in proportion to the reduction of the possible maximum yield. In all cases, the reduction in yield is less than the reduction in the irrigation rate for both crops.

The specificity of agricultural production implies several months of intensive use of the majority of equipment and a longstorage period. Checking the quality of storage of agricultural machinery, controlling all operations, is economically impractical. It is necessary to select the main (key) operations from the whole list of operations, ie. those that provide a reliable assessment of the quality of storage of machinery.
The proposed methodology makes it possible to streamline the assessment of the quality of storage of machinery in agriculture, choosing the main operations, without losing information from the fact that the operations that contain a smal l amount of information are not controlled.