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

In 2020 – 2021, on the territory of the experimental field “Chelopechene” of ISSAPP “N. Poushkarov” an experimental trial was conducted with three varieties of apple plantations, the Florina variety, Zlatna Prevazhodna and Granny Smith, created in 2017. The soil in the research area is leached Cinnamon forest. Three variants of different varieties of apples were studied – T1 – variety Florina, T2 – variety Zlatna Prevazhodna and – T3 – variety Granny Smith under irrigation conditions with maintenance of pre-irrigation humidity 70% of the FC. In terms of precipitation, both years are very dry with a guarantee of 95.67% (2020) and 94.07% (2021). For 2020 on average, during the vegetation period of the apple plantation in the infancy period, to maintain the soil moisture in the range of 70% of FC to 100% of FC, it was necessary to apply 10 watering rates with an irrigation rate of 380 mm, and for 2021. 12 watering cans with an irrigation rate of 510 mm. During the years under review, different yields from the apple plantations were established. The highest yield was found in Florina variety, which was 431% higher compared to Granny Smith variety in third variant T3
Main objective: Establishing the most favorable variety of apples (from three different varieties) grown on leached Cinnamon forest soil for
the Kremikovtsi region under different water-saving technologies.

In order to establish the irrigation regime of short-fruited cucumbers in open areas in the soil-meteorological conditions of the area of the village of Chelopechene – Sofia, researches were carried out in drip irrigation of cucumbers variety “Levina”, testing different regimes – from full satisfaction of daily needs the culture from water to irrigation with reduction by 30% of the irrigation norm. A variant with a 30% increase in the irrigation rate was also tested.
The obtained results show that the cultivation of short-fruited cucumbers for fresh consumption in open areas requires 15 waterings with an average irrigation rate of 18.3 mm, which is realized at different intervals depending on plant development and the stress of metrological factors and irrigation rate 280 mm.
The realized irrigation regimes have influenced the formation of yields of short-fruited cucumbers. The yields during the three years of the experiment varied from 2368 to 5404 kg / dka, with the highest yields being obtained in the first and second years. Yields in the third year were lower by 30% as a result of adverse weather conditions, which led to a shortening of the growing season of the crop.

To determine the total and average evapotranspiration of pears during its cultivation under soil and meteorological conditions in the area of the village of Chelopechene – Sofia, studies were conducted on drip irrigation (KP-4.6 drip trays) of pear plantation of the variety “Hardenponova maslovka”.
Meteorological conditions during the study period influenced the size and daily average values of culture evapotranspiration.
The total evapotranspiration for the pear growth period of 536 mm was determined, and the daily values of biophysical coefficients Z, R and Kp were calculated for practical use and design, which depend on the biological features of the crop and the meteorological factors.

To establish the influence of the irrigation regime on the quantity and quality of tomatoes grown in plastic unheated greenhouses, research was conducted in the experimental field of the Pushkarov Institute in Chelopechene, Sofia. Different irrigation regimes have been tested, keeping from fully satisfying the needs of the crop from water to irrigation with a 20% reduction and a 20% increase in irrigation norms. The control variant is irrigated at 100% realization of the irrigation norm, calculated by (E0) evaporation from a free water surface by an evaporator class “A”.
It has been established that the reduction of the irrigation norm due to the limited water supply leads to a corresponding reduction of the yield, which is not proportional to the reduction of the irrigation norm.
The quality of the obtained production – tomatoes determined by the content of dry matter, vitamin “C” and total sugars deteriorates with increasing amount of irrigation rate.

The production of green beans in plastic unheated greenhouses is relevant when grown as a intercropping culture. Rrotation of crops is an important biological factor for increasing soil fertility, and year round production of vegetables in plastic greenhouses to maximize the economic impact of these expensive facilities.
Considering the biology of the crop and especially its requirements for soil moisture, determinating for obtaining high yields and quality production is the implementation of a proper irrigation regime, as well as the use of suitable irrigation technique.
The aim of the research is to identify the main elements of the irrigation regime of green beans, cultivated as a second intercropping culture, in drip irrigation / watering and irrigation rates, interwatering periods and number of irrigations /.
Irrigation was carried out with a drip irrigation system type Drossbach. Variations have been tested at 85-90% of pre-watering humidity and 120% of irrigation rates- 120%; 100%; 80% and 60%.
It has been found that the productivity of irrigation water in drip irrigation of vegetable crops grown in unheated greenhouses is increased by reducing the irrigation rate. The highest productivity of irrigation water is achieved with the 60% irrigation rate option.

Berry cultures – strawberries, raspberries, blackberries, blackcurrants, etc. are of great economic importance due to growing demand and high productivity. In general, they are susceptible to droughts and are so demanding for soil moisture, and their growth and yield depend to a large extent on the presence of sufficient soil moisture.
In order to establish the irrigation regime of raspberriesin drip irrigation conditions, field experiments were conducted on the experimental field Chelopechene-Sofia. Irrigation was carried out with a pre-irrigation humidity less than 85% of WHC and variants watered with irrigation rate reduction of 20%, 40% compared to the variant irrigated at 100% of WHC and non-irrigated variant.
Realized irrigation regimes in individual years have had an impact on the yields obtained, with the highest yields being obtained for the irrigated variants with 100% irrigation rate and the lowest in non-irrigated variants. The highest increase in yield was obtained in 2004 (dry), which is with 67% more compared to non-irrigated variants, and the smallest increase of 33% was obtained in the humid 2005.
The analysis of meteorological factors shows that the rainfall in the country is insufficient to satisfy the requirements of plants of soil moisture, and the temperature sums over ten-days periods over the whole vegetation period considerably exceed the respective norms. This requires the use of drip irrigation for the successful production of raspberries under conditions of water deficiency and relatively high temperatures.

Drip irrigation provides a fairly even mode of moisture in the soil and, along with this, favorable air, heat, microbiology and nutrition. As a result, there is an increase in yields and an improvement in the quality of production.
In order to determine the impact of drip irrigation, on the size of the yield and the economic indicators, in the cultivation of raspberries in the soil and meteorological conditions of the area of the village of Chelopechene – Sofia researches of an everbearing variety “Lyulin” were carried out. Various options have been tested – from fully satisfying the daily needs of the culture by water, irrigation with 20% and 40% irrigation norms to non- irrigating conditions.
The results obtained in years with different security of meteorological factors show that the drip irrigation of raspberries has a positive effect on the economic indicators of its cultivation, the costs of creating the raspberry crop, the irrigation system and the cultivation of the crop are redeemed for two or three years.

To determine the effect of magnetically treated seeds on the productivity of tomatoes and onion in the area of the Sofia field experimental experiments were carried out with variants with magnetically treated seeds and variants without magnetic treatment of the seeds. Irrigation has been dripped in optimum irrigation mode. The yields obtained with the processed tomato seeds in tomatoes are up to 22% higher than those of untreated and onion onions to 28%, respectively.

A Polish experience with 10 hybrids of sunflower field was made on the Chelopechene Field, Sofia, on cinnamon forest soil. Sunflower hybrids are grown under non-irrigating conditions and under irrigation conditions with drip irrigation and microwaving.

The meteorological conditions during the study period determined the number of irrigations and the size of the irrigation and irrigation norms of the culture.

It has been found that the yields obtained under irrigation conditions are higher than 13 to 46%, with drip irrigation giving better results than sprinkling.

The Maritsa, San Luka and A58xC23 hybrids have been shown to be suitable for growing in non-irrigated conditions, while the hybrids "Vokil", "Michaela" and "Maritsa" hybrids are irrigated.