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

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 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.

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 establish the effect of irrigation of raspberries grown in soil and meteorological conditions in the area of the village of Chelopechene – Sofia, studies were conducted in drip irrigation of plantations with remontant variety “Lyulin”, testing different regimes – from full satisfaction of daily needs of the culture from water to irrigation with reduced by 20% and 40% irrigation rates. A variant under non-irrigated conditions has also been tested.
When determining the effect of irrigation of raspberries by changing the yield compared to the non-irrigated variant, it was found that in the variant with 100% irrigation rate (optimal) the increase in raspberry yield reaches 59%, and in variants irrigated with reduced irrigation rates, the size yields increased by 54% and 47% respectively. It has been proven that the optimization of the moisture in the active soil layer contributes to a significant increase and stabilization of yields, which for the experimental conditions are from 835 to 1074 kg / dka and the additional yield varies from 404 to 627, kg / dka or from 47 up to 59% on average for the study period.
The established productivity of the irrigation water is the highest in the variants with 40% reduction of the optimal norm and changes during the years of the experiment from 13.0 kg.ha-1.mm-1 to 24.0 kg.ha-1 .mm-1. It is the lowest in the variants irrigated with 100% realization of the irrigation norm.

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.

In order to determine the productivity and the effect of irrigation on apples grown under soil and meteorological conditions in the area of the village of Chelopechene – Sofia, research was conducted on drip irrigation of a plantation of the “Florina” variety, and different regimes were tested – from complete satisfaction of the daily needs of water to irrigate the culture with irrigation rates reduced by 20% and 40%. A non-irrigation variant has also been tested.
The productivity of the irrigation rate at optimal irrigation varies by years from 16.3 to 28.0 kg.ha-1.mm-1, and at 40% reduction of the irrigation rate from 19.3 to 26.0 kg.ha-1. mm-1
The highest values of productivity of the irrigation rate are reached at irrigation with a 40% reduction of the irrigation rate, in the dry 2004 high values were obtained and at the variant irrigated with 100% irrigation rate 28,0 kg.ha-1.mm-1
The optimization of moisture in the active soil layer contributes to a significant increase and stabilization of yields, which for the test conditions are from 1266 to 2087 kg / dka. Additional yields ranged from 542 to 821 kg / dka, averaging over the study period.

To determine the overall and average evapotranspiration of tomatoes grown in unheated greenhouses, studies were conducted under soil and meteorological conditions in the area of the village of Chelopechene – Sofia with drip irrigation.
The total evapotranspiration, which reaches 537 mm during the vegetation period of the crop, is experimentally determined, and the established daily evapotranspiration values range from 1.50 to 5.5 mm with two minima – at the beginning and end of the growing season and one maximum in August. . For the purposes of practice and design, the daily values of the biophysical coefficients Z, R and Kp are also calculated, which depends on the biological characteristics of the crop and the meteorological factors.

An analysis has been made of the research work to determine the impact of water deficit on the quantity and quality of sunflower production. Studies have also taken into account the more frequent drought in the last decade – soil and atmospheric. Research shows that its good drought resilience allows it to be grown under irrigation conditions, but is sensitive to severe droughts, especially in the critical stages of development which leads to poor quality and drastic decrease in yield, and in some years to the lack of yields. The results show that sunflower irrigation has a large reserve for obtaining additional yield, which has been established through experiments in different parts of the country. The increase in irrigation is about 30-40%, and critical for water stress is the period of 20 days before and 20 days after flowering.

In order to determine the productivity and the effect of irrigation on apples grown under soil and meteorological conditions in the area of the village of Chelopechene – Sofia, research was conducted on drip irrigation of a plantation of the “Florina” variety, and different regimes were tested – from complete satisfaction of the daily needs of water to irrigate the culture with irrigation rates reduced by 20% and 40%. A non-irrigation variant has also been tested.
The productivity of the irrigation rate at optimal irrigation varies by years from 16.3 to 28.0 kg.ha-1.mm-1, and at 40% reduction of the irrigation rate from 19.3 to 26.0 kg.ha-1. mm-1
The highest values of productivity of the irrigation rate are reached at irrigation with a 40% reduction of the irrigation rate, in the dry 2004 high values were obtained and at the variant irrigated with 100% irrigation rate 28,0 kg.ha-1.mm-1
The optimization of moisture in the active soil layer contributes to a significant increase and stabilization of yields, which for the test conditions are from 1266 to 2087 kg / dka. Additional yields ranged from 542 to 821 kg / dka, averaging over the study period.

An analysis has been made of the research work to determine the impact of water deficit on the quantity and quality of sunflower production. Studies have also taken into account the more frequent drought in the last decade – soil and atmospheric. Research shows that its good drought resilience allows it to be grown under irrigation conditions, but is sensitive to severe droughts, especially in the critical stages of development which leads to poor quality and drastic decrease in yield, and in some years to the lack of yields. The results show that sunflower irrigation has a large reserve for obtaining additional yield, which has been established through experiments in different parts of the country. The increase in irrigation is about 30-40%, and critical for water stress is the period of 20 days before and 20 days after flowering.

To establish the totals and average daily evapotranspiration of raspberry under the soil and climate conditions in the village of Chelopechene, near Sofia city research was conducted with drip irrigation of plantations with variety “Lyulin” adopting varying irrigation schedules – from fully meeting the daily crop water requirements to reduced depths with 20% and 40%.
The meteorological conditions during the study period have been influenced by the totals and average daily On average, during the research period the magnitude of the total evapotranspiration for the vegetation period of the raspberry is 482 mm, with the highest values reaching 592 mm in the dry 2000.
For the needs of the practice and the design are calculated also the ten-day values of the biophysical coefficient Z and kb, which depend on the biological characteristics of the culture and the meteorological factors.