Water is one of the important conditions for plant life, and crop plants need it in optimum amount to be able to form higher output yield. If water supply is insufficient, the fertilizers, used to batten the soil, will not produce the desired effect.

Due to the climate changes causing the tendency to the temperature rate increase and precipitation rate decrease, the achievement of regular high output yield of sugar beet seeds is possible only by applying the irrigation techniques. In recent years, agricultural producers have increasingly preferred sprinkler apparatus to drip irrigation, which primarily leads to considerable water savings. In the course of drip irrigation the limited part of the soil surface is moistened, water runoff and its filtering in deep soil layers are excluded. In addition, by using drip irrigation the decrease of evaporation from the soil surface is observed, as the part of the area remains dry. The efficiency rate of irrigation water absorption by plants is up to 85-95 %.

Nitrogen fertilizers and drip irrigation techniques have improved the plant habitus. The phenological observations of their development were carried out, from the shooting period till the seed maturation period.

In case of fertilizing throughout the growing season and using drip irrigation (option 3.4) the plant height increased from 130 cm on control to 145 cm and number of lateral canes increased from 41 to 50 pcs, the seed maturation rate decreased from 71 % to 60 %.

The trial established a clear pattern of the significant influence of drip irrigation as well the efficiency of the fertilizers in combination with irrigation on the output yield of sugar beet seeds.

The application of Nitrogen (20 kg/ha) and drip irrigation increases the output yield of sugar beet seeds by 51-73 %.

The mineral fertilizers (N₂₀) and drip irrigation improve the quality of the seeds obtained. The full seed output in case of applying fertilizers increases by 10.3 %, applying both fertilizers and drip irrigation by 16.4 %, and by extending irrigation period till the moment of seed harvesting by 20 %, which makes 0.11-0.17 t/ha.

The yielding capacity reduction of all the options in 2015 was caused by the negative impact of high temperature and low relative air humidity during the seed-setting and maturation.

While studying the size of the obtained seeds the output yield of the coarse fraction of about 5.5-4.5 mm in diameter increased from 16 % on control to 24 % in case of applying fertilizers and irrigation techniques. The extension of irrigation period up to the crop harvesting increased the yield of the coarse fraction seeds by 20 %, option 4, compared to the control.

As to the seed quality it is worth mentioning that in the fractional composition the content of the fruits sized 3.0-3.5 mm was almost the same in all the options, and the number of the fruits sized 4.5-5.5 mm increased in the options in which irrigation took place.

The seed fertility property was less dependent on growing conditions, and in general within the frames specified by the standard was following: the small fraction – 96-100 % of single-seed fruits, and the coarse fraction: 93.3-100 % respectively.

The simultaneous combination of irrigation and mineral fertilization increased the seed sprouting energy significantly. In addition, there was a trend, though insignificant, to the increase of other seed quality indicators such as germination and purity with their relatively high level (germination – 86-93 %, purity – 89-97 %).

The calculations of the efficiency of drip irrigation usage demonstrated that the cost of the purchase and use of the irrigation equipment will be repaid during the second year of its operation. Later, the farm is to obtain net profit.

Thus, the use of drip irrigation ensures the seed stand density of the plants during the growing season, high-quality formation of vegetative and generative organs, increases the seed yielding capacity and improves its seed sowing properties as well.

Key words: drip irrigation, sugar beet seeds, seed output yield, seed quality.