Influence of Drip Irrigation and Humic Acids on Yield of Long-Day Onion (Allium cepa L), CV. BGS-196 | Vplyv závlahy a humínových kyselín na úrodu cibule (Allium cepa L),CV.BGS-196

Field experiment with long-day onion, cultivar BGS-196, for investigation of the irrigation regime by two kinds of drip installations and treatment with humic acids were carried out during 2008-2009. Double drip laterals were put in every bed. The distances between the drippers were 0.10 m and 0.25 m. The aims were to investigate the two types of drip irrigation and treatment with humic acids of 23.40% (trade name Humustim), e.g. four treatments replicated four times and arranged in a randomized complete block design. The beds were 1 m wide with experimental block area of 5 m2 with two drip laterals. The time of sowing was the same in 2008 and 2009 - at the beginning of March at seeding rate of 10 kg per ha or 200 plants per square meter. The treatment with humic acid was only once at rate of 400 ml.ha-1 in the two type drip irrigation installations. The number of irrigations was 20 in 2008. The total amount of water applied with drippers spaced 0.10 m was 183.6 mm (1 836 cubic m per ha) and with drippers spaced 0.25 m it was 168.0 mm (1 680 cubic m per ha). The highest yield was by drip distance of 0.10 m. The yield was 42 820 kg per ha in comparison with drip distance 0.25 m, where it was 29 230 g per ha in 2008. The production of onion by 0.10 m drip distance with humic acids was 32 000 kg per ha in 2009. The lowest yield of onion was 27 050 kg per ha by drip irrigation with distance of 0.25 m without treatment with humic acids in 2009. The slopes of the lines of the relationship between relative yield reduction (1-Y/Ymax) and relative evapotranspiration deficit (1-ET/ETmax) showed that during 2008 and 2009 the yield coefficients of onion were Ky=2.63 and Ky=2.56, respectively. From the results it can be concluded that long-day onion, cultivar BGS-196 has got a yield coefficient bigger than 1.0, because it is from 111 group of crops, which are of the greatest extent dependant from the applied water.