Sour cherries become more popular due to their food value. Therefore sour cherries could be a profitable crop for fruit growers in Latvia. Information about sour cherry response to soil moisture adjustment is needed, because based on previous studies it is not possible to predict the influence of irrigation and mulch on sour cherry growing. The trial was carried out at the Latvia State Institute of Fruit Growing in 2007 to determine the effect of soil moisture adjustment on the growth of different sour cherry cultivars. Woodchip mulch and drip irrigation were used as main factors, cultivars 'Bulatnikovskaya', 'Desertnaya Morozovoi', 'Latvijas Zemais', 'Orlica', 'Shokoladnica', 'Tamaris', 'Zentenes' were used as a secondary factor. Vegetative growth, branching angles of lateral shoots, proportions of pruned shoots, spurs and twigs were determined to characterize the response of cultivars to mulching and irrigation. In general use of drip irrigation increased vegetative growth of sour cherries, but the use of woodchip mulch decreased this growth. Branching angles were wider in variant with woodchip mulch. Cultivar 'Zentenes' most positively responded to use of woodchip mulch and drip irrigation.

The aim of this study was to investigate the effect of industrially designed light-emitting diode (LED) lamp lighting on the nutritional quality of Brassicaceae microgreens. Red pak choi (Brassica rapa var. chinensis ‘Rubi F1 ’), tatsoi (Brassica rapa var. rosularis) and mustard (Brassica juncea L. ‘Red Lion’) were grown in a greenhouse (20±2/18±2 °C) during winter season, and the solar daily integral (DLI) was ~3.46±1.16 mol mE-2 dE-1. The light spectra of lamp consist of 8 violet (420-430), 16 blue (460-470 nm), 8 orange (610-615 nm), 3 red (620-630 nm), 56 red (660-670 nm), 8 white (contain blue (400-500 nm), green (500-600 nm) and red (600-700 nm)) LEDs. The treatments of ~150 and ~250 µmol m-2 sE-1 LED irradiance levels (LED 150 and LED 250) for 16 h dE-1 in comparison with high pressure sodium (HPS) lamps (~150 µmol mE-2 sE-1) as a control were performed. Photophysiological response to the artificial light varied among Brassicaceae species. Microgreens treated with LED 150 and LED 250 were significantly (P is less than or equal to 0.05) shorter and formed smaller hypocotyls. The photooxidative changes were evoked by both lighting treatments and led to higher phytochemical (phenols, ascorbic acid, flavonols, anthocyanins) and mineral element (Ca, K, Mg, Na, P, Fe, Zn) contents, and the DPPH and ABTS free radicals scavenging activities in all microgreens. Significantly lower content of nitrate was obtained with LED 150 treatment. Finally, LED lamps have the potential to be used as the main light source for growing high nutritional quality microgreens in greenhouses.