Two field experiments were carried out in Sers EL-Lian Agric. Res. Station, ARC, Minufiya Governorate, during 2015/2016 and 2016/2017 growing seasons, to study the effect of preceding crop (mono preceding) or preceding + catch crop (di preceding) and foliar application of boron as boric acid on yield and quality of sugar beet cv. Gloria. The experimental design was strip-plots design with three replications. Mono and di preceding crops (Maize, Maize/Fahl berseem, soybean and soybean/Fahl berseem) were allocated in horizontal plots and three boron element foliar applications [(zero (B1) control, 0.10 g/L (B2) and 0.20 g/L (B3)] were in vertical plots. The results can be summarized as follows:
Soil content of organic matter, available NPK and boron element were higher after di preceding crop including legume crops, soybean/fahl berseem, compared to maize as a preceding crop.
Di preceding crop had significant effect on growth, root and sugar yields ton/fed as well as Total soluble solids percentage (TSS %), sucrose % and purity % in both seasons. Legumes as preceding crops for sugar beet significantly increased all studied characters, except quality characters of sugar beet compared with maize. The highest root and sugar yields/fed were obtained when sugar beet was planted after soybean/fahl berseem (32.74, 5.00 ton/fed). The same yields were obtained after soybean (31.60 and 4.88 ton/fed) as average of both seasons, with an ignored difference.
Boron application significantly affected all sugar beet characters in both seasons compared to control treatment, except number of leaves/plant in second season and purity % in the first season. Increasing boron concentration from 0 up to 0.20 g/L caused significant increases for all sugar beet characters. Foliar application of B3 (0.20 g B /L) achieved the highest root and sugar yields/fed followed by B2 (0.10 g/L).
Sowing sugar beet after soybean/fahl berseem and boron application at 0.20 g/L, achievedthe highest values for most sugar beet characters compared with the lowest values gained with control following maize.
Growing fahl berseem, as catch crop, following maize and soybean increased soil fertility, maximized total cereal units by 13.46 and 11.49 % and net return by 30.00 and 21.28%, as average of both seasons, compared with maize and soybean as a mono preceding crop < /em>.