EFFECT OF SOWING DATE AND INTERCROPPING SYSTEM OF SUNFLOWER WITH SUGAR BEET ON THE PRODUCTIVITY OF BOTH CROPS.

A field study was conducted during 2018/2019 and 2019/2020 seasons in Itay ELBaroud Agric. Res. Station, Beheira Governorate, Egypt, to study the effect of three sowing dates of sunflower (simultaneously with sugar beet (T1), twenty one days after sowing sugar beet (T2) and thirty five days after sowing sugar beet (T3)) and three intercropping systems (25% (S1), 33.3% (S2) and 50% (S3) of sunflower plant density + 100% sugar beet) on yield and yield components of both crops. A split plot design with four replications was used. Results showed that all studied characters of sugar beet were significantly affected by sowing dates and intercropping systems of sunflower. Intercropping system (S1) significantly increased all characters of sugar beet at T3 over the other treatments. Early sowing date (T1) significantly accelerated days to 50% of flowering and maturity date and recorded the highest values for each of growing degree days (GDD) and seed yield and its components of sunflower. Significant differences were recorded for sunflower studied traits as affected by the intercropping systems. The highest seed and oil yields/fad., were achieved with sole sunflower followed by S3 system at T1 compared with the other treatments. The highest land equivalent ratio (LER) value 1.46 was recorded at T2 with S3, followed by 1.44 with T2 x S1, as average of both seasons. While T2 x S1 had the highest relative crowding coefficient (RCC) and net return. It can be concluded that T2 x S1 had the highest sugar yield valued 4.74 ton/fad., increased net return by 28.30% and produced 26.10 ton sugar beet plus 444.63kg seed of sunflower compared to sole sugar beet which had 26.91 ton sugar beet.