Effect of Preceding Crops and Nitrogen Fertilization on Productivity of Sugarbeet and Some Economic Insect Pests Infestation in Newly Reclaimed Soil at West Nubaryia Region

• Maareg, M.F.; Sahar F. Tawfik and A. A. Abo El-Ftooh
• Sugar Crops Research Institute, ARC, Egypt.
• The Third International Conference onIPM Role in Integrated Crop management and Impacts on Environment and Agricultural Products. 26-29 November 2005, Giza, Egypt.

Abstract

Two field experiments were carried out to study the effect of five preceding crops (maize, peanut, soybean, sunflower and sweet sorghum) and five nitrogen fertilizer levels (0, 30, 60, 90, and 120 Kg N/fed.) on yield and quality as well as the infestation by two common sugarbeet insect pests (beet fly, Pegomyia mixta Vill. and tortoise beetle, Cassida vittata Vill.) in newly reclaimed soil of West Nubaryia region in 2001/2002 and 2002/2003 seasons.

Soybean as a preceding crop was superior to the other crops in increasing soil porosity, N and P and number of microorganisms in the soil. On the other hand, preceding crops did not influence K content and PH value. Soil organic matter was higher after sweet sorghum and maize.

All root characters of sugarbeet plants as well as top, root and sugar yields after soybean and/or peanut significantly surpassed those after maize, sunflower and sweet sorghum which was the worst preceding crop for sugarbeet under investigation conditions. Growing sugarbeet after peanut caused increases in total soluble solids (T.S.S), sucrose and purity percentages in sugarbeet roots more than those after the other four studied crops. Root characters, top yield, root yield and sugar yield of sugarbeet increased significantly with increasing the nitrogen level up to 120 Kg/fad. Also, increasing nitrogen level up to 120 kg/fed caused an increase in T.S.S and sucrose percentages, whereas nitrogen levels did not significantly affect purity. Root yield and sugar yield were significantly affected by the interaction between preceding crops and nitrogen levels. The maximum root and sugar yields were obtained from growing sugarbeet plant after peanut and soybean with the application of 120 kg N/fed. The minimum root and sugar yields were produced from sugarbeet plants preceded by sweet sorghum without nitrogen fertilizer.

The highest rates of infestation by Cassida vittata larvae and adults as well as Pegomyia mixta larvae were recorded on sugarbeet plants that were cultivated after soybean, whereas, the lowest infestation rates were obtained from growing sugarbeet after sweet sorghum. In a positive relation, nitrogen levels significantly affected the infestation rates by both insects.