The effect of crop rotation on performance and qualitative characteristics of sugar beet

Abstract
Sugar beet and sugarcane are two major crops for sugar extraction throughout the world. However, the sugar beet importance is not just about sugar production but it also plays an important role in crop rotation and increased productivity in various industries as well as livestock feed. In this study the long-term (2009-16) field trial effect of alfalfa (4 years)-winter wheat (1 year)–fallow (1year)-sugar beet rotation on yield and quality parameters of sugar beet were evaluated for two consecutive rotations. The field trials were carried out at single location in Karaj, Iran, using randomized complete block design with four replications. Analysis of variance showed that the seasonal factors influenced different traits. In the first and second rotations, the root yield ranged from about 56.5 to 83.2 and 61.4 to 77.8 t ha-1, respectively with significant difference among cultivars in the first rotation. However, no significant difference was observed among both rotations in terms of root yield. Same results were obtained for sugar yield in both rotations which illustrates the stability of the above-mentioned traits. Except for sugar content, significant difference was observed among other traits in both rotations. We show for the first time the effect of completing two rotation sequences on sugar beet performance and quality for decision making into a continual expansion/development of crop cultivation.