Effect of N Fertilization Rate on Sugar Yield and Non‐Sugar Impurities of Sugar Beets (Beta vulgaris) Grown Under Mediterranean Conditions

Abstract

For three successive growing seasons (1999–2001), a completely randomized block design experiment was established at the surrounding area of each of four sugar beet processing plants of Hellenic Sugar Industry SA, Greece (a total of 12 experiments). Nitrogen was applied at five rates (0, 60, 120, 180 and 240 kg N ha−1) and six replications per rate. Nitrogen fertilization had site‐specific effects on quantitative (fresh root and sugar yields) and qualitative (sucrose content, K, Na, α‐amino N) traits. When data were combined over years and sites, fresh root and sugar yields were maximized at high N rates (330.75 and 295 kg N ha−1 respectively), as derived from quadratic functions fitted to data. In three trials, increased N rates had negative effects on root and sugar yield. These sites were characterized by high yield in control plots, light soil texture (sand > 50 %) and low CEC values. When data were converted into relative values (the ratio of the trait values to the control mean of each experiment), root and sugar yield was found to be maximized at higher N rates (350 and 316 kg N ha−1, respectively). Sucrose content was strongly and linearly reduced by the increased N rates when data were combined but a significant reduction with increasing N rates was found in only two sites. Non‐sugar impurities (K, Na, α‐amino N) were positively related to the increased N rates when data were combined. Sodium and α‐amino N showed to be most affected by N fertilization as positive relationships were found in six and eight of 12 locations, respectively. Increased N supply resulted in higher soil NO3‐N concentrations (0–90 cm depth) at harvest which were related with amino N contents in sugar beet roots (in 1999 and 2001).

Sugar Beet Yield and Processing Quality in Relation to Nitrogen Content and Microbiological Diversity of Deep Soil Layer

“…Sodium and a-amino N increase significantly at site B whereas sugar content and purity decreased. Min-N increased potassium concentration in the beets less than sodium and a-amino N. This confirms previous observations by Tsialtas and Maslaris (2005) and Stevanato et al (2010b). The difference in sugar yield between sites is not significant, but, owing to the different processing quality, the extractable sugar yield becomes significant.…”

“…Samples were collected in February, at the beginning of soil warming and the period of more intense organic matter mineralization. The amount of min-N available for plants could therefore increase according to the rising soil temperature (Bilbao et al 2004;Tsialtas and Maslaris 2005).…”

Response of Beta vulgaris L. to nitrogen and micronutrients in dry environment

“…The N level of 350 kg/ha gave the highest impurities, but purity % found to increase by the application of this N rate. Some reports indicated that excess N fertilizer may decrease sugar %, lowering the recoverable sugar and increasing the impurities such as proteins, α-amino N and Na contents (Tsialtas and Maslaris 2005, Manderscheid et al 2010, Mekdad 2015. Micronutrients are important to plant growth and productivity that are the macronutrients in the soils.…”

The Effect of Nitrogen and Potassium Fertilizers on Yield and Quality of Sweet Sorghum Varieties under Arid Regions Conditions

“…Utilization of nitrogen enhanced sugar percentage, root and sugar yield for sugar beet plants (Tsialtas andMaslaris, 2005 andMekdad andRady, 2016). Increasing nitrogen enhance significantly yield and quality of sugar beet plants Mekdad (2015).…”