SUGAR BEET

Family: Chenopodiaceae

Genus: Beta

Species: vulgaris var. saccharifera

(i) General background on the plant

B. vulgaris is the only species of agricultural importance in this small family, it includes sugar and fodder beets and mangels. Several members of the family are common arable weeds. The wild forms of beet from which cultivated forms are thought to derive are sea-coast plants of Europe and Asia and are very variable in habit and duration. Blockade of Continental ports during the Napoleonic wars cut off the supply of sugar cane from the West Indies and favoured development of an alternative source of sugar and sugar beet was developed in Europe in the eighteenth century from white Silesian beet, then a fodder crop. The first beet sugar factory was in Prussia in 1801. Original forms contained only about 4% sugar but careful selection and breeding have raised this to a maximum of 20%.

Cultivated forms are biennials which are grown for their swollen root and harvested at the end of the first year unless being grown for seed. The stem remains very short in the first year and forms the crown of the plant, from which arise numerous large glabrous dark-green leaves, ovate in shape and tapering to a long broad petiole. The primary root is diarch, with two vertical lines of lateral roots produced. Secondary thickening is unusual in that cambial rings are built up, each produces xylem internally and phloem externally. In cultivated beet the 'zones' are very broad and the xylem consists mainly of parenchyma cells, producing a massive succulent swollen root. Plants become dormant in autumn of the first year and are usually lifted from the ground then as they are not resistant to hard frost. Growth naturally starts again the following spring after a cold shock, using up material stored in the root the previous year. The stout stem then grows up to a height of about 1.5 - 2m bearing numerous leaves and forming long, lax spike-like inflorescences.

Sugar beet plants have white roots of conical shape, growing deep into the soil with only the crown exposed. They usually have two shallow vertical grooves in which the two lines of lateral roots emerge. Highest sugar concentration is associated with phloem of vascular rings and roots with numerous narrow rings usually have the highest sugar content. Many cultivars of sugar beet exist, almost all are capable of giving root yield of 40 tonnes or so per hectare at 15.5 - 18% sugar content, giving 6 -7 tonnes of sugar per hectare.

All forms of the species B.vulgaris are mainly cross-pollinated and will intercross freely. Seed production for crops of different forms must therefore be well separated.

(ii) Details of quality characteristics

100kg fresh sugar beet can give 12 - 15kg sucrose, 3.5kg molasses, 4.5kg dried pulp and varying amounts of filter cake.

(iii) Current production and yields

Source: FAO 1997

(iv) Constraints upon production

Seed production and sugar production need to take place in different locations because frost resistance is poor, but plants need a cold shock to flower and produce seed. Requires a deep well drained stone free soil that is not acid. A high standard of management of land is needed to provide a well structured soil, free from compaction. Sowing date is quite crucial, early sowing gives better sugar yields due to increased water availability earlier in the season, but sowing too early leads to a high population of bolters. Seedling stage is a poor competitor with weeds and can be fatally damaged by millipedes, symphalids, spring tails and pigmy-mangel beetle. Beet cyst eelworm (Heterodera schactii) can be damaging and is only satisfactorily controlled by adequate rotation.

(v) Markets and market potential

The annual world production of sucrose is 110 x10⁶ mt, it is produced mainly for utilization in food. Beet pulp is utilized for ruminant nutrition. Filter cake is used as agricultural soil fertilizer. Molasses are combined with beet pulp to provide animal food, or are used as feedstock in the chemical and pharmaceutical industries for fermented products such as citric acid and its esters. Sugar molasses are of limited value for large-scale ethanol fermentation. In Europe the sugar industry has been enabled to provide sucrose for chemical and biotechnological industries at prices similar to those of the world market.

(vi) Other information

The agronomy of sugar beet is well researched and well documented.

Virus yellows and rhizomania disease (beet necrotic yellow vein virus) can affect yields. Careful spray programmes can control the spread of BYV and rhizomania tolerant/resistant varieties are available.

See the following information from the NF-2000 database

AGRE-0038 - Valorization of Sugar Beet Pulp by Solid State Fermentation

AIR1-CT92-0001 - Valorisation of Sugar Beet Pulp by Solid State Fermentation -Proteins and Probiotics

AIR3-CT94-1990 - Novel Fermentation Feedstocks

AIR1-CT92-0026 - New Processes for the Biological Transformation of Agricultural Residues for the Production of High Added Value Flavours

AGRE-0063 - High Temperature Ethanol Fermentation of Lignocellulosic Waste

FAIR-3130 - Production of environmentally-friendly surfactants from agriculturalcoproducts of large-scale farming: agrisurfactants

(vii) Contacts

Biomass Pyrolysis Network

(viii) References

Gill, N.T., Vear K.C. (1980). Agricultural Botany1. Dicotyledonous Crops. Duckworth.

Halley, R.J (1983). The Agricultural Notebook 17th Edition. Butterworths.

Zoebelein, H. (1997). Dictionary of Renewable Resources. Weinheim.