Soybean
Glycine max (Syn. G. soja, G. hispida, Soja max)
Soya, Soy, Soy Bean, Soya Bean, Soyabean;
Soybeans are highly efficient producers of protein and oil for both human and
animal food. They are also widely used in industry, and are the most important of all
the grain legumes in the world in economic terms.. Global production in 2004 was
estimated by FAO at 204 million MT.
The main nutritional attributes of soya are, per 100 g of edible portion of the
soybeans can be considered to be an oil producing crop (they are sometimes referred
to as “oilseed legumes”) because of their high oil content. The oil contains useful
amounts of phosphorus, and is normally considered to be a “drying” type, and
sometimes as “semi-drying” ie it normally forms an elastic film when in contact
with air. The glycerides are of the unsaturated type.
The amino acid distribution of soybean protein is more similar to animal protein
than the protein from most vegetable sources, containing for example 5.4% lysine. It
is thought that the protein in soya may lower blood cholesterol, and its isoflavines
may reduce the risk of some cancers.
They were first cultivated in China around the eleventh century BC, the earliest
soya plants being climbing types. Soybeans need climates with hot, humid summers
to grow well and are rarely satisfactory as a European crop. Plant breeding work is
being done to produce varieties suitable for cultivation in the UK by selecting fast
growing plants able to mature in the short North European growing season.
The plant is an erect, annual legume, 30–170 cm tall, which sheds its leaves at
1–5 seeds, normally 2 or 3, which are highly variable in size and colour between
varieties. The seed is normally either yellow, green, brown or black.
PLANTING
Propagation: by seed. For northern temperate regions, modern quick maturing
varieties are adapted to flower and fruit in the shortening days of July and August.
Traditional varieties only flower during the lengthening days of early summer and so
cannot produce any seed in the cool, short northern summers.
Soil: soya will grow well in slightly acid soil, the optimum being about pH 6–6.5.
On more acid soils lime should be applied 2 or 3 months before planting. Heavy
soils will grow soya if they are well drained, and light soils also if they have
sufficient moisture, but the best soils are rich, sandy loams. Adequate amounts of
phosphate, potash and calcium are essential, and about 25 kg/ha of Nitrogen is
normally beneficial even for soya growing in good soils. Most soya varieties are
moderately tolerant to salinity, and some varieties are tolerant.
maturity. The flowers are small, and either white or lilac/purple. The pods contain
182 TONY WINCH
Soya, Soja (French); Sojabohne (Germany); Soja (Spanish & Portuguese)
seed, 380 kcals energy, 35–40 g protein and 18–24 g oil. In common with groundnuts,