Soybean

Soybean was introduced to Sri Lanka in 1970's, in order to provide an additional source of protein for the consumer, which has a high industrial potential, and some direct consumption as well, and is the most impotent food legumes because of the nutritional and industrial value.

Extent, production and imports from 1997 to 2001.

Year	Extent(ha)	Production(mt)	Imports(mt)
1997	497	418	2000
1998	641	599	179
1999	822	797	78
2000	694	648	2972
2001	641	621	3166

Areas Cultivated

Soybean is mostly cultivated in Anuradhapura and Matale district under irrigation in yala and as a rain fed crop in maha season.
Soybean is cultivated in Matale, Anuradhapura, Kurunegala, NuwaraEliya, Mahaweli 'H',Monaragala, Badulla,and Polonnaruwa disrtcts.

Nutritional value

Soybean is rich in protein and oil. Protein content of the Soybean can be as high 40% with the fat reaching even 22%. Fiber content of the Soybean can be around 9 %.

Proximate analysis of whole Soybean

Nutritional Values of Soybean (per 100g)

Moisture               8.5 g
Protein                36.5 g

Carbohydrates         30.2 g
Fat                     19.9 g
Ash                    4.9 g


Recommended Varieties

Varietal Characteristics

Pb-1
It is an introduction from India and is a selection from variety Nanking. It shows an erect growth with a plant height of around 50-60 cm. It flowers in 25-35 days after planting. Flowers are purple in colour. Pods are tan in colour Its medium sized seed have a thousand seed weight of about 155g. Seed are cream in colour with a buff coloured hilum. This mature in about 80-85 days after planting. Variety Pb-1 is suitable for rainfall uplands during the maha season as well as with supplementation irrigation during the yala season. Average yield 1700-2000 kg ha-1 . Seeds of this varieties PB-1 has on oil content of 20% a protein content of 40%.

PM-13
This variety resembles Pb-1 in many respects. It exhibits an erect growth with a plant height of 50-60 cm. Flowering occurs in 30-35 days after sowing. The flowers are purple in colour. Pods are tan in colour when day. Suds are cream coloured with the a buff in coloured hilum. They are medium sized and 140g on thousand seed weight. The varieties matures in about 90-95 days after sowing. A seed yield of 1700 - 2100 kg ha-1 can be expected from this variety. Its seeds posses a high protein content of 49% an oil content of 18% seeds retain. Availability above 80% for a period of about 4-6 mounts under ambient humid tropical conditions.

PM-25

This variety shows a tall and erect growth habit. It flower is about 35-45 days after growing flowers are purple in colour. This variety matures in about 95-100 days after growing. The pods are tan in colour with tawny pubescent. Suds are cream colour and posses a brown coloured hilum. Variety PM-25 has small seed and thousand weight of 100g. The oil content in about 18% while the protein conduct is about 49%. An average yield of about 1700-2300 kg ha-1 can be obtained from the variety PM-25. It retains high level of seed viability for more then 6 months under humid tropical ambient conditions.

Field Establishment

Climatic Requirements

Soybean can be grown in most agro-climatic regions but preferred areas are Dry zone and drier pats of the intermediate Zone.

Soils

Almost any soil with a pH of 6-7 is adequate, but excessive moisture is not acceptable. Soybean tolerates a degree of poor drainage. Highlands in maha and well-drained paddy fields in yala are preferable for Soybean cultivation. It can also be grown on highlands during yala if there is sufficient soil moisture

Land Preparation

One ploughing followed by a harrowing and shape into furrows & ridges. Ridges should be formed 40-50 cm apart to facilitate irrigation. Seed rate

Pb-1      55kg/ha
PM-13    55Kg/ha
PM-25    50Kg/ha

Time of Planting
Maha - Mid October - Mid November
Yala - Mid April - early May

Method of Planting

Plant on a flat surface if soil drainage is good and on ridges or raised bed when drainage is poor. Plant not more than 3 cm deep at 5 cm intervals in row 40 cm apart. 40 cm x 5 cm, 1 plant /hill.

Crop Management

Fertilizer

Basal                         N 46 kg/ha, P2O5 45 kg/ha, K2O 45 kg/ha
Urea                          50 kg/ha
Triple super phosphate      150 kg/ha
Muriate of potash            75 kg/ha
Top dressing                 50 kg urea at the onset of flowering

Irrigation

Irrigation once in every 4 days during the first month, then 6-7 days until about 3 weeks before harvest when irrigation should be stopped.
In flat bed planting, flood the beds, in ridge and furrow and raised bed systems flood the furrows. Moisture stress must be avoided during flowering and pod filling.

Weed control

Apply one of the flowering pre emergence herbicide first after planting and land weed 2-3 weeks and 4-5 after planting.
Alachlor 45% E.C at 3.3 - 5.5 l/ha
Metalachlor 50% E.C at 3.6 - 4.0 l/ha

Disease
Purple Stain(Cercospora Kikuchi)
Symptoms
Seed discoloration varies from pink to dark purple and is often accompanied by cracks in the seed coat. Infected seed produces diseased seedlings with angular reddish brown stops on leav and often results in seedling death.
Control
Use disease free seed
Treat seed with a fungicide
Use a recommended fungicide as a foliar spray at pod