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. Globally legumes play vital role in human nutrition since they are rich source of protein, calories, certain minerals and vitamins. Among which soybean is probably the largest source of vegetable seed oil (20%) and protein (40%). Owing the nutritional and health benefits of soybean, it excited the growers in recent years. US, Argentina, Brazil and China claims as the biggest producers of this super crop, the modern technologies and changes in their agronomic practices is worth to discuss on its possibility in Indian scenario.
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
((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%.
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.
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.
- SOIL & CLIMATE
Soybean can be grown in most agro-climatic regions but preferred areas are Dry zone and drier pats of the intermediate Zone.
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.
Mixed cropping of soybean with maize, mandua and sesamum has been found feasible and more remunerative. In mixed cropping of maize and soybean, plant maize at 100 cm row spacing keeping plant to plant distance 10 cm and three rows of soybean in between maize rows. A randomized complete block study on row spacing and plant density showed a higher protein content and lower oil content at 19 cm compared to 75 cm row spacing. Soybean has tremendous scope as an intercrop in arhar, cotton, and upland rice in northern India. In southern part of the country, soybean has a good scope as intercrop in sorghum, cotton, sugarcane, arhar and groundnut. In central India, soybean has been found very remunerative on the fallow lands in Kharif.
Some of the common rotations followed in north India are:
Soybean – wheat , Soybean – potato , Soybean – gram , Soybean – tobacco , Soybean – potato – wheat
For obtaining good yields of soybean apply 15-20 tonnes of farm yard manure or compost per hectare. But soybean being a legume crop has the ability to supply their own nitrogen needs provided they have been inoculated and there it efficient nodulation in the plant. An application of 20-30 kg nitrogen per hectare as a starter dose will be sufficient to meet the nitrogen requirement of the crop in the initial stage in low fertility soils having poor organic matter. Soybean requires relatively large amounts of phosphorus than other crops. The soil should be tested for the availability status of phosphorus to meet the requirement of the crop. With the application of phosphorus the number and density of nodules are stimulated and the bacteria become more mobile. Soybean also requires a relatively large amount of potassium than other crops. The rate of potassium uptake climbs to a peak during the period of rapid vegetative growth then slows down about the time the bean begins to form. Soil test is the best guide for the application of potash in the soil. In the absence of soil test, 50-60 kg K2O per hectare should be applied. The fertilizers should preferably be placed, at sowing time, about 5-7 cm away from the seed at a depth of 5-7 cm from seed level. 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 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
Purple Stain(Cercospora Kikuchi
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.
Use disease free seed Treat seed with a fungicide Use a recommended fungicide as a foliar spray at pod set
Bacterial Pustule (Xanthomonas phaseoli var. sojensis
Minute pale green spots on both leaf surfaces become brown pustules with a yellow halo Irregular dark brown patches appear when lesion coalesce Control Plant disease free seed Use crop rotation
Yellow Mosaic Virus
Spray an insecticide for white fly control Destroy weed which habour the virus Use disease free seeds
Bud Blight (a virus
Necrosis and curving of the terminal bud to form a crook, buds become necrotic and fall off Discoloration develops on the stem and branches near and bases of petioles Natural senescence is delayed, plants remain green at harvest if infection occurs at later stages of growthx Plant die in severe attacks
Control:- Remove infected plants Plant disease free seed Control weeds
Charcoal Rot (Macrophomina phaseolina
Reddish brown discoloration of emerging seedlings Dark brown to black discoloration at the base of the stem in young plants Small black bodies of selerotia are visible when the epidermis of the discolored area is removed Leaves turn yellow and wilt. Control Flood the feild 3-4 weeks before planting Avoid excessive seed rate Amend soil with the organic matter several weeks before planting Period a balanced fertilizer to encourage vigorous growth Rotate crops
Yield potential under irrigated condition 3000Kg/ha, rainfed condition 2000Kg/ha
- The crop should be harvested when leaves turn yellow and drop and when 95% of the pods have turned brown
- Cut plant with a sickle & sun dry.
- Thresh by placing dried plants into gunny bays and beating them with sticks.
- Seed for planting must be threshed carefully to avoid seed damage.
Post harvest handling Sun dry seeds for 2-3 days to lower moisture content to about 10-12%.Beans for seed should be dried to 9%. Cool sun -dried seeds for 2-3 hours before bagging, then store in a