In this essay we will discuss about:- 1. Origin and Distribution of Soybean 2. Area and Production of Soybean 3. Climate, Soils and Tillage 4. Growth and Development 5. Varieties and Seasons 6. Seeds and Seeding 7. Nutrient Management 8. Cropping Systems 9. Water Management 10. Weed Management 11. Harvesting and Storage 12. Quality Considerations.
Contents:
- Origin and Distribution of Soybean
- Area and Production of Soybean
- Climate, Soils and Tillage of Soybean
- Growth and Development of Soybean
- Varieties and Seasons of Soybean
- Seeds and Seeding of Soybean
- Nutrient Management for Soybean
- Cropping Systems of Soybean
- Water Management for Soybean
- Weed Management
- Harvesting and Storage of Soybean
- Quality Considerations
1. Origin and Distribution of Soybean:
The primary gene pool occurs in China. Soybeans were domesticated in the northern and eastern regions of China. It spread to India and Nepal during sixth century AD. Soybeans were introduced to Europe during seventeenth century and to the USA during eighteenth century. Soybean cultivation in India was given an impetus during 1970s; otherwise it was cultivated in around 300 ha during 1960s.
Soybean (Glycine max) accounts for approximately 50 per cent of total production of oilseed crops in the world. Its seed, which contains about 40 per cent protein and 20 per cent oil provides approximately 60 per cent of the world supply of vegetable protein and 30 per cent of the oil. The name soya traces to the Chinese “Chiang-yiu”, meaning soy sauce.
The soy sauce in Japanese is pronounced “show-yu” and was shortened to “so-ya”. The English further contracted the common name of Glycine max from soy-a or soya to soy plus bean or soybean. It is also called as soyabean, Chinese pea, Japan pea and Japanese fodder plant. In India, it is known as bhat, bhatmer and rumkut.
The soybean or soya bean is known as the “Golden Bean” of the 20th century. It is grown in tropical, subtropical and temperate climates. Soybeans are the primary ingredients in many processed foods, including dairy product substitutes. Soybean account for about 60 per cent of the total global oilseed production of 390-425 M t with cottonseed, the closest competitor.
2. Area and Production of Soybean:
World production of soybean for 2007-08 was 220.86 M t. The US accounts for 34 per cent of world soybean production, while Brazil accounts 27 per cent, Argentina 20 per cent, China 7 per cent and India contributes only 4 per cent of the total global soybean production. In terms of area (average from 2005-06 to 2009-10), USA ranks first followed by Brazil, Argentina, India and China.
India is the fifth largest soybean producing country in the world. The average domestic production of soybean is at around 8.76 M t with an average area of 8.82 M ha (average from 2005-06 to 2009-10). Major production comes from Madhya Pradesh (53%), followed by Maharashtra (34%) and Rajasthan (8%). Madhya Pradesh accounts for 53 per cent of domestic production with 55 per cent acreage. Other producing states are Andhra Pradesh, Karnataka and Chhattisgarh.
The area under soybean in India during 2009-10 was 9.73 M ha with a production of 9.96 M t accounting for a productivity of 1026 kg ha-1. Largest area (5.35 M ha), highest production (6.41 M t) and yield of soybean (1200 kg ha-1) are from MP. Maharashtra ranks second in area (3.02 M ha) and production (2.20 M t) while Rajasthan ranks second in the yield (1175 kg ha-1).
3. Climate, Soils and Tillage of Soybean:
Climate:
Soybean is a warm season (tropical) crop but its cultivation now extends to subtropics and temperate climates. The major commercial production is between 25° and 45°N latitude at altitudes of less than 1000 m. It can be grown up to 2000 m. The general climatic requirements are approximately those of maize and the greatest development in the USA has been in the maize belt.
Soybean is relatively resistant to low and very high temperature but growth rate decreases above 35°C and below 18°C. Minimum temperature for growth is about 10°C and maximum rate of development between planting and flowering occurs at 30°C. Soybean is basically a short day plant but response to day length varies with variety and temperature and developed verities are adapted only to rather narrow latitude difference. Day-length influences the rate of development of crop.
In short day types, increased day length may result in the delay of flowering and taller plants with more nodes. Short days hasten flowering, particularly for late maturing verities. Vegetative growth normally ceases during yield formation. The critical photoperiod for bud initiation is around 14 hrs.
Subsequent photoperiods influence blossoming. At 16 to 18 hrs, soybean flowers do not open but maximum floral blossoming occurs at 10-13 hrs photoperiod. Night temperatures also influence floral initiation.
Soybean is often cultivated during kharif as rainfed crop and postrainy season (rabi) on stored soil moisture. However, supplemental irrigation to overcome long dry periods is, generally, practiced. It can come up well in areas with rainfall varying from 600 to 1000 mm. Distribution of rainfall during the crop growing season is more important than the total amount.
Agroecological Zones:
Based on the agroclimatic conditions in which the soybean is cultivated in India, five agroecological zones have been recognised.
Soils:
Soybean can be grown on a wide range of well drained soils but thrives best on clay loams. Optimum pH for soybean production is in the range of 6 to 6.5. Soybean is rated as a moderately salt tolerant crop and the reported salinity threshold is about 5 dS m-1. Shallow water tables, particularly during the early growth period can adversely affect the yield. The crop is sensitive to waterlogging, especially during early stages.
Tillage:
Tillage practices for soybean depend on soil type and the cropping system. For a rainfed crop, land preparation is similar to that for other rainfed crops such as sorghum, groundnut, cotton, wheat etc. Ploughing and harrowing is common for the crops on light soils, whereas heavy soils need only harrowing. Minimum or no tillage systems are followed in major soybean producing countries.
4. Growth and Development of Soybean:
Information on growth and development will provide an understanding of soybean production physiology for better crop management and higher yield.
Germination and Vegetative Growth:
Soybean germination is epigeal and under favourable conditions, seedling begins to emerge in 4-5 days. It fails to gemination if the soils moisture tension exceeds 6.5 atm. Optimum temperature for germination is 30°-35°C. Root system continue to grow through ought the life cycle except at physiological maturity and the rate of root penetration is most rapid during early flowering.
As a legume, soybean form symbiotic associated with Rhizobium japonicum and fix atmospheric nitrogen. Nodules may appear around 10 days after emergence and nitrogen fixation begin about two weeks later. Nodulation is limited to sites between the root tip and smallest emergent root hair and does not occur on the walls of mature roots.
Nodules produced with the first infection on the primary root have an average duration of 65 days. Since reinfection of younger roots may occurs during the growing season, a mature soybean plant may have nodules of several age classes. The quantity of nitrogen fixed varies with the environment and the variety, which may range from 20 to 160 kg ha-1.
Soybeans have two growth habits, determinate and indeterminate. In determinate habit, vegetative growth is nearly complete when the plant starts flowering. In the case of indeterminate habit, both vegetative and reproductive growths go on simultaneously.
Soybean plant increases in dry weight slowly at first and then more rapidly. Vegetative growth ceases at about the time seed enlargement starts. The dry weight of vegetative parts decreases during the latter parts of grain development.
Reproductive Growth:
Flower initiation varies with genotype and the environmental factors. Flowers may become visible 20 DAS or may be delayed until 50 DAS. Pods are normally visible around 10 to 15 days after the start of flowering. Flowering may continue for over 4 to 6 weeks depending on the environment. Number of pods varies from 2 to more than 20 in a single inflorescence and up to 400 in a single plant. At maturity, pods usually contain two or three seeds but can contain as many as five.
Growth Stages:
Description of soybean growth stages are given in Table 15.1. Vegetative (V) stages are designated by the number of nodes on the main stem, beginning with the unifoliate node that have or had a completely unrolled leaf. Reproductive stages R1 and R2 are based on flowering, R3 and R4 on pod development, R5 and R6 on seed development and R7 and R8 on maturation.
Dry Matter Production:
Soybean plant dry weight increases up to about 90 days after emergence. Stem and pod dry weight decreases during the late stages of seed filling as tissue loses dry matter because of respiration and mobilisation to the seed. The highest CGR reported for irrigated soybean is 30 g m-1 day-1.
LAI, NAR and HI:
In determinate types, maximum LAI occurs at the beginning of flowering and in indeterminate types, near end of flowering. Maximum values may range from 5 to 8. An LAI around 3 is required for 95 per cent light interception and 95 per cent dry matter production.
The NAR is, generally, constant around 6 to 7 g m-2 day-1 at the beginning of crop growth and then decreases to a relatively constant rate. Harvest index is relatively a stable character. It varies from 30 to 40 per cent depending on the duration of the cultivars and management practices.
5. Varieties and Seasons of Soybean:
Varieties:
In soybean, initial varietal improvement was through selections introduced from AVRDC, Taiwan and Thailand. Subsequently, several high yielding varieties have been developed to suit the needs under different cropping systems. Promising varieties developed for different regions in the recent past are given below in Table 15.2.
Seasons:
In India, soybean is a rainy season crop both during kharif and rabi (postrainy season). Kharif crop is sown during June-July and rabi crop on stored soil moisture during October- November. Soybean is also grown as relay crop in kharif rice, especially in coastal and delta areas in south India. Sowing time extends from November to January depending on kharif rice harvest.
Optimum sowing time for different zones is given below:
If irrigation water is not a limiting factor, soybean can be grown all through the year. In Andhra Pradesh, soybean is seeded as rainfed crop on light soils during June-July and on black cotton soils in second fortnight of August. As an irrigated rabi crop, it is seeded during November- December and as summer crop during January-February.
6. Seeds and Seeding of Soybean:
Seeds are to be treated with fungicides such as Thriam at 3 g kg-1 one week before Rhizobium inoculation.
Seed Rate and Spacing:
Soybean seed lose visibility within two or three months. Optimum seed rate for soybean with 125-140 g 1000-1 grain weight with 80 per cent germination is 75 kg ha-1 for rainfed crop and 100 kg for irrigated crop. For improved soybean cultivars with less than 100 days duration, optimum plant population is 40,000 plants ha-1. For varieties such as Bragg, optimum plant population is around 25,000 plants ha-1.
Spacing depends on plant and soil type as indicated below:
Depth and Method of Seeding:
Adequate soil moisture is essential for optimum germination and desired stand establishment. Optimum depth of seeding is 2-3 cm in heavy soils with adequate moisture and 3-4 cm in medium and light soils of optimum soil moisture. Usually, sowing is in plough furrow behind country plough. Seed drills can be used to cover larger areas. Under irrigated conditions, ridge sowing is advocated. Thinning should be completed within three weeks after emergence to maintain desired crop stand.
7. Nutrient Management for Soybean:
Approximate nutrient uptake by 1.0 t grain crop of soybean is 80 N, 13 P2O5, 40 K2O, 15 Ca, 12 Mg and 2 S kg ha-1. The nutrient requirement vary according to climate, cultivar, yield level, cropping system and management practices.
Nutrient Concentration:
Information on nutrient concentration can be used to study nutrient removal from the soil in order to replenish soil fertility for optimum yield. Nutrient concentrations in soybean plant are given in Table 15.3.
Soybean can fix atmospheric nitrogen if the soil contains Rhizobium japonicum or if the seed is properly inoculated. The plant start to fix substantial amounts of nitrogen about four weeks after sowing. Most estimates show that soybean derives between 25 and 75 per cent nitrogen from fixation. Higher levels of mineral nitrogen retard early nodule development.
However, if the soil is deficient in nitrogen, its early supply enables the plant to maintain reasonable growth rate for nitrogen fixation in the later stages. Soybean response to nitrogen fertilisers is inconsistent, unpredictable and often unexplainable. Conflicting results of nitrogen application to soybean have been reported from response to no response.
NPK Requirement:
Since soybean crop is able to meet most of its nitrogen requirement from atmosphere through Rhizobium, nitrogen fertilisers are not, generally, applied. However, in light textured soils, a starter dose of 20 kg N ha-1 appears to be profitable. If soils are deficient in phosphorus and potassium, depending on soil test values, 40-60 kg P2O5 and 20-40 kg K2O ha-1 can improve the yield considerably. Soybean responds to about 20 kg S ha-1, depending on its availability in the soil.
General, recommended fertilisers schedule for soybean is Rhizobium inoculation plus 20 kg N ha-1 along with 40 kg P2O5 and 40 kg K2O ha-1. Rhizolium culture may be given at the rate of 500 g 75 kg-1 seed. For a crop on light soils, 50 per cent of the nitrogen along with recommended rate of phosphorus and potassium may be applied by drilling at seeding.
The remaining 50 per cent of nitrogen maybe applied at the four-leaf stage. However, for a crop on stored soil moisture (rabi), entire recommended dose of fertilisers should be applied by placement at seeding.
In Andhra Pradesh, relatively higher doses of nitrogen and phosphors are recommended for soybean. Rhizobium inoculation along with 30 N, 60 P2O5 and 40 K2O kg ha-1 is recommended, especially for an irrigated crop and for a crop on moisture retentive black cotton soils.
8. Cropping Systems of Soybean:
Intercropping with soybean is more for production stability than yield advantage under rainfed condition. As a sequence crop during post-rainy season, soybean is preferred to wheat when the stored soil moisture is inadequate for rainfed wheat.
Intercropping:
Soybean is grown as intercrop with cereals, pulses and oilseed crops under rainfed conditions as indicated below:
Soybean + maize (2:1, 2:2)
Soybean + pigeonpea (2:2, 4:2)
Soybean + figermillet (2:2)
Soybean + cotton (1:3, 2:1)
Soybean + groundnut (1:4, 1:6)
Soybean + sorghum (1:2, 2:2)
Soybean + pearlmillet (2:4,2:6)
Paired row technique is the simplest way of accommodating optimum plant population of both the component crops. In the case of maize + soybean system, paired rows of maize to minimise its competitive effect on soybean results in yield and monitory advantage. Paired maize (30/90 cm) and soybean in 2:2 and paired maize (45-90 cm) and soybean in 2:2 appears to be ideal (Table 15.4).
Sequence Cropping:
Sequence cropping on stored soil moisture is possible in deep black as rainy season and post-rainy season crop.
Prominent sequences are:
Soybean – wheat
Soybean – safflower
Soybean – chickpea
Maize – soybean
Soybean – sorghum
Relay Cropping:
Relay cropping is, generally, followed when irrigation water is a limiting factor for the next crop after kharif rice, especially in coastal and delta areas. Usual relay system in these areas is kharif rice-relay greengram or blackgram. Short duration soybean as relay crop in kharif rice is gaining importance in coastal Andhra Pradesh and Cauvery delta of Tamil Nadu.
9. Water Management for Soybean:
Soybean is a rainfed crop in India, especially on deep black soils both during rainy and postrainy seasons. However, when fitted in intensive cropping system under irrigation, it receives adequate irrigation.
Critical Stages for Irrigation:
The soybean crop can draw moisture from about 1.8 m soil depth because of its deep tap root system. As such, it can withstand short duration soil moisture stress. Critical stages for irrigation are flowering and pod development when the crop needs around 8 mm day-1. Soybean has extended period of flowering. The late flowers developing into mature pods can compensate early flower drop due to soil moisture stress.
Scheduling Irrigation:
Scheduling irrigation at 50 per cent DASM or at IW/CPE ratio of 0.6 is optimum for soybean. At these levels, light soils need irrigation once in 10-12 days and heavy soils once in 18-20 days. If water is available for only one irrigation, it should be given at late flowering stage when small pods are beginning to appear.
If two applications can be given, the first should be as presowing irrigation for establishing adequate crop stand. A third application where possible, will give the best results if given at the beginning of pod filling.
Water Requirement:
Water requirement for maximum production vary between 450 and 700 mm depending on climate and crop duration. Water use efficiency ranges from 0.4 to 0.7 kg m-3.
Soybean is usually irrigation by check or border irrigation. Sprinker irrigation can minimise the irrigation needs. Furrow irrigation appears to the ideal for soybean. At times of irrigation water scarcity, alternate furrow irrigation can be followed. Soybeans cannot withstand waterlogging even for a short period. As such, furrows can act as surface draining channels at times of heavy rainfall.
10. Weed Management for Soybean:
First 6 to 7 weeks after seeding is the critical period for crop-weed completion. Clean cultivation is, therefore, essential during the critical period.
Cultural Management:
Since soybean is sown in rows, bullock drawn harrows can be used for controlling the weeds. Two intercultivations, first at 20-30 DAS and the second around 45 DAS along with manual weeding can maintain the soybean field weeds free for economic yield.
Use of Herbicides:
A wide range of soil and foliage applied herbicides provides moderate to excellent control of a wide range of weeds infesting soybean crop.
Combination of Trifuralin and Alachlor or Triallate (1.0-1.5) applied PPI is the best for season long weed control. PRE combination of Pendimethalin (0.5-0.75) and Imazethapyr (50-75 g) is also equally effective for weed free environment.
Package of Production Practices:
Soybean is, largely, a rainfed crop during monsoon and post-monsoon seasons. Major package of crop production practices are summarised.
Tillage:
1. Two to three ploughings followed by final harrowing is common practice for medium and light soils.
2. Deep soils are harrowed two to three times followed by final planking.
3. Deep summer ploughing aids in better perennial weed management besides conserving moisture in the subsoil.
Varieties for AP:
1. Pratikar (MAUS 61), Pratap Soya 2 (RKS 1), JS 335, PK 1029, MACS 450, LSB 1, LSB 3, JS 93-05.
Seeds and Seeding:
1. In general, mid-June to first week of July is optimum seeding time for kharif rainfed crop in different states.
2. October is ideal for a post-rainy season crop on stored soil moisture.
3. Common sowing method is dropping the seed in plough furrows. Drilling is recommended if the area to be covered is extensive.
4. Optimum seed rate is 75 kg ha-1 for rainfed crop and 100 kg for an irrigated crop.
5. Spacing varies from 30 x 8 cm in light soils to 60 x 5 cm in heavy soils.
6. Optimum depth of sowing under conditions of adequate soil moisture is 2-3 in heavy soils and 3-4 cm on light soils.
7. Thinning should be completed within three weeks after sowing.
Fertiliser Schedule:
1. Seed treatment with rhizobium culture at 500 g 75 kg-1 seed.
2. Nitrogen, phosphorus and potassium at 20, 40 and 40 kg ha-1 respectively, all at seeding, by placement for a post-rainy season crop on stored soil moisture.
3. For light soils during kharif and for an irrigated crop, half of the N may be applied as top dressing by placement at four-leaf stage of the crop.
Water Management:
1. Flowering and pod development stages are critical stages for soil moisture stress.
2. If water is available for only one irrigation, it should be given at late flowering stage when small pods begin to appear.
3. If available for two, they should be as pre-sowing irrigation and at late flowering.
4. Pre-sowing irrigation followed by one at flowering and another at pod development stage leads to optimum yield.
Weed Management:
1. Critical stage for weed competition is 6 to 7 weeks after sowing.
2. Two intercultivations (25 and 45 DAS) followed by a manual weeding would be optimum under several situations.
3. PPI Fluchloralin, PRE Alachlor, Metolachlor or Imazethapyr can effectively control the weeds.
4. Integrated weed management involving intercultivation and herbicide application would be cost effective if the crop is not subjected to moisture stress during the crop period.
11. Harvesting and Storage of Soybean:
Harvesting and Cleaning:
When all the leaves are dried and shed, the crop is ready for harvest. Dry pods crack when pressed with fingers. The plant is usually uprooted or cut with sickle above ground level and kept in small heaps for a day or two for sun drying. Threshing is usually by beating with sticks or by mechanical meas. Threshed produce is winnowed to separate the seeds.
Storage:
Cleaned seed is sun dried for a day or two to bring the seed moisture content below 14 per cent. Dried seed is stored in moisture proof bags or moisture proof seed bins. For seed purposes, the seed should be stored after treating with Thiram or Captan at 3 g kg-1.
12. Quality Considerations of Soybean:
Soybean is a protein rich oilseed, which is presently number one edible oil source globally. In China, it is recognised as a valuable component of medicine.
Seed Composition:
Soybean has great potential as an exceptionally nutritive and very rich protein food. It can supply the much needed protein to human diets, because it contains above 40 per cent protein of superior quality and all the essential amino acids particularly glycine, tryptophan and lysine, similar to cow’s milk and animal proteins.
Soybean also contains about 20 per cent oil with an important fatty acid, lecithin and Vitamin A and D. The 4 per cent mineral salts of soybeans are fairly rich in phosphorous and calcium. It plays a significant role in preventing and treating chronic diseases such as heart ailments, osteoporosis, cancer, kidney ailments and menopausal syndromes.
Major constituents of soybean are given below:
Oil Content and Quality:
Average oil content of soybean is normally below 20 per cent. Oil content is influenced by temperature. Higher temperature increases the oil content. The oil contains about 88 per cent neutral lipids, 10 per cent phospholipids and 2 per cent glycolipids. Saturated fatty acid content ranges from 11 to 26 per cent. Commercial oil contains 5 to 9 per cent linolenic and 43 to 56 per cent linoleic acids.
Soybean meal is an excellent protein supplement for lactating cattle and calves. Undehulled press cake contains 41 per cent protein while solvent extracted meal contains 44 per cent protein. Soybean contains relatively higher levels of lysine and hence can be used to supplement cereal- based diets.
Soybean contains many antinutritional factors like protease inhibitors, pectins, phytates, polyphytates etc. Some of these may not present a serious problem. A few of them like trypsin inhibitor and haemaglutinins can be deactivated under moist or dry heat treatment.
Utilisation:
On crushing the mature beans, around 18 per cent oil could be obtained, the rest being the oil cake/meal, which forms the prime source of protein in animal feeds. Of late, the commodity is being exploited for manufacturing of various snack foods like edible grade soy meal soya milk, tofu, nuggets, flour, extruded proteins etc.
Major proportion of soybean (about 85%) produce is crushed and biproducts of soybean are derived. These byproducts are traded individually.
In other words, soybean can be used in different forms into the following categories:
Soybean as a whole:
It includes various types of edible forms of soybean like bean sprouts, baked soybean, soybean flour for baking purposes, roasted soybean for confectionary purposes, soy butter, soy coffee and most importantly soy seed. In this category, seeds of soybean are consumed.
Whole soybean products:
Seed; soy flour; soy sauce; soy paneer (tofu) and soymilk.
Soybean protein products:
Textured vegetable protein and isolated soy protein.
Soybean based industrial products:
Printing inks; cosmetics; paints; soaps/detergents/toiletries Soybean food products; and plastics and rubber industry.
Soybean meal:
The remnant after the soybean oil extraction is called soybean meal. It has high protein content and is easily digestible and that is why it serves as a very good fertilizer and as an animal feed. It accounts for about 65% of the world’s total feed.
Soybean meal products:
Animal feed; poultry feed; and feed for aqua culture.
Soy oil:
It is extracted from the basic soybean through complex refining process. This complex process helps in deriving at the soy oil removing the material, which may affect the color and the taste of the oil. It is the second most traded edible oil in the international market after palm oil.
Soybean oil products:
Cooking oil; baking products; margarine; and salad oil.