Project Topic On DEVELOPMENT AND PERFORMANCE EVALUATION OF AN IMPROVED SOYBEAN THRESHER.
1.0 INTRODUCTION
Soybean (Glycine max (L) men), is a herbaceous annual legume that is usually erect,bushy and rather leafy. Cultivars range from 45-120 cm in height with growth period of 75-150 days and mostly have a main stem that branches from the lower nodes (Smith and Huyser, 1987).The extend of branching depends on environmental conditions (light and available moisture). The stems, leaves and pods are covered with fine towny or grey pubescence. The pods are small, straight or slightly curved and range in colour from light straw to nearly black. The pods contain one or four seeds round to elliptical in shape. Popular commercial cultivars have straw yellow seeds, but cultivars with greenish yellow, brown or black seeds are also found. Soybean is one of the world’s most important food crops having superior amino acid profile compared to other sources of plant protein. It provide about 64 percent of the world’s oil seed meal supply and is a major source of oil, accounting for about 29 percent of total world production (Smith and Huyser, 1987). It contains about 40-41% protein and 20.5-21.5 % oil. Soybean is processed to separate the oil from the protein meal which is incorporated into the animal and poultry feeds. It is known to have been grown in China and Japan for thousands of years.
It is referred to the “meat of the world” because it is the cheapest source of protein and oil. Soybean combines in one corm both the dominant world supply of edible vegetable oil, and the dominant supply of high-protein feed supplements for livestock. Soybean seeds have a wider range of economic importance. It ranges from industrial, food, pharmaceutical and agricultural products (Smith and Huyser, 1987). Worldwide soybean production amounts to around 130 million tonnes per year utilizing around 60 million hectares.(F.A.O, 1980). If processed and used domestically soybean could become as economically attractive in Nigeria as in other parts of the world. Soybean can be the most practical means of relief from kwashiorkor (protein-calorie malnutrition) which is on the increasing prevalence among young African children. Other means of protein like wild animals and fish have disappeared due to indiscriminate hunting and fishing and has become very expensive for an average African family, hence the introduction of soybean crop in west and central African countries being encouraging (Ayagi, 1994).
It can also be processed into a wide range of products for human consumption and utilization, which include oil for making margarine, as cooking oil, salad oils, synthetic gums, soaps and paints. It is also used in making soy flour used for bread, biscuits etc. Whole seeds can be soaked overnight and cooked as bean or for dawadawa (a Northern Nigerian food sweating spice). Other products are soybean milk, soy-source, soybean curd and bean spouts (Marina, 1991). Soybeans are packed with important nutrients including calcium, magnesium and many B-complex vitamins.(Marina, 1991). From investigations it has shown that from 100 g of soymilk, you can get 2.8-3.4 g of protein, 1.5 g lipids, 12-24 mg of calcium, 36-49 mg phosphorus, 50 mg potassium, 15 mg of sodium, 0.02-0.05 mg iron (Marina, 1991). It is also comparable to cow milk for amino acids and vitamin B. In view of this several African countries are embarking upon the commercial production of soymilk as a substitute for cow milk (Marina, 1991). Soybean production represent an important source of foreign currency especially in countries like Brazil and Argentina (Duque,1999).
In Argentina more than 50 percent of the export currency is generated from soybean complex, while in Brazil the soybean complex generates yearly US $24.5 billion in income and earning about US $ 5.7 billion in foreign exchange ( Duque, 1999). In some developing countries such as Nigeria, especially in the rural areas soybean represent the best protein source available for improving the nutritional value of traditional food. The crop has revolutionized the rural economy by raising the living standard of soybean farmers, especially the women and children.
Table 1; Estimated soybean production in major producing countries and regions as at 1980.
S/N Country Region Total Land Area
(1,000 ha) Production
(1,000 MT) Yield Kg/ha
1 World 52,639 83,481 1,586
2 N/C America 57,929 50,468 1,809
3 U. S. A 27,460 49,454 1,801
4 South America 11,256 19,552 1,737
5 Brazil 8,766 15,153 1,728
6 Asia 11,662 11,964 1,026
7 Africa 327 310 946
8 China 9621 F 10,0267 1,046
9 Nigeria 197 F 77 F 388
Source :(F.A.O. 1980)
In Nigeria, improvement in production of soybean can only be possible when relevant machinery and equipments are developed for post harvest processing to encourage small-scale farmers (Ayagi, 1994).
Soybean is a warm season crop and its climatic requirements are about the same as those of maize. For germination and early plant development there is the need for a moderate moisture supply. The period of germination is the most critical stage and an excess or
deficiency of soil moisture at this time could be harmful. Soil temperature of 15oC or more favour rapid germination and vigorous seedling growth which is essential for successful competition with weeds. Growing temperature of 20oC to 25oC appear to be optimum.
Soybean produced in higher temperatures (about 32oC) tend to be low in oil quantity and quality (Marina, 1991). Soybean plants are very sensitive to light duration (photo-period) they are short day plants. Soybean can be grown on a wide range of soil types, but thrive best on sandy or dry loams and alluvial soils of good fertility. The optimum soil PH ranges from 6.0- 6.5(Marina, 1991).
1.1 Cultivation, Harvesting and Threshing
Land preparation for soybean is similar to that for maize, the land is ploughed and harrowed. Seeds are sown at a seed rate of 50-75 kg/ha depending on the plant population required (Hoki and Esmay,1979). The sowing depth for soybeans ranges from 2.5-5.0 cm.
When soybeans are grown for seed, harvesting is done before the pods shatter. The best stage is when the pods are fully mature with the seeds in the hand-dough state. The seeds should have moisture content of less than 15 %. In non-shattering cultivars, harvesting is delayed until the crop is fully dried.
The plants are either cut at ground level or pulled out of the ground. In the developed countries, most soybean crops are harvested with combines. They are dried for some days and then threshed. The seeds should be stored at a moisture content of 10-20% or less
1.1.1 Varieties of soybean.
Soybean is of so many varieties worldwide. Among the varieties found in the United States of America includes Amsay, Corsoy, Harosoy, Lee and Clark. All these varieties are of similar botanical characteristics and are adaptable to only the climatic conditions around the United States of America.
In 1984 due to lack of adaptable soybean varieties in Nigeria and also due to the poor agronomic attributes of the only popular variety “Malaya”. In the limited era where it is adapted, the Nigerian scientist developed high yielding varieties through National Coordinated Research Project on Soybean. (NCRPS, 1988).
Among the varieties developed includes samsoy-I samsoy- 2, TGX 536-020, TGM 344, TGX 814-270, TGX 855-610.(NCRPS,1988). These varieties were found to be very adaptable
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