Cassava, aliased as wood sweet potato and cassava, is one of the three major potato species in the world. Originated from tropical America, it is widely cultivated in the tropics and some sub-tropical regions. It is horizontally distributed between 30 degrees north and south latitude and vertically below 2,000 meters above sea level. The cassava in the world has been cultivated for nearly 5,000 years. It has an area of ​​15 million hectares and annual output of 150 million tons of fresh potatoes. It is one of the seven major crops with an annual output of over 100 million tons and has become a major drought for widespread planting. Grain and feed crops are the main source of heat for everyday food in many countries in the tropics.
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Cassava was introduced into China in the 1820s. It was first cultivated in the Gaozhou area of ​​Guangdong Province and then introduced to Hainan Island. It has now been widely distributed in southern China. The cultivated area is 400,000 hectares across the country. The annual output of fresh potatoes is more than 4 million tons. Guangxi, Guangxi, and Hainan were the most cultivated, followed by Fujian, Yunnan, and southern Hunan, Jiangxi, Sichuan, and Guizhou provinces. Cassava is drought-tolerant and high-yield dryland crops. Its main uses are food, feed, and industrial exploitation.
(I) Consumption: 65% of the total cassava output in the world is used for food, which is the main food crop for low-income rural households in tropical wetlands. Almost all of the cassava in Africa is consumed as food. About 405 in Latin America is processed into various foods and consumed. In addition to Indonesia as a food supplement in Asia, other countries rarely eat, mainly for feed and industrial raw materials or for export.
The leaves of cassava are also edible. The leaves of cassava are rich in protein, vitamin A, vitamin B and vitamin C. Their nutritive price is similar to that of soybean. It is a good vegetable protein and can be eaten as a vegetable because of the solid matter contained therein. It is several times higher than ordinary vegetables and is not as soft as ordinary vegetables when cooked. It is necessary to smash or rub the leaves before cooking, and then serve as a raw material for cooking soup or frying.
In addition, cassava can also produce a variety of foods such as pastries, vermicelli, shrimp slices, and sauces.
(b) Feeding. As a heat energy feed, the thermal energy produced by cassava per unit area is several times higher than that of common cereal crops (Table 1); the cost of each feed unit is lower than that of cereal feed, and its price is 1/3 to 1/2 lower than that of corn. In practical applications, the ratio of meat to meat is 3.7-4.0, which is the same as feeding corn and has good economic benefits.
In recent years, cassava has been widely used in the world as a feed for livestock and poultry. Western European countries have imported cassava instead of corn meal. It is formulated as a cow with soybean meal. Pigs and other livestock and poultry feed. Practice has proved that as long as the amount of cassava in the compound feed and nutrition balance, the carbohydrate content of all livestock and poultry feed can be replaced by cassava meal. Adding 0.2% methionine and glucose to a mixed feed containing 50% cassava meal can further increase the pig's daily gain and food conversion. Under the premise of paying attention to the nutritional balance, the cassava meal can be used to 60% in the piglet's diet; the pig can be used up to 70%; the finishing pigs account for 40-60% of the cassava meal in the diet. Growth and weight gain have no adverse effects. When cassava meal is used as chicken feed, the energy obtained is equivalent to that of corn; when cassava meal is used to replace all the corn in the soybean-maize feed, the egg production rate, egg production, and feed conversion ratio of the chicken are used. No effect.
Cassava leaves are also a good protein feed. In many countries, the use of cassava leaves as a feed is quite common. Cassava leaves are rich in nutrients. Generally, fresh leaves contain 7-9% of crude protein and dry leaves contain 20-30% of protein. Their total amino acid content is 8.4-9.4%. Except for methionine below the critical level, other major amino acids are equivalent. abundant. Carotene minerals and vitamins are also abundant, and the protein content of some of the major pastures is much higher (Table 2). It is a good quality feed.
Table 1 Comparison of powdered and heat energy produced by several crops such as cassava, etc. Crop yield per hectare (tons) Energy per hundred grams (card) Energy per hectare (Mega Cards) Starch content (%) Starch yield per hectare (tons)
Rice 1.12 347 3.89 78.0 0.83
Wheat 1.10 348 3.83 71.0 0.78
Potato 8.68 99 8.58 22.9 1.99
Cassava 17.31 159 37.57 38.7 6.70
Table 2 Comparison of protein content in cassava leaves and several forage grasses (forage) protein (%) crude fiber (%)
Flag Grass 10 27
Kennedy Grass 7 38
Elephant Grass 11 36
Straw flower 14 35
Cassava leaves 23 20
(c) Development and utilization in industry. Cassava is also used for food and feed, and it has important uses in industry. In the fermentation industry, tapioca starch or dried tablets can be used to make alcohol, citric acid, glutamic acid, lysine and cassava protein, etc. Each kilogram of cassava dried tablets can produce 36-37 kilograms of industrial alcohol or produce 30 degrees of drink wine 55- 60 kilograms; 1 ton of citric acid per 2.5-2.8 tons of dried tablets; 1 ton of glutamic acid (monosodium glutamate) produced in 3 tons of tapioca starch; lysine produced by the action of enzymes through the action of cassava starch; , Wash, shred, continuous fermentation, and then vacuum evaporation, can be prepared with protein up to 13-40% of cassava protein. Cassava protein contains all kinds of essential amino acids as long as the addition of calcium and methionine, can become full-price protein, the quality of the equivalent of secondary imports of fish meal, can completely replace imported fish meal. Cassava starch can produce grapes, fructose, etc.; produce sorbitol, mannitol, etc. These products have important uses in beverages, food, feed, seasoning, leather, medicine and papermaking.
Biological learning (1) Organs and functions of cassava (2) Growth and development of cassava (1) Seedling stage. At temperatures above 210C, cassava can be unearthed 7-10 days after planting and 60 days after planting. It is the most prosperous period of young roots in the growing process. In this period, however, the growth of plants is slow, the nutrients required for the early growth of the seedlings, the supply of nutrients for the storage of the main stems, the fresh and robust roots of the stems, and the elongating blocks. The root system is well developed, but the amount of roots is not significantly related to the number of roots.
(2) Root formation period. 60-100 days after planting is the root formation period, of which 70-90 days are the period of potato growth. After 90 days of planting, the number and length of tuberous roots have been basically stable. There are usually 5-9 pieces per plant. At this time, the stems and leaves grow more quickly, the plant height can reach more than 1 meter, and the first apical branching begins to appear. The amount of stems and leaves is about 3-4 times that of the seedling stage.
In addition to the varietal characteristics, the sooner or later the formation of tuberous roots, and the relationship between water and fertilizer and soil environment are also very close. Under the conditions of loose soil, moist and abundant nutrients, the formation of tuberous roots is early and numerous. In the root-forming period, if the soil is hard-edged or severely drought-fed, it will reduce the amount of roots and yield.
(3) Root swelling. The growth process from block stage to pre-harvest production is called the tuber expansion period. At this time, the growth of stems and leaves is very large, and the amount of leaves reaches the highest peak of the whole growth period. After that, the leaves begin to fall off. After October, the root thickening gradually slows down, and in late November, the leaves fall off in large numbers, and the tubers basically stop thickening. .
(4) Mature roots. After 9-10 months of general planting, tuberous roots have fully inflated, the above-ground parts almost stop growing, most of the leaves fall off, and tuberous roots basically stop thickening and contain a large amount of reduction. At this time, the roots mature and can be harvested.
(iii) Requirements for cassava on environmental conditions (1) Temperature: Cassava is high in temperature, frost-resistant, frost-free, and it has a frost-free period of more than 8 months in a year. Areas with an average annual temperature of 180C or more can be cultivated. The minimum temperature for germination of cassava is 14-150C, 18-200C can grow normally, and the optimum temperature is 25-290C. Slow growth at 140C, stop growth below 100C and suffer cold damage. Hainan can cultivate cassava all year round.
(2) Light. Cassava is a short-day tropical crop, hi-positive is not resistant to shade, and it is sensitive to the luminosity and temperature of the light, and sufficient sunlight has an important effect on increasing the yield. Cassava grows in places where there is insufficient sunlight and large shades. The stems and leaves are lengthy, the leaf mats are sparse, the internodes are elongated, the stems are thin and the roots are small, and the leaves are easily detached, resulting in low yield and poor quality. Therefore, intercropping between cassava and forest land is limited to young forest areas, intercropping with other crops, and dwarf leguminous crops should be appropriate.
(3) Rainfall and Humidity: Cassava is widely adaptable to precipitation and can grow in areas between 600-6000 mm. Cassava is a drought-tolerant crop. The annual rainfall of 350-500 mm is also enough for the production of cassava. It is even when the annual rainfall is only 270 mm and evenly distributed, and the soil is moist. Where the annual precipitation is less than 500 mm, the yield is low, the quality is poor, the starch content decreases, and the hydrocyanic acid content increases.
(4) Soil: The adaptability of cassava to the soil is strong, as long as there is no accumulation of water, soil that is not excessively thin or gravel may be cultivated. However, it is well-drained, deep in soil, loose in soil, sandy soil with rich organic matter and potassium, and the soil with poor superficial fertility and susceptible to drought. Although it can grow, it has low yield and poor quality. Soil viscous heavy plate or gravel ground, coarse sand land, etc., unfavorable root elongation, root development, poor quality and quality.
(5) Wind. The breeze facilitates the growth of cassava, but the cassava plant is tall and fears of typhoon. The typhoon often blows the leaves, blows off the branches and stems, shakes the plants, causes lodging, and breaks the roots and rots in the soil, resulting in reduced production.
Major cultivars The vast majority of the cassava varieties cultivated in China are imported from abroad, and a few are selected domestically. The main varieties with large cultivation area and wide distribution are as follows:
(i) China Sculpture 205: Introduced into the Guangdong Province from the Philippines, and later passed through Guangdong to Hainan and Guangxi. With strong adaptability, it has spread all over China's producing areas and is the largest high-yielding species in China. Its main feature is dwarf dense section, few branches, plant height 1.5-2.5 meters, more resistant to wind. Stem brown, leaves 7-9-lobed, lobes narrow, long, linear, petiole red. The potatoes are concentrated, and the chunks are thick and thick, conical, shallow and easy to harvest. Tuber dry matter content 35-40% fresh potato starch content 28-30%, hydrocyanic acid content 7-9 mg / 100 g. Medium-maturing varieties can be harvested 8 months after planting, and cultivated in places with moderate fertility. The per mu produce 2000-3000 kilograms of fresh potatoes, and intensive cultivation can reach 5000 kilograms.
(ii) South China 124: New varieties bred and promoted by the Chinese Academy of Tropical Agricultural Sciences in 1988. Its strong germination power, rapid emergence and growth, good growth potential, resistance to cold, strong adaptability, can be cultivated in all kinds of soil. The main stem has high branches, small angles, dense leaves, and plant type hair. Plant height 1.8-3.0 meters, stem gray green, leaf segments long and narrow, thick and dark green, petiole shallow purple brown potato concentrated and shallow Shengping, potato block hypertrophy, uniform size, long conical. The skin of the potato is thin, light yellow, and the meat is delicate, the dry matter content is 35-40%, the fresh potato starch content is 28-30%, and the hydrocyanic acid is 4-5 mg/100 g. Mid-late-maturing varieties can be harvested 8-9 months after planting, generally yielding 2000-3000 kilograms per mu, and intensively growing over 5,000 kilograms. However, the wind-resistant ability of this species is slightly poor, and it is advisable to choose a sheltered area for planting in the typhoon area.
(3) South China 6068: This variety was identified as the edible high yielding sweet variety in 1980. Its main features are moderate stem height, stem color, yellow-brown, leafy leaves, red petiole, high branch position on the main stem, small branching angle, dense plant type, suitable for close planting and intercropping. Precocious, can be harvested 7-8 months after planting, medium yield, generally 1000-1500 kg per mu, up to 3000 kg. Concentrated potato, shallow raw easy to harvest, large chunks of potato. The skin is brown and the endothelium is red. Root dry matter content of 40-45%, fresh potato starch content of 30-35%, hydrocyanic acid content of 4-5 mg / 100 g. Snow fluffy potato powder, good taste. Grows in a good place where yield and quality are better. However, the wind resistance is poor and should be cultivated in less typhoon areas.
(4) Breaded cassava: Also known as Malay Red, introduced from Malaysia in 1912, it is the earliest food-cultivated variety in China and also the earliest cultivated variety in Hainan. Strong growth, plant height 2-3 meters, stem outer gray brown, dark green endothelium. Leaves broad green, petiole purple. Root tuber dark brown, purple endothelium. Potatoes are more dispersed and deeper into the soil. There are lignified potato stalks in the cylindrical stems of the potato, with more cellulose in the stems of the potato, 30-35% of fresh potato starch, 40-45% dry matter content, and hydrogen cyanide content. 5 mg/100 g or less. Good taste, soft and soft. For early and middle-maturing sweet varieties, 7-8 months after planting can be harvested, but the yield is low, generally about 1000 kg per mu.
(5) South China 102: Also known as glutinous rice cassava, which is imported from Malaysia, and is mainly distributed in the northern part of Hainan Island. It is most cultivated in Dingan. The top branch of the main stem has a larger branch angle and the canopy develops. Stem gray brown, broad leaves, petiole milky yellow, red stalks point. Rooted cylindrical, deeper into the soil, brown skin, rough, light red endothelium. Dry matter content is about 40%, fresh potato starch content is 30-35%, and hydrocyanic acid content is 4-5 mg/100 g. Premature, 6-7 months after planting can be harvested, generally about 1000 kg per mu, suitable for cultivation in areas with higher latitude.
(6) South China 201: Also known as Nanyang Cassava or Zhongguan Hongwei. Introduced from Malaysia in 1935, it is the main species of cultivated area in China's production areas after South China 205. Its plants are tall and vigorous, with large leaves and purple-red petioles. The potato was shallow and easy to harvest. The potato grew up and was spindle-shaped. The epidermis was brownish and the endothelium pink. Dry matter content of about 37%, fresh potato starch content of 25-30%, hydrocyanic acid content of 9-14 mg / 100 g, is a late-maturing high-yield species, can be harvested 9 months after planting, generally 1500-2000 kg per mu.
(7) South China 8002: It is a new high-yield cultivar cultivated by the Chinese Academy of Tropical Agricultural Sciences in 1994. It has the characteristics of high germination rate, rapid emergence, regular growth, and strong growth. Plant height 1.5-2.5 meters, apical branching late, high branches, branches short and compact, suitable for close planting and intercropping. The stem has moderate thickness, dense leaves, and long leaf life. Drought-tolerant and cold, wide adaptability. The potatoes are concentrated and the chunks are thick, uniform in size, and shallow and easy to harvest. Medium cooked. 8 months after planting can be harvested, generally reserve 2000-3000 kilograms, tuber dry matter content 37-40%, fresh starch content 28-30%, hydrocyanic acid content 4-6 mg/100 g, for feeding and industrial The use of fine varieties.
(8) South China 8013: This is a new high-yield variety cultivated by the Chinese Academy of Tropical Agricultural Sciences in 1994. The stems are resistant to storage for winter, with fast emergence, neat growth, moderate apical branching, short and concentrated branches, compact plant type, and hard stems. The leaves are large, the leaves are dense, and the potatoes are surrounded. The tubers are large and uniform in size. The root dry matter content of the tuber is about 40%, the fresh potato starch content is 28-32%, and the hydrocyanic acid content is 3-4 mg/100 g. Precocious, 7-8 months after planting can be harvested, generally between 2000-3000 kg per mu.
Cultivation techniques (1) The selection and cultivation of cassava are highly adaptable and require less stringent soil conditions. As long as there is not too much barren and gravel, land that cannot accumulate water can be used. It should be cultivated in areas that are often hit by typhoons. Choose areas sheltered from winds or protected by forest sections.
Land preparation should be carried out according to different terrains. In the mountainous areas of forests, water and soil conservation must be taken care of when the land is drowned. For mountainous areas of more than 15 degrees, it is best to open terraces or planting heights so as to avoid steep slope cultivation on overly steep slopes. . Sloping grasslands should be fully ploughed before 2-3 months before planting, with hoeing or no-tillage, etc. Slight slopes below 10 degrees can be used for ploughing; hilly areas, small plots, uneven, available plough Plowing or no-tillage or open-air hill cultivation; slopes in the slopes above 20 degrees, not opening the mountain line should not be planted cassava, otherwise it will cause severe soil brush, not worth the candle.
(II) Seed stems of planting materials are fresh and have bright color. See milk for cutting off the incisions. These stems have many nutrients, strong viability, and high germination rate, which is good for seedlings after planting to ensure yield. Therefore, we must choose full maturity, thick and dense knots, pith full and rich in water, buds complete, does not damage the skin buds, no pests and main stems as seedlings. Not fully mature, slender stems, sparse leaf segments, hollow pith, damaged or budded shoots, low germination rate after planting, slow emergence, thin seedlings, fewer tubers, low yield, generally not suitable for planting seedling.
(iii) Planting methods The planting methods of cassava are flat, oblique and straight. It can be placed on a flat surface around a potato, and it is shallow and easy to harvest. However, it is buried in soil and has poor permeability. It is difficult to sprout and unearth, and it is easy to cause shortage of plants. Wind resistance is also poor. Plug-in seedlings quickly, high emergence rate, can ensure the whole seedlings, potato block stretched toward one side, convenient harvest but wind resistance is also poor. The seedlings are inserted straight forward and neatly, the potato is deeper into the soil, and the drought-resistance and wind-resistance performance are better. However, the size of the potato block is not uniform, and the planting time is more, the harvest is more difficult, and the large-area production is less used.
Cut the stems with a knife during planting. The length of the cuttings should be 15-20 cm. Place them flat or obliquely in the hole and cover the soil. The density depends on the soil fertility, and the soil fertility is more sparse, and vice versa. Generally, 800-1000 mu plants are suitable, and the densest plants should not exceed 1600 plants. The planting distance is mostly 10.8 (m) and 0.80.8 (m).
(iv) Field management of cassava
1, make up the seedlings. After cassava is planted, the seedlings are often stored for too long, the water loss is too much, the stems are young and slender, or the cuttings are too short, or the plants are short of dry weather, excessive rain, excessive humidity, etc. Miao must be promptly filled, usually within 20 days after planting and completed within 30 days.
2, seedlings. After cassava is planted, usually there are 2-4 or more sprouts unearthed. If they live naturally, there will be multiple main stems per hole, which will cause shading and consumption of nutrients. Generally the seedlings will be high after the seedlings are raised. When carried out at 20 cm, 1-2 seedlings per hole are suitable.
3, weeding weeding. The roots of cassava need to have loose soil, and well-ventilated topsoil can develop well. Therefore, cultivating and weeding within three months after planting is a key period for promoting root growth and increasing yield per plant. 30-40 days after planting, when the seedling height is 15-20 centimeters, the first cultivating and weeding can be carried out to promote seedling growth. A second cultivator weeding can be performed 60-70 days after planting. 90-100 days after planting, if necessary, a third cultivator can be used to loosen the soil. At this time, the number of tuberous roots has basically stabilized and begins to expand. It should be combined with loose soil to apply strong potato fertilizer. The roots of cassava are superficial, and both deep-rooted and thick-cultivated soils are unfavorable for the expansion of roots. Soil compaction places are generally not soil-cultivated, and soil-poor places and landowners who are often attacked by typhoons can be used to cultivate soil.
4, fertilization. Among various nutrients, cassava has the highest requirements for nitrogen and potassium, followed by phosphorus, calcium, and magnesium. The production of 1 ton of tuberous roots absorbs about 2.3 kg of nitrogen, 4.1 kg of potassium, 0.5 kg of phosphorus, 0.6 kg of calcium and 0.3 kg of magnesium, and N:P:K=5:1:8. The 1500 kilograms per hectare of roots need to absorb 3.5 kg of nitrogen, 0.75 kg of phosphorus and 6.2 kg of potassium from the soil. If the stems and leaves do not return to the field, the amount of N, P, and K consumed per mu will increase to 7.4 kg and 1.6 kg, respectively. And 8.1 kg, but about 50% of these nutrients will be recovered again throughout the growth cycle. Therefore, it is necessary to maintain 1,500 kilograms per year in the past, and it is unclear to reduce land fertility. At least 17 kg of ammonium sulfate, 5 kg of superphosphate, and 18 kg of potassium chloride should be added per mu. Although cassava absorbs large amounts of nutrients from the soil. However, from the point of view of the nutrients absorbed by the production of one ton of dry matter, the absorption of other nutrients except potassium and calcium is much less than that of many crops. The production of one ton of dried cassava chips absorbs 6 kg of nitrogen and 1 kg of phosphorus. Other crops are 1-2 or even several times less (Table 3). Some people think that planting cassava will lead to poor soil fertility, and it turns out that cassava is not a depleted soil crop, but it is the result of people's attention to fertilization management and predatory production. In recent years, this crop has been evaluated fairly.
Table 3 Nutrients absorbed by 1 ton of dry matter produced by different crops Comparison of nutrients absorbed by a ton of dry matter produced by crops (kg)
NPK Ca Mg
Cassava 6 1 11 1.6 0.6
Soybean 21 5 6 0.9 1.4
Corn 15 3 6 0.5 1.7
Potato 10 2 22 0.8 1.3
Rice 13 3 4 0.4 1.6
Sorghum 20 4 4 0.5 1.9
Wheat 18 4 6 0.6 1.8
Cassava fertilization period and method is determined according to its growth cycle, climate characteristics, soil fertility, fertilizer type and economic factors, the principle is to apply base fertilizer, reasonable fertilizer, N, R, K with the application. Under normal circumstances, the ratio of application of the three elements is preferably N:P:K=5:1:5. In production, due to the interaction between the growth of cassava and the soil and climate, especially in places with high temperature, heavy rain and leaching, one application of fertilizer is often difficult to ensure the needs of its full growth period. Therefore, in practice, General topdressing 2-3 times, divided into strong seedling fertilizer, potato fertilizer and potato application. The strong seedling fertilizer is dominated by nitrogen, which is applied within 30-40 days after planting. The combined potato fertilizer is mainly potassium and suitable for nitrogen fertilizer. It can be applied 60-90 days after planting to promote the formation of tuberous roots and ensure the number of single plants. If the soil is barren, it is best to apply a strong potato fertilizer once. Applying it 90-120 days after planting can promote root swelling and starch accumulation.
How to apply reasonable fertilization, in recent years, people conducted soil and plant nutrient diagnostic fertilization studies and pointed out that when the potassium content in the inner layer of the tapioca plug is lower than 0. 7% or the soil's displaceable potassium is lower than 0.6%, it should be Mushi 6. 0-6. 5 kg of potassium fertilizer. In the 3-4 month old cassava fully unfolded young leaves containing less than 4.7%, P less than 0.3%, K less than 6. 05, that is, nutrient deficiency, timely fertilization.
Disease and Insect Pest Control In China, cassava has fewer pests and diseases, and the damage is lighter, with no serious impact on yield. The most common diseases and pests in China are the following:
1. Cassava bacterial fusarium wilt, which is one of the most serious diseases of the cassava, initially threatens the fully developed mature leaves, and then gradually spreads from bottom to top. In the event of damage, the leaf margin or tip of the leaf is impregnated, resulting in spotting of water-stained lesions and rapid enlargement. The lesions often spill out of yellow latex, and then the leaves wilted and fell off. In severe cases, the shoots withered and even the whole plant died. The disease can cause more than 50% yield loss, Guangxi, Hainan and Guangdong have occurred, but no serious epidemic.
2, bacterial leaf spot disease. China has already taken place in Guangxi and Hainan. It is generally popular in May and is more serious from August to September. The main feature is the occurrence of water-stained spots, scattered in all parts of the leaves, visible yellow latex emulsion, which began to immerse when the edge of the yellow-half-like, and then expand the joint into a dark brown, causing the leaves to become yellow pages fall off.
3, brown angular spot disease. In our country, there were irregular brown spots on both sides of the leaves at the time of onset. The boundary of the lesions was obvious and green, and the leaves turned yellow and dried off. It usually occurs in high temperatures and rainy seasons, but it does not affect production.
The cassava varieties that are not immune to the above diseases and effective methods for the control of pesticides can only be controlled through the use of disease-free stems, and the selection of disease-resistant varieties.
4, cassava red clams. In China, it generally occurs on the back of the leaves. It first harms the lower mature leaves, sucks sap along the veins, and leaves the leaves with yellow spots. Afterwards, it damages the upper leaves from the bottom up. In severe cases, the collecting leaves are damaged on both sides. Due to the large number of insects, the last Spots turn red or rusty, causing leaves to fall off. Plants can die in long-term drought conditions. In the rainy season, most parasites are washed away by rain and the damage is reduced.
The prevention and control method is to breed anti-fungus cultivars, use natural enemies such as meat to eat crickets, and also use miticides to kill and control.
Harvesting of cassava (a) Harvesting. Cassava tuber genus vegetative body, there is no obvious maturation period in physiological characteristics, the maturity period in production refers to the period in which tuber yield and starch content reach the highest value in a year. Most of the cassava in China is spring planting, and the harvesting period is mostly from November of that year to February of the following year. During this period, both the dry potato rate and the starch content can maintain the economic indicators of commodity production.
Harvesting is one of the most labor-intensive tasks in cassava cultivation. In general, small-scale production is mostly harvested by hand, and the available animal power from plowing is used to plow the soil for harvesting. Large-area cultivation can be harvested mechanically by cutting off the stems first, and then installing a plowshare without tractors on the tractor so that it can plow the loose soil and flip the roots, and then pick it up manually. Harvest 4-5 acres.
(b) Processing. The cassava roots are not resistant to storage, and they are spoiled and deteriorated 3-7 days after harvest, and must be processed in time. The primary processing is mainly the dry drying of slices and the extraction of starch by pressing. The production of starch has manual processing, semi-mechanical processing and mechanical processing. A small amount of production is commonly used manual processing and semi-mechanical processing. The procedure is: scraping the skin, smashing, sieving, precipitation and drying. Large-scale production requires large-scale machinery for industrial production, and domestic old-style factories mostly adopt hammer-type smashing, sifting and sieving, and flow-tank precipitation. The process flow is: raw material-cleaning-smashing-bubble immersion-screening-neutralization-one Grade precipitation - bleaching - secondary precipitation - centrifugal dewatering - dry packaging. This process is relatively backward, the starch recovery rate is low, only 60-65%, has been replaced by the modern generation of processing technology, using all the matching flow, multi-stage starch extractor and high-speed centrifuge instead of the flow tank sedimentation and starch refining, no need The intermediate storage tank reduces the processing time from a few hours or even several days to only a few minutes, and the commodity recovery rate of starch is more than 90%, which has very good economic benefits. The process flow is: raw material-cleaning-smashing-fine Sieve - sand removal filter - starch refining - dehydration - drying package.
The use of cassava starch in the fermentation, sugar and chemical industries for deep processing, can produce citric acid, glutamic acid, lysine, cassava protein, production of glucose, fructose, sorbitol, mannitol and other fine chemical products, not less than one hundred varieties Species. Its economic benefits can be increased by several times or even more than ten times, which has a very important role in improving cassava output value and promoting cassava production and development.
2, according to Agricultural Product Quality Safety provisions of Article II of
agricultural products is the primary products from agriculture, that is
obtained in the agricultural activities of plants, animals, microorganisms and
their products.