Morphological characteristics:
Erect shrub, 1.5-3m high; The root is cylindrical. The leaves are papery, nearly round,10-20cm long, palmately parted to near the base, with 3-7 lobes, oblanceolate to narrowly elliptic, 8-18cm long and1.5-4cm wide, with tapering tip and (5-) 7 lateral veins. Petiole is 8-22 cm long, slightly peltate, and the edge is not obvious; Stipules triangular-lanceolate, 5-7 mm long, entire or with 1-2 setose fine cracks.
Panicle terminal or axillary, 5-8 cm long, bracts strip-lanceolate; Calyx purple-red, with white cream; Male flowers: calyx is about 7 mm long, lobes are oval, about the same size, 3-4 mm long and 2.5 mm wide, with hairs on the inner surface; Stamens are 6-7 mm long, with white short hairs at the top of anthers; Female flower: the calyx is about 10 mm long, and the lobes are oblong-lanceolate, about 8 mm long and 3 mm wide; The ovary is ovoid with six longitudinal spindles, and the stigma is bent outward and folded into a fan shape.
The capsule is ovoid, with a length of 1.5- 1.8 cm and a diameter of 1- 1.5 cm, with a rough surface and six long, narrow and wavy longitudinal wings. The seed is about 1 cm long, slightly trigonous, with hard shell, stripes and smoothness. Flowering: September-165438+1October.
Geographical distribution:
Originally from Brazil, it is widely planted in tropical areas all over the world. China's Fujian, Taiwan Province, Guangdong, Hainan, Guangxi, Guizhou, Yunnan and other provinces are cultivated, and occasionally there are wild (initially artificially introduced and cultivated, and gradually naturally propagated in the wild). ?
China introduced cultivation in the 1920s of 19, and now Guangdong Province and Guangxi Zhuang Autonomous Region have the largest cultivation area. In the long-term production and development process, cassava gradually merged with the food culture in South China, forming many traditional Hakka cassava snacks with cultural connotations.
Cultivation techniques:
Origin environment
Edible cassava generally needs to be planted in the frost-free period of about 8 months and the annual average temperature is above 18℃. The production environment of pollution-free cultivation of edible cassava should meet the requirements of DB45/T4 10. ?
Land selection and land preparation
The well-drained flat land or sandy soil with gentle slope should be selected for planting. If the cultivated land is cultivated land, it needs two or three years of rotation, and the crops of rotation are peanuts, corn, soybeans and mung beans. Soil preparation should be carried out about 1 month before planting. Generally, two plows and two rakes are used, and the depth of cultivated land should be 30-40cm to make the soil smooth and loose. ?
Variety selection
Varieties with low hydrocyanic acid content (below 100mg/kg), high yield, strong resistance to pests and diseases and stress should be selected. There are mainly local bread cassava, South China No.9, South China 6068, South China 12 and GR89 1 and other edible cassava varieties in China.
plant
The suitable planting time of cassava in China is from February to April. It is advisable to choose a mature and full main stem with a stem diameter of 2-4 cm, dense nodes, no damage to stem skin and bud eyes, and no pests and diseases. Remove the upper part of each seed stem, keep the middle and lower seed stems, and cut into 15-20cm length. There are four planting methods: flat planting, oblique planting, direct planting and flat planting. It is best to use flat planting with ridged plastic film or flat planting with ridged open field to unify the direction of bud eyes. The row spacing of seed plants is 0.8m× 0.8m or 1 m× 0.8m. ..
Tiantuan management
Replanting and thinning
25 days after planting, check the seedlings on cloudy or light rain days; Thinning should be carried out 35 days after planting, and it is appropriate to leave 1-2 strong seedlings per plant. ?
Water and fertilizer management
Cassava is drought-tolerant, and field water management should be timely and properly watered according to seedling conditions and weather. To avoid flooding, drip irrigation is the best way to water. The soil can be kept moist and dry, and it should be drained in time in rainy season. Fertilization must be scientific and reasonable, with organic fertilizer as the main factor, and the amount of chemical fertilizer, especially nitrogen fertilizer, should be controlled. Popularize the application of compost, compost and green manure. And prohibit the use of municipal waste fertilizer. Fertilization should meet the requirements of NY/T394. Fertilization is divided into base fertilizer and topdressing twice. When preparing soil, apply 1.5 million kg/hm2 organic fertilizer as base fertilizer; After planting 1 month, topdressing 300kg/hm2 compound fertilizer after rainy days.
Prevention and control of diseases, pests and weeds
There are few diseases and insect pests of cassava in China, and the prevention and control of diseases, insect pests and weeds must be based on the principle of prevention and comprehensive management, focusing on agricultural control, and it is forbidden to use pesticides and mixed preparations prohibited by the state. When there is no large-scale occurrence of pests and diseases, the diseased plants should be manually pulled out and destroyed in time; Secondly, we can create ecological conditions that are not conducive to the occurrence of pests and diseases, but are beneficial to or not hinder the growth of cassava by weeding, ridging and other measures. If the occurrence area of pests and diseases is large, it is necessary to choose pesticide varieties with high efficiency, low toxicity and low residue for prevention and control. It is suggested that manual, mechanical and cultivation techniques should be used to control cassava weeds, such as plastic film mulching weeding technology, intertillage fertilization and soil improvement technology, interplanting and so on.
harvest
Edible cassava seed stem materials should be harvested in time before frost comes. The harvest period of edible cassava is generally 1 1 to March of the following year, and the annual harvest can also be realized through cultivation techniques. When harvesting root tuber, try not to damage the root tuber, so as not to affect the shelf life.
nutritional ingredient
Chemical composition and nutritional value of cassava tubers, stems and leaves: For a long time, people mainly used the potato meat of cassava tubers, but a large number of cassava peels and cassava stems and leaves were discarded. In recent years, with the further research on the chemical constituents of cassava stems and leaves and potato skins by scholars at home and abroad, it is found that cassava stems and leaves also contain protein, amino acids, vitamins, sugars and other compounds.