2. By the end of 20 15, the promotion area of konjac in Gaocheng, Pingshan, Lingshou, Nangong, Julu and Luquan in Hebei Province was about 3,000 mu, and the commercial konjac sold more than 20 tons. Since 1995, researchers have successfully introduced konjac into Hebei. Through tackling key problems, researchers have achieved rapid propagation of excellent tissue culture seedlings of Amorphophallus konjac and rapid growth of miniature taro, systematically studied Amorphophallus konjac from micro to macro, and obtained six national invention patents, including "liquid tissue culture breeding method of Amorphophallus konjac and intercropping method of Amorphophallus konjac with tall plants in the north", which provided theoretical basis and technical approaches for large-scale planting of Amorphophallus konjac across the Yangtze River and the Yellow River.
Supplementary explanation:
First, the environmental requirements of konjac growth
1, temperature. The initial temperature of konjac growth is 5℃, the highest temperature is 43℃, and the optimum temperature is 20-25℃. When the temperature is too low, the effective growth time of Amorphophallus konjac is short, the annual weight gain multiple is low, and the tuber may suffer from freezing injury. When the temperature is too high, the leaves of Amorphophallus konjac are easy to be burned, which aggravates the disease of Amorphophallus konjac and even directly leads to the death of Amorphophallus konjac plants. Therefore, Amorphophallus konjac is not suitable for large-scale cultivation in low-altitude areas with high temperature, nor for development in high-altitude areas with extremely cold climate and insufficient annual effective accumulated temperature. It should be noted that the soil temperature (ground temperature) also has a great influence on the growth of konjac, especially in low mountainous areas. Too high ground temperature often leads to poor growth and even a large number of deaths of konjac.
2. Lighting. Amorphophallus konjac is a semi-negative crop with a low light saturation point of 20,000 ~ 23,000 lux, which is only half of that of light-loving crops (such as rice). Too strong light will not only help to improve the yield of konjac, but may cause the leaves of konjac to burn. Especially in the low mountainous areas, the intense light in summer will be converted into heat energy, which will cause the temperature of the environment (including soil) to rise sharply, and konjac plants (including roots) exposed to the intense light will be more vulnerable, resulting in decreased resistance and easy infection by bacteria. This is an important reason why planting konjac in low mountainous areas is easy to get sick and difficult to succeed. The light is too weak. Although the disease of Amorphophallus konjac is mild, its photosynthesis is weak and its dry matter accumulation is small, so it is difficult to obtain high yield.
3. Moisture. The root system of Amorphophallus konjac is shallow and the aeration tissue in the root is underdeveloped. Therefore, konjac is wet and afraid of waterlogging, and it is not dry or waterlogged. It needs a soil environment with good moisture, ventilation and water conservation, and the most suitable soil water content is 75% of the maximum soil water capacity. Too high soil water content affects root respiration, which is easy to induce konjac diseases and even lead to the death of the whole plant. Too low soil water content will easily lead to the root death of Amorphophallus konjac, which will lead to the yellowing of leaves and the atrophy of petioles. Severe drought will also aggravate the root rot of Amorphophallus konjac, leading to early seedling setting in autumn and shortened effective growth time. This is common in low mountainous areas with large evaporation, little rainfall and lack of drought-resistant conditions, and it is another important reason for the failure of planting konjac in low altitude areas.
4. soil. Amorphophallus konjac has shallow root system distribution and weak absorption ability, but high yield requires a large amount of fertilization, and requires a soil environment with high organic matter content, strong fertilizer conservation ability, fertility, looseness, air permeability and slightly acidic to slightly alkaline PH value (pH 6.5-7.5). The annual average temperature in mountainous areas is low, and the decomposition of organic matter in soil is slow. In addition, limited by traffic conditions, the application amount of chemical fertilizer is relatively small, and more farm manure such as ring fertilizer is applied, so the soil has high organic matter content, and the soil is loose and breathable, which is suitable for konjac growth. Most of the cultivated land in the low mountains has low organic matter content, and some cultivated land has strong acidity, relatively hardened soil and poor air permeability. The cultivated Amorphophallus konjac is poor in growth, easy to get sick and difficult to obtain high yield.
5. stubble. Konjac is the most taboo for continuous cropping. After planting konjac in the same cultivated land for 2-3 years, the disease will be obviously aggravated and the yield will drop sharply. Therefore, the cultivation of konjac must be replaced by crop rotation, and it is best to implement paddy-upland crop rotation. Among the previous crops planted with konjac, the newly reclaimed land is the best, followed by the plots planted with gramineous crops such as corn and wheat. When Amorphophallus konjac is planted in plots where solanaceae crops such as potatoes and tobacco leaves have been planted (including solanaceae vegetables such as peppers and tomatoes), the bacterial blight is serious, so this kind of crops can neither be used as the previous crops of Amorphophallus konjac nor intercropped with Amorphophallus konjac.
Second, choose or create an environment suitable for konjac growth.
In order to obtain high yield and high efficiency, it is best to choose suitable environment for planting konjac. If the environment is not suitable, try to create an environment suitable for konjac growth. According to the environmental requirements of konjac growth, the following measures can be taken in mountainous areas:
1, and the planting area is concentrated in higher altitude areas. Investigation shows that although Amorphophallus konjac can grow in low altitude areas, it is only scattered in front of farmers' houses or on the edge of forest land because of the inadaptability to the environment, so it is difficult to get twice the result with half the effort in field planting. The large-scale planting and development of konjac should focus on the two high mountains and one high mountain area with suitable environment. The suitable altitude range for planting konjac in the mountainous area of northwest Hubei is 800- 1500m, among which 1000- 1200m is the best, which has abundant rainfall, dense vegetation, moderate temperature, high humidity, loose soil, rich soil quality and more scattered light.
2. Choose suitable plots and stick to rotation. According to the requirements of konjac growth on soil, sandy soil and yellow brown soil with high organic matter content, loose and fertile soil and slightly acidic to alkaline pH value were selected as plots for planting konjac in suitable areas. Before planting, sufficient farmyard manure should be applied, and more than 4,000 kilograms of decomposed circle manure or soil miscellaneous manure and burnt soil should be applied per mu. Then, the kang ridge should be deeply ploughed, fertilized and ripened. When planting, ditch, middle ditch and enclosure ditch should be made according to the topography and groundwater level to prevent waterlogging in the field and lay a good foundation for high yield of konjac. In addition, it is necessary to make a long-term plan for the whole area or plot, and prepare the plot for planting konjac. Potatoes, tobacco leaves or other solanaceae crops cannot be planted. At the same time, pay attention to crop rotation and avoid multiple cropping as much as possible.
3. The mountain is pure, and the plastic film is applied. In the mountainous area of northwest Hubei, the high yield of Amorphophallus konjac is mainly limited by the good vegetation in the alpine region above 1000 meters above sea level, abundant rain and fog in summer, little threat of strong light, insufficient annual effective accumulated temperature and short growth time. Therefore, in order to improve the yield of Amorphophallus konjac planted in high mountains, it is necessary to give priority to pure varieties and reduce shading. If interplanting with corn, the planting density of corn should be reduced, and a row of corn should be planted every 2 meters, and 800- 1000 corn plants can be planted per mu. The second is to implement plastic film mulching to increase soil temperature and prolong the growth time of konjac. In addition, plastic film mulching can also play a comprehensive role in inhibiting weeds, balancing soil moisture, loosening soil, accelerating fertilizer decomposition and reducing fertilizer loss, and the yield increase effect is very significant.
4, low mountains must be interplanted, paying special attention to shading and cooling. In order to plant Amorphophallus konjac in low mountainous areas, we must improve the planting environment besides choosing suitable plots and insisting on rotation. The specific measures are as follows: first, interplanting with economic trees such as Eucommia ulmoides and other crops, or interplanting with tall crops such as corn, so that konjac can get the "flowering sun" in summer, avoiding direct sunlight and reducing the light intensity and environmental temperature; 2. Ground covering, preferably interplanting konjac and sweet potato, covering the ground where konjac is planted with sweet potato stems and vines, or directly covering the ground where konjac is planted with grass, so that the soil temperature can be reduced in summer and the soil moisture can be maintained; The third is drought and waterlogging prevention. During the growth of Amorphophallus konjac, water should be used to fight drought and keep the soil moist, but it should not be flooded. At the same time, it is necessary to clear and dredge the "three ditches" in the rainy season to prevent waterlogging in the field.