Growth and development of radish.
The growth and development process of radish can be divided into vegetative growth period, seedling period and fleshy root growth period.
(1) vegetative growth period
Germination period: the germination period is from seed germination to two cotyledons unfolding. Depending on the nutrients stored in the seeds, they germinate and the cotyledons are unearthed. Sufficient moisture and suitable temperature are needed. It takes about 3-4 days to plant in high mountains.
Seedling stage: the seedling stage is the time when the first true leaf of the seedling is unfolded and the belly is broken. Large and medium-sized radishes usually have true leaves for 4-7 days. High temperature and strong light are needed for the seedlings to fully develop. This cycle takes about 15 days. Because the true roots keep growing, the external primary cortex can't grow and expand correspondingly, and the primary cortex breaks, which is called "broken belly", and the growth of fleshy roots will accelerate in the future. During this period, it is necessary to prevent the seedlings from being crowded and overgrown, and to interplant and fix seedlings in time. Sow 1 seed per hole in plastic film mulching cultivation, without thinning seedlings, but cultivate the soil.
Carnivorous root growth period: from fleshy root fracture to harvest. At this stage, the fleshy root grows again, and the intercellular space is also increasing, forming lateral growth, so the fleshy root gradually thickens from slender shape at seedling stage, showing variety characteristics. The growth situation in this period is different, which can be divided into vigorous growth period of leaves and vigorous growth period of fleshy roots.
(2) Reproductive growth period
Radish is a biennial vegetable, which goes through vernalization at low temperature in winter and sunshine at long sunshine in the following spring. After each stage of plant development, flower bud differentiation, bolting, budding, flowering and fruiting, their life cycle is completed. Generally, it takes 20-30 days, and the flowering period varies greatly, generally about 30 days, up to 40 days at the longest, and it takes about 30 days until the seeds mature. From bolting to flowering, nutrients produced by assimilation organs and nutrients stored by fleshy roots are transported to flowering moss for bolting, flowering and fruiting. After bolting and flowering, the fleshy root becomes hollow and loses its edible value. In order to raise the seeds well, sufficient water and fertilizer should be supplied during this period, and the seeds should be dried when they are close to maturity, which is beneficial to the maturity of the seeds. The cultivation and propagation of new radish varieties can be carried out in the high mountains, but Xiao Mu only produces fresh vegetables without seeds, so plants are not allowed to go through the reproductive growth period.
2. Requirements of radish growth on environmental conditions
(1) Temperature: The optimum temperature for radish seed germination is 20-25℃, and the initial germination temperature is 2-3℃. The seedling stage can tolerate high temperature of 25℃ and short-term low temperature of -2 ~-3℃. The optimum temperature for leaf growth is 18-22℃, and the optimum temperature for endosperm root growth is 15- 18℃. When the temperature is higher than 25℃, the plant growth is weak and the product quality is poor. Therefore, the suitable temperature for radish growth is high in the early stage and low in the later stage. Alpine radish planting is often low in the early stage and high in the late stage. If the cultivation is covered with plastic film, it is not affected by temperature. At present, Korean cold-resistant varieties are selected, which has wide adaptability. If the early temperature is slightly lower than 10℃, the growth and quality will not be affected. In summer and autumn, the temperature is high during the day and low at night, which is also beneficial to nutrient accumulation and endosperm root expansion.
(2) Lighting: In a sunny environment, plants grow healthily and the product quality is good. Insufficient light leads to weak growth, thin and pale leaves, small fleshy roots and poor quality.
(3) Moisture: In the growth process of radish, if water is insufficient, not only the yield will be reduced, but also the fleshy roots will be easily scratched, bitter, spicy and rough; Too much water and poor soil permeability affect the expansion of fleshy roots and are easy to rot; Uneven water supply often leads to root cracking. Only when the maximum water holding capacity of soil is 65-80% and the air humidity is 80-90%, it is easy to obtain high-quality and high-yield products. Plastic film mulching cultivation is a better way to save water and preserve water in high mountains.
(4) Soil and nutrition: Radish is suitable for deep soil, rich in organic matter, good in water retention and drainage, and loose and fertile sandy loam is the best. The soil layer is too shallow and the core soil is too tight, which is easy to cause the root system to diverge directly; Too sticky soil or poor drainage will affect the quality of radish. Radish has a strong ability to absorb fertilizer, so it should be mainly slow-release organic fertilizer, and pay attention to the coordination of nitrogen, phosphorus and potassium. Especially in the growth period of fleshy roots, adding potassium fertilizer can significantly improve the quality. In addition to the three elements of fertilizer, applying more organic fertilizer and supplementing trace fertilizer are essential nutrients for radish.
Second, the planting season and supply period
According to the radish cultivation season, autumn radish is usually sown in the middle and late July. Harvest in mid-September, if the climate is suitable, with high yield and good quality; Radish in summer and autumn is sown in May-June and harvested in July-August. It is sown too early and is easy to pluck the moss in advance, so it is mainly used as a supplement in autumn.
As an out-of-season radish cultivation, according to different varieties, the middle altitude area of 800- 1200m generally starts sowing in April-May, harvesting in June-July, sowing in May-July and harvesting in July-September in high altitude areas. Alpine radish is a winter-strong variety, which is planted twice and can be put on the market from June to the end of 10.
Third, variety selection.
Radish varieties suitable for semi-alpine and alpine planting should be selected on the principle of early maturity, cold tolerance, high yield and high quality. At present, due to the small market demand for carrots, white carrots are mainly planted in summer and autumn.
Fourth, cultivation techniques.
1, soil preparation and base fertilizer application
Select cultivation plots according to different varieties. Generally, radish varieties with deep soil layer should choose deep soil layer, and small and medium-sized varieties can choose plots with shallow soil layer. The land where radishes are planted should be ploughed as soon as possible, and the depth of cultivated land should be turned over 26-40 cm. The border cultivation method adopts deep furrow and high border cultivation to facilitate drainage.
Radish fertilization should be based on base fertilizer, and attention should be paid to the coordination of phosphate fertilizer. Generally, 2500-4000 kg of livestock manure, 5000 kg of fireclay fertilizer and 0/5-20 kg of calcium superphosphate/kloc are applied before soil preparation or sowing. Summer and autumn radishes are planted in alpine vegetable bases in Yichang and Enshi, Hubei. Generally, 3000kg farmyard manure (pig, sheep, cow dung) was applied to 666.7m2 (mu), and NPK compound fertilizer 100kg was applied as base fertilizer, which had a good effect. Pollution-free production should be based on the application of bio-organic fertilizer, which can improve soil structure and quality. For example, "He Run" brand bio-organic fertilizer in Yichang, Hubei Province, the base fertilizer per mu is 100kg, and Beijing "Harmony" brand bio-fertilizer is 3kg, with low investment and high benefit.
Radish is planted in high mountains and semi-high mountains in summer and autumn. Different cultivation methods are adopted in different seasons. Sowing takes place in April and May. At an altitude of 800- 1200m, the plastic film coverage area is generally 2.2 feet, that is, the ditch is 1 foot, and the box surface is 1.2- 1.4 feet. Ditching and fertilization. Planting at an altitude of 1300- 1800m, sowing without plastic film in June-August, and planting radish below 700m in May-July, its high temperature causes low yield and poor quality.
Step 2 sow seeds
The sowing amount of radish varies with varieties, seed plumpness, germination rate, sowing method and cultivation season. Before sowing, the quality of seeds should be strictly checked. Planting imported white radish varieties or Pannan white radish varieties as required, each hole 1 or 2 grains, about 7600-8000 holes per 666.7m2 (mu), and the seed consumption is 90- 100g.
For fields planted on demand, holes should be drilled in plastic film rows first. Generally, two rows should be planted in a compartment, with a row spacing of 7-8 inches and a plant spacing of 6-7 inches. A plant should stay in a hole, which should be drilled half an inch deep. Then after sowing, cover the nutrient soil (fine fertile soil prepared according to local conditions) with a film. After sowing the whole field, spray a small amount of water evenly on the soil covered by the hole surface with a sprayer to achieve the purpose of covering. The planting mode without plastic film mulching in the open field is 2-2. 1 ft, and other operations are the same as plastic film mulching cultivation.
3. Tian Tuan management
(1) Timely seedling thinning: We should master the principles of early seedling thinning, sub-seedling thinning and late seedling fixing. There are 1 seedling in the variety on demand, and the seedlings with diseases and insect pests, weak growth, deformity and no original variety characteristics should be pulled out during thinning. After the seedlings are fixed, carefully cultivate the seedlings with fine soil between rows or specially prepared fine fertile soil to avoid bending the seedlings.
(2) Topdressing and watering: Proper fertilization and watering to make the aboveground and underground parts grow in balance is the key to obtain high quality and high yield of radish. In management, we should promote the robust growth of leaves and absorbing roots in the early stage, and lay a material foundation for the expansion of fleshy roots in the later stage. However, when nutrients grow to a certain extent, they must be controlled to promote the timely transportation of nutrients to storage organs. During the rapid expansion period of fleshy roots, it is necessary to ensure the long life and strong vitality of leaves, so as to make more nutrients and ensure the fleshy expansion.
Radish needs a lot of fertilizer during its growth. In addition to base fertilizer, top dressing is also needed for seedlings. At the early stage of taproot growth, topdressing the quick-acting nitrogen fertilizer once, and spraying the biological fertilizer on the leaf surface 1-2 times. To promote the growth of assimilating leaves and absorbing roots, topdressing should be carried out after the fleshy roots begin to swell, that is, after the belly is broken, and decomposed human excrement and urine can be applied together with watering, and phosphorus and potassium fertilizer can also be added to promote the transfer and accumulation of nutrients. If the soil fertility is poor or the base fertilizer is insufficient, a small amount of available nitrogen fertilizer can be applied at seedling stage, and the effect is better. Small varieties with short growth period can be topdressing less. When applying fertilizer, be careful not to harm the seedlings. After drilling a small hole between the two holes, put in fertilizer and cover it with soil. In production, the base fertilizer is sufficient, and foliar fertilization is the best topdressing.
Radish has different requirements for water at different growth stages. Sufficient water should be supplied when sowing, so as to germinate quickly and emerge neatly. The seedlings should be watered less for a period of time before the "broken belly", so that the roots can be deeply rooted in the soil layer. In the vigorous growth period of leaves, appropriate amount of water should be used to ensure the growth of leaves. To the fleshy root growth period, it is necessary to ensure that the soil is moist and prevent the alternation of dry and wet. At this time, if the water supply is insufficient, it will not only affect the expansion of fleshy roots, but also increase fibrous roots, produce chaff cores and excessive soil moisture. Drainage should be done in time to prevent rot. Plastic film mulching cultivation is one of the good methods to liberate uneven water.
(3) Intertillage and weeding: After sowing radish cultivated in the open field, if the soil is hardened due to rain or watering, intertillage and weeding should be done in time. Large and medium-sized radishes should be cultivated 1 time from the seedling stage to the line closure to keep the soil loose. Intertillage should be combined with weeding, and root prevention and soil cultivation should be combined in the later stage. Radish cultivated with plastic film mulching only needs to pull out weeds in rows and ditches in time without intertillage.
(4) Pest control: 90% crystal trichlorfon or 48% ground insect net 1000 times should be sprayed on the soil surface in time after radish sowing to control needle flies, cutworms and flea beetles (larvae). 0.5g water 15kg 70% water dispersant was used at seedling stage, and sprayed 1 time to control aphids.
The main disease of radish is bacterial black spot. Control methods include selecting disease-resistant varieties, doing well in crop rotation, controlling bacteria in seeds and fields, and using chemicals. During chemical control, 30% Mycobacterium powder was sprayed 500 times or 72% Tektronix 3500 times, 14% copper chloride 350 times or 47% Grannon wettable powder 900 times at the initial stage of discovery.
Radish is in the period of fleshy root growth, which is also the period of vigorous leaf growth. At this time, leaf-eating pests such as Pieris rapae and Spodoptera exigua should be controlled. Generally, spray 65,438+00 times liquid, 5,000 times liquid of Kaku or 3,000 times liquid of 2.5% Green Kung Fu EC every 7-65,438+00 days.
Generally speaking, there are few diseases of off-season radish, mainly viral diseases and bacterial black spot. For viral diseases, 800 times of 1.5% Phytophthora Ⅱ solution or 25 grams of 20% virus Qing Er or 25% virus-killing powder is added with water 15 kg, and sprayed 1-2 times. There are few plots of bacterial black rot, and at present, agricultural lianmycin and neophytomycin have certain effects. In addition, radish planting should pay attention to rotation, choose disease-free plots for planting, and rotate with non-cruciferous vegetables for more than two years. White rust of radish is a common disease of radish.
Pathogenic characteristics:
Mainly harmful to leaves. At the beginning of the disease, there are yellowish spots on both sides of the leaves, and the edges are not obvious. After the disease, there are white micro-raised blisters with a size of about1-5 mm. After maturity, the epidermis is broken and scattered with white powder, which is the sporangium of the pathogen. When there are many diseased spots, the diseased leaves turn yellow. Pedicels of seed plants are diseased, and floral axis is swollen and twisted.
Law of occurrence:
Mycelia and oospores overwinter on diseased residues and seed plants. In cold areas, the pathogen is inoculated with oospores as the initial inoculation, spread by irrigation water, and directly germinates and infects the germination tube to cause disease. In warm areas, the bacteria are mainly inoculated with asexual sporangia and zoospores produced by germination. With the help of rain, the bacteria have no obvious wintering period. High humidity and rainy weather are beneficial to the disease, and the disease of plants with partial nitrogen application is aggravated. The difference of disease resistance among varieties is unknown.
Prevention and control methods:
(1) and non-cruciferous vegetables are planted every other year.
(2) After the previous harvest, remove the sick and disabled in the field and reduce the source of bacteria in the field.
(3) Chemical control: spray 1000 times of 25% metalaxyl wettable powder or 500 times of 58% metalaxyl manganese zinc wettable powder at the initial stage of the disease.
Radish bran heart disease:
Pathogenic characteristics:
It mainly harms the fleshy roots of radish underground. It is characterized by pathological changes and even cavitation in the center of radish fleshy roots, commonly known as bran heart. The early symptom is that the fleshy roots are annular or radial brown lesions, which leads to the decrease of commodity value or inedible. If there is hollowing out, the value of goods will be almost completely lost and the loss will be even greater.
Law of occurrence:
Radish fleshy root chaff disease is a physiological or non-infectious disease. The reason is quite complicated, which is related to at least the following six aspects: (1) variety maturity. Generally speaking, the bran core of radish varieties with different maturity stages is early maturity > medium heat > late maturity. (2) sowing date. Sowing too early and the nutrient area is too large, which is easy to cause radish fleshy root chaff. (3) Weather and water management. When there is too much water supply in the early growth stage of radish and the fleshy roots expand rapidly in the middle and late growth stage, such as insufficient water supply or dry weather, it is easy to induce chaff heart. (4) transport of nutrients. When radish bolting, the nutrients in the fleshy root are transported to the growing point, which is easy to cause chaff heart. (5) Tissue structure of fleshy roots. It is generally believed that radish varieties with loose fleshy root tissue are prone to chaff heart. (6) storage environment. Stored radish is easy to produce chaff core in high temperature and dry environment. There are also differences in disease resistance among varieties.
Prevention and control methods:
(1) Choose radish varieties that are not easy to chaff according to local conditions.
(2) Strengthen fertilizer and water management, ensure sufficient fertilizer and water, avoid soil dryness and wetness, and timely spray foliar fertilizer.
(3) Pay attention to the temperature and humidity control during radish storage, and the relative humidity should be 90% ~ 95%.
(4) Pay attention to timely sowing and timely harvesting.
Tips for healthy living: Radish is eaten in sections, with different nutrition: the top contains the most vitamin C, so it is appropriate to stir-fry and cook soup; The middle part has high sugar content and can be shredded and cold; The tail is spicy and contains amylase and mustard oil, which is suitable for pan-oiling.