The Agricultural Product Quality and Safety Risk Assessment Laboratory (Hefei) of the Ministry of Agriculture and Rural Affairs, based on the investigation of production bases, combined with the actual conditions of safe production, put forward the key points for the safety production and control of leeks. Disclaimer: Some articles on this website are transferred from the Internet. If third party legal rights are involved, please inform this website to deal with them. phone
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Key points in the production process of leek 1. The environment in the place of production is an organism, and the safety of the place of production is the most important basis for vegetable production. Safe production cannot be separated from the high-quality ecological environment and soil conditions. Therefore, the choice of planting bases should first meet NY / T5010 Relevant indicators in the "Environmental Conditions of Producing Areas of Pollution-free Agricultural Planting Industry" require that conditional growers can send environmental samples to qualified units for testing of relevant indicators.
2. Variety selection Planters should choose suitable varieties according to their own conditions and climate distribution, based on varieties that are resistant to diseases and insect pests, low temperature resistance, high temperature resistance, strong ability to divide, and have good appearance and intrinsic quality. For continuous production, in the greenhouse in autumn and winter, varieties with short dormant periods should be selected.
3. The fertilized seedbed for soil preparation should choose sandy soil that is easy to drain and irrigate, and the pH value should be below 7.5. Plow and fertilize before sowing, and harrow it carefully after plowing, then level and do the hoeing. Fertilizers should be consumed reasonably, and production should be considered under the premise of ensuring the environment and product safety. Fertilizers should be selected from regular production enterprises to minimize the use of chemical nitrogen fertilizers. The type of base fertilizer should be high-quality organic fertilizers, ordinary chemical fertilizers, and compound fertilizers that have been harmlessly treated. And dig deep into the soil.
4. Planting management When planting, try to provide seedlings with a sufficient nutrient supply environment and a suitable growth environment. The high temperature and high humidity season is not conducive to the slow growth of leeks, and this period should be avoided. Seedlings seeded in spring and planted after the summer solstice; seedlings seeded in summer and planted before and after the summer heat; seedlings seeded in autumn and planted before and after Qingming the following year.
When planting leek seedlings, cut off the fibrous roots after leaving, leaving 2-3 cm; in order to maintain the balance between root absorption and leaf transpiration, the leaf ends should be cut off. The inner row of the pupae is 18-20 cm, the hole spacing is 10 cm, and 8-10 seedlings are planted in each hole. The cultivation depth should not exceed the tillering section.
5. Management of open field growth stage after planting. Water management. After planting, pay attention to soil moisture retention, irrigate twice, and squash the seedlings 2-3 times to promote the growth of new roots. At this time, the soil should be kept wet; during the rainy season, the soil status of the plot should be observed in time. Prepare for drainage at any time. The suitable growth temperature of chives is 12 ° C-24 ° C. When the maximum ambient temperature drops below 12 ° C, please reduce the amount and frequency of irrigation water accordingly, keep the soil surface dry and prevent rotten seedlings. Fertilization management. Fertilization is based on the growth of leeks and environmental conditions, such as weather and soil moisture. Choose the amount and frequency of fertilization. For seedlings below 35 cm in height, 500 kg of 10% -20% decomposed organic fertilizer is applied per acre; for seedlings above 35 cm in height, 800 kg of 30% decomposed organic fertilizer is applied per acre, and 5-10 kg of urea is added reasonably, or The compound fertilizer is 5 kg, and the dilution ratio should be increased in the case of drought to avoid burning the seedlings due to excessive local application.
Shed production management. If the chives mainly harvest leaves, they can be buttoned in autumn or winter and transferred to greenhouse cultivation. If they are mainly harvested, they do not need to be buttoned. Leeks must be subjected to low temperature before they are pumped. Before buttoning, remove dead leaves of leek and loosen the surface soil. For varieties with a long dormant period, in order to break the dormant period of leeks and guarantee the market before the new year, a wind barrier can be set up on the south side of the greenhouse to artificially create a cold microclimate on the ground of the greenhouse. When the local surface is frozen 10 cm, the wind barrier is removed and the film is removed. Cover insulation measures.
6. Pest control During the planting process of leek, the main pests are leek, leaf miner, thrips; the diseases are mainly gray mold, blight, downy mildew, etc. The control of leek pests and diseases is based on the principle of "prevention-oriented, comprehensive control". It is based on agricultural control, physical control, and biological control. It is one of the most effective means for the safe production of chives, based on the use of low-toxic, high-efficiency, low-residue chemical agents.
Agricultural control: According to local conditions, choose disease-resistant and insect-resistant varieties, adopt correct cultivation methods, cultivate strong seedlings, and improve their ability to resist diseases and insects.
Physical control: If trapped with sugar and wine, evenly place 1-3 pots per acre, and formulate a solution according to the ratio of sugar: vinegar: wine: water: 90% trichlorfon = 3: 3: 1: 10: 0.6 to trap and kill A variety of fly pests.
Biological pesticide prevention and control: Use registered biological pesticides to control leek diseases and insect pests, such as 15 billion spores per gram of Beauveria bassiana 75-90 g / mu can be used to control chives.
Prevention and control of chemical agents: The use of chemical pesticides prohibited or restricted on vegetables as prescribed by the state is strictly prohibited. According to the actual occurrence of field diseases and insects, select appropriate chemical agents for prevention and control, and use them in accordance with the guidelines for reasonable use of pesticides. Use different action mechanisms or agents with negative cross-resistance to overcome or delay the resistance that may be caused by diseases and insect pests. At the same time, use the medicine in strict accordance with the safe intervals specified in the instructions for use of the agent to ensure the safety of leek products.
The main points of leek harvesting technology are the first year of planting. It is not recommended to harvest. It is mainly rooting and strong seedlings. The leek flowers that appear in the growing period must be removed in time. Spring and autumn are the main harvesting seasons, but in order to keep the leeks in winter for harvest, the number of harvests should be 1-2 times; the environmental temperature in summer exceeds the maximum temperature at which leeks are suitable for growth. At this time, the quality of leeks is poor, and harvesting is generally not recommended. When the leek is harvested, when it is rainless in the early morning, the blade should be 2-4 cm from the ground, and the incision should be yellow and uniform. The stubble should not be too low, otherwise it will affect the leek tillering. The interval between harvests should be kept at about 30 days. After each harvest, you can't water immediately, you need to scratch the leeks, and 2-3 days until the leek wound heals, new leaves are coming out, watering, topdressing fertilizer, 300-400 kg / mu organic fertilizer, At the same time, 10-15 kg / mu of urea and 10-15 kg / mu of compound fertilizer were added. To prevent leeks from jumping roots, soil cultivation should be carried out once a year starting from the second year.
Removing ribosomal RNAs that account for more than 80% helps to focus sequencing on less abundant but informative RNAs. At present, the removal of rRNA is mainly through the combined use of probe and RNase H. The processed RNA will be mixed with many digestion products, enzymes and ions, which is not conducive to the subsequent construction of RNA library. Take the Columnar RNA Purification Kit as an example. Trizol is a ready-to-use reagent that can be used to purify total RNA from tissues and cells. This is a single-phase solution of phenol and guanidine isothiocyanate that facilitates lysis of tissues and cells, inhibiting RNases to maintain RNA integrity.