Method for preventing runt seedlings in root extending period of ridged mulching film tobaccos

Abstract

The invention discloses a method for preventing runt seedlings in the root extending period of ridged mulching film tobaccos. Ridging is performed in a tobacco field, the widths on the surfaces of ridges for film covering are 60-70 cm, the vertical heights between the ridge tops and the furrows are 25-30 cm, the widths of the bottoms of the ridges are 35-50 cm, the ridge top faces are cambered surfaces, the ridge side edges are oblique planes, film covering is performed on the surfaces of the ridges, vertical planting holes are drilled in the cambered surfaces of the ridge top faces, and transplanted tobacco seedlings are placed in the vertical planting holes; after the transplanted tobacco seedlings are placed in the vertical planting holes for 5-10 days, oblique holes are drilled in onesides or two sides of ridges; the diameters of the oblique holes are 2-3 cm, the hole depths are 25-30 cm, the included angles between the oblique holes and front projection planes of the ridge top faces are 44-48 degrees, the vertical distance between the openings of the surfaces of the oblique holes and the ridge top faces are 3-8 cm, and the vertical distance between the openings of the bottomsof the oblique holes and the ridge top faces are 15-20 cm; the surface area sum of the openings of the surfaces of the multiple oblique holes is 0.002-0.004% of the surface area of the ridges. The method for preventing the runt seedlings in the root extending period of the ridged mulching film tobaccos has the advantage that the occurrence rate of runt seedlings in the root extending period can be effectively reduced.

Description

technical field [0001] The invention relates to a method for planting ridge-planted film-mulched tobacco at the root-extending stage, in particular to a method for preventing stiff seedlings at the root-extending stage of ridge-planted film-mulched tobacco. technical background [0002] From the transplanting of tobacco seedlings to the field to the completion of harvesting of tobacco leaves is the field period, which is about 120-150 days. According to the characteristics of tobacco growth and development, the dynamic changes of tobacco plant growth and the staged morphological characteristics, it is divided into the seedling stage (from transplanting to survival), the rooting stage (from survival to clusters), and the flourishing period (from clusters to clusters). budding) and maturity (from budding to the end of tobacco leaf harvesting) are four closely related growth and development stages. Seedling return period refers to the period from transplanting to the survival ...

AI Technical Summary

Problems solved by technology

[0005] Before 2015, the method of transplanting high-stem and strong seedlings was adopted. The stem height of the tobacco seedlings was 8-10cm, and it was generally transplanted in the middle and late May. Thin, the height of the ridge body is not high, usually less than 25cm, or less than 20cm, resulting in high-legged seedlings and exposed-stem seedlings when transplanting are more common, and it is easy to cause some stiff seedlings, which must be removed 15-20 days after planting The Measures of Uncovering the Film and Cultivating the Soil Promote the Development of Lateral Roots in the Rhizome

The second is the impact of climate. The rainfall before and after planting (mid-April-mid-May) is relatively large, and it will continue to rain after planting. The diameter of the pit opening of the smoke nest is 9-10 cm. Excessive humidity in the smoke nest is not conducive to downward extension. Roots, water control and squatting seedlings are poor, the rooting period is prolonged, and the growth of the tree is stunted, resulting in stiff seedlings

One is high temperature burns during the day. The highest temperature in the Zhongshan tobacco area (about 800 meters) at noon in early May is above 30°C, and the cellar mouth of the tobacco planting well covered by plastic film can reach 42-46°C. The high temperature may damage the leaves or scald the leaves , causing growth stagnation; the second is low temperature and freezing damage at night. In the alpine tobacco area (about 1200 meters), the temperature difference between night and night is large in the middle or late May. In the middle of the night, the temperature is close to zero, and the severe temperature difference causes the growth of the aboveground part and the underground part to stagnate or form obvious freezing damage, which affects root extension, resulting in stiff seedlings

[0011] 3. Differences in fertilizer concentration: First, dry moisture mulching is adopted in alpine tobacco areas, and fertilization, ridge formation and mulching are integrated operations. There are some phenomena of uneven application of fertilizers and insufficient dissolution and fermentation of chemical fertilizers. After transplanting tobacco leaves, the root system Exposure to high-concentration fertilizers will cause root burn, and failure to contact fertilizers will cause growth retardation, which can easily lead to poor root development

The second is that under frequent drastic temperature changes, the phenomenon of salt precipitation on the ridge surface covered by plastic film is obvious, and the salinization of the ridge surface and the soil around the root system affects the growth of the root system.

[0012] 4. Impacts of diseases and insect pests: First, because the tobacco seedlings are transplanted under the film under the film, the humidity in the well cellar is high, and the moisture-loving insects (such as wild slugs, etc.) are serious and harmful, and the lack of seedlings is more than that of seedlings or the field uniformity is poor; Under the condition of high temperature and high humidity, the high humidity will cause the premature occurrence of bacterial diseases, such as anthracnose, which will aggravate the rate of stiff seedlings

[0013] 5. Impact of agricultural operations: First, the impact of the use of pesticides. Transplanting with pesticides is emphasized in transplanting. The commonly used insect repellent is mainly beta-halothrin, and the liquid medicine is directly applied to the roots from the upper part of the tobacco plant, which is easy to touch the heart leaves. , causing phytotoxicity of some heart leaves or tobacco plants, which can easily cause leaf deformity, arbuscular branches and agglomerative buds, and result in stiff seedlings; the second is the impact of improper topdressing. Potassium nitrate fertilizer is used for topdressing fertilizer, emphasizing chemical water topdressing, and about 500 kg of water is needed per mu. Restricted by water source conditions or labor input, some farmers adopt dry fertilization method to directly break the film around the tobacco plants and spread the fertilizer. The fertilizer does not enter the root system, and the concentration of fertilizer on the surface of the ridge is too high. Increase the salt damage on the ridge surface and aggravate the stiff seedlings; the third is that there are many agricultural operations, such as seedling replenishment after planting, insect control, top dressing, and soil rupture, or the impact of hot sun, windy, and rainfall, some fields have mechanical damage, Affected by the flow of soil covering the core, thus aggravating the stiffness of the seedlings

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