Brief introduction and detailed information of plastic film mulching

Principle The biggest function of plastic film mulching cultivation is to increase soil temperature. The temperature in 0- 10 cm deep soil layer can be increased by 1-6℃ after being exposed to sunlight during the daytime in the low temperature period in spring, and the highest temperature can be above 8℃. In high temperature period, if there is no shading, the surface temperature of soil under plastic film can reach 50-60℃, and the surface temperature of soil will be higher when it is dry. However, when there is crop shading, or when the plastic film surface is covered with soil or silt, the soil temperature is only 1-5℃ higher than that in the open field, and when the soil is wet, it will be 0.5- 1.0℃ lower than that in the open field, at most 3℃ lower. Affected by cold air at night, the soil temperature under plastic film is only 1-2℃ higher than that in open field. The warming effect of plastic film mulching varies with different mulching periods, mulching methods, weather conditions and plastic film types.

Because of the strong air tightness of the film, film mulching can significantly reduce the evaporation of soil moisture, make soil moisture stable and keep moist for a long time, which is beneficial to root growth. In arid areas, drought-resistant sowing can be carried out by artificial soil moisture creation and soil moisture supplement. Under drought conditions, the soil water content in 0-25 cm soil layer is generally higher than that in the open field by more than 50%. With the deepening of soil layer, the water difference gradually decreases.

The crops covered with plastic film grow vigorously, consume a lot of water for transpiration, and are prone to water shortage under the same management situation. Pay attention to irrigation to prevent drought from reducing production. Because plastic film mulching has the function of warming and moisturizing, it is beneficial to the proliferation of soil microorganisms, accelerating the transformation of humus into inorganic salts and benefiting crop absorption. According to the determination, after plastic film mulching, available nitrogen, potassium and phosphorus increased by 30-50%, 10-20% and 20-30% respectively. Plastic film mulching can reduce the leaching, loss and volatilization of nutrients and improve the utilization rate of nutrients. However, the nutrients under plastic film mulching were higher in the early stage of crop growth, but they tended to decrease in the later stage. When producing vegetables, we should pay attention to topdressing in the later stage, otherwise it will affect the yield. In addition, plastic film mulching can avoid soil hardening caused by irrigation or rain erosion, reduce intertillage labor, and make the soil loose and breathable. Can increase the total porosity of soil 1- 10% and reduce the bulk density by 0.02-0.3g? Cm -3 can increase soil stable aggregates by 65438 0.5%, and make the conditions of fertilizer, water, gas and heat in the soil coordinate. At the same time, it can prevent alkali return and reduce the harm of salinization.

After plastic film mulching, the leaves in the middle and lower parts of the plant can get 12- 14% more reflected light at noon, which is 3-4 times more than that in the open field, so that the apples in the lower part of the trunk can be well colored, the flowers are bright and the color of tobacco leaves is good. The photosynthetic intensity of tomato can be increased by 13.5-46.8%, and the chlorophyll content can be increased by about 5%. It can also delay the senescence period of middle and lower leaves and promote the accumulation of dry matter, thus increasing the yield.

When the temperature between the plastic film and the surface is high on sunny days, the high temperature of about 50℃ often occurs, which makes the grass buds and weeds die. Using herbicides before and after film mulching can prevent weeds from growing and reduce the labor force occupied by weeding. However, poor quality of plastic film mulching or no herbicide application will also cause grass shortage. Because the plants grow vigorously after plastic film mulching, the disease resistance can be enhanced and the incidence rate can be reduced. Covering with silver-gray reflective film can avoid aphids and reduce the spread of virus diseases.

However, plastic film mulching cultivation also has some adverse effects. For example, after years of plastic film mulching, the residual film can not be completely removed, resulting in soil pollution. Due to the rapid decomposition of organic matter after plastic film mulching, the crop utilization rate is high, but the fertilizer supplement is less, and the soil fertility is reduced, or due to improper management of plastic film mulching, it will lead to premature failure to increase production or even reduce production. Plastic film mulching is not suitable for planting in dry sandy land, barren land and heavy clay land. Because the soil temperature after film mulching in arid sandy land is easy to produce high temperature at noon, it will reduce production in severe drought. In barren land, it is not convenient to topdressing after film mulching, and it is not enough to apply base fertilizer when sowing, and film mulching can not increase production. Heavy clay ground is difficult to rake when it is dry, and it is difficult to stick to the ground after film mulching. When the wind blows, the film is easily blown away by the wind. Therefore, it is necessary to master certain conditions to achieve the goal of early maturity, high and stable yield by using plastic film mulching cultivation.

Mode The mode of plastic film mulching varies according to local natural conditions, crop species, production season and cultivation habits.

The flat boundary is covered with ridges, and the width is 1.00- 1.65 m, and the length of the boundary depends on the plot. Before sowing or planting, spread the plastic film on the edge and compact it with the surrounding soil. Or temporary coverage in a short period of time. It is labor-saving and easy to water when covering, but it is easy to cause boundary silt pollution after watering. At the initial stage of mulching, it has a warming effect, and with the aggravation of pollution, it has a cooling effect at the later stage. Generally, it is used for planting onions, garlic and vegetables with high seedling protection, and also for cutting crops such as wheat and cotton, fruit trees and seedlings.

Covering ridges with high ridges, the width of ridge bottom is 50-85cm, the width of ridge surface is 30-50cm, and the ridge height is10-15cm. Plastic film covers the ridge surface. Ridge spacing is 50-70cm. Plant single or double rows of cabbage, lettuce, sweet pepper, cauliflower, etc. On every ridge. Plastic film mulching with high ridges has good light reception, the ground temperature is easy to rise, and it is also convenient for watering, but the ridge height in arid areas should not exceed 10 cm.

The coverage of the high ridge is flat-topped, which is 10- 15cm higher than the ground, and the ridge width is1.00-1.65m. The plastic film is laid flat on the surface of the high frame. Vegetables with high seedling support are generally planted, such as melons, beans, eggplant and grain and cotton crops. The effect of high temperature is good, but the center of the boundary is prone to drought.

Cover the furrow Make the furrow about 50 cm wide and the furrow depth 15-20 cm. Plant the cultivated seedlings in the border, and then cover the border with plastic film. When the seedlings grow against the plastic film, cut the plastic film into a cross at the top of the seedlings, which is called cutting and drying. After the late frost, the seedlings grow a film from the crevasse. When the seedlings grow taller, cut the plastic film and let it fall to the ground to cover the roots. It is commonly known that heaven was created first, and then land was created. This can be planted 7- 10 days in advance. Protect seedlings from late frost. Not only protect seedlings, but also protect roots, so as to achieve the effect of early maturity and increase production and income. Vegetables such as Chinese cabbage, cauliflower, lettuce, kidney beans, sweet peppers, tomatoes and cucumbers can be planted in advance in early spring, and melons such as watermelons and melons and crops such as grain can also be planted in advance.

An inclined trench with a depth of 40 cm and an upper width of 60-80 cm is formed on the ground. The distance between the two ditches is 2-5 meters (2 meters for melons and 5 meters for watermelons), and the ground between the two ditches is like a ridge. Both sides of the ditch are covered with 70-75 cm plastic film along the slope, and the ground on both sides of the ditch is ridge-shaped. Both sides of the ditch are covered with 70-75 cm plastic film along the slope, and melons are planted on both sides of the ditch.

The hole is covered on a flat, high or raised edge and drilled with a puncher. The hole depth is about 10 cm, and the diameter is 10- 15 cm. When crops are sown or planted in the air, the plant spacing shall be determined according to the requirements of crops. Then, cover the top of the hole with plastic film, and cut the mouth after the top film of the seedling is formed. You can grow crops such as potatoes.

Form 1. Suitable for covering forms of cucumber, green pepper, tomato, eggplant and other vegetables. A plastic film with a width of 90- 100 cm and a thickness of 0.0 1-0.008 mm is laid flat on the high ridge, and both sides of the plastic film are buried in the lower two thirds of the ridge. The specifications of high ridge are: ridge bottom width100-10 cm, ridge surface width 80-85 cm, ridge height10-/5 cm, and furrow width 30. When making the border, the center of the border should be slightly higher to facilitate the film laying.

2. The covering form suitable for planting vegetables such as onion and cabbage is 100- 1 10 cm, and the covering length can be determined according to the plot. Before planting, the plastic film can be laid flat on the boundary and compacted with the surrounding soil. This form is more labor-saving than high border, but it is easy to pollute the border surface during irrigation, and it is not obvious to improve the ground temperature.

3. The specifications of the ridge suitable for planting green peppers, Chinese cabbage and other vegetables are: the width of the ridge bottom is 73 cm, the width of the ridge surface is 40 cm, and the ridge height is 17 cm. Cover the ridges with plastic film and plant two or three rows per ridge.

4. The covering form suitable for kidney bean cultivation in large frame is 53cm wide at the bottom, 33cm wide at the top and16cm high. Cover the ridge with plastic film.

5. Spring is suitable for covering forms of Chinese cabbage, radish and reverse root vegetables. After sowing Chinese cabbage and radish in early spring, or before perennial vegetables such as spinach and leek turn green, covering the border with plastic film for a short time can promote their growth and market early.

6. Covering forms suitable for planting green peppers, cucumbers, Chinese cabbage, tomatoes, kidney beans and other vegetables. Make a ditch with a width of 40-50 cm and a depth of 15-20 cm on the high side, plant (or directly broadcast) vegetable seedlings in the ditch, and then cover with plastic film. After delayed emergence (after emergence), puncture or cut off the plastic film at the top of the plant for ventilation, and take the seedlings out of the film after late frost. This form can be planted early before the local late frost.

7. The mulching form suitable for potato cultivation is high ridge surface or long ridge surface. Punching holes with the depth of 15cm according to the plant spacing with a punching machine, sowing or planting seeds or vegetable seedlings in the holes, then covering with plastic film, and punching holes for ventilation after seedling emergence or seedling delay.

8. Suitable for planting green pepper, cucumber, eggplant and other vegetables. Divide the monopoly into double ridges, sow or plant seeds or vegetable seedlings inside the double ridges, and then cover them with plastic film. Let seeds or vegetable seedlings grow in the space between two ridges for a period of time. Take the seedlings out of the film after the late frost.

Rice plastic film technology can not only greatly improve the rice yield in cold-soaked mud fields, high-port fields and water-deficient fields, but also play an important role in solving the water shortage problem in China. The average yield per mu of rice covered with plastic film increased by more than 100 kg, and the water saving per mu was 100~400 cubic meters, which has development prospects in both north and south. The technical system mainly includes wet cultivation technology of rice transplanting with plastic film and wet sowing technology of rice with plastic film. The wet cultivation technology of rice transplanting with plastic film is suitable for popularization and application in cold, cold soaking, dry hillock and water-deficient areas in the south, and the wet sowing technology of rice with plastic film hole is suitable for application in arid or semi-arid areas with little precipitation and poor water and heat resources in the north.

Operating rules of wet cultivation techniques for rice transplanting with plastic film (1)

Selecting seeds for dry seedling raising; Select improved varieties whose growth period is slightly longer than that of local conventional cultivation; Carry out dry seedling raising.

The best choice is alpine field, cold soaking field, dry hillock field and water-deficient field, and the whole field should be flat and muddy. After leveling and dewatering in the field, before making boxes, apply base fertilizer and more slow-release fertilizer.

Cover the trunk with plastic film and open "three ditches", that is, deep trench, waist trench and shallow trench. After the "three ditches" are opened, the car surface will be leveled, and then wrapped with rolled film.

Specification for transplanting rice seedlings: firstly, nail wooden nails on the board according to the plant spacing to make a "punch", punch holes in the film for sowing, and transplant rice seedlings according to the holes. The transplanting time is about 10 days earlier than the local routine. After transplanting, clean the ditch and let the water flow through, so that there is a thin layer of water on the film surface.

Tobacco cultivation techniques Plastic film mulching cultivation of tobacco grassland can be divided into two types: under-film cultivation and on-film cultivation.

Operating rules: soil preparation, ridging and fertilization. In the tobacco-rice rotation area, tobacco leaves will be planted in mid-March, and the favorable weather should be seized before February to prepare soil, ridge and fertilize. After ridging, herbicide is applied, then hole fertilizer is applied in the construction, and the topsoil is broken to cover the film.

Covering film. The soil surface must be wet, and the water holding capacity can reach 80% before film mulching. Otherwise, the film cannot be covered. When laminating, it should be close to the compartment surface, taut and straight, and tamped with soil around it, so it is advisable that the wind can't blow.

Grow cigarettes. Under-film cultivation, if the tobacco is covered with film before planting, one side of the film is uncovered when planting tobacco, and the seedlings are watered and then covered with film. Do not film before planting tobacco, and film immediately after planting tobacco. If it is cultivated on the film, a small hole is opened in the structure on the surface of the compartment, tobacco seedlings are planted in the hole, water and fertilizer are poured, and the film mouth is pressed with soil.

Check seedlings to fill vacancies. Within 7 days after planting, check the tobacco field and replace the dead seedlings in time.

Open holes to raise seedlings. When the leaves of tobacco seedlings cultivated under the film are long enough to resist the plastic film, they must be punched in time, or when the temperature in the film exceeds 30℃, the leaves of tobacco seedlings must be exposed on the film surface, and the holes must be pressed with soil. Otherwise, it will burn the tobacco seedlings.

Uncover the film. When tobacco seedlings are covered with plastic film for about 40 days, or as long as they reach the clumping stage, the plastic film must be removed in time. Residual film must be uncovered, centralized treatment, not allowed to throw.