What is plastic film mulching? What is a greenhouse?

A greenhouse is a plastic shed in the field, where vegetables are generally grown. Because they are covered with plastic film, it will produce high temperature, and there will be fresh vegetables in winter.

plastic mulch

In the mid-20th century, with the development of plastic industry, especially the appearance of agricultural plastic film, some developed countries covered the ground with plastic film to produce vegetables and other crops, and achieved good results. The research and utilization in Japan began with 1948, and 1955 was first applied to strawberry mulching production, and it was popularized. The research work was officially carried out on 1965. 1977, there were10.2 million hectares of dryland crops (including vegetables) in Japan, and the ground coverage area exceeded 200,000 hectares, accounting for 16% of the dryland crop planting area. The ground coverage area in the reserve accounts for 93%. Ground cover cultivation in Japan is mostly used for economic crops such as vegetables with high output value and great benefits. 196 1 year, France began to try to plant film-covered melon crops in the southeast of the country. Italy planted main crops in 1965, such as vegetables, strawberries, coffee and tobacco. The United States began to cover cotton with black film in the late 1960s. In the Soviet Union, plastic film mulching cultivation was mainly carried out in low temperature and dry season to increase ground temperature and reduce land evaporation. In the early 1970s, China used waste film to cover a small area of flat land and grow vegetables and cotton. 1978, and 1979 began to test, demonstrate and popularize in parts of North China, Northeast China, Northwest China and the Yangtze River Basin. Then the polyethylene film with the thickness of 0.0 1.5-0.02 mm was produced, which created conditions for the development of plastic film. Because of the remarkable effect of plastic film mulching, plastic film mulching production has been carried out all over the country, referred to as plastic film mulching. At present, it is not only used for vegetable cultivation, but also for the production of field crops, fruit trees, forestry, flowers and cash crops. The masses call it a measure of "not pushing yourself and others". So far, there are dozens of crops and fruit forest seedlings covered with plastic films. At present, plastic film is not only used for open field cultivation, but also for covering early spring protection facilities. Not only in early spring, but also in summer and autumn when the temperature is high. The application of plastic film mulching in arid areas of northern China has the function of drought resistance and moisture conservation. In rainy season, plastic film mulching also has waterproof and drainage effects, which is very popular among producers.

In some arid areas of Hebei Province, in order to sow peanuts and cotton in time during the spring drought, we have adopted methods such as ditching, artificial soil moisture building, furrow-by-furrow watering, sowing, soil covering and plastic film mulching to promote soil moisture, improve soil moisture, and increase lint yield by 20-40% and peanut yield by 50-60%. In order to solve the unfavorable factors such as low temperature in spring, short frost-free period and drought in spring, deep ploughing, fertilization, plastic film mulching in spring, or artificial supplement of soil moisture to prevent drought in Liaoning Province have increased peanut production in a large area, with an average increase of 45%. In some areas with severe drought and insufficient rainfall 100 mm from July to September, the average yield of 260,000 mu of peanuts was 2 17 kg, and the yield increase rate reached 132.6%. Peanut can't be planted in Yichun City, Heilongjiang Province due to low temperature and drought over the years. Peanut 150 kg was obtained by plastic film mulching cultivation. In the arid and cold areas of Inner Mongolia, the temperature is low in spring, with heavy sandstorm and little rainfall. Crops such as vegetables, grains, cigarettes, fruits and flowers are greatly affected by climate. Using plastic film mulching cultivation, the main fruit vegetables cultivated in greenhouse are listed 2- 10 days in advance, and the yield per mu is increased by 30-70%. Plastic film mulching in the open field 12 vegetable yield increase (early maturity) 6500. The soil salinization of old vegetable fields in urban suburbs is serious, and plastic film mulching can reduce the surface salinity of soil. In the saline-alkali land of Chifeng County, 86% of eggplant is covered with plastic film. The yield of sugarbeet covered with plastic film increased by 26-33%, and the sugar content increased by 1.2- 1.5%. The yield per mu of tobacco leaves increased by 27.8%, and the yield of corn increased by 32.9%. The plastic film of Zalantun in Hulunbeier League covers six kinds of flowers, such as chrysanthemum and cordate telosma, so that the flowering period is advanced, with many branches and bright colors. Plastic film mulching cultivation in Hexi Corridor, Longquan Mountain, Longnan Mountain, river basins and central arid areas of Gansu Province has the functions of heat preservation, moisture preservation, fertilizer conservation, weeding, pest reduction, early maturity and yield increase. More than ten kinds of vegetables increased by 30-70%, melons increased by 30-50%, lint increased by 30-40%, and flue-cured tobacco, peanuts and sugar beets increased by about 50%.

Plastic film mulching cultivation can generally achieve the effect of early maturity and yield increase, and its effect is manifested in several aspects, such as warming temperature, maintaining heat and water, maintaining nutrients, improving photosynthetic efficiency, preventing diseases and weeds, etc.

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.

First, the way of plastic film mulching

The way of plastic film mulching varies with local natural conditions, crop species, production season and cultivation habits.

(1) Flat Boundary Coverage

The border is flat and ridged, the width of the border is 1.00- 1.65m, and the length of the border 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.

(2) High ridge coverage rate

The ridge is ridge-shaped, with a base width of 50-85cm, a ridge surface width of 30-50cm and a ridge height of 10- 15cm. Plastic film covers the ridge surface. Ridge spacing is 50-70cm. Gan Lan, lettuce, sweet pepper and cauliflower are planted. One or two rows per 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.

(3) High border coverage.

The boundary is flat-topped, higher than the ground 10- 15cm, and the 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.

(4) Ridge and furrow mulching

Make the border into a ditch with a width of about 50 cm and a depth of 15-20 cm, plant the cultivated seedlings in the ditch, and then cover the ditch 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. It not only plays the role of protecting seedlings, but also plays the role of protecting roots, thus achieving the effects of early maturity, increasing production and income. Gan Lan, cauliflower, lettuce, kidney beans, sweet peppers, tomatoes, cucumbers and other vegetables can be sown in early spring, and crops such as melons and grains can also be sown in advance.

(5) planting slope mulch in the ditch

An inclined trench with a depth of 40 cm and a width of 60-80 cm is opened 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.

(6) Covering of holes and pits

Punch holes on flat edges, high edges or high ridges with a hole depth of about 10 cm and a diameter of 10- 15 cm. When sowing or planting crops in the air, the plant spacing shall be determined according to the requirements of the crops. Then cover the top of the cave with plastic film, and cut the hole for fresh air after the seedlings are covered with plastic film. You can grow crops such as potatoes.

Second, plastic film mulching cultivation.

(1) Plastic film mulching cultivation in Gan Lan.

Ganlan has strong cold tolerance. Early-maturing varieties are mostly used for early spring cultivation, and seedlings are raised early in the sun bed or small arch shed from late February to early October of the current year 1. In the early spring of the following year, cover with flat bed, which can be planted 5-7 days earlier than those suitable for open planting. In recent years, ditch mulching has been adopted in the suburbs of Dalian. Because there is a plastic film on the top of the seedlings to prevent the harm of late frost, the sowing date is 4-6 days earlier than that of plastic film mulching, which not only improves the ground temperature, but also improves the microclimate of local space, creating good conditions for frost prevention, temperature increase, moisture retention and growth promotion of Ganlan seedlings. Therefore, the yield per mu can be generally increased by 20-30%, because the yield can be harvested 7- 10 days in advance. According to reports from Liaoning, Heilongjiang, Shaanxi, Shandong, Beijing and Tianjin, the yield per mu increased by 3 1.5-4.7%, and the output value per mu increased by 1 15-253.7 yuan, which is a noteworthy measure in early-maturing cultivation in Gan Lan. According to the mulching technique in Gan Lan, other vegetables, such as cauliflower and lettuce, can also be covered with high ridges or ditches.

(2) Covering cultivation of kidney beans

Beans are warm-loving crops, and the sowing date of open field cultivation is around Grain Rain. Bean seedlings covered with plastic film can be raised in greenhouse about 20 days in advance. When the bean sprouts show their heart leaves, they can be planted after Tomb-Sweeping Day. In this way, sowing is 20-30 days earlier than in the open field or plastic film mulching, and the harvest time is 15-20 days earlier, and the yield per mu can be increased by 23-75%. In Beijing, the yield can be increased by 42.4%, the output value can be increased by 77.3%, and the yield can be increased by more than 15 days at maturity 136 yuan. Yichun City and Harbin City in Heilongjiang Province increased production by 27.3- 125%.

Dwarf kidney beans can be covered by flat edge, high ridge, high edge and ditch edge. Planting beans can also be covered with high ridges, high ridges or furrows. Cowpea and so on can also be covered according to the covering method of kidney beans, and the effect of increasing production and income is also remarkable.

(3) Cultivation of cucumber with plastic film mulching

Cucumber is the most widely cultivated vegetable, with various cultivation methods, which can be supplied all year round. It can be cultivated in early spring, hot summer and late autumn, with high yield, high output value and quick effect. Cucumber seedlings are mostly raised in plastic film mulching in greenhouses and small arch sheds. When four true leaves are planted, they are generally covered with high ridges or furrows before the Grain Rain Festival, which is 5- 15 days earlier than the open cultivation, and the yield is increased by more than 30%. The output of Shandong, Liaoning, Xinjiang and Gansu increased by more than 50%. The output value per mu increased by 100 yuan, reaching 500-600 yuan. In addition to plastic film mulching cultivation in spring, plastic film mulching in summer and autumn also has a good effect.

When cucumber is covered with plastic film in summer, the ground temperature is higher at the initial stage of sowing, but the soil is moist and will not cause high temperature harm. When the seedlings grow tall, they will be blocked by the ground, and the soil temperature will be slightly higher than that in the open field. Because the plastic film can keep the proper temperature of the soil and protect the roots and seedlings, the seedlings grow vigorously and normally. It can be seen that plastic film mulching is a necessary cultivation measure for summer sowing cucumber.

By the way, tomatoes, eggplant, sweet peppers and other vegetables can also be covered with cucumbers. Sweet pepper covered with silver-gray reflective film can avoid aphids and prevent virus infection, thus achieving significant yield increase.

(4) Cucurbita pepo is cultivated with plastic film mulching.

Compared with early-maturing cultivation in spring, zucchini prefers mild climate. Seedling raising in late February to early March in spring. Before Grain Rain, high ridges and small high ridges will be used, or ditches and ridges and plastic film arches and holes will be used. In recent years, most people are covered with film by ditches. Because the planting period can be advanced, the effect of early maturity and high yield can be obtained. Output per mu increased 100-400 yuan. It is well received by producers, and at the same time, it also increases the variety of colors on the market.

(5) Cotton plastic film mulching cultivation

Plastic film mulching cultivation of cotton is one of the cash crops with early popularization, large area and remarkable benefits in China. Liaoning, Shanxi, Henan, Xinjiang and other provinces have all set a high-yield record of lint per mu 150 kg, which is generally about 50% higher than that of open cultivation. The popularization of this technology has contributed to reversing China's long-term import of cotton and promoting the take-off of textile industry.

Cotton plastic film mulching cultivation can be divided into three types: high ridge, flat ridge and furrow ridge, which are selected according to local conditions. Ridge mulching is suitable for areas with insufficient heat resources in extra-early cotton areas. Flat cover or furrow cover is better for cotton fields with drought and water shortage. Plastic film mulching in cotton fields can also be divided into three types: high (90% in the left), medium (about 70%) and low (about 50%). Low mulch is better in cotton fields with good water and fertilizer conditions, high mulch is better in water-deficient cotton fields, and moderate mulch is the best in general cotton fields.

The thermal effect of plastic film mulching should be exerted as much as possible in the extra-early cotton area, and the best effect is "ditch-shed mulching", that is, sowing with small colors with a width of about 17cm, and covering the ditch with plastic film can advance seedling emergence by 7- 10 days and prevent freezing injury. Dry land cotton field should give full play to the role of moisture conservation and temperature increase. Using "furrow sowing slope cover" can increase the runoff of plastic film, make the dripping water return to soup, and increase the yield by 10-20% compared with conventional plastic film mulching. In the cotton field in saline-alkali land, fresh water should be used to press alkali, and the ditch should be covered with low film to facilitate the whole seedling.

1983, the Ministry of Agriculture, Animal Husbandry and Fisheries organized the National Cotton Plastic Film Mulching Cultivation Research Collaboration Group, which was presided over by Shanxi Cotton Research Institute, systematically studied the supporting techniques of plastic film cotton cultivation in different types of cotton fields, published more than 200 related papers, and won the first prize of scientific and technological progress awarded by the Ministry in 1985. The cooperative research holds that the mechanism of increasing cotton yield by plastic film planting is mainly due to three benefits, namely, compensation effect, soil and environmental stability effect and photothermal effect. So as to promote the overall emergence of cotton, speed up the growth process, prolong the effective flowering and bolling period, make peaches big and rich, improve the quality and increase the yield.

Compensation effect refers to the compensation of ground temperature to air temperature and root system to stem and leaf. The concept of "ground accumulated temperature" is put forward and suggested as the heat index of cotton growth process. The relative stability effect of soil environment refers to the increase of ground temperature and humidity, while maintaining the relative stability of soil humidity and reducing the adverse effects of dry-wet alternation and drought on root growth. Photothermal effect is the concentrated expression of the first two effects, which leads to the coordination and acceleration of cotton growth and development.

(6) Plastic film mulching cultivation of peanuts

Peanut plastic film mulching cultivation has also been widely used in North China and Northeast China, with remarkable economic benefits, which is well received by the masses. According to incomplete statistics reported by various places, the national output of more than 6,000 mu has exceeded 1000 kg. 1983 In Liaoning Province, 370,000 mu of plastic film was planted, with an average yield of 282 kg per mu, which can increase the income by 50- 100 kg per mu compared with open planting.

Plastic film peanuts are mainly planted on ridges, so it is necessary to apply sufficient fertilizer and irrigate enough soil moisture. Now there are corresponding machines that can complete these crops at one time.

(7) Plastic film mulching cultivation in paddy field

The application of plastic film in rice seedling raising is basically the same as the previous plastic film seedling raising, that is, simple plastic film mulching, and the seedling field grows in the shed formed by plastic film, but the amount of plastic film used is a new technology which is drought-resistant, water-saving, labor-saving and efficient, and has been popularized in northern and southern provinces. In Bijie County, Guizhou Province, the yield per mu of rice planted in dry land can reach 1000 kg.

(8) Cultivation of wheat with plastic film mulching

The temperature in northern China is low and the frost-free period is short, so it is difficult to grow winter families. In recent years, large-scale development of plastic film planting wheat, that is, after sowing before winter, simply cover the border with plastic film for 2-3 weeks, and then carefully uncover the film to cover wheat before winter or cover early spring crops once in spring. At the same time, mulching plastic film in winter wheat field in early spring also has obvious yield-increasing effect. This technology not only increases the income of farmers in mountainous areas, but also solves the long-term pain of flour and rice.

(9) Plastic film mulching cultivation of corn

Corn is also a thermophilic crop, which has poor growth and low yield in alpine regions. In recent years, plastic film corn has developed rapidly and its yield has increased significantly. The yield per mu of high-yield corn can reach 1000 kg. In the mountainous areas of Guizhou, plastic film corn is known as the road to poverty alleviation. In some places in northern Shanxi, the yield per mu of plastic film sorghum can reach 1000 kg.

(10) Plastic film mulching cultivation of other crops

Plastic film mulching cultivation of tobacco not only improves the yield, but also increases the proportion of middle and high-grade tobacco leaves, which has been popularized and applied in China.

In recent years, the Sugarcane Sugar Industry Research Institute of the Ministry of Light Industry has studied and popularized the plastic film seedling raising technology of sugarcane. Combining sugarcane seedling raising technology with plastic film mulching can quickly cultivate strong seedlings, reduce pests and diseases, adapt to unfavorable soil environmental conditions, and increase production and income. The sugarcane planted by this method can increase the yield by 65,438 0.5 tons per mu, increase the sugar content by 0.8%, and increase the 250 yuan per mu.

Grape cuttings require rooting at 25-28℃, and the germination of buds begins at 13℃, so cuttings often germinate first and then take root. Causing the cuttings to dry up and die. The Forestry Bureau of Zhangjiakou City, Hebei Province, made use of the characteristics of plastic film to improve the ground temperature, and popularized the plastic film cutting of grapes in a large area, which greatly improved the survival rate of cuttings and increased (decreased) the yield per mu by about18kg.

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