Greenhouse vegetable planting method
It is one of the effective means to increase farmers' income by planting plastic film vegetables in greenhouse, artificially creating suitable ecological environment, adjusting vegetable production season and market demand, and promoting high quality and high yield of vegetables. From the survey of most vegetable farmers in greenhouses, the benefits are obvious. However, some farmers grow vegetables in greenhouses, and the effect is not ideal, except that the vegetable varieties are wrong. Four evils? Constraints are often important factors that cause losses. So-called? Four evils? Namely, fertilizer damage, drug damage, drought damage and continuous cropping obstacle.
First, fat damage. In fact, it is the harm of salt accumulation, the main reason is that part of the application of chemical fertilizer or excessive fertilization makes the soil salinized. The problems caused by fertilizer damage are: first, inhibiting the root development of vegetables and weakening the function of absorbing water and fertilizer; Second, the concentration of soil solution is too high, which leads to reverse osmosis of vegetable plants and physiological wilting or leaf edge scorching; Third, the harm of toxic gases; The fourth is to cause plant element deficiency.
Second, plant toxicity. The toxicity is obvious and the symptoms are obvious. Potential phytotoxicity, potential symptoms or extension to the next crop of vegetables. The causes of phytotoxicity are as follows: first, the wrong choice of pesticide varieties or improper use of herbicides; Second, the application concentration is too large; The third is to buy inferior pesticides; Fourthly, the application in high temperature season is not avoided. After plant poisoning, some vegetable leaves turn green quickly; Some produce focal spots and perforations; Some leaves, flowers, fruits or deformities appear; The most serious whole plant withered.
Third, drought. This is one of the most critical factors restricting the development of greenhouse vegetables. The reasons are: firstly, improper location of vegetable greenhouses and lack of local water sources; Second, although there is water source, the water quality is poor; Third, there is sufficient water, but ditches, canals and irrigation facilities are not matched. It is difficult to draw water, but it is a sigh. Drought disaster not only affects the timely sowing and seedling safety of vegetables, but also affects the normal growth of vegetables, and also brings great difficulties to the management of fertilization and pesticide application of vegetables. The impact of drought sometimes exceeds that of fertilizers and drugs.
Fourth, continuous cropping obstacles. That is to say, in the same greenhouse, the same category or vegetable is planted every year or every season, and the yield and product quality are declining year by year. The reasons for the obstacles are: first, the same kind of vegetables prefer a certain nutrient element, and if they are not supplemented in time, they are prone to element deficiency; Second, the accumulation of soil pathogenic bacteria causes diseases and causes dead seedlings, such as Fusarium wilt and Fusarium wilt; Thirdly, the substances secreted by the roots of the same vegetable easily lead to the imbalance of soil microbial community structure and cause soil aging.
Therefore, in the process of greenhouse site selection and production, it is necessary to sum up experiences and lessons and take effective measures in time to produce more high-quality vegetables.
First of all, we should choose a good shed location and improve the water system. Before determining the greenhouse, it is necessary to check whether there is enough water in the shed site and whether the water is polluted. With sufficient water, ditches should be opened to facilitate water diversion and drainage. Where conditions permit, each greenhouse should be equipped with a water supply faucet. High standards should also be equipped with sprinkler irrigation facilities.
Secondly, it is necessary to balance fertilization and promote the stable growth of vegetables. First, we should apply fully decomposed organic farmyard manure all the year round; The second is to apply refined organic fertilizer and high-energy organic fertilizer, such as Ye Meifeng and Guo Meifeng; Third, it is necessary to change the partial application of nitrogen and phosphorus into reducing nitrogen, stabilizing phosphorus and increasing potassium, and applying micro-fertilizer; Fourth, fertilization should be carried out in several stages; Fifth, if fertilizer damage occurs in one day, it is necessary to spray various active liquid fertilizers to reduce the damage.
Thirdly, we should use drugs scientifically to ensure the safety of vegetables. First, slight phytotoxicity occurs, and the normal fertility function of vegetables can be restored by strengthening fertilizer and water management; Second, choose the right pesticides, especially herbicides, and use them carefully; Third, control the dosage and concentration of pesticides, while avoiding the repeated use of a pesticide; Fourth, avoid mixing pesticides at will; Fifth, high temperature should be avoided in application; Sixth, the instruments that have been applied with herbicides must be cleaned before they can be used again.
The fourth is to rotate crops and adjust the vegetable planting environment. First, eggplant, tomato and melon are prone to diseases, and other vegetable varieties should be replaced in different years or seasons; Second, it is necessary to apply more organic fertilizer to improve the greenhouse soil that is prone to repeated obstacles; Third, choose soil continuous cropping agent to inhibit germs; The fourth is to replenish the missing nutrients for the soil lacking elements in time.
Planting forms of greenhouse vegetables
Natsuna in spring.
Early-maturing cultivation of eggplant and melon vegetables [1] is the most common project in greenhouse cultivation. Open field cultivation is generally sown in late March to mid-April and harvested in early May to July. Greenhouse cultivation can be planted1-March in advance and harvested from late March to July. Early listing, high yield, long flowering and fruiting period and obvious economic benefits. In addition, according to market demand, warm green leafy vegetables such as amaranth, auricularia auricula and water spinach can be planted in advance and listed in advance.
Delayed culture
The general harvesting period of delayed cultivation in autumn and winter in Natsuna is 10 ~ 12. If preserved, it can last until the Spring Festival with high economic benefits.
Leafy vegetables
In the greenhouse, in addition to tall vegetables such as melons and eggplants, there are leafy vegetables with high economic value, such as fungus, water spinach, celery and lettuce. It can be cultivated in advance in spring and overwintering in autumn to avoid freezing injury, promote growth, increase production and supply, and go on the market out of season, with good economic benefits.
Thermotolerant leafy vegetables, such as auricularia auricula and water spinach, can be planted in 9- 10 greenhouse, covered with heat preservation in the later stage, put on the market in advance, and basically realize annual supply with conventional cultivation. Lettuce and other vegetables like cold, but they are not resistant to frost. It is best to plant them in open fields from the end of August to the beginning of September and from March to April in spring. If it is planted from June 165438+ 10 to March of the following year, it is cultivated in greenhouse.
cultivation by setting seedlings
From late June to early August, strong light, high temperature, thunderstorm and typhoon rainstorm in southern China seriously affected vegetable production and early autumn vegetable seedling. In recent years, the application of sunshade nets and non-woven fabrics has promoted the role of greenhouse in seedling cultivation in summer.
Matters needing attention in greenhouse vegetable planting
I. Types and hazards of harmful gases
1, ammonia gas and nitrous acid gas mainly come from nitrogen fertilizer and organic fertilizer applied to the soil, especially in the case of excessive fertilization and soil drought, when the fertilizer encounters high temperature in the shed, it will decompose to produce a large amount of ammonia gas in a short time. When the concentration of ammonia exceeds 5ppm, some sensitive vegetables, such as cucumbers and tomatoes, will be hurt. At first, the leaves turned brown after drying, as if they had been scalded by boiling water. When the concentration of ammonia reaches 4%, the vegetable seedlings will die after 24 hours. When the content of nitrite gas in the air reaches 2-3ppm, it will harm sensitive vegetables such as eggplant, tomato and pepper, and its symptoms mainly occur on leaves near the ground, and rarely harm new leaves. It was like being scalded by boiling water at first. Later, due to the acidification of nitrite, the veins gradually turned white, and in severe cases, only the veins were left, and the mesophyll bleached and died.
2. When the plastic greenhouse containing carbon monoxide and sulfur dioxide gas is heated by coal fire, a large amount of carbon monoxide and sulfur dioxide gas will often be produced due to incomplete combustion or unsmooth flue. The harm of these two gases can be divided into three types: first, hidden poisoning, vegetables themselves have no obvious harm, but the assimilation function is reduced and the quality is worse, which generally has little effect on yield; Second, chronic poisoning, gas invades from the stomata on the back of the leaves, brown spots appear in and around the stomata, and the surface is yellow; The third is acute poisoning, which produces whitening symptoms similar to the harm of nitrous acid gas.
3. Toxic gas emitted by plastic film itself Some plastic films will produce some volatile substances, such as ethylene and chlorine. It can invade plants through stomata or water holes on leaves, destroy cell tissues and chloroplasts, obviously weaken photosynthesis, and seriously affect the yield and quality of vegetables. According to some data, the concentration of chlorine in the air reaches 0. 1ppm, radish can be damaged after 2 hours of contact, and the concentration reaches 0.5-0.8ppm. Most vegetables can be damaged after only 4 hours of contact. At first, white or light brown irregular spots or blocks appeared between the veins, and in severe cases, the whole leaves turned white or even fell off. When the concentration of ethylene gas in the protected field reaches more than 1ppm, the leaves between the veins of vegetables can turn yellow, and then turn white until they die. According to experimental observation, ethylene can also make many vegetable leaves droop and inhibit tomato seedlings; In the concentration range of 0. 1-3ppm, the flowers, buds, young fruits and leaves of tomato and eggplant will fall off abnormally.
In addition, excessive use of aerosol pesticides in greenhouses will also cause harm to vegetables.
Second, prevention and control measures
The harmful gases in the greenhouse not only affect the growth and development of vegetables, but also directly endanger the health of vegetable farmers. Therefore, we must take active measures to prevent and control it.
1, scientific fertilization of greenhouse vegetables should be based on high-quality soil mixed fertilizer, appropriately increasing phosphorus and potassium fertilizer, and appropriately increasing nitrogen fertilizer, and insisting on base fertilizer as the main fertilizer, supplemented by topdressing. Top dressing should be strictly observed? How many times? The principle of preventing excessive fertilization. Topdressing method adopts furrowing and deep application, and then it is covered tightly with soil and watered in time to dilute the fertilizer.
2. Ventilation in time. When the temperature is high at noon, open the vent to let the air circulate; Even if it is cloudy or snowy, it should be ventilated for a short time at noon to minimize harmful gases in the shed and reduce air humidity.
3. Reduce the source of toxic gas when heating plastic greenhouse with coal fire, make the fuel burn fully as far as possible, install chimney on the stove, and lead the harmful gas out of the greenhouse.