Can soilless vegetable greenhouses be grown all year round in the cold climate of northeastern Inner Mongolia?

The northeastern region is relatively cold, and greenhouse technology is relatively difficult to master. Pay attention to the control of temperature and humidity, the management of nutrient solutions, the supply of inorganic nutrients and moisture, etc.

Reprinted from "Rural Science Experiment"

With the widespread cultivation of vegetables in greenhouses, more and more vegetable diseases have appeared in some places in recent years. The obstacles to continuous cropping in greenhouse soil have become an urgent production problem that needs to be solved. "Vegetable soilless cultivation technology" is one of the ways to solve this problem. The technology is now introduced as follows:

1. Fermentation of straw cultivation substrate

1. Preparation before straw composting: ① Crop straws can be wheat straw, corn straw and other crop straws , the amount of straw should be greater than 2 times the volume of the cultivation tank. For example, when planting cherry tomatoes in a standard greenhouse, the volume of the cultivation tank is about 20 cubic meters. Prepare a volume of wheat straw of more than 40 cubic meters. First chop the straw into pieces, and the length is less than 4cm. , then soak it with water and set aside. ② Use straw composite microbial preparation to compost and ferment straw. ③Use 4 cubic meters of cow dung. One week before the straw is piled to rot, it is mixed with the straw-rotating bacteria to spread the straw-rotating bacteria in the cow dung. ④The dosage of urea is about 0.5% of the amount of straw. 40 cubic meters of straw requires 25 kilograms of urea.

2. Method of stacking straw: the bottom width of the straw pile is 2 meters, the height is 1.8-2 meters, and the length is not limited. For every 20cm of straw spread, sprinkle a layer of cow dung mixed with straw-rotted bacteria and an appropriate amount of urea. If the straw is not immersed in enough water, spray an appropriate amount of water. Hold the straw tightly with your hands until the water is squeezed out between your fingers. . After the straw is piled to a height of 1.8-2 meters, the pile construction is completed. Then cover it with plastic film to reduce the evaporation of water in the pile. After 2-3 days, the temperature in the pile can reach above 70℃; turn the pile around 15 days, and turn the straw at the edge into the middle of the pile to further mix the straw and cow dung. When the straw is dry, appropriate amount of water can be added; after turning over, pile it for about 15 days, at which time the straw will be half-rotted. It has no toughness and can be broken when held in the hand, so it can be used as a substrate for soilless cultivation.

2. Cultivation operation technology

1. Cultivation trough: The cultivation trough adopts the method of digging trenches in the ground and laying them with plastic film. Take cherry tomatoes as an example: Cherry tomatoes are planted in large and small rows, with a row spacing of 60-70cm, and cultivation trenches are dug in a single row. The beginning of the cultivation trench is triangular, with an upper opening of 20cm and a depth of 25cm. The bottom of the trench should be flat to avoid local water accumulation; Spread plastic film inside: Fill the plastic film with fermented straw as a substrate and firmly use your feet; then plant cherry tomato seedlings with a spacing of 35cm.

2. Install drip irrigation equipment: Drip irrigation facilities are very important for soilless cultivation and are essential equipment for supplying inorganic nutrients and moisture. The main drip irrigation equipment includes power equipment, fertilizer tanks, filters, water meters, branch pipes and capillary pipes. Power equipment includes water towers, frequency conversion water pumps for centralized water supply, etc. In areas with shallow groundwater levels, a well with a plastic hose can be dug in a greenhouse, and a self-priming pump can be used as power to meet the needs of drip irrigation in a greenhouse; the fertilizer tank is specially designed to reduce water pressure loss and solve the problem of fertilizer The problem of clogging the filter; the branch pipe can use a polyethylene pipe with a diameter of 32-40 mm; the distance between the drippers of the capillary tube is 20cm. The distance between the drippers is close, and there are many points for moistening the straw substrate, which is beneficial to the root system of vegetables. The drip irrigation pipes should be laid so that the branch pipes are parallel to the back wall of the greenhouse. It is best to disconnect it in the middle and connect it to the fertilizer tank with a tee to divert the water flow from the middle to both ends; lay a capillary tube in each row so that the capillary tube is in the middle of the cultivation tank as much as possible, with the dripper facing upward, which can reduce the blockage of drip irrigation.

3. Management of nutrient solutions: The method of grouping nutrient solutions and fertilizers and adding them directly to the substrate is different from the traditional management method of nutrient solutions. The traditional preparation of nutrient solution is to dissolve large, medium and trace element fertilizers together. Since the groundwater in the north is generally alkaline, chemical precipitation is prone to occur during the preparation process. Generally, acid must be used to adjust the pH value of the nutrient solution, which is difficult for farmers to master. This technology uses the method of adding nutrient solution fertilizers into groups and directly adding them to the substrate. The fertilizers that can form chemical precipitation are separated. First, add one group of fertilizers to the fertilizer tank, and then During the drip irrigation process, dissolve the fertilizer and drip it into the substrate. When it is fully dissolved, stop drip irrigation and add another set of fertilizer until the drip irrigation ends.

Management method of nutrient solution: In the early stage of planting, drip irrigation is not required to supply nutrient solution. The root system of vegetables is very small, and the nutrient solution from most drippers cannot be absorbed by the root system, causing waste. A certain amount of nitrogen, phosphorus and potassium fertilizer can be dissolved in a bucket, with a concentration of about 1 g/L, and poured around the seedlings manually. Water once a day for 10 consecutive days. In the early stage of drip irrigation supplying nutrient solution, the seedlings are small. It consumes less water and fertilizer. It can drip irrigate 0.5 cubic meters of water and fertilizer every day, once in the morning and afternoon, and add one set of fertilizer each time. In autumn and winter, depending on the seedling condition and weather, the daily irrigation amount is generally controlled at about 1 cubic meter. , drip irrigation in the morning on a sunny day, and no irrigation on cloudy days; the amount of irrigation can be determined by observing the accumulation of nutrient solution in the cultivation tank. The temperature in spring is high, the light is sufficient, and cherry tomatoes grow quickly. The amount of drip irrigation water and fertilizer is controlled at about 1.5-2 cubic meters per day.

3. Cultivation effect

The sugar content of cherry tomatoes cultivated using soilless technology is 26.3% higher than that of cherry tomatoes cultivated in soil. The taste is pure, sweet and sour.

It tastes better; it can reduce the amount of pesticides, which is 1/4 of soil cultivation; it saves water and fertilizer, 150 cubic meters of water per shed, and the purchase price of fertilizer is 1,500 yuan/shed, and the fertilizer investment is about 350 yuan/shed less than that of soil cultivation. ; Output is basically the same, and overall efficiency increases by more than 20%.