A simple soilless cultivation technique for vegetables

A simple soilless cultivation technique for vegetables

Soilless cultivation refers to the cultivation method of irrigating with nutrient solution instead of natural soil. In vegetable production, it has the advantages of high yield, good quality, early maturity, light disease, no pollution, water saving, labor saving and so on, which is conducive to the realization of agricultural modernization. According to the experiment, the cost of the nutrient solution used to produce 1 kg of vegetables is only a few cents, and the method is simple and cost-effective. According to the fixation method of crop root system, it can be divided into two categories: non-substrate (also known as medium) cultivation and substrate cultivation. Substrate cultivation is to fix the roots of crops in organic or inorganic substrates and supply crop nutrient solution through drip irrigation or trickle irrigation. The cultivation substrate can be packed in plastic bags or laid in cultivation ditches or grooves. The nutrient solution cultivated in the substrate is not recycled, which can also prevent the disease from spreading through the circulation of the nutrient solution. Substrate cultivation has strong buffer capacity, there is no contradiction between water, nutrients and O2 supply, and the equipment is simpler than non-substrate cultivation, even without power, so it has the advantages of low investment and low cost, so it is widely used in production. A good matrix needs to meet the following requirements: it can fix and support crops; it has the characteristics of water holding, air permeability and buffering; it can provide nutrition. Rockwool is the most widely used matrix in many European countries. However, inorganic substrates like this need to be thoroughly sterilized before each use, and they can no longer be used after a few years, and it is difficult to recycle. In the Netherlands, which has the largest cultivation area of rock wool, it has become a public hazard. Therefore, more and more people advocate the development and utilization of organic matrix, which can be turned into the soil as fertilizer without polluting the environment.

A simple soilless cultivation technique is introduced below.

1. Fermented straw culture substrate

Preliminary preparation work: select crop (wheat, corn, etc.) straw, the amount of straw should be more than 2 times the volume of the cultivation tank, cut up the straw, the length is less than 4 cm, and then soak it with water; 4 cubic meters of cow dung, one week before the straw rot, mixed with straw mature bacteria to propagate straw mature bacteria in cow manure; the amount of urea is about 0.5% of straw.

Rotten straw: (1) the bottom width of the straw pile is 2 meters, and the length is unlimited. Each shop 20 cm straw, sprinkle a layer of cow dung mixed with straw mature bacteria and an appropriate amount of urea, if the straw infiltration of water is insufficient, and then spray the right amount of water, in order to hold the straw tightly with hands, the water between the fingers is extruded for the degree. According to this method, the straw was piled up to a height of 1.8 to 2.0 meters, and the heap was completed. (2) cover the plastic film to reduce the evaporation of water in the reactor. After 2 to 3 days, the temperature in the reactor can reach more than 70 ℃. (3) turn the pile in about 15 days, turn the straw at the edge into the middle of the pile, and further mix the straw with cow dung. If the straw is dry, it can replenish water properly. (4) after turning the pile and then composting for about 15 days, the straw is semi-rotten and has no toughness, the grip is broken, and the C / N ratio is between 30 and 40, which can be used as the substrate for soilless cultivation.

2. Cultivation and management techniques.

The main results are as follows: (1) set up the cultivation trough: the cultivation trough adopts the way of digging trench and laying plastic film. According to the row-plant distance of the cultivated crops, the width of the groove is about 25 cm, and the bottom of the groove should be flat to avoid local stagnant water; in the cultivation trough, spread 0.1 mm plastic film; fill the plastic film with fermented straw as substrate, with solid feet; planting.

(2) installation of drip irrigation equipment: drip irrigation facilities are very important for soilless cultivation and are necessary equipment for supplying inorganic nutrition and water. The main drip irrigation equipment includes power equipment, fertilizer tanks, filters, water meters, branches and capillaries. Power equipment includes water towers, frequency conversion submersible pumps for centralized water supply, etc.; fertilizer tanks are specially designed to reduce water pressure loss and solve the problem of fertilizer clogging the filter; polyethylene pipes with a diameter of 32mm to 40mm can be used in branch pipes; the distance between the drip heads of the capillaries should be 20 cm. For the laying of drip irrigation pipe, the branch pipe is parallel to the back wall of the greenhouse, it is best to disconnect in the middle and connect with the fertilizer tank with a tee, so that the water flow is diverted from the middle to both ends, and the pressure of the whole drip irrigation is more uniform; a capillary is laid in each row, so that the capillary is in the middle of the cultivation groove as far as possible, and the drip head faces up, which can reduce the blockage of drip irrigation.

(3) Management of nutrient solution: large, medium and trace element fertilizers are directly added to the substrate, that is, the fertilizers that can form chemical precipitation are separated. First, a group of fertilizers are added to the fertilizer tank, and in the process of drip irrigation, the fertilizer is dissolved into the substrate. When it is fully dissolved, stop drip irrigation and add another group of fertilizers until the end of drip irrigation. At the initial stage of planting, the root system of vegetables is very small, and a certain amount of nitrogen, phosphorus and potassium fertilizer can be dissolved in buckets with a concentration of about 1 g / liter and artificially irrigated around the seedlings once a day for about 10 days. After the roots are basically connected, drip irrigation is normally used to supply nutrient solution. 0.5 cubic meters of water and fertilizer can be irrigated every day in the early stage, and one group of fertilizer is added each time in the morning and afternoon. In autumn and winter, according to the seedling situation and weather, the amount of irrigation is generally about 1 cubic meter per day, the temperature in spring is high, the light is sufficient, the crop growth is large, and the amount of water and fertilizer under drip irrigation is 1.5-2 cubic meters per day. Drip irrigation in the morning in sunny days, no irrigation in cloudy days; the amount of irrigation can be determined by observing the accumulation of nutrient solution in the cultivation trough. Or instead of using fertilizer tanks, use solid fertilizer for soilless cultivation, and then spray clear water with eyedropper equipment, so that drip irrigation equipment can be simplified and do not have to worry about the precipitation of nutrient solution.

3. Technological advantages

The main results are as follows: (1) digging trenches can make the temperature of the cultivation substrate more stable, and the temperature difference between day and night of the substrate is much smaller than that of the permanent brick-concrete structure on the ground or half the ground, so as to avoid the too low substrate temperature at night in winter and cause damage to the root system; it can also reduce the input cost of cultivation trough equipment.

(2) crop straw is rich in resources and cheap in our country; during the use of straw matrix, CO2 is produced by microbial decomposition, which plays the role of CO2 gas fertilizer. The concentration of CO2 in the soilless cultivation greenhouse of straw substrate is more than 2000 mg / kg in the morning. Straw matrix can regulate the physiological acidity and basicity of nutrient solution, and the pH value of straw matrix is stable at about 7. At the same time, in the process of decomposition, sugars, amino acids and other small molecular organic matter can be absorbed by vegetable roots to improve the quality of vegetables; straw matrix can be used as organic fertilizer in farmland without environmental pollution.

(3) convenient management, reducing the preparation operation of traditional nutrient solution and nutrient pool facilities, saving water and fertilizer, high yield and increasing income of vegetable farmers.