Lettuce is a vegetable variety with high yield and good economic benefits. The development of lettuce in many places has become an important way for farmers to increase their income. For example, Pengzhou City, Sichuan Province, has planted lettuce with an area of ​​64,000 mu and a total output of 250 million kilograms. It has now developed into the largest production base in the southwest region. Most of its winter and spring lettuce products are exported to the northwest, northeast and other provinces. It is very popular among customers and consumers. The high-yield cultivation techniques of winter and spring lettuce mainly have the following aspects:
1, variety selection
Overwintering lettuce and spring lettuce have selected cold-tolerant, adaptable, and late-twisting varieties, such as cold-resistant extra large white skin, special cold-resistant two green skin, cold-resistant extra large new hanging silk red, special cold-resistant two white skin, cold-resistant white leaves, cold-resistant white Skin, bitter leaves, etc.
2. The sowing date is determined
Overwinter lettuce shoots 10-November open seedlings, spring lettuce shoots from December to March next year, and seedlings in the open field from mid-February to late March.
3. Cultivate strong seedlings
(1) Site preparation. Select the plot with high dryness and good drainage as the seedbed. Apply 10 kg of decomposed organic fertilizer per square meter or 0.5 kg of compound fertilizer for 5-7 days before sowing. After being applied before the soil preparation, it is turned deep, flattened and covered, and covered with plastic film for planting. (2) Sowing. Spring lettuce, when planting seedlings in greenhouses, first uncover the film on the nursery and pour the bottom water. After the water has been infiltrated, mix the seeds in a small amount of fine sand or fine soil and mix well. 10 to 30 grams of seedlings of 10 square meters seedbed. After sowing, cover the soil by 0.30-0.50 cm, cover the film tightly, and cover the sunshade net or grasshopper at night. Open field nursery with a small arch shed. Before the seedlings are unearthed, cover the cover early and keep the bed temperature. After the seedlings are unearthed, properly ventilate, keep the bed temperature at 12-20 °C during the day and 5-8 °C at night.
4. Planting and management
When planting, choose loam with good drainage conditions, and apply 4000-5000 kg of decomposed organic fertilizer per acre. Deeply flattened and made into a sorghum of 1.20 to 1.50 meters wide. Before the seedlings, water the seedbed first. Overwintering lettuce, the seedling age is about 40 days old and covered with plastic film, the plant spacing (30-35) cm × (30-40) cm. After surviving, apply 1-2 times of light manure water. Before winter, you should pay attention to refining the seedlings. It is not suitable for fertilizing water to prevent excessive growth during seedling stage. It is necessary to reapply 1 cold-proof fertilizer. Hunchun timely cleared weeds and ploughed for 1 time. The concentration of topdressing was from small to large. After the stem base begins to expand, the number of top dressings decreases and the concentration decreases. For mulch and greenhouse cultivation, it is necessary to apply sufficient fertilizer and pay attention to ventilation management. Spring lettuce, seedling age 25-30 days, 5-6 leaves when planting, plant spacing 20 cm × 27 cm, depth to bury the first petiole base is appropriate. Lettuce listed on the leaf, the row spacing is 15 cm × 20 cm. If the mulch is covered and cultivated, the base fertilizer should be applied at one time, and the mulch film should be covered, and the rain can be drained to prevent stains. Cultivation in greenhouses and open fields, 1-2 times in sunny and warm weather, timely watering and topdressing, early pouring of dry manure, keeping the surface moist, and when the plants are basically closed, the tender plants can be listed. Take the stem as the product, apply urea 15 kg per mu for 1-2 times.
5. Pest control
Lettuce downy mildew, use 75% chlorothalonil WP 600-800 times, or 58% Redolmer 500 times solution, or 40% fox cream WP 200 times solution, or 72.20% Plex water agent 800 times liquid and other rotating spray. Lettuce sclerotinia sclerotiorum, using 70% methyl thiophanate WP 700 times solution, 50% keiling WP 1500 times solution, 50% phlegm WP 1000 times solution and other rotation. Lettuce black spot disease, using 50% seawater WP 1500 times solution, 40% captan WP 400 times solution, 70% ethyl phosphine manganese zinc wettable powder 500 times solution, 75% chlorothalonil WP 600 times liquid spray.
This article URL: The main points of high-yield cultivation and fertilization techniques for lettuce
SE-12B Digital Three Channel Color Touch Screen ECG Machine(electrocardiograph)
Features
- The system is designed with a high-resolution thermal printer featuring 8dot/mm
vertical resolution and 40dot/mm horizontal resolution(at 25mm/s) speed and filter as
well as related marks.
- Simultaneously 12 lead signal acquisitions.
- Digital filter to prevent baseline drift and automatic positioning of the baseline provide
accurate ECG trace.
- Able to detect and alarm on electrode disconnection.
- LED indicator and LCD display show operation status of the unit.
- Isolated input circuit guarantees safety standard in compliance to Class I type CF.
- AC/Rechargeable battery supports continuous operation when AC power supply is not
available. For the battery operation, the system is equipped with a battery charger and
a system for battery capacity management and protection.
- Compact size.
Specifications
Lead: Standard or Cabrera 12 leads,Simultaneously 12 leads acquisition
Sampling rate: 1000Hz(1ms)
Frequency Response: 0.05 ~ 150Hz
Time Constant: ≥3.2s
CMRR: >100dB
Input Circuit: <0.1 µA
Noise Level: ≤ 8 µVp∽p
Polarization Voltage: ±500mV
Sensitivity valve: 20 µV
Calibration Voltage: 1mV ±0%
Filter: AC: 50Hz-20dB(or 60Hz); EMG
filter:25-35-45Hz-3dB;
Drift filter: 0.5Hz -3dB
Sensitivity: 1.25, 2.5, 5, 10, 20mm/mV±2%,40 when format setted at 6ch or 3+3ch
Paper Speed: 5, 6.25, 10, 12.5, 25, 50mm/s ±3%
Recording MODE: Thermal array printer 8 dot/mm(Vertical) 40 dot/mm(Horizontal, 25mm/s)
Paper Size: 210mm20m or 216mm20m, thermal roll paper
Ecg Machine,Ecg Machine 12 Channel,Electrocardiograph Machine 6 Channel,Three Channel Ecg Machine
Guangzhou Sonostar Technologies Co., Limited , https://www.sonoeye.com