Detailed Explanation of Key Cultivation and Management Techniques for Bell Peppers in Greenhouses
Bell pepper belongs to the plant kingdom, class Dicotyledoneae, subclass Asteridae, family Solanaceae. Together with red chili peppers, it is collectively called pepper. The fruit is a berry. It has many aliases - big pepper, lantern pepper, and persimmon pepper are all names for it; because it can bear sweet berries, it is also called sweet pepper or vegetable pepper. It is an annual or perennial herbaceous plant, characterized by relatively large fruit with mild pungency or no pungency at all, used as a vegetable rather than as a seasoning. Because of its bright emerald green color, and newly bred varieties that also come in red, yellow, purple and other colors, it can not only stand alone as a dish but is also widely used as a side ingredient.
Environmental requirements of bell pepper
Temperature requirements: The adaptable temperature range is 15-35 °C, the suitable temperature range is 25-28 °C, and the germination temperature is 28-30 °C.
Moisture conditions: It likes moisture and fears drought and waterlogging; the soil should be moist but not waterlogged.
Light conditions: It is not strict about light, requiring moderate light intensity; 10-12 hours of light per day is favorable for flowering and fruiting. The growth and development of bell pepper require sufficient nutritional conditions. For every 1000 kg of bell peppers produced, 2 kg of nitrogen, 1 kg of phosphorus, and 1.45 kg of potassium are needed, along with an appropriate amount of calcium fertilizer. As for soil requirements, moist sandy loam that drains easily is best; the soil pH should preferably be neutral, and slightly acidic is also acceptable.
Cultivation and management techniques for bell peppers in greenhouses
Greenhouse vegetable cultivation is a cultivation form that uses the heat-retention performance of greenhouses during cold seasons to grow warm-season vegetables inside the greenhouse, achieving early maturity, high yield, and high efficiency.
1. Reasonable close planting
After the previous crop is harvested, plow and sun the soil in time. Apply 2-3 tons of decomposed farmyard manure, one bag of compound fertilizer, and one bag of ordinary calcium superphosphate per mu as base fertilizer. The reasonable planting density for peppers is 50-60 cm between rows and 30-40 cm between plants, using single-row planting, with about 3000 plants per mu.
2. Field management work
1. Temperature management: Do not ventilate within one week after planting; focus on heat preservation. The suitable growth temperature for peppers (sweet peppers, wrinkled peppers) is 20-25 °C; the nighttime temperature must not be lower than 10 °C. As the temperature rises, during the seedling stage, ventilate by removing the film between 9:00-10:00, and after 15:00-16:00 close the door and cover the film again. Spray the new high-lipid film early to shorten the seedling recovery period.
2. Moisture management: Peppers are relatively drought-tolerant and not waterlogging-tolerant. To obtain high yield, moisture management must be strengthened. If drought occurs during the flowering and fruiting period, irrigate in a timely manner to keep the soil moist.
3. Topdressing: (1) Light application of seedling fertilizer: After planting and survival, apply 1000 kg of human excrement and urine per mu, or 5-6 kg of urea, combined with intertillage and irrigation. (2) Stable application of flower bud fertilizer, appropriately increasing phosphorus and potassium fertilizer to promote more branching and fruiting. Apply 15-20 kg of urea, 10 kg of ordinary calcium superphosphate plus 10 kg of potassium sulfate per mu. (3) Heavy application of flower and fruit fertilizer: Combine nitrogen, phosphorus, and potassium fertilizers. Apply 2000 kg of human excrement and urine, 15-20 kg of ordinary calcium superphosphate, 15 kg of potassium sulfate, and 20-25 kg of cake fertilizer per mu, or 30 kg of compound fertilizer plus 2 kg of zinc sulfate. Apply in holes, cover with soil and water after application. Combined with spraying pepper stalk-strengthening agent, it can enhance the nutritional matching function of various pepper plants and thicken the fruit stalk. Note to keep 8-10 cm away from the plant root to avoid burning the roots, or fertilizer directly contacting the root stem and causing rot.
3. Pest and disease control
Greenhouses are used to grow vegetables most of the time, especially in winter, providing suitable environmental conditions for pests and diseases to overwinter and reproduce, which will make vegetable pests and diseases increasingly serious. Therefore, pest and disease control is the key to successful vegetable cultivation in greenhouses. Targeted pesticides + new high-lipid film should be sprayed for control.
As the number of planting years increases, brown spot disease of greenhouse bell peppers worsens year by year, seriously affecting the yield and quality of bell peppers.
Brown spot disease of bell pepper mainly damages leaves and can also damage stems and branches. Affected leaves first show nearly circular brown spots, which gradually become grayish brown, with the surface slightly raised. The lesions have an obvious light gray center, surrounded by dark brown concentric rings, with a yellow halo at the edge. In severe cases, multiple lesions connect, and the leaves turn yellow and fall off. The pathogen belongs to the subphylum Deuteromycotina fungi, overwintering as conidia and mycelium in diseased residues and on seeds, becoming the primary infection source the following year. High temperature and high humidity favor the disease.
The occurrence of brown spot disease in greenhouse bell peppers has 4 characteristics: (1) Long duration; it can be found throughout the year. (2) Large area. (3) Obvious peak periods. It occurs lightly in February, spreads slowly from March to April, and the first disease peak appears in spring greenhouses from late May to mid-June. The second disease peak appears in autumn greenhouses from late October to early November, and the severity of the disease is greater than in spring. (4) Severe damage. In the past two years, it has occurred relatively heavily. During peak periods, the diseased greenhouse rate is generally 70%, the diseased leaf rate is 20%-30%, and in severely diseased fields the diseased leaf rate reaches more than 95%, with a large number of fallen leaves.
To control brown spot disease of greenhouse bell peppers, agricultural measures can be taken for prevention. Implement paddy-upland rotation and choose well-drained sandy loam soil for planting; avoid using soil from diseased fields for seedling raising; open the three ditches well and irrigate reasonably; cover with plastic film to reduce humidity inside the greenhouse; clean up diseased residues in time. When temperature and humidity are high inside the greenhouse, apply pesticide early for protection. When diseased plants are found, use chlorothalonil, procymidone, and flusilazole alternately for spray control. In continuous cloudy and rainy weather with insufficient light, when humidity inside the greenhouse is too high, fumigation is advisable, using 300 g of 15% procymidone fumigant per mu.