Detailed Explanation of High-Yield Cultivation Techniques for Broccoli
Selection of varieties and determination of sowing dates. Broccoli is suitable for growing in cool climates and can only be cultivated in autumn and winter. It is generally used for processing and export, requiring firm heads, dark green color, small to medium florets, mid-to-late maturity, high yield, and a relatively long harvest period to facilitate factory production scheduling. Based on these requirements, in recent years mainly excellent early-maturing and heat-tolerant varieties such as Weilai and Youxiu have been selected.
Selection of field plots. Select plots with good drainage and irrigation conditions and where the previous crop was not a cruciferous plant (Chinese cabbage, cabbage, cauliflower, radish) as the seedling nursery and transplanting field.
Seedlings should be raised in facility greenhouses that are well-ventilated, well-drained, shaded, and rain-proof.
After sowing, immediately cover the seedbed with plastic film to preserve moisture, add shade netting on top of the film to reduce temperature, cover the greenhouse with an overhead film, and add shade netting on top of the overhead film, keeping the temperature inside the greenhouse at around 25°C. Check germination 2 days after sowing; when about 70% of seeds have germinated, remove the plastic film and shade netting from the seedbed in the evening.
Seedbed management: Do not water before the seedlings break through the heart stage to prevent excessive hypocotyl elongation that forms leggy seedlings. The seedling period should not exceed 25——30 days. Main seedling diseases include: damping-off and Rhizoctonia rot. The control method is to alternately use 75% chlorothalonil 500x solution or 50% carbendazim 500x solution and other agents 2——3 times after the seedlings emerge through the soil.
Apply sufficient base fertilizer and plant at reasonable density. Before transplanting, apply 100——200 loads of decomposed organic fertilizer per mu, 50 kg of high-concentration compound fertilizer, and about 0.8 kg of boron fertilizer. (Without boron fertilizer, the stalks are prone to hollowing; it can also be sprayed on the leaves during the vigorous growth period at 10——12 leaves.) Then plow and make beds, using high ridges with double rows, ridge surface width 1 m, plant spacing about 40 cm, planting 2700——3000 plants per mu. After transplanting, immediately water thoroughly to settle the roots.
Field management. Broccoli likes fertilizer and water; timely topdressing and watering in stages are the key to high quality and high yield.
Fertilizer management. The entire growth process requires sufficient nutrients, especially before bud initiation; forming sufficient vegetative mass is the key to achieving high yield and improving the qualification rate, otherwise the heads will be loose. The fertilization principle is to apply light seedling-promoting fertilizer, sufficient plant-developing fertilizer, and skillful head-enlarging fertilizer. On the premise of applying sufficient base fertilizer, topdress three times, namely: 7——10 days after transplanting, apply seedling-promoting fertilizer once, with 5 kg of urea plus 100 kg of dilute decomposed human manure per mu. At 10——12 leaves, apply plant-developing fertilizer, with 15 kg of urea plus 10 kg of high-concentration compound fertilizer per mu. At the bud initiation stage, when the flower buds are about the size of a ping-pong ball, apply head-enlarging fertilizer, with 5 kg of urea per mu.
Water management. Broccoli has relatively strict water requirements; it is neither tolerant of waterlogging nor drought. Water management should be based on field soil moisture conditions, carrying out irrigation and drainage. Irrigation should be done after evening as run-through water, with no standing water left in the field the next day. After rain, pay attention to timely drainage as well as intertillage and hilling to increase soil permeability and promote root development.