Detailed Explanation of Broccoli Cultivation Techniques and Field Management Key Points
Broccoli, also known as stem broccoli, Italian kale, green cauliflower, tree cauliflower, tender-stem cauliflower, etc., is a variety of cabbage and an annual or biennial herbaceous plant. Its green flower heads are used for food. It has good flavor and high nutritional value. Its fresh green and crisp texture and refreshing taste have been recognized by...
Broccoli, also known as stem broccoli, Italian kale, green cauliflower, tree cauliflower, tender-stem cauliflower, etc., is a variety of cabbage and an annual or biennial herbaceous plant. Its green flower heads are used for food. It has good flavor and high nutritional value. Its fresh green and crisp texture and refreshing taste have been recognized by many urban and rural consumers, consumption momentum is rising day by day, and the cultivation area is becoming larger and larger.
1. Variety Characteristics
Broccoli has a well-developed root system and an obvious main root; the leaves are lanceolate or long ovate, and the leaf color changes from blue-green to dark blue-green, with a relatively thick waxy layer, forming a leaf rosette composed of more than 20 leaves; the flower head, which is the economic yield part, is composed of fleshy flower stems, their branched pedicels, and dense flower buds; after the main flower head is harvested, axillary buds branch and can continue to grow small flower heads, and their flavor and edible value remain unchanged. Therefore, it can also be harvested continuously many times for market. The seeds are round and brown, generally with a 1000-seed weight of 2.5-4 grams.
2. Requirements for Environmental Conditions
1. Temperature: Broccoli has relatively strong cold tolerance and heat tolerance. The suitable temperature for seed germination is 25°C, the suitable temperature for growth and development is 20-22°C, and the suitable temperature for flower bud development is 15-18°C. Above 25°C, development is poor; below 5°C, growth is slow; it can withstand short-term frost. Although flower bud clusters can still emerge in hot summer, they are relatively thin and small, and the quality is relatively poor.
2. Light: Broccoli is a low-temperature long-day plant and grows normally under sufficient light conditions. Insufficient light causes the plant to grow excessively, the flower stem and pedicel to elongate, and the flower head to become loose and yellow. The production and formation conditions of broccoli flower heads are relatively complex. Only after certain light and temperature conditions have been passed and the vernalization stage has been completed can flower bud differentiation begin.
3. Soil and Nutrients: Broccoli is not very strict about soil requirements, but fertile loam fields are better for cultivation. During its growth and development, it needs sufficient nutritional conditions. In addition to major elements such as nitrogen, phosphorus, potassium, magnesium, and sulfur, it also needs a certain amount of trace elements. When fertilizing, pay attention to applying various elements together. In particular, nitrogen fertilizer must not be excessive, otherwise it will easily cause excessive plant growth, excessive vegetative growth, delay the appearance of flower heads, and easily cause rotting diseases.
4. Water: Broccoli likes a warm and humid environment, but must not be waterlogged. The suitable relative soil humidity is 70-80%, and it grows and develops well in moist soil.
3. Variety Selection
Broccoli can be divided into three types according to maturity period: early, medium, and late maturing. Most broccoli varieties currently cultivated in China are introduced from countries such as the United States and Japan. Different suitable varieties should be selected according to different cultivation seasons. For summer production, varieties with strong heat tolerance and early maturity should be selected; for winter production, varieties with cold tolerance, compact plant type, and firm flower heads should be selected, mainly medium-maturing or medium-early maturing varieties.
1. American Broccoli is a first-generation hybrid introduced from the United States. The plant has strong growth vigor, disease resistance, and high yield. The plant height is about 55 cm, the flower head is loose and dark green, and a single top head weighs 300-400 grams. Side branches are well developed, and side head yield is high.
2. Zhulü was introduced by the Yulin City Institute of Agricultural Sciences. The plant height is about 40 cm. The flower head weighs about 350 grams and is dark green. The plant has more waxy bloom, black rot occurs less, and it can be harvested about 60 days after planting, belonging to an early-maturing variety. Its flower bud differentiation period is uniform, and the harvest period is relatively concentrated. It has strong heat tolerance and wide adaptability, and is suitable for sowing and cultivation in spring and summer-autumn. The yield per mu is 1000-1500 kg.
3. Luling is a first-generation hybrid introduced from Japan. The plant has strong growth vigor. The plant height is about 40 cm. The flower head is oblate and light green. The flower head weighs 500-700 grams, the head is firm, there are many side branches, and the branching ability is strong, making it relatively high-yielding.
4. Qiulü is a first-generation hybrid introduced from Japan. It can be harvested about 80 days after planting and belongs to a medium-maturing variety. The flower head weighs about 400 grams, has few bumps and hollows, and the flower head is plump and round, beautiful. The flower head is compact, and the buds are fine, dense, and uniform. The main stem is slightly thick and not prone to hollowing. Because it is a top flower bud type, it is not prone to producing side flower buds, and harvesting work efficiency is high. It can be cultivated in autumn and winter.
4. Cultivation Techniques
1. Cultivation Season: In South China, sowing can be done at any time from July to January of the following year. Early and medium-maturing varieties are mainly used. Late-maturing varieties are not suitable because the required low-temperature conditions cannot be met.
2. Sowing and Seedling Raising:
(1) Preparation before sowing: Broccoli can be raised using nutrient cups or seedbeds. For nutrient cup seedling raising, first prepare nutrient soil; choose 3 parts garden soil or paddy field soil that has not grown cruciferous vegetables within 3 years, add 1 part fully decomposed farmyard manure, then add 1 kg calcium superphosphate per cubic meter of nutrient soil, 0.6 kg potassium sulfate or 0.5 kg biological potassium, mix thoroughly, and fill cups; for seedbed seedling raising, choose loam with convenient irrigation and drainage and make beds with a width of 1.7-1.8 m including trenches and a bed height of 20-25 cm as the seedbed, apply 10-15 kg decomposed organic fertilizer per square meter, and apply a certain amount of phosphate fertilizer and potassium fertilizer, then mix the fertilizer evenly with the soil, rake it fine, and level it for sowing.
(2) Sowing: For sowing in nutrient cups, wet the nutrient soil before sowing, sow 1 seed per cup, cover with thin soil after sowing, and spray with Duel herbicide; for seedbed sowing, mix the seeds evenly with a certain amount of fine sand before sowing, with a sowing rate of 4-5 grams per square meter (that is, sowing 5 square meters of seedlings is enough to plant one mu of field). After sowing, cover with 0.5-1 cm of thin soil, wet it, spray with Duel herbicide, and then cover with a thin layer of rice straw. When sowing in late summer and early autumn, the weather is still in a period of high temperature and rain. Whether using nutrient cups or seedbed seedling raising, it is necessary to pull up shade nets to shade and protect from rain.
(3) Seedling management after sowing: After sowing, pay attention to watering and often keep the soil moist. For seedbed seedling raising, seedlings can emerge in about 3 days, and the rice straw should be removed in time. During the emergence period, the relative soil humidity should be kept at 70-80%. After the seedlings emerge uniformly, supplement water as appropriate. For summer seedling raising, special attention should be paid during the seedling stage to controlling damage from striped flea beetles and cabbage caterpillars. Remove the shade net 7-10 days before transplanting to allow the seedlings to receive sufficient light for hardening. Standards for strong broccoli seedlings: plant height about 15 cm, stem diameter 0.6-0.8 cm, and 4-5 leaves.
3. Planting and Field Fertilizer and Water Management
(1) Planting: Before planting, the land must be prepared well and sufficient base fertilizer applied. Broccoli plants are tall and have a large growth volume, and they have relatively high requirements for soil nutrient conditions. Choose a place with convenient irrigation and drainage and apply sufficient base fertilizer, applying 2000-2500 kg decomposed farmyard manure per mu, appropriately applying boron fertilizer and calcium fertilizer, and evenly mixing the base fertilizer into the soil. Choose a sunny afternoon for planting, use double-row planting, with a plant spacing of 30-40 cm. Early-maturing varieties are generally planted at 3000 plants per mu, and medium-maturing varieties at 2000-2500 plants.
(2) Field fertilizer and water management: Broccoli likes fertilizer and water. Timely topdressing and watering in stages are the key to high yield. The topdressing type is mainly nitrogen fertilizer. In the early growth stage, topdress 2-3 times, each time applying 25-30 loads of decomposed manure and urine water per mu, or 8-10 kg urea. When entering the flower head formation stage, apply heavy fertilizer, applying 25-30 kg compound fertilizer (preferably organic compound fertilizer) per mu, plus an appropriate amount of magnesium, calcium, sulfur, boron fertilizer, etc., and combine with intertillage and hilling. When entering the harvest stage, topdress once after each harvest to promote the growth of side flower heads, applying 15-20 kg compound fertilizer per mu.
Broccoli requires a relatively large amount of water, especially during the flower head formation stage, when it should be irrigated in time to keep the soil moist. During the rainy season, drainage should be done in time to avoid root rotting.
4. Pest and Disease Control: Common main pests and diseases of broccoli include black spot disease, downy mildew, aphids, cabbage caterpillars, diamondback moths, striped flea beetles, cabbage armyworms, etc.
(1) Disease control: For black spot disease, in the early stage of the disease, spray with 50% carbendazim 500-fold solution, or 65% zineb 500-fold solution, or 50% thiophanate-methyl 500-fold solution, spraying continuously 2-3 times, once every 7 days; for downy mildew: in the early stage of the disease, spray with 58% metalaxyl 600-fold solution, or 64% oxadixyl-mancozeb 500-600-fold solution; or 75% chlorothalonil 600-fold solution, spraying continuously 2-3 times, once every 7 days, and pay attention to alternating medications.
(2) Pest control: For aphids, spray with 40% dimethoate 1000-fold solution; for cabbage caterpillars, diamondback moths, striped flea beetles, and cabbage armyworms, spray with 80% dichlorvos emulsion 1000-fold solution, or 2.5% deltamethrin 2500-fold solution; or 20% fenpropathrin 2000-fold solution.
5. Harvesting: When the top flower head of the broccoli plant has fully expanded and the flower buds have not yet opened, harvest in time to avoid loose heads or flowering caused by harvesting too late. When harvesting, cut off the flower head together with about 10 cm of the lower flower stem. After the top head is harvested, the axillary buds of the plant germinate and quickly grow side branches, and flower heads, namely side flower heads, form at the tips of the side branches. When the side flower heads grow to a certain size and the flower buds have not yet opened, they can be harvested again, so that 2-3 harvests can be made successively.