The Latest Rapeseed Planting Techniques and Methods Tutorial
Growing Strong Seedlings
1. Select good varieties: According to the local cultivation system and climate conditions, combined with the local soil fertility level and production situation, choose varieties with strong stress resistance and good yield performance.
2. Prepare the seedbed well: The seedbed should be chosen in a ventilated, sunny spot with fertile, loose soil, close to a water source, and the land should be finely prepared. Seedbed preparation should achieve “level”, “fine” and “firm” conditions.
3. Sow at the right time: Rapeseed is very sensitive to sowing date. Therefore, determining the sowing date is an important issue in rapeseed cultivation. Rapeseed germination, seedling emergence and root and leaf development all require certain temperature conditions. The suitable temperature for germination requires a daily average temperature of 16-22°C, and seedling leaf emergence also requires above 10-15°C to proceed smoothly. In addition, it is necessary to ensure at least 40-50 days of effective growth period after transplanting before entering winter.
4. Seedbed management: The day before transplanting, water thoroughly with “lifting water” to make it easier to pull the seedlings and reduce root damage. In fertilizer management, grasp the principle of “promote early, control in the middle, stabilize later”. On the basis of applying sufficient base fertilizer before sowing, at the three-leaf stage, combine with thinning to topdress seedling fertilizer, generally applying 20-30 loads of clear water manure or 2-3 kg of urea per mu to promote leaf opening and seedling development. 5-6 days before transplanting, apply 7.5 kg of urea per mu as lifting fertilizer, which is beneficial for early seedling development after planting. Timely control pests and diseases: aphids and cabbage caterpillars are the main pests in rapeseed seedling fields, so apply pesticides promptly, and at the same time clear weeds around the seedbed to reduce pest sources. 3-4 days before transplanting, apply a complete “lifting pesticide” treatment to prevent pests from being brought into the main field.
Transplant at the Right Time
1. Apply sufficient base fertilizer: Rapeseed plants are tall and require a lot of fertilizer, so attention should be paid to the application of base fertilizer. Insufficient base fertilizer leads to weak seedlings, which in turn affects plant growth and even the economic yield of rapeseed. Base fertilizer should be mainly organic fertilizer, supplemented by chemical fertilizer, to lay a good foundation for the fertilizer needs of rapeseed throughout its life. Generally, apply 2000 kg of organic fertilizer per mu, 25-30 kg of 45% general-purpose compound fertilizer or 30-40 kg of 36% compound fertilizer (15-10-11), and 0.5-1 kg of boron fertilizer. Application method: Combine plowing and land preparation to apply organic fertilizer, compound fertilizer and boron fertilizer deeply. Never apply fertilizer too shallowly, so as to avoid fertilizer deficiency in the middle and late stages of rapeseed.
2. Transplant at the right time: Reasonable close planting. When seedlings are 30-35 days old, have 5-6 green leaves, and roots are 5-6 mm thick, transplant large, strong seedlings with soil, fertilizer and pesticide. Do not transplant tall-footed seedlings, bent-footed seedlings, or thin, weak, diseased seedlings. Transplanting spacing is 50cm×20cm, with about 7000 plants per mu. Transplant while covering with soil, and water thoroughly with root-setting water promptly after transplanting. 3 days after transplanting rapeseed, check for missing plants and fill gaps.
Reasonable Topdressing
1. Seedling fertilizer: Apply seedling fertilizer early and frequently, promptly supply the nutrients needed during the rapeseed seedling stage, and use the brief higher temperatures before winter to promote rapeseed growth, achieve strong seedlings overwintering, and lay the foundation for high and stable rapeseed yield. Seedling fertilizer can be divided into two topdressings: early seedling stage and late seedling stage. Early seedling fertilizer is applied at thinning or at the 5 true-leaf stage, generally applying 5-6 kg of urea per mu. In phosphorus- and potassium-deficient soils, if phosphate and potassium fertilizers were not applied as base fertilizer, supplement with phosphate and potassium fertilizers. Late seedling topdressing should be determined according to seedling condition and climate. Generally, apply 8-10 kg of high-nitrogen compound fertilizer per mu. Varieties with strong spring growth habit or areas with warmer winters should be fertilized early; areas with low winter temperatures or triple-cropping rapeseed areas may be fertilized appropriately later.
2. Bolting fertilizer: The bolting stage of rapeseed is a period when vegetative growth and reproductive growth proceed together. The plant rapidly bolts and grows branches, leaf area increases, and flower buds differentiate in large numbers. This is the period of greatest fertilizer demand and also the key period for increasing branches and pods. Therefore, based on the application of base fertilizer and seedling fertilizer and the growth condition, apply bolting fertilizer steadily as appropriate. If base fertilizer and seedling fertilizer are sufficient and plants grow vigorously, apply less or no bolting fertilizer; if base fertilizer and seedling fertilizer are insufficient and there is a trend of fertilizer deficiency, apply bolting fertilizer early. Generally, apply 15-20 kg of high-nitrogen compound fertilizer per mu. The fertilization time is generally in the middle bolting stage, when the bolt height is 15-30 cm. However, for weak growth, fertilizer can be applied at the early bolting stage to avoid premature aging; for strong growth, it can be applied at the late bolting stage, when the bolt height is 30-50 cm, to avoid excessive growth at flowering that causes closure of the canopy.
3. Flower fertilizer: After rapeseed bolts, it flowers while forming pods. The number and weight of seeds are closely related to the nutritional conditions after flowering. For vigorous growth with a large amount of fertilizer applied at the bolting stage, it may be omitted or applied less; for early-maturing varieties, do not apply, or apply less at the initial flowering stage. Flowering topdressing can be done by foliar spraying. During the flowering and pod-setting period, spray 0.1-0.2% urea or 0.2% potassium dihydrogen phosphate. In addition, at the late seedling stage and bolting stage, spray a 0.2% borax aqueous solution once each to prevent the phenomenon of “flowers but no seeds” and increase yield.
Irrigation and Drainage
Reasonable irrigation and drainage are important measures to ensure high and stable rapeseed yield. Rapeseed has a long growth period, large vegetative mass, luxuriant foliage and many fruiting organs, and requires a relatively large amount of water throughout its life. In rapeseed-producing areas, rainfall in autumn, winter and spring is generally low, and the soil is dry, which is not conducive to sowing, seedling emergence and growing strong seedlings. In northern regions, winter drought often aggravates freezing damage and causes dead seedlings. In southern regions, excessive rainfall in the later period causes waterlogging damage. Therefore, it is necessary to irrigate and drain promptly according to local conditions based on the water requirements of rapeseed.
Scientific Topping
45-50 days after rapeseed transplanting, when flower buds appear at the top of the plant, topping should be done at the right time to encourage rapeseed to produce more robust primary branches, form an excellent population structure, and obtain the best yield. The flower buds should be manually removed during the shortened-base growth stage after budding but before bolting. After topping, the plant should retain 8-9 leaves. If done too early, the flower buds have not completed differentiation and growth is insufficient, which is unfavorable to rapeseed growth; if done too late, rapeseed has already bolted and cannot form an excellent population structure, and is prone to forming branches at high nodes, which are easily broken and lodge in the later growth stage.
Pest and Disease Control
The main pests and diseases harming rapeseed include cabbage caterpillars, flea beetles, aphids, cotton bollworms and so on. For damage by cabbage caterpillars, flea beetles and aphids, use 25% deltamethrin 3000-fold solution or 40% dimethoate 1000-fold solution by spray control. For cotton bollworm damage, at the young larval stage, use 40 g of Baode plus 20 g of Wanling per mu mixed with water and spray, once every 5-7 days, for 2-3 consecutive sprays.
Harvest at the Right Time
Rapeseed should be harvested at the right time when mature. If harvested too early, the siliques have not developed to maturity; if harvested too late, the siliques are overripe, the pod shells easily split, and seeds scatter, causing waste. When the siliques are in the yellow-ripe stage, that is, when 2/3 of the siliques of the whole field have turned yellow, it is the best time to harvest rapeseed. Harvesting at this time can obtain the highest oil content and highest yield of rapeseed.