Detailed Explanation of Key Techniques for High-Yield Rapeseed Cultivation

In recent years, the demand for rapeseed in our country has been growing, and its price has been increasing year by year, so growing rapeseed has become a choice for some people to increase their income. Some people experience poor yields when growing rapeseed because they do not use the right methods. To achieve high rapeseed yields, you also need to understand some techniques.

High-Yield Rapeseed Cultivation Techniques

1. Seedbed preparation: Choose a field with level land, fertile texture, a sunny slope, and convenient irrigation and drainage as the seedbed; dry land, dry stubble land, and half-sandy half-loam land are good seedbed sites. Enough seedbed area should be reserved to help cultivate strong seedlings. Too dense planting easily forms tall, spindly seedlings and weak seedlings. The ratio to the main field is generally 1:4.5. Rapeseed seeds are small, so the seedbed should be level, fine, and firm, that is, the bed surface level, the soil layer finely crushed and appropriately compacted, to ensure uniform seed distribution and consistent depth, and early and rapid emergence. Prepare the land and apply sufficient base fertilizer, mainly organic fertilizer, with N, P, and K combined. Per mu, 2000-2500 kg of farmyard manure, 20-30 kg of superphosphate, and 100-150 kg of plant ash can be applied. After preparing the seedbed, open ditches and make beds. Bed width 1.3-1.7 m, field width 0.27-033 m.

2. Seed treatment and sowing: Before sowing, the seeds should be sun-dried for 1-2 days, 3-4 hours per day. Select seeds with 8-10% salt water, and soak seeds in warm water at 50-54 degrees C for 15-20 minutes, which can both kill pathogens and promote germination. Soaking seeds in 0.8% urea and 1.6% boron solution for 5 hours can promote strong seedlings and early development. Generally, for Brassica napus rapeseed, sow 0.2-0.3 liang per mu on average. For uniform sowing, the seeds can be divided and quantified by bed. Mix with appropriate fine soil or plant ash and broadcast, then cover lightly after sowing.

Seedbed Management for High-Yield Rapeseed

Strengthen management after sowing, achieving two earlies and two diligents, namely early thinning and final thinning of seedlings. Early topdressing and weeding, diligent watering and drainage, diligent pest and disease control. After full emergence, thin the seedlings so that seedlings do not crowd each other. Leaves should not overlap leaves; final thinning at the true leaf stage. Seedling spacing 8-225px. Topdressing should be early; fertilizing should be combined with weeding. Apply one topdressing at final thinning. Before the leaf stage, cultivate and apply less; after 5 leaves, control appropriately. Apply a “starting fertilizer” 6-7 days before transplanting. In case of drought, water promptly. Seedling-stage pests are mainly aphids, cabbage caterpillars, and flea beetles, with aphids causing the most serious damage. They can be controlled with 2.5% deltamethrin 300-fold solution. Using growth regulators to cultivate short, strong seedlings is a technique adopted more in recent years. Spraying 100 mg/kg paclobutrazol on the leaves at the 3-leaf stage significantly dwarfs rapeseed seedlings, thickens the root crown laterally, makes the number of branches obvious, and leads to quick survival after transplanting, which is beneficial for increasing yield.

Fertilization Techniques for High-Yield Rapeseed

1. Apply seedling fertilizer early. Apply seedling fertilizer early and frequently, promptly supplying the nutrients needed by rapeseed seedlings, taking advantage of the brief higher temperatures before winter to promote rapeseed growth, achieve strong seedlings overwintering, and lay the foundation for high and stable rapeseed yields. Seedling fertilizer can be applied as two topdressings: early seedling stage and late seedling stage. Early seedling fertilizer is applied at final thinning or at the 5 true-leaf stage, generally 5-6 kg of urea per mu. In soils deficient in phosphorus and potassium, if no phosphorus and potassium fertilizer was applied as base fertilizer, phosphorus and potassium fertilizer should be supplemented. Late seedling topdressing should depend on seedling condition and climate. Generally, 8-10 kg of high-nitrogen compound fertilizer per mu. For varieties with strong spring growth or in warmer winter areas, apply early; in areas with low winter temperatures or triple-cropping rapeseed regions, it can be applied somewhat later.

2. Skillfully apply flower fertilizer. After rapeseed bolts, it flowers while forming pods. The number of seeds and seed weight 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 reduced; for early-maturing varieties, do not apply, or apply less at the beginning of flowering. Flowering topdressing can be done by foliar spraying. During flowering and pod formation, spray 0.1-0.2% urea or 0.2% monopotassium phosphate. In addition, at the late seedling stage and bolting stage, spray once each with 0.2% borax aqueous solution to prevent the phenomenon of “flowers but no seeds” and increase yield.

Pest Control Methods for High-Yield Rapeseed

1. Rapeseed sclerotinia stem rot. Control methods. Use disease-resistant varieties. Reduce primary infection sources. Improve the rapeseed ecological environment. Such as heavily applying base fertilizer and seedling fertilizer, applying bud and bolting fertilizer early or in a controlled way, applying sufficient phosphorus and potassium fertilizer, and preventing excessive vegetative growth and lodging. Deep ditches and narrow beds, clean ditches to prevent waterlogging. During the rapeseed flowering period, remove diseased, yellow, and old leaves. Sow at the proper time, appropriately delayed sowing. Chemical control. The types and amounts of chemicals are: 40% dimethachlon (formerly known as wenkulili) wettable powder 1000-1500-fold solution 1-2 times, 50% carbendazim powder or 40% miebingwei suspension concentrate 500-fold solution 2-3 times.

2. Rapeseed viral disease. Control methods: The key is to prevent infection at the seedling stage. Use disease-resistant varieties. Appropriately delay the sowing date. Control aphids and repel aphids to prevent disease. Before rapeseed emergence and during the seedling stage, strengthen the control of aphids on host plants such as cabbage and radish in the cruciferous vegetables near rapeseed fields. Yellow boards can also be set up in rapeseed areas to trap and kill aphids. For specific control measures, see the aphid section.

At the initial stage of rapeseed planting, good varieties should be selected and seed treatment should be done well. At this time, the seedbed should also be prepared well, so as to ensure its survival rate. The fertilization techniques for rapeseed at different stages are also different, so this aspect of technology should also be mastered well. As long as these tasks are done well, the rapeseed planted will presumably be high-yielding.