Rapeseed In the past two years, rapeseed in Jiangsu Province has encountered strong cold wave weather before the wintering period (mid-December) and during the wintering period, and the minimum temperature in the Huai area is about -8, with a large cooling range and a long duration of low temperature, resulting in a wide range of rapeseed peripheral leaves being frozen and white and dying. Due to the late sowing, the leaf age and seedling body are small, and the cold resistance is weak, and the whole field is seriously frozen and killed, which affects the expansion of rapeseed area and yield in the province.
In order to ensure that the area of rapeseed is planted sufficiently, the production capacity of rapeseed is effectively improved, and the income is compensated, we have organized experts to formulate a high-yield cultivation technology for rapeseed replanting after spring on the basis of the demonstration experience of rapeseed replanting experiments in previous years, which can be used as a reference for large growers in need of replanting.
1 Variety selection
Based on the factors of experimental demonstration planting and provenance in previous years, it is recommended to select early-maturing and high-yield spring rape varieties with partial spring, such as: Qingza No. 7 (selected by Qinghai Academy of Agricultural Sciences), Yingchun No. 1 (selected by Zhejiang Academy of Agricultural Sciences), etc. Qingza No. 7 has been experimentally planted in Lianshui, Xinghua, Xiangshui, Nanjing and other places, and in 2023, the average yield per mu of spring-sown rape in Lianshui County will be more than 100 kg per mu (the sowing period is from February 2 to 16).
2. Early sowing at the right time
In the area south of the Huaihe River in Jiangsu Province, before and after the "beginning of spring", the average temperature of the day can be sown when the average temperature reaches more than 3, and the latest can be sown until February 20, and early sowing in the appropriate period is conducive to high yield. The results of different sowing dates showed that after sowing after February 20, the growth period of rapeseed was delayed, and the yield formation period was very easy to encounter high temperature to ripen and the deflated seed rate was high.
3. Fertilize the land
After spring, the stubble mouth of rapeseed is relatively wide, and the frozen soil can be deeply turned before winter, and the depth of ploughing is 20 30 cm to improve the soil structure. Before sowing, plough the land in time according to soil moisture and weather conditions. Apply sufficient basal fertilizer before sowing, and rotary tillage into the soil.
4 Fine seeding.
Mechanical strip seeding is recommended in order to improve the quality of seeding. The sowing depth is 1 2 cm, and the amount of seeds per mu is 05～0.6 kg, the sowing row is equipped with a suppression device in order to suppress and retain moisture. Ensure that 30,000 and 35,000 seedlings per mu are grown. If drones are used for aerial sowing, the seeds must be covered after sowing. The amount of seed per mu is 06～0.8 kg, first sowing and then ditching, using a disc ditching machine to ditch and throw soil, ditch soil evenly throw furrow cover seeds.
5 Fertilizer management.
The target yield per mu is more than 100 kg, and 20 kg of 45% ternary high-efficiency compound fertilizer and 3 5 kg of urea are applied per mu of base fertilizer; Seedling fertilizer was topdressed with 3 5 kg of urea per mu at the 4 5 leaf stage; When the height of the sprout is 5 10 cm, 5 kg of urea per mu is applied.
6 Moisture management
After sowing, the "three ditches" (compartment ditch, surrounding ditch, waist ditch) are excavated in time, and the ditches and ditches are required to be connected, and they can be drained and irrigated. When excavating the compartment trench, pay attention to the width of the compartment and the cutting width of the harvester, and the width of the compartment is generally 20～2.4 meters. After the completion of rapeseed sowing, if the soil moisture is insufficient, the method of furrow irrigation and leaching box can be used to promote seed germination. For fields that do not have irrigation conditions, a suppression device should be added during sowing to retain water and moisture. There is a lot of rain, so drain it in time and make sure that the rain stops the field from drying.
7. Green prevention and control
Within 3 days before germination after sowing of rapeseed, the soil can be sealed with acetochlormonium or metolachlor; In fields where weeds occur heavily, selective weeding is carried out at the weed 2 3 leaf stage or rape 4 5 leaves. Foliar spraying was carried out with fungicides, insecticides, potassium dihydrogen phosphate and boron fertilizer at the early flowering stage to achieve the effects of "one promotion and four preventions" such as promoting growth, preventing sclerotinia sclerotinia disease, preventing flowers and fruits, preventing premature aging in the later stage, and preventing rat tails. Weak growth of the field can also be in the compound solution, add 05 kg of urea or other water-soluble fertilizer containing amino acids. When soil sealing and chemical removal are carried out, they must be used correctly in accordance with the herbicide instructions, and do not increase the dosage and compound pesticides at will. When using drones for soil sealing treatment and weed removal, the total amount of liquid medicine per mu is not less than 5 liters to ensure the amount of water. Choose to spray on windless and sunny days to prevent the liquid medicine from drifting to the surrounding wheat fields and causing pesticide damage.
8. Timely machine receipt
Spring-sown rape is generally harvested in early to mid-June. When more than 90% of the shorn fruits in the field are loquat yellow, a special rape harvester is used for one-time mechanical combined harvesting, and the straw is crushed and returned to the field. If you need to ripen and harvest, you can spray ethephon or "immediate harvest oil" 5 to 7 days before harvest to improve the consistency of silica ripening and reduce the loss of machine harvest. If there is no special harvester for rapeseed, the rapeseed plants can be manually cut down first, dried in the field for 3-5 days, and then mechanically concentrated threshing. Do not use a rice and wheat harvester without any modification to directly harvest rapeseed, and the loss rate is extremely high.