Detailed Explanation of the Five Major Characteristics of the Rice-Rapeseed Combined Planting Model

Rapeseed is an important oil crop in the Yangtze River Basin. Traditional rapeseed cultivation involves raising seedlings and transplanting them. Because raising seedlings and transplanting rapeseed in paddy fields requires large inputs of labor and materials, with low yields and low returns, and crops are easily lost when unsuitable weather occurs, this affects farmers' enthusiasm for planting rapeseed. Changing traditional seedling transplanting to no-till broadcast direct seeding with rice straw mulching simplifies the production process and achieves the goal of cost saving and efficiency improvement. Compared with traditional seedling transplanting, the rice-rapeseed combined model has the following characteristics:

First, for no-till broadcast direct-seeded rapeseed, the labor used for rice straw mulching is 5 workdays per mu, and the yield per mu can reach 90-170 kg, so the return can reach 35 yuan per workday, which is 4-5 times that of transplanted rapeseed.

Second, it eases seasonal conflicts. The growth period of direct-seeded rapeseed becomes shorter, and the maturity period is correspondingly earlier, which is conducive to connecting the stubble of the next crop.

Third, it helps ensure the planting density of rapeseed and promotes balanced yield increases over large areas. In addition, rice straw mulching cultivation can also loosen the soil, improve soil structure, reduce damage to soil aggregate structure, increase soil organic matter content, stimulate the massive reproduction of soil microorganisms, and improve soil fertility.

Fourth, it is conducive to rapeseed emergence. When rice is harvested, the soil moisture content is relatively high, and seedlings emerge quickly after sowing. No-till direct-seeded rapeseed is generally sown in mid-to-late October, later than transplanted rapeseed, avoiding the period of high incidence of autumn drought, with a high seed germination rate and uniform emergence. In particular, because sowing is late, there is no aphid damage, and virus disease is relatively mild; especially with no-till direct seeding, it overcomes root damage caused by transplanting, the main root penetrates deeply into the soil, and it eliminates the phenomena of crooked roots, hanging roots and curved necks, with a well-developed root system, short and sturdy plants, and good lodging resistance. At the same time, during the overwintering period, with direct seeding on rice stubble plus rice straw mulching, the soil temperature at a depth of 5-10 cm in the rapeseed field is 0.2-2.0°C higher than in plowed fields, and cold resistance is enhanced.

Fifth, it is simple to operate, reducing procedures such as seedling raising, plowing, transplanting and intertillage, simplifying cultivation techniques, reducing labor use, and lowering labor production intensity. It is conducive to developing winter agriculture and stabilizing the development of rapeseed production. It is an efficient conservation tillage planting model for paddy fields.