Explained: Causes of Red Leaves in Rapeseed and Their Solutions
Rapeseed is a common vegetable and one of China's main oilseed crops, and it is a source of household income for many farmers, but during cultivation, large areas of rapeseed red leaves can appear. What is going on here? Follow the editor to take a look at the causes and solutions for rapeseed.
1. Fertilizer deficiency
If rapeseed is planted too densely at the seedling stage, the seedlings may develop red leaves due to insufficient nutrients. When nitrogen is lacking, the plants become short, new leaves emerge slowly, and the leaves are small, forming yellow-red leaves; when phosphorus is lacking, plant growth slows, the leaves are small and thick, and the leaves turn purplish red; when boron is lacking, the roots swell and blue-red spots appear on the leaves.
Solution: When planting, keep a reasonable density, thin the seedlings in time, remove dense ones and keep sparse ones, remove weak ones and keep strong ones, and topdress promptly after thinning. For nitrogen deficiency, apply 8-10 kg of urea or 20-30 kg of ammonium bicarbonate per mu, and later spray urea solution to maintain nitrogen. For phosphorus deficiency, apply 25-30 kg of superphosphate per mu, and later spray superphosphate solution to maintain it; for boron deficiency, use 100 g of borax per mu diluted with water for spraying.
2. Drought
If rapeseed encounters drought during growth, the soil moisture is seriously insufficient, which weakens the root system's ability to absorb water and fertilizer, causing the plants to be short and the leaves to turn pale red.
Solution: In weather with long-lasting drought and no rain, water and irrigate in time to avoid red leaves, but when watering, do not use flood irrigation, so as not to kill the seedlings.
3. Waterlogging
Drought can cause rapeseed red leaves, and excessive rain or poor soil drainage can form waterlogging, which in mild cases causes rapeseed leaves to turn red, and in severe cases leads to root rot and dead seedlings.
Solution: Choose land with higher terrain and good drainage for planting, drain water in time after the rainy season, and loosen the soil at the same time to maintain soil permeability and promote root growth and development.
4. Freeze damage
When rapeseed encounters temperatures below zero, its root absorption capacity weakens, causing a physiological fertilizer deficiency, which blocks chlorophyll production in the leaves, and a large amount of anthocyanin appears, causing the leaves to turn purplish red. In northern low-temperature freeze damage, red rapeseed leaves are relatively common.
Solution: Choose varieties with strong cold resistance for planting, and in low temperatures combine intertillage, hilling, and increased application of organic fertilizer and other measures to reduce freeze damage to the plants and allow them to grow normally.
The above is an introduction to the causes of rapeseed red leaves and their solutions. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.