What causes red leaves in rapeseed? Causes and solutions

Rapeseed is a common vegetable and one of the main oil crops in China, and it is a source of household income for many farmers, but during cultivation, large areas of rapeseed plants develop red leaves. What is going on here? Follow the editor to take a look at the causes and solutions for rapeseed red leaves.

1. Nutrient deficiency

If rapeseed is planted too densely at the seedling stage, the seedlings develop red leaves due to insufficient nutrition. When nitrogen is lacking, the plants become short and small, 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 develop a purplish-red color; when boron is lacking, the roots swell and the leaves develop blue-red spots.

Solution: When planting, maintain a reasonable density, thin the seedlings in time, remove the dense and keep the sparse, remove the weak and keep the strong, and topdress fertilizer in time after thinning. When nitrogen is lacking, apply 8-10 kg of urea or 20-30 kg of ammonium bicarbonate per mu, and later spray a urea solution to maintain nitrogen levels. When phosphorus is lacking, apply 25-30 kg of superphosphate per mu, and later spray a superphosphate solution to maintain it; when boron is lacking, use 100 grams of borax diluted with water per mu for spraying.

2. Drought

If rapeseed encounters dry weather during growth, the soil moisture is severely insufficient, which weakens the root system's ability to absorb water and nutrients, causing the plants to become short and small 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, be careful not to flood-irrigate, so as to avoid seedling death.

3. Waterlogging

Drought can cause red leaves in rapeseed, 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 plots 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 nutrient deficiency, which hinders chlorophyll production in the leaves, and large amounts of anthocyanins appear, causing the leaves to become purplish-red. In the low-temperature freeze damage of the north, the phenomenon of rapeseed leaves turning red is relatively common.

Solution: Choose varieties with strong cold tolerance for planting. During low temperatures, combine measures such as intertillage, earthing up, and increasing the application of organic fertilizer to reduce freeze damage to the plants and allow them to grow normally.

The above is an introduction to the causes of and solutions for red leaves in rapeseed. I hope it can help you. If you want to learn more related knowledge, please follow us.