What to Do About Boron Deficiency in Rapeseed? Symptom Identification and Control Methods
Rapeseed is grown extremely widely in China, and it is highly sensitive to the element boron. Boron deficiency can seriously affect rapeseed yield, and boron deficiency is fairly widespread in most of China's soils. Therefore, applying borax at planting time has a clearly noticeable effect on rapeseed. So what are the symptoms of boron deficiency in rapeseed? How should it be controlled? Let's take a look.
1. Symptoms of boron deficiency
When boron is deficient at the seedling stage, the seedlings show dark green leaves and crinkled blades, and later purple-red spots appear, the leaves drop early, and in severe cases the seedlings die. When boron is deficient at the bolting stage, the leaf margins turn red, the leaves become thick and brittle, the top of the main stem withers and is unable to feed, sometimes stem splitting occurs, and the flower buds develop abnormally, or even dry up and drop off. When boron is deficient at the flowering stage, the inflorescence is noticeably dwarfed and the tip shrivels, flowering is delayed, large numbers of flower buds drop, young pods are deformed, and there may even be a complete absence of pods. When boron is deficient at the pod stage, flowers form but no seed sets, pods contain no seeds or only small and deformed seeds, and seed size is uneven.
2. Causes of boron deficiency
First, boron deficiency is related to the soil. When the soil has poor water-holding capacity, the element boron is very easily lost, causing boron deficiency. It is also related to environmental factors. Research shows that the plant's uptake of the element boron weakens as light intensity decreases; during drought, the transport of the element boron is blocked, which also causes boron deficiency; and when moisture content is high, boron is lost. Boron also has mutually restraining relationships with elements such as nitrogen, phosphorus and potassium. When the plant's nitrogen content is relatively high, it will take up boron to balance it; generally, boron-deficient plants are found to have higher nitrogen levels than normal plants. In addition, boron deficiency affects the plant's uptake of phosphate fertilizer, yet it can promote the uptake of potash fertilizer. Therefore, when a plant is boron deficient, potash fertilizer should not be applied, so as to avoid worsening the boron deficiency symptoms.
3. Control methods
Before sowing or transplanting rapeseed, apply an appropriate amount of borax, so as to meet the rapeseed's demand for the element boron throughout the whole growth period. Generally, applying 1-2 jin of boron fertilizer per mu is sufficient; mix it into the base fertilizer and apply it together. At the seedling stage and bolting stage, the foliar spraying method can be used to supplement the plant's boron needs; generally, spray a very low-concentration borax solution once each at the seedling stage, bolting stage and flowering stage. When topdressing, apply nitrogen, phosphorus and potassium fertilizers reasonably, and do not over-apply any single one, so as to increase the soil's boron content. Water promptly during drought, and drain promptly during the rainy season.
The above is an introduction to boron deficiency symptoms in rapeseed and control methods. We hope it helps you. To learn more related knowledge, please stay tuned to us.