What causes yellow leaves on tomatoes
Tomatoes are a vegetable with a relatively large planting area in our country. No matter what you plant, you will often encounter many problems during the growing process. Tomatoes are certainly no exception. For example, when growing tomatoes, poor conditions such as leaf curling, freezing damage and yellow leaves often occur. So today, what we bring you is the causes of yellow leaves on tomatoes and the control methods. Let's take a look together below!
1. Causes of yellow leaves
Soil salinization
Tomatoes cannot be grown in continuous cropping. With the soil used year after year, substances such as nitrogen, phosphorus and potassium in the soil are fixed. This forms a large amount of salts that cannot be absorbed by tomatoes, leading to soil salinization. When tomatoes are planted continuously for more than three years, the probability of soil salinization reaches more than 30%. This causes poor nutritional growth of tomatoes and the appearance of yellow leaves.
Nutrient deficiency
The nutritional demands of tomato growth are relatively large and comprehensive. If nutrients such as nitrogen, potassium and magnesium are lacking, the leaves in the middle and lower parts of the plant will gradually turn yellow; if iron and zinc are lacking, the upper leaves will turn yellow. And if chemical fertilizers are applied excessively, the yellowing will be worsened. The root cause of nutrient deficiency lies in the soil and the plant roots. Poor soil quality or poor root development will both affect the plant's nutrient absorption and cause yellow leaves.
Root diseases
Root diseases are also a main cause of tomato yellowing, such as root rot, fusarium wilt and so on. A mild outbreak will affect root development, leading to poor nutrient absorption and naturally causing yellow leaves. If the outbreak is severe, it will not only cause yellow leaves but also lead to dead plants. In addition, excessive watering, which causes soil compaction, or improper pesticide use, will both cause yellow leaves on tomatoes.
2. Control methods
Soil salinization
Before planting, the soil should be deeply plowed and given one heavy watering to leach the saline substances down to the bottom of the soil. Then increase the proportion of farmyard manure applied, raise the organic matter content in the soil, promote the adsorption of saline substances and protect root growth. Then appropriately apply microbial fertilizer by flushing to let microorganisms decompose the saline substances.
Nutrient deficiency
First, we need to reduce the amount of chemical fertilizer applied and increase the proportion of organic fertilizer. Carry out scientific fertilization according to the growth stage of tomatoes. For example, during the full fruit stage of tomatoes, appropriately carry out foliar topdressing, supplement nitrogen, potassium and magnesium fertilizers, and reasonably supplement the corresponding nutrient elements according to the soil fertility conditions. You can also use substances such as seaweed fertilizer to drench the roots, promoting root growth and strong plants in tomatoes. Finally, do a good job in preventing and controlling root diseases and insect pests, reduce the occurrence of diseases and insect pests, protect the roots, and control the amount of watering well. Do not water too much. When water accumulates, drain it in time and use pesticides reasonably.
The above is a brief introduction to what causes yellow leaves on tomatoes. There are many causes of yellow leaves on tomatoes. When growing tomatoes, we should pay attention not to use continuous cropping and solve the problem from the root. That is all for today's introduction. This article is for reference only. I hope it can help everyone!