In recent years, tomato umbilical rot has occurred from time to time in the production of tomato in protected fields. The disease is a physiological disease and has a great influence on the yield and quality of tomato.
First, symptom recognition
Umbilical rot disease can develop in tomatoes, such as the size of the thumb until the color matures. The lesions only occur in the umbilicus at the top of the fruit. At the beginning of the lesion, the water was immersed in dark green, and soon became dark brown or black with a necrotic spot 1 to 2 cm in diameter or larger. The flesh of the lower part of the lesion was rotted and rotted, the umbilical portion was sunken, sometimes cracked, and the fruit became flat. Sweeten. In severe cases, the lesions expand to half of the fruit surface. The fruit stops expanding and turns red earlier. The peel is pliable and dull and loses its food value.
Second, the cause of the incidence of umbilical rot
First, fruit enlargement period, water supply is not balanced, especially under drought conditions, or when the water absorption ability of the root system is weak, the water supply is unbalanced, the fruit umbilical contends for lack of water to hinder its growth and development, forms umbilical rot, and secondly, calcium deficiency causes umbilicus. Department of cell physiology disorders, leading to disease.
Third, affect the incidence of umbilical rot disease conditions
1. Soil texture. The sand is strong, the leakage of water leakage is serious and the weight of saline-alkali heavy land is heavy.
2. The terrain. The slope is large, and the land where water and fertilizer are easily lost is heavy.
3. Soil calcium content. The soil contains less calcium and organic acids, especially when soluble calcium is insufficient.
4. Fertility stage. During the fruitful flowering of tomatoes, water supply was insufficient, or fertilizers were recovered too late, and when the concentration of soil solution suddenly increased, the disease became severe.
Fourth, control methods
The control of nitrogen application, balanced fertilization of nitrogen, phosphorus, and potassium, and proper amount of foliar-sprayed calcium are all beneficial to the prevention of the occurrence of umbilical rot.
1. Applying basal fertilizer when leveling the ground, applying organic fertilizer with phosphorus and potassium as fertilizer in tomato base fertilizer, such as using pre-calcium and potassium sulfate or compound fertilizer with medium-nitrogen and medium-phosphorus-potassium as base fertilizer.
2. Irrigate the water in a timely manner to prevent it from drying out when wet, and in particular not to make the soil excessively dry. Pour the first water when planting, and the second time the water is poured when the flower begins to set, and the amount of water should not be too large. After the third inflorescence was opened, the first fruit was as large as an egg before pouring water. To keep the soil moist, summer irrigation should be carried out in the early morning or early evening. Pay attention to diligence and shallow pouring.
3. Calcium supplementation using a combination of leaf and root methods. After the topdressing of calcium fertilizer, tomato is the key period for absorbing calcium within 30 days after fruit set, so from the beginning of flowering stage, foliar spray of 1% of superphosphate or 0.1% of calcium chloride or calcium compound fertilizer is sprayed every 15 days. 1 time, continuous spraying 2 to 3 times.
A Viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Thus, a rheometer can be considered as a special type of viscometer.[1] Viscometers only measure under one flow condition.
In general, either the fluid remains stationary and an object moves through it, or the object is stationary and the fluid moves past it. The drag caused by relative motion of the fluid and a surface is a measure of the viscosity. The flow conditions must have a sufficiently small value of Reynolds number for there to be laminar flow.
At 20 °C, the dynamic viscosity (kinematic viscosity × density) of water is 1.0038 mPa·s and its kinematic viscosity (product of flow time × factor) is 1.0022 mm2/s. These values are used for calibrating certain types of viscometers.
Viscometer
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