One is the most common water damage to root and leaf yellow. Often occurs in the third or four days after pouring water, and the standard symptoms of iron deficiency is very similar, that is, near the growth point of the new leaves become yellow, green veins. After a large amount of water is poured on vegetables, the air in the soil is squeezed out by water, and most of the gaps in the soil are occupied by water. The roots of vegetables need to breathe. In such an environment of air shortage, the capillary roots of vegetables will suffocate and die due to breathing difficulties.
Farmers often find that after pouring a large amount of water, the "white root" is gone, some become brown, which is called the "red root". This injury causes the capillaries to die and get injured in large Numbers. Their ability to attract iron suddenly drops. It's not really the lack of iron in the soil, it's the damage to the capillaries that makes the iron less attractive. It is a temporary deficiency of iron in the plant, and there is no shortage of iron in the soil, so it is unnecessary to apply iron fertilizer to the soil.
It is necessary to spray iron-zinc leaf fertilizer around the growth point where yellowing occurs, and the effect will be very good. Some people misjudged the lack of nitrogen, increased nitrogen fertilizer and water, then the yellow leaves become particularly serious, long time difficult to recover. In this case, never water it again. Second, it is necessary to seize the time to dig the ground, loose soil, increase soil moisture evaporation, change air permeability, restore the normal growth of capillary roots is the key to the problem. Exposure about 1/4-1/3 of the greenhouse in winter has the problem of excessive watering and root injury, such as the use of biological fermentation organic fertilizer
, so that the soil solubility weight reduced, better permeability, such as attention to the use of alternate watering, drip irrigation, improve the water temperature and other methods, this kind of yellow leaf problem is not difficult to prevent.
Root damage caused by excessive water and yellow leaves is similar to that of root damage at low temperature. Which occurs in winter, greenhouse vegetables in low temperature even in the rain and snow, greenhouse temperature drops caused ground temperature reduction, ground temperature around 10 ℃ will interfere with root to absorb nutrition, including the absorption of iron.
And yellow leaves of vegetable leaves also can produce similar to iron deficiency, through improving canopy temperature and ground temperature is the key to solve the problem, after the rain and snow, or watering in the winter usually enhance canopy temperature 1-32 ℃ higher than that of normal, such as watering in the winter, well water maximum temperature will reach 5-10 ℃, a lot of cold water to make ground temperature sudden drop, and yellow leaves of pouring water cause more severe than usual, So on the day and the second day of watering, we should increase the canopy temperature reach 32 ℃ so as to improve the ground temperature to prevent this damage of cold water.Yellow leaves caused by root injury due to the Sticky soil, large water and low ground. which can be improved by applying organic fertilizer and increasing the tempetature.
Yellow leaves often occur on clay ground, which is caused by poor permeability of clay soil. Increasing the application of organic fertilizer and npk compound fertilizer are the best way to improve soil permeability
. A large number of cheap organic matters, such as corn straw and wheat straw, pig, chicken and cow manure can be used for organic compost fermentation
, finally can be processed into high-quality organic fertilizer by the whole set of organic fertilizer production line
If the three conditions of sticky soil, large water and low ground could be improved, the yellow leaves caused by root injury won not occur.