When the crop is deficient in potassium, the old leaves and leaf margins are usually yellow, and then brown, causing burns like burning; brown spots or plaques appear on the leaves, but the middle leaves, veins and proximal veins are still green. As the degree of potassium deficiency increases, the whole leaf becomes reddish brown or dry, and necrosis occurs; the root system is short and few, easy to prematurely decay, severely decay, and easy to fall. The symptoms of potassium deficiency in major crops are as follows.
● Wheat: The plants are blue-green, the leaves are weakly draped, and the tips and edges of the upper, middle and lower leaves are yellow and the old leaves are scorched. The stem is weak, prematurely aging, and easy to fall.
● Corn: the length of the leaves and stem sections is out of proportion, the leaves are long, the stems are short, the tips and edges of the old leaves are brown and scorched, and the stems are small and weak, and easy to fall.
● Potato: Slow growth, short internodes, reduced leaf area, tightly arranged leaflets, forming a small angle with the petiole, rough, shrinking and curling downward. The early leaves are dark green, then turn yellow, then turn brown, the leaf color changes gradually from the tip and edge to the whole leaf, the lower old leaves dry and fall off, and the inside of the tuber is blue.
● Rice: At the seedling stage, the leaves are green with blue, the old leaves are weakly covered, the heart leaves are straight, the red-brown tissue necrosis appears at the tip of the middle and lower leaves, and the leaves have amorphous red-brown spots. Then the old leaves are burnt and prematurely fading. The rice bushes are scattered. The leaf sheath is short, the leaves are relatively long, the root system is significantly damaged, and the grain is lacking in luster and is not full. Easy to fall and infected with leaf spot and red blight.
● soybean; potassium deficiency at seedling stage, small leaves, dark green leaves, lack of luster. In the middle and late stages of potassium deficiency, the tip and edge of the old leaves are chlorotic and yellow, and the veins are convex. Shrinking, the front end of the blade curls downwards, sometimes the petiole becomes brown, and the roots age and prematurely decay.
● Cotton: In the early stage of cotton deficiency, the mesophyll tissue chlorotic appeared yellow-colored plaques. The severely deficient potassium leaves are burnt like burnt, curling toward the buck. The cotton boll is small, the vomiting is poor, the disease resistance is low, the premature aging is easy, the yield is low, and the quality is poor.
● Rapeseed: the tip and edge of the leaf begin to yellow, and the veins are chlorotic. There are brown patches or partial self-drying. When the potassium is severely deficient, the mesophyll tissue is obviously burning, the leaves are scorched, and then withered. Some stems have brown streaks on the surface, and the lesions continue to develop, causing the whole plant to wither and die.
● Chinese cabbage: browning from the lower leaf margin, gradually developing to the inner or upper leaves, and the lower leaves withering, the ability to resist soft rot and downy mildew decreased.
● Tomato: The leaf margin of the old leaf is curled, and the veins are chlorotic. In this chlorotic area, there are small brown spots on the edge. After the old leaves fall off, the stem becomes thick, lignified and the roots are weak. The fruit is unevenly colored, and the back is often green and does not fade. It is called "green back disease".
● Cucumber: The plant is dwarfed, the internodes are short, and the leaves are small. The leaves are bronzed, the leaf margins are yellowish green, and the main veins are sunken. In the later stage, the chlorosis is severe, and it expands to the middle of the blade, and then the leaves die. Symptoms develop from the base of the plant to the top, and the old leaves are the most affected. Fruit dysplasia, easy to produce "big belly melon."
● Apple: The middle and lower leaves of the new shoots are dark purple at the beginning of the leaf, and then scorched, curled and curled. In severe cases, almost the entire leaves showed a reddish-brown color, with ten curls and a significant burning sensation.
● Peach: The middle part of the new shoot is wrinkled and curled, and then necrotic. The symptom leaves develop into cracks and cracks, which are reddish or purplish red, with small branches and few flower buds.
● Grape: The leaves are yellow with brown spots and necrosis. The brown spots may fall off and perforate, and the leaves become brittle and the fruit maturity is inconsistent.
● Pear: The leaves are marginal necrosis or dark brown burns, and the twigs grow very weakly.