Potash fertilizer, full name potash fertilizer. In fertilizers with potassium as the main nutrient, potassium in plants generally accounts for 0.2% ~ 4. 1% of dry matter weight, second only to nitrogen. Potassium is involved in the activation of more than 60 enzyme systems, photosynthesis, assimilate transport, carbohydrate metabolism and protein synthesis during plant growth and development.
When crops are deficient in potassium, old leaves and leaf margins usually turn yellow, then turn brown and burn like burning; Brown spots or patches appear on the leaves, but the middle, veins and near veins of the leaves are still green. With the aggravation of potassium deficiency, the whole leaves become reddish brown or dry, necrotic and fall off; The root system is short and few, which is prone to premature aging, rot and lodging in severe cases. The symptoms of potassium deficiency in main crops are as follows.
① Wheat: the plant is blue-green, the leaves are weak and drooping, the tips and edges of the upper, middle and lower leaves are yellow, and the old leaves are brown. The stems are thin, precocious and prone to lodging.
② Corn: The ratio of leaf and stem length is out of balance, the leaves are long and the stems are short, the tips and edges of the old leaves are brown, and the stems are small and weak, so they are prone to lodging.
(3) Potato: slow growth, short internodes, reduced leaf area, closely arranged leaflets, forming a small angle with petiole, rough, shriveled and curled downward. In the early stage, the leaves were dark green, then turned yellow and then brown. The leaf color changes gradually from the tip and edge to the whole leaf, the old leaves at the lower part dry up and fall off, and the inside of the tuber is blue.
④ Rice: At seedling stage, the leaves are green with blue, the old leaves droop weakly, the heart Ye Ting is straight, reddish-brown tissue necrosis appears at the tip of the middle and lower leaves, and there are amorphous reddish-brown spots on the leaves. Then the old leaves withered, premature aging, and the rice bushes were scattered. The leaf sheath is short, the leaves are relatively long, the root system development is obviously damaged, and the seeds lack luster and are not full. It is easy to lodging, infected with leaf spot and bacterial leaf blight.
5 soybeans; Potassium deficiency at seedling stage, small leaves, dark green leaves, lack of luster. In the middle and late stage, potassium deficiency, the tip and edge of old leaves turn green and yellow, the veins between leaves swell and contract, the front end of leaves curls down, sometimes the petiole turns brown, and the roots age prematurely.
⑥ Cotton: At the early stage of potassium deficiency in cotton, mesophyll tissue faded and Huang Zi spots appeared. The lower leaves with severe potassium deficiency are scorched and curled outward. Small boll, poor boll opening, low disease resistance, premature aging, low yield and poor quality.
⑦ Rape: The tips and edges of leaves begin to turn yellow, and lose green along the veins. There are brown patches or local self-color dryness. When potassium deficiency is serious, the mesophyll tissue is obviously burnt, the leaf edge is scorched, brown stripes appear on the surface of some stems, and the diseased spots continue to develop, causing the whole plant to wither and die.
(8) Chinese cabbage: browned and died from the lower leaf edge, and gradually developed to the inner leaf or upper leaf, and the lower leaf withered, and the resistance to soft rot and downy mildew decreased.
Pet-name ruby tomato: The leaves of the old leaves are curly, the veins are green, and there are small brown spots in this green area. Later, the old leaves fell off, the stems became thicker and lignified, and the roots were thin and weak. Fruit color is uneven, and the back is often green, which is called "green back disease".
Attending cucumber: short plant, short internodes and small leaves. The leaves are bronzed, the leaves are gradually yellowish green, and the main veins are depressed. In the late stage, the interveinal chlorosis is serious, which extends to the middle of the leaf, and then the leaf dies. The symptoms developed from the base to the top of the plant, and the old leaves suffered the most. Poor fruit development is easy to produce "pot-bellied melon"
⑾ Apple: The middle and lower leaves of the new branches were dark purple at first, and then dried up, shriveled and curled. In severe cases, almost all the leaves are obviously reddish brown, curled and withered, and the anxiety is obvious.
⑿ Peach: The leaves in the middle of the new shoots become wrinkled and curled, and then die. Symptomatic leaves develop into cracks and fissures, red or purplish red, slender branchlets and few flower buds.
[13] Grape: The leaves are yellow with brown spots and necrosis. Brown spots may fall off and be perforated, and then the leaves become brittle and the fruits ripen inconsistently.
[14] Pear: The leaves are necrotic or brown, and the growth of branchlets is weak.
Potassium fertilizer can be used as base fertilizer and topdressing, and some varieties can also be used as foliar fertilizer, but the application effect of base fertilizer and foliar fertilizer is better. Using potassium fertilizer as base fertilizer can meet the demand of potassium in the whole growth period of crops, which is especially important for crops with short growth period and soil with obvious potassium deficiency. For crops with long growth period, such as cotton, the combination of base fertilizer and foliar spraying can be used. For sandy soil, the method of combining basic application with topdressing can be adopted. The mobility of potassium in soil is between nitrogen and phosphorus. The content of available potassium in soil is less than 100mg/kg/ mu; The content of available potassium in soil is below 100 ~ 150mg/kg, and only 5 kg is needed per mu. When the content of available potassium in soil is above 150 mg/kg, chemical potassium fertilizer should not be applied or applied less according to crop types.