Potassium is one of three elements of fertilizer, many vegetables often greater than the required amount of nitrogen, potassium, phosphorus, potassium content vegetables grow well as its dry matter content of 2.5% --7% higher than the nitrogen and phosphorus content. Most vegetables absorb more potassium than nitrogen. For example, the ratio of nitrogen to potassium absorbed by cucumber is 1: (1.5-1.7), pumpkin is 1 : 2.1 , tomato is 1:1.9 , eggplant is 1 : (1.5-1.65) , green pepper is 1:1.3 , carrots are 1 : (1.1-1.3) , radishes are 1 : (1.1-1.35) , onions are 1 : (1.1-1.4) , lettuce is 1: (1.6-1.9) , and cabbage is 1: (1.1) - 1.3) .

Potassium applied to the soil is fixed in a form that is difficult to absorb, and some becomes a replacement potassium that is easily absorbed by vegetables. The applied potassium fertilizer is actually absorbed and utilized by vegetables only about 50% . In general, the effectiveness of sandy soil potassium is higher than the clay soil, calcareous soil less effective in potassium.

The potassium concentration most suitable for vegetable growth is about 5 % of the total replacement potassium of the soil . When substitution of the soil is low potassium content, such as sand below 85mg / kg, loam and sandy loam soil is less than 100mg / kg, clay less than 125mg / kg, potash vegetables have good yield and improved The effect of quality.

0.8 Conventional vegetable amount of potassium absorption amount - 1.5 times, with equal amounts in most vegetable NPK as basal administration generally administered every 667M2 hydroxide 10 - 15kg, but at the same time increasing nitrogen fertilizer, potassium fertilizer must increase The amount used. For vegetables with large potassium content such as solanaceous fruits and melons, we must also pay attention to increasing the proportion of potassium fertilizer, and in the case of base fertilizer application, the potassium fertilizer should be applied in a timely manner. Fruits and vegetables 50 to recover the total amount of potassium of Potassium - 60% as well.

There are many types of potash, and different types of potash have different application methods. Commonly used potassium fertilizers include potassium chloride, potassium sulfate, potassium magnesium fertilizer and grass ash. Potassium chloride, potassium sulfate is a physiological acidic fertilizer, should be administered together with lime and organic fertilizers. It is not advisable to apply potassium chloride and potassium magnesium fertilizers with higher chlorine content for the avoidance of chlorine by potatoes. Potassium magnesium fertilizer is suitable for acidic soils. The grass ash is suitable for vegetable seedlings, which not only supplies nutrients, but also absorbs heat to increase the surface temperature of the soil and promotes early emergence of seedlings. In addition, 1 % straw ash leaching solution is used as top dressing for roots, which also has a good effect on controlling vegetable mites. According to the test, the application of acupoint application, ditch application and strip application is better than application. Generally, potassium is applied 10cm near the root of the vegetable , so that the root can be prevented from being burned and the potassium absorption of the plant is facilitated.