Door Viewers
The door observer is a small optical instrument installed on the door of a residence, which is convenient for residents to observe the outdoor situation. Has become a necessity for home safety.
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Years of research have shown that about two-thirds of paddy soils and 1/2 of dryland soils are deficient in potassium in the south, and potassium-deficient areas in the south of the Yangtze River account for about 80% of the country's potassium-deficient area. In the north, the soil's ability to supply potassium from west to east is gradually reduced, and the ability to fix potassium is gradually enhanced, and there is a clear zonal distribution. On the basis of applying appropriate amount of nitrogen and phosphorus fertilizers to the main crops in the northeast and north China, attention should be paid to the application of potassium fertilizer. In the northwest region, the yield increase effect of food crops is still unstable. However, in potash crops such as cotton, potatoes, melons, fruits, vegetables and other crops, the application of potash fertilizer has already had an obvious effect of increasing yield.
In the high-efficiency application technology of potassium fertilizer, the soil potassium supply capacity should be considered firstly, and the optimal potassium application amount should be determined mainly according to the soil potassium supply level. The results showed that the yield increase of crop potassium was significantly correlated with the soil available potassium content. Also consider the interaction between potassium and other nutrients in the soil, pay attention to the balanced application of potassium fertilizer with nitrogen, phosphorus and medium and trace elements.
In many areas of China, partial application and large-scale application of nitrogen fertilizer are common, resulting in a decline in nitrogen production efficiency, a decrease in nitrogen use efficiency and nitrogen production efficiency, and sometimes a crop yield reduction due to partial application of nitrogen fertilizer. Potassium fertilizer must be fully applied under the conditions of applying nitrogen fertilizer, and there is a clear mutual promotion between nitrogen and potassium.
In addition, potash application should also consider crop rotation systems and planting methods. For example, in the cotton-canola and flue-cured-corn rotation system, the principle of “potassium weight, light rapeseed†and “boiled tobacco weight, corn light†should be adopted; in corn-soybean-canola and peanut-corn-canola rotation In the system, potassium fertilizer is preferentially distributed on peanuts, soybeans and corn, and the economic benefits of potassium application can be exerted. Under the wheat-maize rotation system in northern China, potash should be preferentially distributed on corn. When applying potassium fertilizer to corn, other factors such as water conditions, soil type, potash type and climatic factors cannot be ignored.
Author: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences researcher Kim Ji-yun
Source: Farmers Daily
It is composed of a concave lens (objective lens) and a convex lens. The focal length of the objective lens is extremely short, it makes the outdoor person or object into an upright and reduced virtual image, which falls just within the focus of the eyepiece, and finally a reduced upright virtual image is obtained, which is exactly at the clear viewing distance of the human eye. Nearby, you can see the situation outside the door clearly.
Potassium fertilizer quality and high yield
Potassium is one of the essential nutrients necessary for plants. Potassium has an important influence on the normal growth and development of plants, yield formation, stress resistance and quality. At present, the imbalance of soil potassium deficiency or potassium balance has become an obstacle to further increase in crop yield and quality.
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