The test soil was sandy sandy loam and the soil fertility was lower. Cotton variety 81-3. With pressure drip irrigation, 1 membrane 1 tube 4. During the flowering period, 311.25 kg of pure nitrogen, 94.2 kg of phosphorus pentoxide and 37.5 kg of potassium oxide were injected per hectare. The ratio of nitrogen, phosphorus and potassium is 1:0.3:0.12. Nitrogen 10%, phosphorus and potassium 70% deep application, the remaining fertilizer in the fertility period of a water and a fertilizer by a certain percentage of drip. Irrigation 4650 meters 3/ha. The output of cotton lint was 2970 kg/ha. In the drip irrigation cotton field, various soil layers were taken from the soil under the drip irrigation belt in the middle of the drip irrigation belt, in the middle of the two rows of cotton, and 10 cm away from the side. The soil was tested using the soil nutrient tester to analyze the indexes of alkaline nitrogen, available phosphorus, and available potassium.
Through the analysis of soil nutrient tester, it was found that the vertical distribution of nutrient content of alkali-hydrolyzable N and available P in soils during the whole growth period of cotton was gradually reduced from top to bottom. The content of alkali-hydrolyzed nitrogen in the soil around 20 cm tends to be stable, with little variation. Different levels of soil available phosphorus declined rapidly around July 10, and investment needed to be increased to meet the needs of cotton. The vertical distribution of soil available potassium content is 0-40 cm soil layer below 40 cm, indicating that cotton root activity layer absorbs more potassium. 20 to 40 cm of soil available potassium is relatively stable, 0 ~ 20 cm, 40 ~ 60 cm soil available potassium changes. Under the 1–4 drip irrigation pattern, the alkali hydrolysis of nitrogen in the middle soil of 10-30 cm soil layers was higher than that under the drip irrigation belt, which was conducive to the absorption and utilization of cotton roots. The alkali-hydrolyzable nitrogen in the soil below 15 cm in the soil outside the border line 10 centimeters decreased significantly, and it could not meet the nitrogen demand of the cotton in the flowering and bolling stage of the border line. The available phosphorus of 0 to 10 cm under the drip irrigation belt is significantly higher than that of the middle row, indicating that the phosphate fertilizer is also fixed by the soil with the water droplets. Therefore, the phosphate fertilizer should not be applied 100%. There is no significant difference in soil available phosphorus in the horizontal direction of 10-30 cm soil layers. The distribution of soil available potassium was gradually increased in the downward direction of the drip irrigation belt, and the horizontal direction of 0-30 cm soil layer did not change much.
The soil nutrient tester measured the soil nutrient content in the drip irrigation cotton field and found that the total amount of fertilizer applied in the drip irrigation cotton field was 330 kg of pure nitrogen, 105 kg of phosphorus pentoxide, and 45 kg of potassium oxide per hectare. This will not only meet the growth needs of cotton, but also maintain the basic fertility of the soil. The method of fertilization can adopt the principle of “few meals, one water and one fertilizer, and two less and more in the middle†to fully meet the demand for water and fertilizer during the whole growth period of cotton, and maintain the soil nutrients in the state of stable supply for the whole growth period of cotton.
Galvanized steel coil is a material produced by continuous hot-dip galvanizing process with hot-rolled steel strip or cold-rolled steel strip as the substrate. Hot dip galvanized coil supplied in coil form after coiling. Therefore, galvanized steel sheet (coil) can be divided into hot-rolled galvanized sheet coil and cold-rolled hot-dip galvanized sheet coil. They are mainly used in the fields of construction, household appliances, automobiles, containers, transportation and household industry. Especially in steel structure construction, automobile manufacturing, steel warehouse manufacturing and other industries. Their main characteristics are: strong corrosion resistance, good surface quality, benefit from deep processing, economy and practicality, etc.
Galvanization is the leading method to protect metals from environmental elements that cause corrosion, rust, and the eventual weakening of the steel. Hot-dip galvanizing deposits a thick, robust layer of zinc iron alloys on the surface of a steel item.When exposed to the atmosphere, pure zinc reacts with oxygen to form zinc oxide which further reacts with carbon dioxide to form zinc carbonate. A dull, grey, fairly strong material that stops further corrosion in most circumstances, protecting the steel from the elements. Galvanized steel is widely used in applications where rust resistance is needed. Galvanized steel is commonly used in the automotive industry to enhance the corrosion performance of exterior body parts. Galvanized Steel is magnetic.
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