The existing arable land area of ​​Kangping County is 50,000 hO, which is one of the national commodity grain production bases. However, in Kangping County, soil salinity is heavier, and grain yield per unit area is lower. The average yield is about 5.25 t/hO. In order to comprehensively understand the soil fertility of cultivated land in Kangping County, in 2006, 4 015 soil samples were collected and measured using a soil tester. The results were compared with the data from the 2nd soil survey and suggested fertilization. The purpose was to improve the soil and improve fertilization. Fertility, so as to increase food production in Kangping County. Table 1 Evaluation Standards for Soil Nutrient Abundance Table 2 Status of Soil Organic Matter Table 3 Soil Total Nitrogen Content Table 4 Soil Hydrolysis Nitrogen Content Table 5 Status of Available Phosphorus in Soil Table 6 Status of Available K Content in Soil Table 7 Status of Available Zinc in Soil KF94 Fish Shape Mask Making Machine HTD is a professional machinery manufacturer with more than 12 years. We have experience in Mask making machine market industry for more than 5 years. We are a professional manufacturer for automatic Mask making machinery, Flat Mask Making Machine, N95 mask making machine fully automatic, Cup Type Mask Making Machine, Fish Mask Making Machine, Earloop Tape Machine, Disposable Mask Packaging Machine. We offer professional after-sales service, such as installation instruction, training and machine repairing. To provide customers high quality products and high quality service is always our aim of work. We look forward to be your reliable business partner! Machine Mask, KF94 Mask Making Machine, Fish Mask Making Machine, Fish Shape Mask Machine GUANGZHOU HTD INTERNATIONAL , https://www.htdmask.com
1 Soil collection and analysis method 1.1 Soil sample collection According to the main soil types and production conditions in Kangping County, from May 2006 to April 2007, Zhang Qiang Town, Dongsheng Township, Xiaochengzi Town, Haizhou Township, and Kangping Town in Kangping County were collected. Soil samples were collected from cultivated land in some townships (towns) and development zones in Shenyang Shengli Economic Development Zone, and a total of 4,015 soil samples were collected. The method of artificial soil drilling and multi-point mixing is as follows: 15 spots in S shape are uniformly taken to remove impurities, and 0.5 kg is retained in the quaternary method and naturally dried.
1.2 Determination method Organic matter was heated on a hot plate to determine the potassium dichromate oxidation capacity method; soil nutrients were measured using a soil analyzer; total nitrogen was measured by Kjeldahl distillation; hydrolyzed nitrogen was measured by alkali-diffusion method; available phosphorus was sodium bicarbonate molybdenum. Antimony resistance to colorimetric determination; Available potassium was determined by ammonium acetate extraction-flame photometry; Available zinc was determined by DTPA extraction atomic absorption spectrophotometry.
1.3 Evaluation method of soil nutrient status The analysis of soil nutrient abundance is based on the Technical Specifications for the Second Soil Census (Table 1). 
2 Results and Analysis 2.1 Soil Organic Matter Content and Fertilization Recommendations The soil organic matter content of cultivated land in Kangping County is shown in Table 2. It can be seen from Table 2 that the content of soil organic matter in cultivated land is relatively low, and the content of cultivated land with less than the following level accounts for 96.5% of the total area of ​​cultivated land. Compared with the second soil survey, the area of ​​cultivated land with missing or extremely low levels is reduced by 12.8. %. In general, soil organic matter content has not changed much in the past 20 years. In order to cultivate fertility, it is necessary to increase the input of organic fertilizer, and it is recommended to increase organic fertilizer by 30 to 45 t/hO. 
2.2 Soil Nitrogen Content and Nitrogen Recommendations The total nitrogen and hydrolyzable nitrogen contents of cultivated land in Kangping County are shown in Tables 3 and 4, respectively. As can be seen from Table 3 and Table 4, the cultivated land with rich soil hydrolyzable nitrogen content accounts for 6.8% of the total area of ​​cultivated land, and the medium-level cultivated land accounts for 31.8% of the total cultivated area, which is less than the cultivated land with the following content levels. It accounts for 61.4% of the total area of ​​cultivated land. Compared with the second soil survey, soil total nitrogen content has increased, the area of ​​cultivated land above the medium level has increased by 11.5%, and the area of ​​cultivated land with missing and extremely low levels has decreased by 12.5%. However, the cultivated land that lacks the following levels still accounts for 73.0% of the total cultivated land area. Therefore, we must pay attention to the application of nitrogen fertilizer, it is recommended to use pure nitrogen 150 ~ 240 kg/hO, urea 300 ~ 450 kg/hO. 
2.3 Available Phosphorus Content in Soil and Suggested Phosphorus Application The soil available phosphorus content in Kangping County is shown in Table 5. From Table 5, it can be seen that: The cultivated land with rich soil available phosphorus content accounts for 18.0% of the total cultivated land, the richer cultivated land accounts for 20.8% of the total farmland area, and the medium-sized cultivated land accounts for 23.7% of the total cultivated land area. The sum accounted for 62.5% of the total area of ​​cultivated land, which was 59.2% higher than that of the second soil survey. The amount of cultivated land that lacked the following levels accounted for 37.5% of the total area of ​​cultivated land, which was 59.2% lower than that of the second soil survey. In the past more than 20 years, since farmers attached importance to the input of phosphate fertilizer, the soil available phosphorus content has greatly improved. 
Fertilization Recommendation: When the available phosphorus content is greater than 20 mg/kg, apply P2O545 kg/hO; When the available phosphorus content is 5-20 mg/kg, apply P2O545-90 kg/hO; When the available phosphorus content is less than 5 mg/kg, apply P2O590～135 kg/hO. 
2.4 Available K Content and Potassium Recommendations The available soil K content in cultivated land in Kangping County is shown in Table 6. It can be seen from Table 6 that: The cultivated land with rich soil available potassium content accounts for 2.9% of the total cultivated area, and the cultivated land with more abundant level accounts for 10.2% of the total cultivated area. The sum of the two accounts for 13.1% of the total cultivated area. Compared with the second soil survey, the area decreased by 75.4%; the medium-level cultivated land accounted for 39.2% of the total area of ​​the arable land, which was increased by 28.3% when compared with the second soil census; the cultivars lacked the following levels of arable land. It accounted for 47.7% of the total area of ​​cultivated land, an increase of 46.7% compared with the second soil survey. The reasons for the rapid decline in soil available potassium content are: Increased crop yields, taking a large amount of potassium from the soil, coupled with the lack of attention to the application of farmyard manure and straw return, so that the content of available potassium in the soil dropped significantly.
Fertilization Recommendations: When the effective potassium content is greater than 150 mg/kg, apply K2O45 kg/hO; When the available potassium content is 50-150 mg/kg, apply K2O45-90 kg/hO; The available potassium content is less than 50 mg/kg, apply K2O 90 to 135 kg/hO. 
2.5 Soil Available Zinc Content and Zinc Recommendations The status of available soil zinc in Kangping County is shown in Table 7. The level of available zinc in cultivated soil of Kangping County is relatively low, with an average of 0.87 mg/kg. From Table 7 it can be seen that: The cultivated land with a medium-level or higher level accounts for 19.5% of the total cultivated land area; the farmland with a low and very low-level content accounts for 80.5% of the total area of ​​cultivated land.
Fertilization Recommendations: Apply zinc fertilizer to the general field of crops, especially corn and rice, which are more sensitive to zinc. At present, zinc fertilizers are applied in the form of zinc sulfate and compound micronutrients, zinc sulfate 15 to 30 kg/hm2 or composite micro-fertilizer 30 to 45 kg/hm2, applied once every 2 to 3 years. When fertilizing, they cannot be mixed with phosphate fertilizers. It is best to mix some organic fertilizers. 
3 Conclusion Although the organic matter content of farmland soil in Kangping County is slightly higher than that in the second soil survey, the area at the middle and lower levels is still relatively large, accounting for about 92.2%. In order to maintain and improve soil fertility, organic fertilization should be applied at 30-45 t/hO for 3 to 4 years. The average content of soil hydrolyzed nitrogen is slightly higher than that of the second soil survey, which is in the middle and lower levels. Due to the large amount of nitrogen required by crops, it is recommended to apply 150-240 kg/h of nitrogen; the average content of available phosphorus in the soil is 28.9 mg/kg, which is a significant increase compared with the second soil survey. Phosphorus fertilizer should be reasonably applied in production; the content of soil available potassium decreased from 257.0 mg/kg at the second soil survey to 112.6 mg/kg, a decrease of 56.2%. Therefore, attention must be paid to the application of potash fertilizer; the average effective zinc content in soil is The area of ​​0.87 mg/kg, less than 1.00 mg/kg, accounted for 80.5%. Zinc fertilizer was required for such cultivated land.