Benefits and methods of Deep Application of Chemical Fertilizer

In recent years, production practice has proved that deep application of chemical fertilizer is a technical measure to improve fertilizer efficiency, reduce cost and increase yield. 1. The main form of deep application of chemical fertilizer  1.1.The soil preparation machine for deep application of bottom fertilizer or the addition of fertilizer box and fertilizer discharge device to the moldboard plough and paddy field ploughing machine to make it apply chemical fertilizer to the soil layer at the same time.  1.2 Deep fertilization at the same time sowing using the machine seeder equipped with fertilization device to synchronously complete fertilization, sowing, mulching, suppression and other operations, the chemical fertilizer is applied under the seed or under the side, and there is a soil isolation layer with a thickness of 3-5 cm between the fertilizer and the seed to avoid chemical fertilizer burning the seed.  1.3 Deep topdressing in the middle stage of crop growth, chemical fertilizer is applied deeply to the soil using mechanical, semi-mechanized intertilling and fertilizing machines or manual tools.  II. The advantages of deep application of chemical fertilizer  2.1 improving the utilization rate of chemical fertilizer deep application of chemical fertilizer can reduce the loss and waste of chemical fertilizer. According to the isotope tracking test of the Institute of soil and Fertilizer of the Chinese Academy of Agricultural Sciences, the utilization rate of nitrogen applied by ammonium bicarbonate and urea can be increased from 27% and 37% to 58% and 50%, respectively. The utilization rate of deep application is 115% and 35% higher than that of surface application. After the deep application of chemical fertilizer mechanization technology in a large area, the average utilization rate of nitrogen fertilizer can be increased from 30% to more than 40%. The deep application of phosphorus and potassium can also reduce the loss of wind erosion, promote crop absorption and prolong fertilizer efficiency, and improve the utilization rate of chemical fertilizer.  2.2 increasing crop yield deep application of chemical fertilizer can promote root development, enhance crop absorption of nutrients, water and drought resistance, which is beneficial to plant growth, thus increasing crop yield. The results of comparative experiment showed that under the same conditions, deep application could increase the yield of wheat and corn by 225,675 kg/hm2, cotton (lint) by 75,120 kg/hm2, and soybean by 225,375 kg/hm2, with an average increase of 5% to 15%.  3. Implementation points of deep application technology of chemical fertilizer  3.1Deep application of bottom fertilizer  3.1.1 is a deep application method of spraying fertilizer first and then ploughing. It is necessary to shorten the exposure time of chemical fertilizers to the surface as much as possible, especially for ammonium bicarbonate and other chemical fertilizers that are volatile in the air, and to bury them deeply with spreading fertilizer and ploughing. This fertilization method can be equipped with a fertilizer spreading device in front of the plow, or a special fertilizer spreader can be used, and the fertilizer bandwidth is basically the same as the ploughing width behind. The operation requirements of fertilizing before ploughing are as follows: chemical fertilizer is spread evenly, and the application rate meets the agronomic requirements of crop cultivation. After ploughing, the depth of chemical fertilizer buried in the soil is more than 6 cm, and there are no visible particles on the surface. 3.1.2 the method of fertilizing while ploughing and flanging. Basically, the operation of ploughing and fertilization can be achieved synchronously, and the volatilization loss caused by the open air of chemical fertilizer can be avoided. Generally, the existing ploughing plough can be reformed, the fertilizer discharge device can be added, and the fertilizer discharge pipe is usually installed behind the ploughshare. As the ploughshare turns, the bottom of the furrow is applied (the depth of the bottom fertilizer is adjusted according to the local agronomic requirements), and then the ploughshare is covered to achieve the purpose of deep fertilization. Many places are accustomed to calling this method furrow fertilization. The operation requirements of applying base fertilizer while ploughing are as follows: the depth of fertilization is more than 6 cm, the width of fertilizer band is 3 ~ 5 cm, the discharge of fertilizer is uniform and continuous, there is no obvious broken strip, and the amount of fertilizer application meets the agronomic requirements of crop cultivation.  3.2.The deep application of seed fertilizer should be done by installing fertilizer box and fertilizer discharge device on the seeder. The requirement of machinery and tools is not only to ensure the sowing rate, depth, plant spacing and row spacing of fertilizer and seed strictly according to the agronomic requirements, but also to form a soil isolation layer with a certain thickness (usually more than 3 cm) between seed and fertilizer, which can not only meet the nutrient demand of crop seedling growth, but also avoid the phenomenon of burning seed and seedling. The application of this technology has higher requirements for soil treatment in the field, and it is necessary to ensure consistent soil tillage depth, no leakage tillage, broken soil and proper soil. According to the position of fertilization and seed, there are two forms of lateral deep application and positive deep application (commonly known as fertilizer and seed stratification). The technical requirements are as follows:  3.2.1 lateral deep application of seed fertilizer. When the fertilizer is applied below the side of the seed, the seed fertilizer of wheat is 2.5 cm on the side and 2.5 cm below the seed, the depth of fertilizer application of maize is 5.5 cm, the width of fertilizer band is more than 3 cm, the fertilizer strip is uniform and continuous, and there is no obvious break and missed application.  3.2.2 deep application of seed fertilizer in positive position. The seed fertilizer is applied directly under the seed bed, the soil isolation layer between the fertilizer layer and the seed is more than 3 cm, and the depth of the seed and fertilizer is the same, the fertilizer strip is uniform and continuous, and the width of the fertilizer band is slightly larger than the sowing width. It should be noted that when chemical fertilizer is applied to the soil at one time while sowing, the distance between seed and fertilizer should be determined according to the variety and amount of fertilizer, so as to prevent the burning of seeds and seedlings caused by too close to seed and fertilizer.  3.3 Deep topdressing according to agronomic requirements, using topdressing machines and tools to complete topdressing operations such as ditching, fertilizer drainage, soil covering and suppression, compared with artificial surface application and deep topdressing with manual tools, the utilization rate and working efficiency of chemical fertilizer can be significantly improved, and topdressing machines and tools should have good inter-row passing performance. It has no obvious adverse effect on crop growth in the later stage (such as root injury, seedling injury and lodging, etc.). The depth of topdressing (based on the intersection of crop plants and the ground) should be 6: 10 cm. The topdressing position should be between 10-20 cm on both sides of the crop row (depending on the crop variety), the width of the fertilizer band is more than 3 cm, there is no obvious broken strip, and the cover is tight after fertilization.