Use method for improving nitrogen fertilizer utilization of rain-fed sugarcane

Abstract

The invention relates to the technical field of agricultural planting, and discloses a use method for improving nitrogen fertilizer utilization of rain-fed sugarcanes, which comprises the following steps: S1, laying a base fertilizer: before planting sugarcanes, applying a part of nitrogen fertilizer as the base fertilizer into soil in combination with soil preparation; s4, performing secondary topdressing and staging: performing secondary topdressing after the second period is ended, S501, accurately regulating and controlling the fertilizing amount: judging the demand condition of the sugarcane on the nitrogen fertilizer according to the results of the previous soil nutrient detection and the sugarcane in each growth stage; and S502, supplementing medium trace elements: judging whether the soil is lack of the medium trace elements or not by combining a soil detection result. By accurately regulating and controlling the application amount of the nitrogen fertilizer and reasonably matching the application of other nutrients, the sugarcane can obtain appropriate nutrient supply in different growth stages, optimal allocation of fertilizer resources is achieved, the yield is increased, and meanwhile the situation that fertilizer is wasted due to excessive fertilization and the negative effect that the nitrogen fertilizer of the sugarcane is excessive is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural planting, and in particular to a method for improving nitrogen fertilizer utilization of rain-fed sugarcane. Background Art

[0002] In the global sugarcane planting industry, rain-fed sugarcane planting occupies an important position. In many areas, it relies on natural precipitation to meet the water needs of sugarcane growth, without relying on large-scale irrigation facilities, and has the advantages of low cost and eco-friendliness. However, rain-fed sugarcane planting has long faced many challenges and problems in fertilizer utilization, especially nitrogen fertilizer utilization.

[0003] The soil fertility conditions in rain-fed sugarcane growing areas are quite different and complex. Different regions have different soil types, such as red soil, yellow soil, sandy loam, etc., and their nutrient content, texture structure, and fertilizer and water retention capacity are different. For example, in some acidic soil areas, the effectiveness of phosphorus in the soil is low and it is easy to be fixed, making it difficult for sugarcane to fully absorb and utilize it; in some sandy loam areas, the soil has poor fertilizer retention capacity and nutrients are easily lost with precipitation runoff.

[0004] In the traditional sugarcane planting process, fertilization methods are often extensive and lack precision and scientificity. Many growers do not determine the amount and time of fertilizer application based on the actual growth of sugarcane and the results of soil nutrient testing, resulting in the application of nitrogen fertilizer and other nutrients being out of touch with the actual needs of sugarcane and the inability to achieve accurate supply. This may cause nutrient deficiency to affect sugarcane growth, or excessive nutrients to bring negative effects. Fertilization is blindly applied according to a fixed pattern without considering the soil fertility and the differences in sugarcane demand at different stages, causing some nutrients to accumulate in the soil and be unable to be effectively used. At the same time, nutrients such as phosphorus and potassium that were originally sufficient continue to be applied in large quantities, resulting in a huge waste of fertilizer resources. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for improving the utilization of nitrogen fertilizer in rain-fed sugarcane, thereby solving the problem of blindly applying fertilizers according to a fixed pattern without considering the soil fertility status and the differences in demand for sugarcane at different stages, resulting in the application of nitrogen fertilizers and other nutrients being out of touch with the actual demand of sugarcane and the inability to achieve accurate supply, which may cause nutrient deficiencies that affect sugarcane growth and cause a huge waste of fertilizer resources.

[0006] To achieve the above object, the present invention is implemented by the following technical scheme: a method for improving nitrogen fertilizer utilization of rain-fed sugarcane, comprising the following steps: S1. Laying basal fertilizer: Before planting sugarcane, apply part of nitrogen fertilizer to the soil as basal fertilizer in combination with land preparation, use organic fertilizer mixed with nitrogen fertilizer as basal fertilizer, and test the soil for nutrients after the first cycle. According to the test results, determine the basic fertility and nitrogen supply capacity of the soil, and then plant sugarcane; S2. Increase nutrients: According to the soil test results and the needs of sugarcane, choose to apply fertilizers containing nitrogen, phosphorus and potassium, and fertilize by digging trenches or holes in the sugarcane to allow the roots and stems of the sugarcane to effectively absorb the elements and improve the surrounding soil at the same time; S3, first topdressing stage: after the first cycle, by observing the sugarcane seedlings growing new fields, the first topdressing is carried out on the seedlings, at which time the seedlings enter the second cycle, and the soil is tested for nutrients in the second cycle after fertilization; S4. Second topdressing stage: After the second cycle, enter the third cycle and observe the sugarcane entering the tillering stage, and then carry out the second topdressing. Use the method of furrow application or hole application to make the fertilizer close to the root system, apply nitrogen fertilizer into the soil, and then cover the soil, and then test the soil for nutrients; S5. Third topdressing stage: After the third cycle, the sugarcane enters the elongation period by observing that the sugarcane has entered the elongation period. The third topdressing is carried out during the elongation period. During this stage, the sugarcane stalks elongate rapidly, which is the fourth cycle. The fertilization method is the same as the previous two times, and the soil is tested after fertilization; S501. Accurately control the amount of fertilizer: According to the results of the previous soil nutrient tests and the growth stages of sugarcane, determine the demand for nitrogen fertilizer of sugarcane. If the sugarcane shows signs of nitrogen deficiency, increase the amount of nitrogen fertilizer. If the sugarcane shows signs of excessive nitrogen fertilizer, reduce the amount of nitrogen fertilizer. S502. Supplementing trace elements: Based on the soil test results, determine whether the soil is lacking in trace elements. If there is a deficiency, supplement the soil with trace element fertilizers.

[0007] Preferably, in S1, the mixing ratio of organic fertilizer and nitrogen fertilizer is 15-30 tons of decomposed farmyard manure and 150-200 kg of nitrogen fertilizer per hectare, wherein the first cycle is 7-14 days, and the detected nutrients include nitrogen, phosphorus and potassium. The base fertilizer is applied deeply and covered with soil, and the base fertilizer is applied to the soil at a depth of less than 10-15 cm and covered and compacted. The detection time is 1-2 weeks after fertilization.

[0008] Preferably, the nitrogen fertilizer includes urea, and the application amount is 200-300 kg per hectare, the phosphorus fertilizer includes superphosphate, and the application amount is 80-120 kg per hectare, and the potash fertilizer includes potassium sulfate, and the application amount is 150-250 kg per hectare, wherein the furrow application or hole application is dug to a depth of 5-20 cm beside the sugarcane planting row.

[0009] Preferably, in S3, the second cycle is 30-40 days after the seedlings are planted, and the first topdressing is 50-75 kg of urea per hectare, using the furrow application or hole application method, with a depth of 5-10 cm, and covering with soil after application. The detection time is 1-2 weeks after fertilization.

[0010] Preferably, in S4, the third cycle is 60-90 days after planting, and the third cycle fertilization is 100-150 kg of nitrogen fertilizer per hectare, using the furrow application or hole application method, with a depth of 10-15 cm, and covering with soil after application. The detection time is 1-2 weeks after fertilization.

[0011] Preferably, in S5, the fourth cycle is 90-150 days after planting. In the fourth cycle, 150-200 kg of nitrogen fertilizer can be applied per hectare by furrow application or hole application at a depth of 15-20 cm. The soil is covered after application, and the detection time is 1-2 weeks after fertilization.

[0012] Preferably, in S501, actual growth performance includes plant height, stem thickness, leaf color and number, signs of nitrogen deficiency include slow growth and yellowing leaves, and signs of excessive nitrogen fertilizer include excessive growth, dark green leaves and a tendency to grow too long. The increased nitrogen fertilizer dosage is 20-50 kg per hectare, and reduced to 20-40 kg per hectare.

[0013] Preferably, the medium and trace elements in S502 include zinc, boron and manganese. When the soil is zinc deficient, zinc sulfate can be applied at 3-7.5 kg per hectare by foliar spraying or applying it into the soil together with topdressing. When the soil is boron deficient, 7.5-15 kg of borax can be applied per hectare by broadcasting or strip application. When the soil is manganese deficient, chelated manganese fertilizer can be applied, and the concentration of foliar spraying should be controlled at 0.05%-0.1%, and spraying should be done in the early morning or evening on a sunny day.

[0014] The present invention provides a method for improving nitrogen fertilizer utilization in rain-fed sugarcane, which has the following beneficial effects: 1. The present invention avoids the waste of resources and environmental pollution caused by excessive use of fertilizers by accurately controlling the amount of nitrogen fertilizer applied and reasonably matching the application of other nutrients. It also ensures that sugarcane can obtain just the right nutrient supply at different growth stages, achieves optimal allocation of fertilizer resources, and increases yield without wasting fertilizer due to excessive fertilization, nor causing the negative effect of excess nitrogen fertilizer on sugarcane.

[0015] 2. The present invention increases the nutrient link, applies nitrogen, phosphorus and potassium fertilizers in a reasonable combination according to the needs of sugarcane, and timely supplements medium and trace elements according to the soil test results, thereby realizing the coordinated supply of multiple nutrients. This balanced nutrient environment helps the sugarcane root system to better absorb and utilize nitrogen fertilizer, because nutrients such as phosphorus and potassium and medium and trace elements have a mutually promoting effect with nitrogen in the physiological process of the plant body, thereby enhancing the absorption capacity of nitrogen fertilizer, improving the stress resistance of the plant, and ensuring that the nitrogen fertilizer plays a better role.

[0016] 3. The fertilizer of the present invention is applied in a deep soil covering manner, and the fertilizer is applied to the soil at a depth of less than 10-15 cm and the soil is covered and compacted, which can effectively prevent the loss of nitrogen fertilizer due to volatilization. Because under rain-fed conditions, if nitrogen fertilizer is applied on the surface, it is easy to volatilize into ammonia gas and escape when encountering rainfall or high temperature. Deep application and soil covering can greatly reduce such volatilization losses, ensuring that more nitrogen remains in the soil for absorption and utilization by sugarcane. The furrow application or hole application and soil covering operation during each topdressing also plays a role in reducing the loss of nitrogen fertilizer. Soil covering can prevent nitrogen fertilizer from flowing away with water, so that nitrogen fertilizer can continue to play a role in the soil, thereby improving the utilization efficiency of nitrogen fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example: Please refer to the attached Figure 1 The embodiment of the present invention provides a method for improving nitrogen fertilizer utilization in rain-fed sugarcane, comprising the following steps: S1. Laying basal fertilizer: Before planting sugarcane, apply part of nitrogen fertilizer to the soil as basal fertilizer in combination with land preparation, use organic fertilizer mixed with nitrogen fertilizer as basal fertilizer, and test the soil for nutrients after the first cycle. According to the test results, determine the basic fertility and nitrogen supply capacity of the soil, and then plant sugarcane; S2. Increase nutrients: According to the soil test results and the needs of sugarcane, choose to apply fertilizers containing nitrogen, phosphorus and potassium, and fertilize by digging trenches or holes in the sugarcane to allow the roots and stems of the sugarcane to effectively absorb the elements and improve the surrounding soil at the same time; S3, first topdressing stage: after the first cycle, by observing the sugarcane seedlings growing new fields, the first topdressing is carried out on the seedlings, at which time the seedlings enter the second cycle, and the soil is tested for nutrients in the second cycle after fertilization; S4. Second topdressing stage: After the second cycle, enter the third cycle and observe the sugarcane entering the tillering stage, and then carry out the second topdressing. Use the method of furrow application or hole application to make the fertilizer close to the root system, apply nitrogen fertilizer into the soil, and then cover the soil, and then test the soil for nutrients; S5. Third topdressing stage: After the third cycle, the sugarcane enters the elongation period by observing that the sugarcane has entered the elongation period. The third topdressing is carried out during the elongation period. During this stage, the sugarcane stalks elongate rapidly, which is the fourth cycle. The fertilization method is the same as the previous two times, and the soil is tested after fertilization; S501. Accurately control the amount of fertilizer: According to the results of the previous soil nutrient tests and the growth stages of sugarcane, determine the demand for nitrogen fertilizer of sugarcane. If the sugarcane shows signs of nitrogen deficiency, increase the amount of nitrogen fertilizer. If the sugarcane shows signs of excessive nitrogen fertilizer, reduce the amount of nitrogen fertilizer. S502. Supplementing trace elements: Based on the soil test results, determine whether the soil is lacking in trace elements. If there is a deficiency, supplement the soil with trace element fertilizers.

[0020] In S1, the mixing ratio of organic fertilizer and nitrogen fertilizer is 15-30 tons of decomposed farmyard manure and 150-200 kg of nitrogen fertilizer per hectare. The first cycle is 7-14 days. The tested nutrients include nitrogen, phosphorus and potassium. The base fertilizer is applied deep into the soil and covered with soil. The base fertilizer is applied to the soil at a depth of 10-15 cm and the soil is covered and compacted. The testing time is 1-2 weeks after fertilization.

[0021] Specifically, decomposed farmyard manure contains a large amount of organic matter, such as humus. After these organic substances enter the soil, they can increase the agglomeration between soil particles, making the soil that may have been relatively compact become loose and porous, which is conducive to the sugarcane roots to better stretch and take root in the soil. The roots can penetrate the soil more smoothly and contact a wider area of ​​the soil, thereby creating good physical conditions for absorbing nutrients and water. Nitrogen fertilizer not only promotes the growth of the aboveground part, but is also important for the development of the root system. Adequate supply of nitrogen fertilizer can accelerate the division of sugarcane root cells and make the root system more developed. A developed root system can better absorb water and other nutrients, such as phosphorus and potassium, from the soil, further supporting the growth of the aboveground part of the sugarcane, forming a virtuous circle and improving the overall growth vitality of the sugarcane.

[0022] Nitrogen fertilizers include urea, with an application rate of 200-300 kg per hectare, phosphorus fertilizers include superphosphate, with an application rate of 80-120 kg per hectare, and potash fertilizers include potassium sulfate, with an application rate of 150-250 kg per hectare. Furrow application or hole application should be done in a depth of 5-20 cm beside the sugarcane planting rows.

[0023] Specifically, in the process of sugarcane planting, reasonable fertilization is crucial. Urea is used as nitrogen fertilizer, and the application rate is 200-300 kg per hectare; superphosphate is used as phosphorus fertilizer, and 80-120 kg per hectare is applied; potassium sulfate is used as potassium fertilizer, and 150-250 kg per hectare is applied. The fertilization method is to dig a 5-20 cm deep trench or hole beside the sugarcane planting row for application. Nitrogen fertilizer can promote the growth of sugarcane leaves, lengthen and thicken the stems, and enhance the plant's resistance to stress, so that it can better adapt to the environment and resist diseases and pests. Phosphorus fertilizer can stimulate the division and differentiation of root cells, shape a developed root system, and improve the absorption efficiency of other nutrients. Potassium fertilizer also plays a role in many aspects of sugarcane growth. The three work together to provide sufficient and balanced nutrients for sugarcane growth through scientific application rates and appropriate fertilization methods, helping sugarcane to thrive and improve yield and quality.

[0024] In S3, the second cycle is 30-40 days after the seedlings are planted. The first topdressing is 50-75 kg of urea per hectare, applied in furrows or holes, with a depth of 5-10 cm. Cover with soil after application, and the detection time is 1-2 weeks after fertilization.

[0025] Specifically, in the process of sugarcane planting, the second cycle refers to the stage of 30-40 days after the seedlings are planted. At this time, the growth of sugarcane seedlings gradually accelerates, and the demand for nutrients also increases day by day, so the first topdressing is needed. Urea is used as nitrogen fertilizer for this topdressing, and the amount of topdressing per hectare is controlled at 50-75 kg. The fertilization method is furrow application or hole application, that is, a furrow or hole with a depth of 5-10 cm is dug at a suitable position near the sugarcane plant, and then urea is evenly applied into it, and then the soil is covered. There are many advantages to doing this. Furrow application or hole application can make the fertilizer closer to the sugarcane root system more accurately, which is convenient for the root system to quickly absorb and utilize, and reduce the diffusion of fertilizer in the soil. The waste in the process of topdressing can be effectively prevented by covering the soil, which can effectively prevent the loss of urea due to volatilization caused by exposure to the air, and also avoid the loss of fertilizer caused by factors such as rain erosion, so as to ensure that the fertilizer can be fully absorbed by sugarcane. 1-2 weeks after the completion of fertilization, the soil nutrient test is also required. The role of this step is that through the test, the changes in the content of various nutrients in the soil after this topdressing can be accurately understood, and then it can be judged whether the applied urea can meet the demand for nitrogen fertilizer in the current growth stage of sugarcane, so as to provide a scientific basis for whether the fertilization strategy needs to be further adjusted in the future, and ensure that sugarcane can obtain sufficient and appropriate nutrient supply in this critical growth period, and grow healthily and vigorously.

[0026] The third cycle of S4 is 60-90 days after planting. The third cycle fertilization is to apply 100-150 kg of nitrogen fertilizer per hectare, using the furrow or hole application method, with a depth of 10-15 cm. Cover the soil after application, and the detection time is 1-2 weeks after fertilization.

[0027] Specifically, 60-90 days after sugarcane planting, the important third cycle comes. At this stage, sugarcane grows rapidly and has an urgent need for nutrients, especially nitrogen fertilizer. Therefore, targeted fertilization operations are required. The amount of nitrogen fertilizer applied per hectare is set at 100-150 kg. Furrow or hole application methods are used to ensure that the fertilizer can be efficiently absorbed and utilized by sugarcane. Specifically, a 10-15 cm deep ditch or hole is dug at a suitable location around the sugarcane plant. The reason for choosing such a depth is that the sugarcane root system has grown and extended compared to the seedling stage. A deeper fertilization position can bring the fertilizer closer to the densely distributed root area, so that the root system can more conveniently absorb sufficient nitrogen nutrition. After the nitrogen fertilizer is evenly applied into the ditch or hole, the soil covering operation is immediately carried out. Soil covering plays a vital role. On the one hand, it can effectively block the outside air and prevent the ammonium nitrogen and other components in the nitrogen fertilizer from being absorbed. A large amount of nitrogen loss is caused by volatilization, ensuring that the fertilizer can be stably retained in the soil; on the other hand, covering the soil can also resist the influence of natural factors such as rain erosion to a certain extent, preventing the fertilizer from flowing away with water, thereby maximizing the guarantee that nitrogen fertilizer can continue to play a role in sugarcane growth. 1-2 weeks after the completion of this fertilization, nutrient testing of the soil is arranged. This testing link is of great significance. By accurately measuring the content of various nutrients in the soil, especially the remaining amount and effectiveness of nitrogen fertilizer, the actual effect of this topdressing of nitrogen fertilizer can be clearly understood. According to the test results, it can be judged whether the applied nitrogen fertilizer accurately meets the nitrogen demand of sugarcane at this growth stage, thereby providing a scientific and reliable basis for further optimization and adjustment of subsequent fertilization strategies, ensuring that sugarcane can obtain just the right nutrient supply throughout the growth cycle, achieving healthy and vigorous growth, and laying a solid foundation for the ultimate high yield and high quality.

[0028] The fourth cycle of S5 is 90-150 days after planting. In the fourth cycle, 150-200 kg of nitrogen fertilizer can be applied per hectare by furrow application or hole application at a depth of 15-20 cm. Cover the soil after application. The detection time is 1-2 weeks after fertilization.

[0029] Specifically, 90-150 days after sugarcane planting, it enters the critical fourth cycle. This period is crucial for the growth and development of sugarcane. The sugarcane stalks elongate rapidly at this stage, and the demand for nutrients reaches a peak, among which the adequate supply of nitrogen fertilizer is particularly critical. The amount of nitrogen fertilizer that can be applied per hectare is set at 150-200 kg, and the fertilization method is furrow application or hole application. The specific operation is to dig a furrow or hole with a depth of 15-20 cm at a suitable location around the sugarcane plant. The reason for choosing such a relatively deeper depth is that as the growth process of sugarcane progresses, by the fourth cycle, its root system has further expanded downward and extended to the surrounding areas. The deeper fertilization position can make nitrogen fertilizer more accurately delivered to the most active and dense root areas, ensuring that the root system can efficiently absorb sufficient nitrogen nutrition, thereby strongly supporting the rapid elongation of the sugarcane stalks and the healthy growth of the overall plant. After the nitrogen fertilizer is evenly applied into the furrow or hole, the soil covering operation should be carried out in time. The soil covering step has many aspects. The important role of nitrogen fertilizer: First, it can effectively isolate the air and reduce the loss of nitrogen caused by volatilization of nitrogen fertilizer. In the soil environment, some components in nitrogen fertilizer, such as ammonium nitrogen, are easy to volatilize and dissipate when in contact with air. After covering with soil, a barrier can be formed to relatively isolate the fertilizer from the air, and retain nitrogen to the greatest extent for sugarcane to absorb and utilize. Second, covering with soil can also resist the influence of factors such as rain erosion and surface runoff on fertilizer, prevent fertilizer from flowing away with water, ensure that fertilizer can remain stably in the soil, and continue to provide nutrient support for sugarcane growth. 1-2 weeks after the completion of fertilization, arrange for nutrient testing of the soil. This testing link is of great significance. Through the accurate determination of the content of various nutrients in the soil, especially the detailed understanding of the remaining amount, effectiveness and conversion of nitrogen fertilizer in the soil, the actual effect of the topdressing of nitrogen fertilizer can be accurately evaluated. According to the test results, it can be clearly judged whether the applied nitrogen fertilizer just meets the nitrogen demand of sugarcane at this growth stage.

[0030] For S501, actual growth performance includes plant height, stem thickness, leaf color and number. Signs of nitrogen deficiency include slow growth and yellowing leaves. Signs of excessive nitrogen fertilizer include excessive growth, dark green leaves and a tendency to grow too long. Increase the amount of nitrogen fertilizer to 20-50 kg per hectare, and reduce it to 20-40 kg per hectare.

[0031] Specifically, in the management of sugarcane planting, attention should be paid to its actual growth performance, such as plant height, stem thickness, leaf color and number, etc. When nitrogen is deficient, sugarcane grows slowly and the leaves turn yellow, because insufficient nitrogen affects photosynthesis and growth and development. If nitrogen fertilizer is too strong, there will be excessive growth, dark green leaves and a tendency to grow too long, and the stems may be thin, affecting the yield quality. Therefore, it is necessary to accurately judge the nitrogen situation based on these performances, and timely adjust the strategies such as the amount and frequency of nitrogen fertilizer application to ensure that sugarcane obtains appropriate nitrogen fertilizer supply and achieves healthy growth and high yield and high quality.

[0032] S502 medium and trace elements include zinc, boron, and manganese. When the soil is deficient in zinc, zinc sulfate can be applied at a rate of 3-7.5 kg per hectare, either by foliar spraying or by applying it into the soil together with topdressing. When the soil is deficient in boron, 7.5-15 kg of borax can be applied per hectare, either by broadcasting or in strips. When the soil is deficient in manganese, chelated manganese fertilizer can be applied, with the foliar spray concentration controlled at 0.05%-0.1%, and spraying should be done in the early morning or evening on a sunny day.

[0033] Specifically, attention should be paid to trace elements such as zinc, boron, and manganese in the growth of sugarcane. When the soil is zinc deficient, 3-7.5 kg of zinc sulfate can be used per hectare, which can be sprayed on the leaves or applied to the soil as topdressing. When the soil is boron deficient, 7.5-15 kg of borax can be applied per hectare, which can be supplemented by broadcasting or strip application. When the soil is manganese deficient, chelated manganese fertilizer should be applied, and the concentration of foliar spraying should be 0.05%-0.1%, and it should be sprayed in the early morning or evening on a sunny day. Such reasonable supplementation of trace elements can improve the nutrition system of sugarcane and promote its healthy growth.

[0034] Embodiment 1 Base fertilizer: organic fertilizer (decomposed farmyard manure): 20 tons / hectare, nitrogen fertilizer (urea): 150 kg / hectare, base fertilizer deep application soil depth: 12 cm, soil nutrient detection time after the first cycle: 10 days, increase nutrients: nitrogen fertilizer (urea): 250 kg / hectare, phosphorus fertilizer (superphosphate): 100 kg / hectare, potash fertilizer (potassium sulfate): 200 kg / hectare, furrow or hole application depth: 15 cm, first topdressing (second cycle): time: 35 days after seedlings are planted, nitrogen fertilizer (urea) topdressing amount: 60 kg / hectare, fertilization depth: 8 cm, soil nutrient detection time after fertilization: 12 days, second topdressing (third ... cycle): Time: 75 days after planting, nitrogen fertilizer (urea) topdressing amount: 120 kg / hectare, fertilization depth: 12 cm, soil nutrient detection time after fertilization: 10 days, third topdressing (fourth cycle): Time: 120 days after planting, nitrogen fertilizer (urea) topdressing amount: 180 kg / hectare, fertilization depth: 18 cm, soil nutrient detection time after fertilization: 14 days, precise control of fertilization amount: actual growth performance is normal, there is no sign of nitrogen deficiency or excessive nitrogen fertilizer, the nitrogen fertilizer application amount is not adjusted, supplement of trace elements: soil zinc deficiency, zinc sulfate application amount: 5 kg / hectare, foliar spraying and topdressing are applied to the soil together.

[0035] Embodiment 2 Base fertilizer: organic fertilizer (decomposed farmyard manure): 25 tons / hectare, nitrogen fertilizer (urea): 180 kg / hectare, base fertilizer deep application soil depth: 13 cm, soil nutrient detection time after the first cycle: 12 days, increase nutrients: nitrogen fertilizer (urea): 280 kg / hectare, phosphorus fertilizer (superphosphate): 110 kg / hectare, potash fertilizer (potassium sulfate): 220 kg / hectare, furrow or hole application depth: 18 cm, first topdressing (second cycle): time: 32 days after seedlings are planted, nitrogen fertilizer (urea) topdressing amount: 65 kg / hectare, fertilization depth: 7 cm, soil nutrient detection time after fertilization: 14 days, second topdressing (third cycle): Time: 80 days after planting, nitrogen fertilizer (urea) topdressing amount: 130 kg / hectare, fertilization depth: 13 cm, soil nutrient detection time after fertilization: 12 days, third topdressing (fourth cycle): Time: 130 days after planting, nitrogen fertilizer (urea) topdressing amount: 190 kg / hectare, fertilization depth: 19 cm, soil nutrient detection time after fertilization: 15 days, actual growth performance: plant height growth is slightly slower, stem thickness is thin, leaves are yellowing, showing signs of nitrogen deficiency, in subsequent topdressing, the amount of nitrogen fertilizer applied is increased by 10%-15% each time compared with the original plan, to supplement trace elements: the soil is deficient in boron, borax application amount: 10 kg / hectare, adopted the strip application method.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for improving nitrogen fertilizer utilization in rain-fed sugarcane, characterized in that: The following steps are involved: S1. Laying basal fertilizer: Before planting sugarcane, apply part of nitrogen fertilizer to the soil as basal fertilizer in combination with land preparation, use organic fertilizer mixed with nitrogen fertilizer as basal fertilizer, and test the soil for nutrients after the first cycle. According to the test results, determine the basic fertility and nitrogen supply capacity of the soil, and then plant sugarcane; S2. Increase nutrients: According to the soil test results and the needs of sugarcane, choose to apply fertilizers containing nitrogen, phosphorus and potassium, and fertilize by digging trenches or holes in the sugarcane to allow the roots and stems of the sugarcane to effectively absorb the elements and improve the surrounding soil at the same time; S3, first topdressing stage: after the first cycle, by observing the sugarcane seedlings growing new fields, the first topdressing is carried out on the seedlings, at which time the seedlings enter the second cycle, and the soil is tested for nutrients in the second cycle after fertilization; S4. Second topdressing stage: After the second cycle, enter the third cycle and observe the sugarcane entering the tillering stage, and then carry out the second topdressing. Use the method of furrow application or hole application to make the fertilizer close to the root system, apply nitrogen fertilizer into the soil, and then cover the soil, and then test the soil for nutrients; S5. Third topdressing stage: After the third cycle, the sugarcane enters the elongation period by observing that the sugarcane has entered the elongation period. The third topdressing is carried out during the elongation period. During this stage, the sugarcane stalks elongate rapidly, which is the fourth cycle. The fertilization method is the same as the previous two times, and the soil is tested after fertilization; S501. Accurately control the amount of fertilizer: According to the results of the previous soil nutrient tests and the growth stages of sugarcane, determine the demand for nitrogen fertilizer of sugarcane. If the sugarcane shows signs of nitrogen deficiency, increase the amount of nitrogen fertilizer. If the sugarcane shows signs of excessive nitrogen fertilizer, reduce the amount of nitrogen fertilizer. S502. Supplementing trace elements: Based on the soil test results, determine whether the soil is lacking in trace elements. If there is a deficiency, supplement the soil with trace element fertilizers.

2. The method for improving nitrogen fertilizer utilization of rain-fed sugarcane according to claim 1, characterized in that: In S1, the mixing ratio of organic fertilizer and nitrogen fertilizer is 15-30 tons of decomposed farmyard manure and 150-200 kg of nitrogen fertilizer per hectare, wherein the first cycle is 7-14 days, and the tested nutrients include nitrogen, phosphorus and potassium. The base fertilizer is applied deeply and covered with soil. The base fertilizer is applied to the soil at a depth of 10-15 cm and the soil is covered and compacted. The testing time is 1-2 weeks after fertilization.

3. The method for improving nitrogen fertilizer utilization of rain-fed sugarcane according to claim 1, characterized in that: Nitrogen fertilizers include urea, with an application rate of 200-300 kg per hectare, phosphorus fertilizers include superphosphate, with an application rate of 80-120 kg per hectare, and potash fertilizers include potassium sulfate, with an application rate of 150-250 kg per hectare. Furrow application or hole application should be done in a depth of 5-20 cm beside the sugarcane planting rows.

4. The method for improving nitrogen fertilizer utilization of rain-fed sugarcane according to claim 1, characterized in that: In S3, the second cycle is 30-40 days after the seedlings are planted. The first topdressing is 50-75 kg of urea per hectare, applied in furrows or holes, with a depth of 5-10 cm. Cover with soil after application, and the detection time is 1-2 weeks after fertilization.

5. The method for improving nitrogen fertilizer utilization of rain-fed sugarcane according to claim 1, characterized in that: The third cycle of S4 is 60-90 days after planting. The third cycle fertilization is to apply 100-150 kg of nitrogen fertilizer per hectare, using the furrow or hole application method, with a depth of 10-15 cm. Cover the soil after application, and the detection time is 1-2 weeks after fertilization.

6. The method for improving nitrogen fertilizer utilization of rain-fed sugarcane according to claim 1, characterized in that: The fourth cycle of S5 is 90-150 days after planting. In the fourth cycle, 150-200 kg of nitrogen fertilizer can be applied per hectare by furrow application or hole application at a depth of 15-20 cm. Cover the soil after application. The detection time is 1-2 weeks after fertilization.

7. The method for improving nitrogen fertilizer utilization in rain-fed sugarcane according to claim 1, characterized in that: In S501, actual growth performance includes plant height, stem thickness, leaf color and number. Signs of nitrogen deficiency include slow growth and yellowing leaves. Signs of excessive nitrogen fertilizer include excessive growth, dark green leaves and a tendency to grow too long. The increased nitrogen fertilizer dosage is 20-50 kg per hectare, and the reduced dosage is 20-40 kg per hectare.

8. The method for improving nitrogen fertilizer utilization of rain-fed sugarcane according to claim 1, characterized in that: S502 medium and trace elements include zinc, boron, and manganese. When the soil is deficient in zinc, zinc sulfate can be applied at a rate of 3-7.5 kg per hectare, either by foliar spraying or by applying it into the soil together with topdressing. When the soil is deficient in boron, 7.5-15 kg of borax can be applied per hectare, either by broadcasting or in strips. When the soil is deficient in manganese, chelated manganese fertilizer can be applied, with the foliar spray concentration controlled at 0.05%-0.1%, and spraying should be done in the early morning or evening on a sunny day.

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