Fertilizing method for reducing nitrogen loss of apple orchard

Abstract

The invention relates to the technical field of agricultural resources and environment, in particular to a fertilization method for reducing nitrogen loss of an apple orchard. The apple branch biochar is prepared from the apple orchard pruning waste, and resource utilization of the waste is achieved. Through the synergistic effect of the apple branch charcoal, dicyandiamide and the reduced nitrogen fertilizer, the loss of nitrate nitrogen in soil is obviously slowed down, the conversion of ammonium nitrogen is inhibited, and a nitrogen cycle functional microflora is regulated, so that the application amount of the nitrogen fertilizer is reduced, the utilization rate of the nitrogen fertilizer is improved, and the environmental pollution is reduced; the growth of apple plants can be obviously promoted, the root configuration is improved, and the root activity and the nitrate reductase activity are improved.

Description

Technical Field

[0001] This invention relates to the field of agricultural resources and environmental technology, specifically to a fertilization method for reducing nitrogen loss in apple orchards. Background Technology

[0002] As a major apple producer, my country ranks among the world's top countries in apple cultivation area, yield, and exports. However, while nitrogen fertilizer plays a crucial role in improving apple yield and quality during apple production, excessive application of nitrogen fertilizer has led to a series of environmental problems, such as soil acidification, compaction, eutrophication of water bodies, and increased greenhouse gas emissions.

[0003] For a long time, nitrogen fertilizer management in my country's apple orchards has faced a series of problems. First, nitrogen fertilizer application is generally excessive, far exceeding the actual needs of apple trees. Statistics show that the average annual nitrogen application in major apple-producing areas of my country reaches approximately 500 kg / ha, with some areas, such as the Weibei region, reaching as high as 558 kg / ha, and the Jiaodong Peninsula exceeding 800 kg / ha. This is far higher than the recommended nitrogen application rates in other apple-growing countries. Second, nitrogen fertilizer application methods are relatively extensive and lack precision management. Traditionally, fruit growers often fertilize based on experience, neglecting soil nutrient conditions and the actual needs of apple trees, resulting in low nitrogen fertilizer utilization. Excessive nitrogen fertilizer cannot be effectively absorbed and utilized by apple trees; instead, it is largely lost through ammonia volatilization, leaching, and denitrification, causing resource waste and environmental pollution. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a fertilization method to reduce nitrogen loss in apple orchards. By synergistically applying apple branch biochar, nitrification inhibitor dicyandiamide, and reduced nitrogen fertilizer application (by 1 / 3 of the conventional amount), the method effectively reduces N2O emissions from nitrate nitrogen leaching and denitrification, improves nitrogen fertilizer utilization, enhances soil physicochemical properties, promotes healthy growth of apple trees, and lowers nitrogen fertilizer input costs in orchards.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a fertilization method for reducing nitrogen loss in apple orchards, comprising the following steps: S1. Apply base fertilizer before and after leaf fall in autumn: Apply fertilizer in holes or ring trenches. In the first year, from mid to late September to mid to late October, mix apple branch biochar, carrier, organic fertilizer and compound fertilizer and apply it into the soil.

[0006] S2. Before budding: Apply nitrogen fertilizer for the first time by drip irrigation in mid-to-late March of the following year.

[0007] S3. From flowering to fruit setting: In May of the following year, apply nitrogen fertilizer and dicyandiamide through a second drip irrigation.

[0008] S4. Fruit enlargement period: From early July to mid-August of the second year, apply nitrogen fertilizer and dicyandiamide through a third drip irrigation.

[0009] S5. Before and after autumn leaf fall: Apply dicyandiamide via drip irrigation for the fourth time from mid-September to mid-October of the following year.

[0010] The mass ratio of apple branch biochar to dicyandiamide is 100-200:0.10-0.25; the application rate of apple branch biochar is 100-200 kg / mu; the application rates of dicyandiamide during the period from flowering to fruit setting, fruit enlargement, and before and after autumn leaf fall are 0.02-0.075 kg / mu, 0.01-0.05 kg / mu, and 0.024-0.125 kg / mu, respectively; the total nitrogen application in the soil, based on nitrogen content, is 10-25 kg / mu. In this invention, the total nitrogen application is based on the nitrogen content in compound fertilizer and nitrogen fertilizer; the nitrogen content in organic fertilizer is not included in the statistics. The compound fertilizer has a total nutrient content (N+P2O5+K2O) ≥45%, total N content ≥15%, P2O5 content ≥15%, and K2O content ≥15%. When nitrogen fertilizer is a water-soluble fertilizer containing macronutrients, with total nutrients (N+P2O5+K2O) ≥50%, total N content ≥4%, P2O5 content ≥4%, and K2O content ≥4%, the application rate of water-soluble fertilizer containing macronutrients is 16.7 kg / mu to 312.5 kg / mu.

[0011] Existing nitrification inhibitors include dicyandiamide, 3,4-dimethylpyrazole phosphate, or 2-chloro-6-trichloromethylpyridine. Dicyandiamide's advantages lie in its high water solubility, strong mobility in the soil profile, and ease of interaction with NH4+. + Nitrapyrin exhibits spatial separation in the soil; due to adsorption by soil colloids and organic matter, 3,4-dimethylpyrazole phosphate has very limited mobility in the soil and degrades slowly; 2-chloro-6-trichloromethylpyridine readily decomposes into 6-chloro-pyridinecarboxylic acid upon exposure to light, resulting in volatilization loss and making it unsuitable for surface application; furthermore, studies have shown that the nitrification effect of the three is ranked as follows: 3,4-dimethylpyrazole phosphate (Nitrapyrin) > 2-chloro-6-trichloromethylpyridine (DMPP) > dicyandiamide (DCD), with DCD showing the best nitrification inhibition performance. Based on the above considerations, dicyandiamide is selected as the nitrification inhibitor in this invention. Moreover, apples are nitrifying crops; the use of dicyandiamide as a nitrification inhibitor can delay nitrogen nitrification loss without affecting the conversion of nitrogen in fertilizer into nitrate nitrogen, which can be directly absorbed and utilized by the apple roots.

[0012] Preferably, apple branch biochar is prepared by the following steps: under oxygen-limited conditions, apple branches are heated to 300℃~700℃ at a rate of 10℃ / min~15℃ / min and pyrolyzed at 300℃~700℃ for 1.5h~2h to obtain apple branch biochar.

[0013] Preferably, the application rate of compound fertilizer is 26 kg / mu to 84 kg / mu, and the application rate of nitrogen fertilizer is 16.7 kg / mu to 312.5 kg / mu; the ratio of nitrogen fertilizer application rate before bud break, after flowering to fruit setting period and during fruit enlargement period is 3:2:1.

[0014] The preferred procedure for the first drip irrigation application of nitrogen fertilizer is as follows: first irrigate with water for 2 hours per acre, then add nitrogen fertilizer to the water and continue irrigating for 2 to 3 hours per acre, followed by irrigating with water for another 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

[0015] Preferably, the second drip irrigation application of nitrogen fertilizer and dicyandiamide is performed as follows: first, irrigate with water for 2 hours per acre, then add dicyandiamide and nitrogen fertilizer to the water, continue irrigating for 2 to 3 hours per acre, and then irrigate with water for 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

[0016] The preferred procedure for the third drip irrigation application of nitrogen fertilizer and dicyandiamide is as follows: first, irrigate with water for 2 hours per acre; then, add dicyandiamide and nitrogen fertilizer to the water and continue irrigating for 2 to 3 hours per acre; finally, irrigate with water for 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

[0017] The preferred procedure for the fourth drip irrigation application of dicyandiamide is as follows: first, irrigate with water for 2 hours per acre, then add dicyandiamide to the water and continue irrigating for 2 to 3 hours per acre, followed by irrigating with water for another 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

[0018] Preferably, the nitrogen fertilizer is a water-soluble nitrogen fertilizer, which is selected from at least one of nitrogen-containing compound fertilizer, urea, potassium nitrate, calcium nitrate, and monoammonium phosphate.

[0019] Preferably, the organic fertilizer is selected from well-rotted farmyard manure or commercial organic fertilizer; wherein, the well-rotted farmyard manure has an organic matter content of ≥25%, a nitrogen content of ≥0.7%, a phosphorus content of ≥0.5%, and a potassium content of ≥0.5%; and the commercial organic fertilizer has an organic matter content of ≥30% and a total content of nitrogen, P2O5 and K2O of ≥5.0%.

[0020] Preferably, when the organic fertilizer is well-rotted farmyard manure, the application rate is 1500 kg / mu to 2000 kg / mu; when the organic fertilizer is commercial organic fertilizer, the application rate is 200 kg / mu to 400 kg / mu.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a fertilization method to reduce nitrogen loss in apple orchards. It utilizes the synergistic effect of apple branch biochar and the nitrification inhibitor dicyandiamide to construct a dual-effect technology system for soil improvement and nutrient regulation. The porous structure of apple branch biochar increases soil porosity by 20%–30%, improving water retention and aeration while neutralizing acidic soils. Dicyandiamide inhibits the conversion of ammonium nitrogen to nitrate nitrogen, reducing nitrogen leaching and ammonia volatilization. The synergistic effect of these two technologies increases nitrogen fertilizer utilization by 15%–20% compared to traditional fertilization methods. With a 1 / 3 reduction in total nitrogen application, soil nitrate nitrogen loss is reduced by 22.8% within 7 days, nitrogen runoff loss is reduced by 30%–40%, ammonia volatilization is reduced by 20%–30%, and N2O emissions are significantly reduced.

[0022] Furthermore, the fertilization method of this invention for reducing nitrogen loss in apple orchards adopts a "base fertilizer + staged topdressing" model: Apple branch biochar (100kg / mu~200kg / mu), organic fertilizer, and compound fertilizer are applied in holes or ring trenches before and after autumn leaf fall; water-soluble nitrogen fertilizer is drip-irrigated at a ratio of 3:2:1 before bud break, during flowering to fruit setting, and during fruit enlargement (total nitrogen application is 10kg / mu~25kg / mu); and dicyandiamide (total 0.054g / mu~0.25kg / mu) is applied in conjunction with these fertilizers after flowering to fruit setting, during fruit enlargement, and before and after autumn leaf fall. This model precisely matches the nitrogen requirements of apples during the early shoot growth stage, mid-fruit stabilization stage, and late-fruit enlargement stage.

[0023] 2. This invention uses orchard pruning waste as raw material to prepare apple branch biochar (char yield 0.3-0.4 tons / ton), achieving resource recycling and reducing production costs. This technology significantly enhances soil nitrogen-fixing genes. nifH and denitrification genes nirS , nosZ The method increases nitrogen abundance and inhibits the activity of ammonia-oxidizing bacteria, thus optimizing nitrogen transformation pathways at the microecological level. Application results show that: the aboveground dry weight of apple plants increases by more than 49%, the total root length increases by 182%, and root vitality and nitrate reductase activity are simultaneously enhanced; new shoot growth increases by 10%–15%, flower bud quality improves by 20%–25%, soluble solids content in fruit increases by 1.5%–2.0%, and the sugar-acid ratio is optimized by 15%–20%, achieving multiple goals of nitrogen reduction, quality improvement, and efficiency enhancement, while saving costs and demonstrating significant economic and ecological benefits. Attached Figure Description

[0024] Figure 1SEM images of apple branch biochar at different pyrolysis temperatures are shown. In the images, a is a cross section, b is a longitudinal section, a1 and b1 are at 300℃, a2 and b2 are at 500℃, and a3 and b3 are at 700℃. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that the technical terms used in this invention are only for describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased on the market or prepared by existing methods. Apple branches: Healthy branches pruned from apple orchards are selected as raw materials, including one-year-old, two-year-old, perennial and mixed-age (randomly sampled without branching age) apple branches pruned in winter from apple orchards. Water-soluble fertilizer containing macro-elements: Henan Agricultural Fertilizer (2018) Approval No. 12597 and Henan Agricultural Fertilizer (2020) Approval No. 16235; Organic fertilizer: Hubei Agricultural Fertilizer (2018) Approval No. 3501; Compound fertilizer: Hunan Agricultural Fertilizer (2009) Approval No. 0323. The total nutrients (N+P2O5+K2O) of water-soluble nitrogen fertilizer are ≥50%, the total N content is ≥4%, the P2O5 content is ≥4%, the K2O content is ≥4%, and the application rate of water-soluble fertilizer containing macro-elements is 16.7 kg / mu to 312.5 kg / mu.

[0027] In current technology, the application of nitrogen fertilizer in apple orchards in my country is generally too high (average 500 kg / ha / year to 800 kg / ha / year), far exceeding actual needs. Furthermore, the application methods are extensive and lack precise management, resulting in low nitrogen fertilizer utilization. Large amounts of nitrogen are lost through ammonia volatilization, leaching, and denitrification, causing not only resource waste but also environmental problems such as soil acidification and compaction, reduced organic matter content, microbial community imbalance, eutrophication of water bodies, and N2O emissions. At the same time, a large amount of branch waste generated from orchard pruning is often burned or discarded, causing environmental pollution and resource waste.

[0028] To address the problems of existing technologies, this invention prepares apple branch biochar from apple orchard pruning waste and scientifically combines it with DCD and reduced-volume nitrogen fertilizer, solving the dual challenges of excessive nitrogen fertilizer application and apple branch waste disposal. By constructing a dual-effect technology system of soil improvement and nutrient regulation, it overcomes the problem of severe nitrogen loss associated with traditional fertilization methods. Simultaneously, while reducing the total amount of nitrogen fertilizer applied to less than one-third of the conventional amount, it achieves multiple objectives: increasing nitrogen fertilizer utilization by 15%–20%, reducing nitrogen runoff loss by 30%–40%, reducing ammonia volatilization by 20%–30%, increasing the aboveground dry weight of apple trees by more than 49%, increasing the total root length by 182%, and significantly improving soil pH and porosity. This achieves a balance between nitrogen reduction and efficiency improvement, waste resource utilization, environmental friendliness, and economic benefits.

[0029] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will provide a detailed description in conjunction with specific embodiments: Apple branch biochar is prepared according to the following steps: After washing the apple branches, dry them at 80℃ to constant weight. Once drying is complete, cut them into 1cm-2cm sections and place them in a muffle furnace. Pyrolyze them at 500℃ for 2 hours under a nitrogen atmosphere at a rate of 10℃ / min. Allow them to cool naturally to room temperature to obtain carbonized material. Remove the carbonized material, pulverize it using a pulverizer, and sieve it through a 2mm sieve to obtain apple branch biochar.

[0030] Based on the above-mentioned process, this invention also investigated the effects of pyrolysis temperature (300℃, 500℃, 700℃) and the growth status of apple branches (one-year-old, two-year-old, multi-year-old, and mixed-growth) on apple branch biochar. The results are shown in Table 1. Multi-year-old refers to branches three years or older; mixed-growth refers to branches of various ages without age distinction, randomly sampled, and without any mixing ratio. In actual production, pruned branches of various ages are randomly sampled. This invention examines the differences between mixed-growth branches and branches of other ages.

[0031] Table 1 shows the analysis of apple branch biochar. Table 1 shows that with increasing temperature, the ash content, carbonization level, and aromaticity of apple branch biochar increase, while hydrophilicity and polarity decrease. Among these, mixed-generation branches exhibit a more comprehensive effect than other branch ages at different carbonization temperatures, especially at a carbonization temperature of 500℃, where the ash content is lowest, the carbon content is highest, and the hydrophilicity and polarity are relatively high. Considering the wide availability, low cost, diverse composition, and sustainability of apple branch biochar raw materials in actual production, mixed-generation waste apple branches were selected as raw material to produce apple branch biochar at a carbonization temperature of 500℃.

[0032] Depend on Figure 1The results showed that the apple branch biochar obtained by pyrolysis at 300℃ had relatively fewer pores and maintained the structure of the raw material. The apple branch biochar obtained by pyrolysis at 500℃ had a denser and more regular pore structure. The apple branch biochar obtained by pyrolysis at 700℃ had a pore structure that was partially collapsed or destroyed due to excessive pyrolysis, with the pores gradually becoming larger and more ash particles adhering to the surface.

[0033] The apple branch biochar used in this embodiment of the invention is obtained by carbonizing the above-mentioned mixed waste apple branches at 500°C.

[0034] Before and after leaf fall in autumn, apply apple branch biochar (100kg / mu to 200kg / mu), organic fertilizer, and compound fertilizer in holes or ring trenches. At the same time, reduce the amount of conventional nitrogen fertilizer. Before bud break, during flowering and fruit setting, and during fruit enlargement, drip irrigate water-soluble nitrogen fertilizer (total pure nitrogen 10kg / mu to 25kg / mu) at a ratio of 3:2:1 to accurately match the nitrogen demand pattern of apple trees in "early stage to promote shoot growth, mid-stage to stabilize fruit production, and late stage to enlarge fruit size" and supply the nitrogen required by the apple trees.

[0035] During the growth of apple trees, the critical periods for nitrogen requirement are from flowering to fruit set, fruit enlargement, and around the time of autumn leaf fall. During these three stages, DCD (totaling 0.054 kg / mu to 0.25 kg / mu) is applied to the soil using a drip irrigation system. Specifically, irrigate for 2 hours per mu, then add dicyandiamide to the water and continue irrigating for 2 to 3 hours per mu, followed by 1 hour of irrigation per mu, with an irrigation flow rate of 4 m³ / mu. 3 / h~5m 3 / h. Dicyandiamide is evenly injected into the soil through a drip irrigation system to ensure that the nitrification inhibitor can accurately reach the root zone of the fruit trees and exert its effect in inhibiting nitrification.

[0036] The pit application method involves digging pits with a diameter of 15cm to 20cm and a depth of 20cm to 30cm at intervals of 30cm to 50cm below the edge of the tree canopy projection. After applying a measured amount of apple branch biochar, cover it with soil and compact it to ensure close contact with the surrounding soil.

[0037] Circular trench application method: Dig a circular trench 30cm-50cm wide and 30cm-40cm deep at the edge of the tree canopy projection. Evenly apply apple branch biochar, then cover and level with soil, ensuring thorough mixing with the soil. This method promotes the even distribution of apple branch biochar in the soil, provides a suitable environment for microorganisms, and accelerates soil carbon fixation and accumulation.

[0038] Example 1 Experimental field: Two-year-old apple saplings in an apple orchard in Shandong.

[0039] Before and after the fall of leaves in autumn (late October), dig a trench 30cm wide and 30cm deep along the inner edge of the tree canopy projection line. Mix commercial organic fertilizer, compound fertilizer, apple branch biochar and soil and apply it. Then, use drip irrigation to apply water-soluble fertilizer (Yu Nong Fei (2018) No. 12597) and dicyandiamide before bud break, after flowering to fruit setting, during fruit enlargement, and after the fall of leaves in autumn. The amount of commercial organic fertilizer is 200kg / mu, the amount of compound fertilizer is 33.3kg / mu, and the amount of apple branch biochar is 100kg / mu.

[0040] The specific operation of drip irrigation fertilization is as follows (flow rate is 4m³ / min). 3 (h): Before bud break, irrigate for 2 hours per mu, then add water-soluble fertilizer containing macro-elements to the water, continue irrigating for 2 hours per mu, and then irrigate for 1 hour per mu. From flowering to fruit setting and during fruit enlargement, irrigate for 2 hours per mu, then add water-soluble fertilizer containing macro-elements and dicyandiamide to the water, continue irrigating for 2 hours per mu, and then irrigate for 1 hour per mu. After leaf fall in autumn, irrigate for 2 hours per mu, then add dicyandiamide to the water, continue irrigating for 2 hours per mu, and then irrigate for 1 hour per mu. Specifically, the application rates of water-soluble fertilizer containing macro-elements are 20 kg / mu, 13.3 kg / mu, and 6.7 kg / mu for before bud break, from flowering to fruit setting, and during fruit enlargement, respectively; and the application rates of dicyandiamide are 0.03 kg / mu, 0.02 kg / mu, and 0.05 kg / mu for after flowering to fruit setting, during fruit enlargement, and after leaf fall in autumn, respectively.

[0041] Example 2 Experimental field: A Red Fuji apple orchard in Shandong with a yield of 2,500 kg per mu.

[0042] Around the time of autumn leaf fall (late September), dig a trench 40cm wide and 40cm deep along the inner edge of the tree canopy projection line. Mix well-rotted farmyard manure, compound fertilizer, apple branch biochar, and soil and apply the mixture. Then, use drip irrigation to apply water-soluble fertilizer (Yu Nong Fei (2020) No. 16235) and dicyandiamide before bud break, after flowering to fruit setting, during fruit enlargement, and after autumn leaf fall. The amount of well-rotted farmyard manure used is 2000kg / mu, the amount of compound fertilizer used is 44.5kg / mu, and the amount of apple branch biochar used is 150kg / mu.

[0043] The specific operation of drip irrigation fertilization is as follows (flow rate is 4m³ / min). 3(h): Before bud break, irrigate for 2 hours per mu, then add water-soluble fertilizer containing macro-elements to the water, continue irrigating for 2 hours per mu, and then irrigate for 1 hour per mu. From flowering to fruit setting and during fruit enlargement, irrigate for 2 hours per mu, then add water-soluble fertilizer containing macro-elements and dicyandiamide to the water, continue irrigating for 2 hours per mu, and then irrigate for 1 hour per mu. After leaf fall in autumn, irrigate for 2 hours per mu, then add dicyandiamide to the water, continue irrigating for 2 hours per mu, and then irrigate for 1 hour per mu. Specifically, the application rates of water-soluble fertilizer containing macro-elements are 38.46 kg / mu, 25.7 kg / mu, and 12.8 kg / mu for before bud break, from flowering to fruit setting, and during fruit enlargement, respectively; and the application rates of dicyandiamide are 0.05 kg / mu, 0.03 kg / mu, and 0.07 kg / mu for after flowering to fruit setting, during fruit enlargement, and after leaf fall in autumn, respectively.

[0044] Comparative Example 1 Experimental field: Two-year-old apple saplings in an apple orchard in Shandong.

[0045] Around the time of leaf fall in autumn (late October), dig a trench 30cm wide and 30cm deep inside the canopy projection line. Mix organic fertilizer and compound fertilizer with the soil and apply it. Then, before bud break, after flowering to the fruit setting period, and during the fruit enlargement period, apply water-soluble fertilizer (Yu Nong Fei (2018) No. 12597) using drip irrigation. The amount of commercial organic fertilizer used is 200kg / mu, and the amount of compound fertilizer used is 50kg / mu.

[0046] Each time a large amount of water-soluble fertilizer is applied, it should be applied at a rate of 4m 3 The irrigation process involves applying water at a flow rate of / h, first irrigating for 2 hours per acre, then adding a large amount of water-soluble fertilizer solution to the water and continuing irrigation for another 2 hours per acre, followed by irrigating for another 1 hour per acre. The application rates of the large amount of water-soluble fertilizer solution are 30 kg / acre before bud break, 20 kg / acre after flowering to fruit setting, and 10 kg / acre during fruit enlargement.

[0047] Comparative Example 2 Experimental field: A Red Fuji apple orchard in Shandong with a yield of 2,500 kg per mu.

[0048] Around the time of leaf fall in autumn (late September), dig a trench 40cm wide and 40cm deep along the inner edge of the tree canopy projection line. Mix well-rotted farmyard manure, compound fertilizer and soil and apply it. Then, before bud break, after flowering to the fruit setting period and during the fruit enlargement period, apply water-soluble fertilizer (Yu Nong Fei (2020) No. 16235) by drip irrigation. The amount of well-rotted farmyard manure is 2000kg / mu and the amount of compound fertilizer is 66.7kg / mu.

[0049] Each time a large amount of water-soluble fertilizer is applied, it should be applied at a rate of 4m 3The irrigation process involves applying water at a flow rate of / h, first irrigating for 2 hours per acre, then adding a large amount of water-soluble fertilizer solution to the water and continuing irrigation for another 2 hours per acre, followed by irrigating for another 1 hour per acre. Specifically, the application rates of the large amount of water-soluble fertilizer solution are 57.7 kg / acre before bud break, 38.5 kg / acre after flowering to fruit setting, and 19.2 kg / acre during fruit enlargement.

[0050] Comparative Example 1 was conventional fertilization. Example 1 involved conventional fertilization with a 1 / 3 reduction in nitrogen fertilizer application, along with the simultaneous application of apple branch biochar and dicyandiamide (100 kg / mu of apple branch biochar and 0.10 kg / mu of total DCD). Three replicates were set up for each treatment group, and the results are shown in Table 2. Table 2 shows the effects of different fertilization methods on apple plant growth and soil nitrogen in Example 1 and Comparative Example 1, with mean ± standard deviation. The results in Table 2 show that, compared with conventional fertilization in Comparative Example 1, the application of apple branch biochar and dicyandiamide can still significantly promote the growth of apple plants, improve their root system architecture, and increase nitrogen metabolism efficiency, even with a reduction of 1 / 3 in nitrogen fertilizer application, thus achieving the multiple goals of reducing nitrogen, increasing efficiency, and promoting growth.

[0051] Comparative Example 2 involved conventional fertilization. Example 2 involved conventional fertilization with a reduction of 1 / 3 in nitrogen fertilizer application, along with the simultaneous application of apple branch biochar and dicyandiamide (150 kg / mu for apple branch biochar and 0.15 kg / mu for total DCD). Three replicates were set up for each treatment group. The results are shown in Tables 3 and 4. Table 3 shows the results of different fertilization methods on soil physicochemical properties and nitrogen fertilizer utilization in Example 2 and Comparative Example 2, with mean ± standard deviation. Table 3 shows that, compared with the conventional fertilization in Comparative Example 2, even with a reduction of 1 / 3 in nitrogen fertilizer application, the simultaneous application of apple branch biochar and dicyandiamide still increases soil aeration, improves soil structure, increases soil ammonium nitrogen and nitrate nitrogen content, inhibits nitrification, and enhances soil nitrogen fixation capacity, thereby reducing soil nitrogen loss and improving the apple trees' ability to utilize nitrogen fertilizer, achieving multiple goals of nitrogen reduction, greening, and increased efficiency.

[0052] Table 4 shows the results of different fertilization methods on fruit tree growth and apple quality in Example 2 and Comparative Example 2, with mean ± standard deviation. Table 4 shows that, compared with the conventional fertilization in Comparative Example 2, applying apple branch biochar and dicyandiamide simultaneously while reducing nitrogen fertilizer application by 1 / 3 can promote new shoot growth, improve flower bud quality, reduce fruit drop rate, and improve fruit quality, thus achieving multiple goals of reducing nitrogen, improving quality, and increasing efficiency.

[0053] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A fertilization method for reducing nitrogen loss in apple orchards, characterized in that, Includes the following steps: Apply base fertilizer before and after leaf fall in autumn: Use hole application or ring trench application. In the middle to late September to middle to late October of the first year, mix apple branch biochar, carrier, organic fertilizer and compound fertilizer and apply it into the soil. Before budding: Apply nitrogen fertilizer for the first time via drip irrigation in mid-to-late March of the following year; From flowering to fruit setting: In May of the following year, apply nitrogen fertilizer and dicyandiamide via drip irrigation for the second time; Fruit enlargement period: From early July to mid-August of the following year, apply nitrogen fertilizer and dicyandiamide via drip irrigation for the third time; Before and after autumn leaf fall: Apply dicyandiamide via drip irrigation for the fourth time from mid-to-late September to mid-to-late October of the following year; The mass ratio of apple branch biochar to dicyandiamide is 100~200:0.10~0.

25. The application rate of apple branch biochar is 100 kg / mu to 200 kg / mu; The application rates of dicyandiamide during the period from flowering to fruit setting, fruit enlargement, and before and after autumn leaf fall are 0.02 kg / mu to 0.075 kg / mu, 0.01 kg / mu to 0.05 kg / mu, and 0.024 kg / mu to 0.125 kg / mu, respectively. Based on nitrogen content, the total amount of nitrogen applied to the soil is 10 kg / mu to 25 kg / mu.

2. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, Apple branch biochar was prepared by the following steps: under limited oxygen conditions, apple branches were heated to 300℃~700℃ at a rate of 10℃ / min~15℃ / min and pyrolyzed at 300℃~700℃ for 1.5h~2h to obtain apple branch biochar.

3. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, The application rate of compound fertilizer is 26 kg / mu to 84 kg / mu, and the application rate of nitrogen fertilizer is 16.7 kg / mu to 312.5 kg / mu. The ratio of nitrogen fertilizer application rate before bud break, after flowering to fruit setting, and during fruit enlargement is 3:2:

1.

4. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, The procedure for the first drip irrigation application of nitrogen fertilizer is as follows: first irrigate with water for 2 hours per acre, then add nitrogen fertilizer to the water and continue irrigating for 2 to 3 hours per acre, followed by irrigating with water for another 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

5. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, The second drip irrigation application of nitrogen fertilizer and dicyandiamide is as follows: first, irrigate with water for 2 hours per acre, then add dicyandiamide and nitrogen fertilizer to the water, continue irrigating for 2 to 3 hours per acre, and then irrigate with water for 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

6. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, The third drip irrigation application of nitrogen fertilizer and dicyandiamide is as follows: first, irrigate with water for 2 hours per acre, then add dicyandiamide and nitrogen fertilizer to the water, continue irrigating for 2 to 3 hours per acre, and then irrigate with water for 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

7. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, The procedure for the fourth drip irrigation application of dicyandiamide is as follows: first, irrigate with water for 2 hours per acre, then add dicyandiamide to the water and continue irrigating for 2 to 3 hours per acre, followed by irrigating with water for another 1 hour per acre, with an irrigation flow rate of 4 m³ / acre. 3 / h~5m 3 / h.

8. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, The nitrogen fertilizer is a water-soluble nitrogen fertilizer, which is selected from at least one of nitrogen-containing compound fertilizer, urea, potassium nitrate, calcium nitrate, and monoammonium phosphate.

9. The fertilization method for reducing nitrogen loss in apple orchards according to claim 1, characterized in that, Organic fertilizer is selected from well-rotted farmyard manure or commercial organic fertilizer; Among them, well-rotted farmyard manure contains ≥25% organic matter, ≥0.7% nitrogen, ≥0.5% phosphorus, and ≥0.5% potassium. Commercial organic fertilizers contain ≥30% organic matter and ≥5.0% total N, P2O5 and K2O.

10. The fertilization method for reducing nitrogen loss in apple orchards according to claim 9, characterized in that, When the organic fertilizer is well-rotted farmyard manure, the application rate is 1500 kg / mu to 2000 kg / mu; when the organic fertilizer is commercial organic fertilizer, the application rate is 200 kg / mu to 400 kg / mu.

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