Soil conditioner and its application in improving soil and fruit quality of jujube garden in sandy area

Abstract

The application provides a soil conditioner for jujube garden soil in a sandy area and application of the soil conditioner in improving jujube garden soil in the sandy area and fruit quality. The application first proposes a combination of phosphoric acid modified biochar and graphene modified bentonite, which is applied to improve the jujube garden soil in the sandy area, has excellent synergistic effects on improving soil cation exchange capacity content, increasing soil water content, and increasing the percentage content of water stable aggregates, and the like. The application also studies the effect of soil conditioner treatment on improving jujube fruit quality, wherein the soil improved by the soil conditioner has outstanding effect on improving fruit quality, especially in increasing the vitamin C content, protein content, total sugar content, fruit transverse diameter, single fruit weight in Junzao fruit, and reducing the organic acid content in the fruit.

Description

Technical Field

[0002] This invention relates to the field of agricultural cultivation, specifically to a soil conditioner and its application in improving the soil and fruit quality of jujube orchards in sandy areas. Background Technology

[0004] In recent years, research on the application of various types of soil conditioners in jujube cultivation has been increasing, demonstrating their potential to improve soil and enhance jujube production. Regarding soil salinization in jujube orchards in the oasis-desert transition zone of Xinjiang, current research mainly focuses on the application of single soil conditioners. There are few reports on the systematic evaluation of the application of combinations of multiple types of soil conditioners in jujube orchards in Xinjiang's sandy areas, and no multi-purpose soil conditioners that can synergistically improve soil physicochemical properties, enhance fruit quality, and increase yield have been disclosed.

[0005] Therefore, it is urgent to propose a soil conditioner and its application in improving the soil and fruit quality of jujube orchards in sandy areas, based on the above-mentioned problems, to solve the problem of soil salinization in jujube orchards from multiple perspectives, improve the physical and chemical properties of the soil, and enhance the quality of jujube fruit. Summary of the Invention

[0007] To achieve the above objectives, the present invention provides a soil conditioner and its application in improving the soil and fruit quality of jujube orchards in sandy areas.

[0008] This application provides a soil conditioner comprising the following components in parts by weight: 1-2 parts modified biochar, 1-2 parts modified bentonite, 0.5-1 parts fly ash, and 0.1-0.2 parts crosslinking agent.

[0009] This application provides a soil conditioner comprising the following components in parts by weight: 1-2 parts modified biochar, 1-2 parts modified bentonite, and 0.5-1 parts fly ash.

[0010] This application provides a soil conditioner comprising the following components in parts by weight: 1-2 parts modified biochar and 1-2 parts modified bentonite.

[0011] Preferably, the soil conditioner comprises the following components in parts by weight: 1 part modified biochar, 1.8 parts modified bentonite, 0.5 parts fly ash, and 0.1 parts crosslinking agent.

[0012] Preferably, the soil conditioner comprises the following components in parts by weight: 1 part modified biochar, 1.8 parts modified bentonite, and 0.5 parts fly ash.

[0013] Preferably, the soil conditioner comprises the following components in parts by weight: 1 part modified biochar and 1.8 parts modified bentonite.

[0014] Preferably, the modified biochar is phosphoric acid modified biochar.

[0015] Preferably, the modified bentonite is graphene-modified bentonite.

[0016] This application also provides a method for preparing a soil conditioner, specifically including the following steps:

[0017] (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use.

[0018] (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar;

[0019] (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite;

[0020] (4) Mix xanthan gum and chitosan in a weight ratio of 1:5, grind them into powder, pass them through a 100-mesh sieve, and finally obtain the crosslinking agent;

[0021] (5) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar of step (2), the graphene modified bentonite of step (3), fly ash, and the crosslinking agent of step (4) in a weight ratio of 1:1.8:0.5:0.1.

[0022] This application also provides a method for preparing a soil conditioner, specifically including the following steps:

[0023] (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use.

[0024] (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar;

[0025] (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite;

[0026] (4) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar from step (2), the graphene modified bentonite from step (3), and fly ash in a weight ratio of 1:1.8:0.5.

[0027] A method for preparing a soil conditioner specifically includes the following steps:

[0028] (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use.

[0029] (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar;

[0030] (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite;

[0031] (4) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar from step (2) and the graphene modified bentonite from step (3) in a weight ratio of 1:1.8.

[0032] This application also provides an application of a soil conditioner in improving soil and fruit quality in sandy jujube orchards, specifically including the following steps:

[0033] Before the jujube trees sprout, apply a ring fertilizer around the trunk. Specifically, dig a trench (1 m long, 0.3 m wide, and 0.35 m deep) 0.45 m along both the east and west sides of the trunk. Mix the uniform base fertilizer and soil conditioner evenly and apply it as a single base fertilizer. The base fertilizer is 659 kg / hm² of urea (N≥46%). 2 219 kg / hm² of superphosphate (P₂O₅≥46%) 2 Potassium sulfate (K2O≥50%) 202 kg / hm 2 30,000 kg / hm² of well-rotted sheep manure 2 The soil conditioner is any one of the above-mentioned soil conditioners, and is applied at a rate of 5000 kg / hm². 2 It is applied as a base fertilizer along with other basic fertilizers all at once. First, it is mixed evenly with the brown desert soil, and then the soil is covered and leveled.

[0034] The beneficial effects of this application are:

[0035] 1. The product obtained by phosphoric acid-modified biochar in this application exhibits significantly increased specific surface area and porosity, and a significantly increased oxygen-containing functional content. The modified biochar promotes soil aggregate formation and significantly affects the pH of the biochar. Phosphoric acid-modified biochar also effectively promotes the leaching of Na+ in saline-alkali soils, i.e., it enhances the surface complexation ability with Na+, forming a biochar-organic matter-mineral complex, thereby promoting the formation of aggregates in saline-alkali soils. Phosphoric acid-modified biochar significantly increases the proportion of soil aggregates with a surface depth of 0-20 cm.

[0036] 2. This application proposes for the first time a combination of phosphoric acid modified biochar and graphene modified bentonite, which is applied to improve the soil of jujube orchards in sandy areas. Experiments have shown that the combination of phosphoric acid modified biochar and graphene modified bentonite has excellent synergistic effects in increasing the content of soil cation exchange capacity, increasing soil moisture content, and increasing the percentage of water-stable aggregates.

[0037] 3. This application is the first to develop a soil conditioner consisting of a combination of phosphoric acid-modified biochar, graphene-modified bentonite, fly ash, and a crosslinking agent, as well as its preparation method. The phosphoric acid-modified biochar can adsorb monovalent ions, while the graphene-modified bentonite can effectively adsorb divalent basic ions, forming a double-layer structure. The addition of fly ash and a crosslinking agent significantly enhances the soil's nutrient retention capacity. Furthermore, the resulting soil conditioner improves saline-alkali soils with excellent physicochemical properties. Example 1 showed the best soil improvement effect, significantly increasing the content of available nitrogen, available phosphorus, and available potassium, reducing the soluble salt content, and significantly increasing the percentage of water-stable aggregates in the soil.

[0038] 4. Studies have shown that fly ash can enhance soil water retention and reduce soil compaction in soil improvement experiments in sandy areas of Xinjiang. When combined with phosphoric acid-modified biochar and graphene-modified bentonite, fly ash can significantly improve soil water retention. Example 2 of this application also has a better soil improvement effect.

[0039] 5. The phosphoric acid modified biochar of the combination of rice husk and peanut shell in this application is more effective in improving saline-alkali soil than rice husk, peanut shell or corn stalk alone. The experiment only gives examples of using rice husk alone and the comparative experiment of using rice husk and peanut shell in a 1:1 weight ratio. The biomass after combination is more effective in improving saline-alkali soil.

[0040] 6. The cross-linking agent xanthan gum and chitosan, mixed at a weight ratio of 1:5, show the best effect in this application. This application is the first to use xanthan gum as a cross-linking agent in a soil conditioner, and its combined use with chitosan can improve the soil's aggregate structure and enhance the effects of other conditioners. It increases the viscosity of phosphate-modified biochar, graphene-modified bentonite, and fly ash in sandy soils, further improving the soil's water and fertilizer retention capacity. Adding a cross-linking agent to the soil conditioner forms a new cementing framework after soil improvement, making the soil structure in sandy areas more compact. At the same time, it can adjust soil porosity and improve soil aeration. Studies have shown that its combined use with the phosphate-modified biochar, graphene-modified bentonite, and fly ash of this application is more effective. However, the amount of xanthan gum added must not be too high, especially when used in sandy soils. Excessive use will lead to a decrease in soil porosity and affect plant growth.

[0041] 7. This application has adjusted the raw materials and reaction conditions of the modified biochar, and found that the soil improvement effect of the combination of phosphoric acid modified biochar and the amendment raw materials of this application is better than that of hydrochloric acid, alkali and high concentration of phosphoric acid; phosphoric acid modified biochar has a rich pore structure, which significantly increases the specific surface area of ​​biochar.

[0042] 8. Graphene-modified bentonite has significantly increased porosity compared to original bentonite. After high-temperature modification, graphene-modified bentonite exhibits more folds and curls on its surface compared to original bentonite, with a looser structure and thinner sheets, forming a more complete and micro-porous structure, which increases the contact area between the particle interior and the outside world.

[0043] 9. This application also studied the effect of soil conditioner treatment on improving the quality of jujube fruit. Among them, Examples 1-2 showed the best effect. The soil improved by the soil conditioner had a significant effect on improving the quality of the fruit. The vitamin C content, protein content, total sugar content, fruit diameter, and single fruit weight of the jujube fruit were all higher than those of the control (CK), while the organic acid content was lower than that of the control (CK). Attached Figure Description

[0045] Figure 1 Scanning electron microscope images of the surface morphology of the original rice husk and peanut shell biochar in this application;

[0046] Figure 2 Scanning electron microscope image of the surface morphology of phosphoric acid modified biochar in this application;

[0047] Figure 3 Scanning electron microscope image of the original bentonite surface morphology in this application;

[0048] Figure 4 Scanning electron microscope image of the surface morphology of graphene-modified bentonite in this application;

[0049] Figure 5 The following diagram illustrates the effects of different soil conditioners on the physical and chemical properties of improved soil (A represents soil pH, B represents soil soluble salts, C represents soil organic matter, D represents soil cation exchange capacity, E represents soil bulk density, F represents soil moisture content, G represents soil total porosity, and H represents the analysis of soil water-stable aggregates). Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention. Bentonite was purchased from Xinjiang Baohua Crystal Stone New Material Technology Co., Ltd.; graphene was purchased from Tangshan Jianhua Technology Development Co., Ltd.; microbial inoculant was purchased from Biowish Company as a liquid composite inoculant containing Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus pumilus.

[0052] Example 1

[0053] A method for preparing a soil conditioner specifically includes the following steps:

[0054] (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use.

[0055] (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar;

[0056] (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite;

[0057] (4) Mix xanthan gum and chitosan in a weight ratio of 1:5, grind them into powder, pass them through a 100-mesh sieve, and finally obtain the crosslinking agent;

[0058] (5) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar of step (2), the graphene modified bentonite of step (3), fly ash, and the crosslinking agent of step (4) in a weight ratio of 1:1.8:0.5:0.1.

[0059] Example 2

[0060] A method for preparing a soil conditioner specifically includes the following steps:

[0061] (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use.

[0062] (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar;

[0063] (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite;

[0064] (4) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar from step (2), the graphene modified bentonite from step (3), and the fly ash in a weight ratio of 1:1.8:0.5.

[0065] Example 3

[0066] A method for preparing a soil conditioner specifically includes the following steps:

[0067] (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use.

[0068] (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar;

[0069] (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite;

[0070] (4) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar from step (2) and the graphene modified bentonite from step (3) in a weight ratio of 1:1.8.

[0071] Experiment 1: Effects of different soil conditioners on the improvement of soil physicochemical properties

[0072] Experimental method: Before the jujube trees sprouted, strip trenches (1 m long, 0.3 m wide, and 0.35 m deep) were dug on both the east and west sides of the tree canopy, 0.45 m from the trunk. A uniform base fertilizer of urea (N≥46%) was applied at 659 kg / hm². 2 219 kg / hm² of superphosphate (P₂O₅≥46%) 2 Potassium sulfate (K2O≥50%) 202 kg / hm 2 30,000 kg / hm² of well-rotted sheep manure 2 Soil conditioners and brown desert soil from each treatment group were mixed evenly and applied as base fertilizer in one application, followed by covering with soil and leveling. Cultivation and management were completely consistent across all treatments during the experiment. The indoor experiment was conducted in 2024 at the National-Local Joint Engineering Laboratory for High-Efficiency and High-Quality Cultivation and Deep Processing Technology of Characteristic Fruit Trees in Southern Xinjiang, Tarim University. The tested soil type was local jujube orchard brown desert soil, a product of the combined effects of warm temperate extreme arid climate, specific topographic parent material, and long-term salt accumulation. Different soil conditioners were applied to saline-alkali soil (total water-soluble salt content of 2.3 g / kg and soil pH of 8.5 in the top 0-20 cm soil layer) of the 1st Company, 224th Regiment, Kunyu City, 14th Division of Xinjiang Production and Construction Corps. After 30 days, soil samples from the top 0-20 cm layer were taken for physicochemical property determination (five-point sampling method, mixed thoroughly, three replicates). Soil pH was determined using carbon dioxide-free distilled water extraction (water-to-soil ratio 1:5) and a precision pH meter. Soil soluble salt content was determined using a gravimetric method. Soil organic matter content was determined using the potassium dichromate titration method with external heating. Cation exchange capacity (CEC) was determined using hexaamminecobalt trichloride extraction with spectrophotometry. Soil physical properties, including bulk density, water content, and total porosity, were determined using the ring sieving method. The percentage of water-stable aggregates in the soil was determined using the wet sieving method. The experiment included six treatments: ①CK (original soil control, no amendment applied); ②BI (phosphate-modified biochar, 5000 kg·hm²). -2 ); ③GR (graphene, 3.57 kg·hm) -2 ); ④BE (graphene-modified bentonite, 9000 kg·hm -2 ); ⑤ MI (microbial inoculant, 2.14 kg·hm -2 ); ⑥BB (Example 3, phosphoric acid modified biochar + graphene modified bentonite, application rate 5000 kg·hm -2 The two are mixed in a weight ratio of 1:1.8 and then applied.

[0073] Experimental results:

[0074] Figure 5Soil physicochemical properties: Analysis of pH, soluble salts, cation exchange capacity, bulk density, water content, total porosity, and water-stable aggregates. As shown in the graphs, compared to the control (CK), all amendment treatments significantly increased soil organic matter, cation exchange capacity, and the percentage of water-stable aggregates. Compared to the CK, the BE treatment significantly reduced soil pH, with the largest decrease reaching 3.33%, and significantly lower than the GR and BB treatments. Figure 5 A), GR and BB treatments also significantly reduced soil pH, but the reduction was small, at 1.78% and 1.19%, respectively. In terms of reducing soil soluble salt content, BI, BE, and BB treatments were significantly effective, with reductions compared to CK ranging from 13.42% to 19.48%, and there were no significant differences among the three treatments. Figure 5 B). The BB treatment significantly increased the soil cation exchange capacity (19.4 cmol). + ·kg -1 The increase was as high as 92.27% compared to CK, and significantly higher than other treatments ( Figure 5 D), the cation exchange capacity of the soil was higher than that of the BI and BE treatments alone, indicating that the combination of phosphoric acid-modified biochar and graphene-modified bentonite has a synergistic effect. BI, MI, and BB treatments all significantly reduced soil bulk density, with a reduction of 8.21% compared to the control (CK), and there was no significant difference among the three treatments. Figure 5 E). Except for the GR treatment, all other amendment treatments significantly increased soil moisture content (E). Figure 5 F), among which the BB treatment showed the most significant effect, with an increase of 243.90% compared to the CK, and significantly higher than other treatments. The BI, MI, and BE treatments also significantly increased soil moisture content, with increases ranging from 80.49% to 174.39%, but the effect was weaker than that of the BB treatment, indicating that the combination of phosphate-modified biochar and graphene-modified bentonite has a synergistic effect. The BE, BI, MI, and BB treatments significantly increased the total soil porosity, with increases ranging from 5.09% to 9.21% compared to the CK, and there were no significant differences among the treatments. Figure 5 G). The BB treatment was the most effective in increasing the percentage of water-stable aggregates, significantly increasing it by 152.38% compared to the CK, and significantly higher than all other modifier treatments (G). Figure 5 H). Other modifier treatments also significantly increased the percentage of water-stable aggregates, but the effect was not as good as the BB treatment, indicating that the combination of phosphate-modified biochar and graphene-modified bentonite has a synergistic effect.

[0075] Experiment 2: Effects of different preparation methods on the physicochemical properties of soil conditioners

[0076] Experimental Methods: The experiment was conducted in 2024 at the National-Local Joint Engineering Laboratory for High-Efficiency and High-Quality Cultivation and Deep Processing Technology of Characteristic Fruit Trees in Southern Xinjiang, Tarim University. The tested soil type was local jujube orchard brown desert soil, a product of the combined effects of warm temperate extreme arid climate, specific topographic parent material, and long-term salt accumulation. Different soil conditioners were applied to the saline-alkali soil (total water-soluble salt content of 2.3 g / kg and soil pH of 8.5 in the top 0-20 cm soil layer) of the 1st Company of the 224th Regiment of the 14th Division of Xinjiang Production and Construction Corps. Before the jujube trees sprouted, strip trenches (1 m long, 0.3 m wide, and 0.35 m deep) were dug on the east and west sides of the tree canopy, 0.45 m away from the trunk. A uniform base fertilizer, namely urea (N≥46%), was applied at 659 kg / hm². 2 219 kg / hm² of superphosphate (P₂O₅≥46%) 2 Potassium sulfate (K2O≥50%) 202 kg / hm 2 30,000 kg / hm² of well-rotted sheep manure 2 The soil conditioner for each treatment group was applied at a rate of 5000 kg / hm². 2 The mixture was thoroughly mixed with brown desert soil and applied as a single application as base fertilizer, followed by covering with soil and leveling. All treatments maintained identical cultivation and management practices during the experimental period. After 30 days, soil samples from the top 0-20 cm depth were taken for physicochemical property testing (five-point sampling method, thorough mixing, three replicates). Soil available nitrogen content was determined using the alkaline diffusion method; available phosphorus content was determined using a 0.05 mol·L⁻¹ solution. -1 The molybdenum-antimony colorimetric method was used to determine the content of available potassium in the soil after extraction with NaHCO3 solution; the ammonium acetate extraction-flame photometric method was used to determine the content of other indicators, and the methods for determining other indicators were the same as in Experiment 1.

[0077] Experimental Example 1

[0078] The preparation method is the same as in Example 1, except that the biomass raw materials are replaced, and rice husks and peanut shells are mixed in a 1:1 weight ratio.

[0079] Experimental Example 2

[0080] The preparation method is the same as in Example 1, except that the biomass raw material is replaced with rice husk.

[0081] Experimental Example 3

[0082] The preparation method is the same as in Example 1, except that the crosslinking agent is replaced with xanthan gum and chitosan in a weight ratio of 1:3.

[0083] Experiment Example 4

[0084] The preparation method is the same as in Example 1, except that the crosslinking agent is replaced with chitosan.

[0085] Experimental Example 5

[0086] The preparation method is the same as in Example 1, except that the oxygen-limited pyrolysis condition in step (1) is changed to pyrolysis at 500 °C for 3 hours.

[0087] Experimental Example 6

[0088] The preparation method is the same as in Example 1, except that the oxygen-limited pyrolysis condition in step (1) is changed to 600 °C for 2.5 h.

[0089] Experimental Example 7

[0090] Same as Example 1, except that the phosphoric acid in step (2) is replaced with hydrochloric acid.

[0091] Experimental Example 8

[0092] Same as Example 1, except that the phosphoric acid in step (2) is replaced with sodium hydroxide.

[0093] Experimental Example 9

[0094] Same as Example 1, except that step (2) is replaced with a 2 mol / L phosphoric acid solution.

[0095] Experimental Example 10

[0096] Same as Example 1, except that step (3) involves heating the reactor at 500°C for 1 hour.

[0097] Experimental Example 11

[0098] Same as Example 1, except that in step (3), 100 mL of deionized water is added to 0.1 g of graphene.

[0099] Experimental Example 12

[0100] Same as in Example 1, except that the phosphoric acid modified biochar, graphene modified bentonite, fly ash, and crosslinking agent were mixed in a weight ratio of 1:1:0.5:0.1 to obtain the final soil conditioner.

[0101] Compare with Example 1

[0102] Same as Example 1, except that the raw material is replaced with unmodified biomass, that is, step (2) modification step is omitted.

[0103] Compare with Example 2

[0104] Same as Example 1, except that the raw material is replaced with unmodified bentonite, i.e., step (3) modification step is omitted.

[0105] Table 1. Effects of amendments prepared by different methods on the physical and chemical properties of improved soil.

[0106]

[0107] Experimental Results: The saline-alkali soils improved using the soil conditioners prepared by the methods in Examples 1-2 of this application exhibit excellent physicochemical properties. The soil conditioner in Example 1, consisting of phosphoric acid-modified biochar, graphene-modified bentonite, fly ash, and a cross-linking agent, showed the best soil improvement effect. It significantly increased the content of available nitrogen, available phosphorus, and available potassium in the improved soil, reduced the soluble salt content, and significantly increased the percentage of water-stable aggregates in the soil. Studies have shown that fly ash enhances soil water retention and reduces soil compaction in soil improvement experiments in sandy areas of Xinjiang. Its combination with phosphoric acid-modified biochar and graphene-modified bentonite significantly improves soil water retention. Example 2 also showed superior soil improvement effects.

[0108] Experimental Examples 1-2 show that the phosphoric acid-modified biochar made from the combination of rice husks and peanut shells in this application is more effective in improving saline-alkali soil than using rice husks or corn stalks alone. The experiment compared the effects of using rice husks alone and using rice husks and peanut shells in a 1:1 weight ratio. The results show that the biochar prepared from the biomass raw materials in a 3:1 ratio is more effective in improving saline-alkali soil, and there is a significant synergistic effect between the two.

[0109] Experimental Examples 3-4 show that the crosslinking agent xanthan gum and chitosan, mixed at a weight ratio of 1:5, exhibit the best effect. This application is the first to use xanthan gum as a crosslinking agent in a soil conditioner, and its combined use with chitosan improves soil aggregate structure and enhances the effectiveness of other conditioners. It also increases the viscosity of phosphate-modified biochar, graphene-modified bentonite, and fly ash in sandy soils, further improving the soil's water and fertilizer retention capacity. Adding a crosslinking agent to the soil conditioner forms a new cementing framework after soil improvement, making the soil structure in sandy areas more compact. Simultaneously, it adjusts soil porosity and improves soil aeration. Studies have shown that its combined use with the phosphate-modified biochar, graphene-modified bentonite, and fly ash of this application yields even better results. However, the amount of xanthan gum added must not be too high, especially when used in sandy soils. Excessive use will lead to a decrease in soil porosity, affecting the respiration and growth of plant roots. Experiments have shown that when the ratio of xanthan gum to chitosan is higher than 1:3 (too high a proportion of xanthan gum), soil porosity begins to decrease significantly.

[0110] Experiments 5-6, which examined the pyrolysis reaction conditions of biochar, showed that reaction temperature and time significantly affect the soil-improving effect of biochar. The pyrolysis temperature may influence the surface porosity of the biochar, thus affecting its adsorption and other effects. Experiments 7-9 adjusted the raw materials and reaction conditions for modified biochar, demonstrating that the soil-improving effect of the combination of phosphoric acid-modified biochar and the soil conditioner raw materials of this application was superior to that of hydrochloric acid, alkali, and high-concentration phosphoric acid (2 mol / L). Phosphoric acid-modified biochar possesses a rich pore structure, thereby significantly increasing the specific surface area of ​​the biochar. Figure 1 and Figure 2 The comparison showed that phosphoric acid-modified biochar, due to its high porosity, large specific surface area, and thus abundant surface functional groups, is more effective in improving the soil environment and enhancing nutrient utilization.

[0111] Experimental Examples 10-11 show that the optimal conditions for graphene-modified bentonite are 400℃ / 1.5h and graphene addition of 0.2g. Excessive temperature will destroy the layered structure of bentonite, while insufficient addition will result in a weak improvement in porosity. Figure 3 and Figure 4 It can be seen that graphene-modified bentonite, after high-temperature modification, exhibits more folds and curls on its surface compared to the original bentonite. The structure is looser, the layers are thinner, and a more complete and microscopic pore structure is formed, increasing the contact area between the particle interior and the external environment. Experiments show that the amount of graphene and the reaction temperature both affect the soil improvement effect of the modified bentonite. Excessively high temperatures (e.g., 500℃) will destroy the layered structure of bentonite, leading to a decrease in porosity; insufficient graphene addition will fail to effectively improve the pore structure. Example 12 shows that a core composition ratio deviating from 1:1.8 will lead to a decrease in the improvement effect; optimizing the ratio is key to synergistic effects. In Control Examples 1-2, omitting the modification step significantly reduces the soil improvement effect. Unmodified biomass and bentonite have poor pore structure and weak adsorption capacity, failing to effectively improve brown desert soil.

[0112] Experiment 3: Effects of different soil conditioners on improving fruit quality

[0113] Experimental Methods: The experiment was conducted in 2024 at the Jujube Orchard, 1st Company, 224th Regiment, 14th Division, Kunyu City, Xinjiang Production and Construction Corps (79°19'56"E, 37°16'27"N). The plant spacing in the orchard was 2 m × 4 m. The experimental trees were vigorous and uniform, and a unified management model was adopted during the experiment, except for soil amendment treatment. The soil type was brown desert soil, and other methods were the same as in Experiment II. The methods for determining the internal quality indicators of the fruit were based on "Experimental Guide to Plant Physiology" edited by Gao Junfeng. Soluble solids content was determined using a handheld digital saccharimeter (PAL-1); protein content was determined using the Coomassie Brilliant Blue G-250 staining method; vitamin C content was determined using the molybdenum blue colorimetric method; total sugar content was determined using the anthrone colorimetric method; organic acid content was determined using the acid-base titration method; the ratio of total sugar content to the corresponding organic acid content was the sugar-acid ratio; total flavonoid content was determined using the aluminum nitrate-sodium nitrite colorimetric method; and total phenolic content was determined using the Folin-Ciocalteu colorimetric method. For fruit appearance quality indicators, the weight of a single jujube fruit was weighed using an electronic analytical balance with a sensitivity of 0.0001 g; the longitudinal and transverse diameters were measured using vernier calipers with an accuracy of 0.01 mm; the fruit shape index was calculated as the ratio of the fruit's longitudinal diameter to its transverse diameter. In early November, jujubes were harvested from 10 randomly selected sample trees for each treatment, and the yield per tree was determined by weighing.

[0114] Table 2. Effects of different soil conditioners on improving fruit quality

[0115]

[0116] Experimental Results: Compared with the control (CK), the different soil conditioner treatments in Examples 1-2 significantly improved fruit quality, while the protein and total sugar content of the fruit in Example 3 was lower than that in the CK. The soil improved by the soil conditioners in Examples 1-2 showed outstanding effects in improving fruit quality. Specifically, the vitamin C content, protein content, total sugar content, fruit diameter, and single fruit weight of the jujube fruit were all higher than those in the CK, while the organic acid content was lower. The soil conditioner in Example 1, consisting of phosphate-modified biochar, graphene-modified bentonite, fly ash, and a cross-linking agent, showed the best soil improvement effect and also demonstrated excellent results in improving fruit quality. The core combination plus fly ash formulation in Example 2 was the next best, both demonstrating the synergistic effect of the compound system. After omitting the modification steps of this application in Comparative Examples 1-2, the soil improvement effect was significantly reduced, especially in Comparative Example 2 with unmodified bentonite, where all fruit quality indicators were close to the control (CK), proving that graphene-modified bentonite plays a key role in improving fruit quality; at the same time, its effect on improving fruit quality was also significantly reduced; especially when the control group with modified bentonite was replaced with unmodified bentonite, the corresponding fruit quality was significantly reduced. Example 3 only uses the core composition, without fly ash and cross-linking agents. Although it increased the transverse diameter and single fruit weight, the internal nutrients (protein, total sugar) were significantly reduced, indicating that the auxiliary components are of great significance for improving the internal quality of the fruit.

[0117] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A soil conditioner for jujube orchards in sandy areas, characterized in that, The soil is brown desert soil, and the soil conditioner comprises the following components in parts by weight: 1-2 parts modified biochar, 1-2 parts modified bentonite, 0.5-1 parts fly ash, and 0.1-0.2 parts crosslinking agent; the modified biochar is phosphoric acid modified biochar, the modified bentonite is graphene modified bentonite, and the crosslinking agent is a mixture of xanthan gum and chitosan in a 1:5 ratio by weight.

2. A soil conditioner for jujube orchards in sandy areas, characterized in that, The soil is brown desert soil, and the soil conditioner comprises the following components in parts by weight: 1-2 parts modified biochar, 1-2 parts modified bentonite, and 0.5-1 parts fly ash; the modified biochar is phosphoric acid modified biochar, and the modified bentonite is graphene modified bentonite.

3. A soil conditioner for jujube orchards in sandy areas, characterized in that, The soil is brown desert soil, and the soil conditioner includes the following components in parts by weight: 1-2 parts modified biochar and 1-2 parts modified bentonite. The modified biochar is phosphoric acid modified biochar, and the modified bentonite is graphene modified bentonite.

4. A soil conditioner for improving the fruit quality of jujube orchards in sandy areas, characterized in that, The soil is brown desert soil, and the soil conditioner comprises the following components in parts by weight: 1-2 parts modified biochar, 1-2 parts modified bentonite, 0.5-1 parts fly ash, and 0.1-0.2 parts crosslinking agent; the modified biochar is phosphoric acid modified biochar, the modified bentonite is graphene modified bentonite, and the crosslinking agent is a mixture of xanthan gum and chitosan in a 1:5 ratio by weight.

5. A soil conditioner for improving the fruit quality of jujube orchards in sandy areas, characterized in that, The soil is brown desert soil, and the soil conditioner comprises the following components in parts by weight: 1-2 parts modified biochar, 1-2 parts modified bentonite, and 0.5-1 parts fly ash; the modified biochar is phosphoric acid modified biochar, and the modified bentonite is graphene modified bentonite.

6. The method for preparing the soil conditioner according to claim 1 or 4, characterized in that, Specifically, the steps include the following: (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use. (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar; (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite; (4) Mix xanthan gum and chitosan in a weight ratio of 1:5, grind them into powder, pass them through a 100-mesh sieve, and finally obtain the crosslinking agent; (5) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar of step (2), the graphene modified bentonite of step (3), fly ash, and the crosslinking agent of step (4) in a weight ratio of 1:1.8:0.5:0.

1.

7. The method for preparing the soil conditioner according to claim 2 or 5, characterized in that, Specifically, the steps include the following: (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use. (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar; (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite; (4) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar from step (2), the graphene modified bentonite from step (3), and the fly ash in a weight ratio of 1:1.8:0.

5.

8. The method for preparing the soil conditioner as described in claim 3, characterized in that, Specifically, the steps include the following: (1) Pretreatment of biomass raw materials: Rice husks and peanut shells are mixed in a weight ratio of 3:1, crushed and passed through a 20-mesh sieve, sealed and subjected to oxygen-limited pyrolysis at 650 ℃ for 2 hours. After the pyrolysis is completed, the mixture is cooled naturally and passed through a 100-mesh sieve. It is then stored in the dark for later use. (2) Place 100g of biochar obtained in step (1) in a glass container, add 1000ML of 1 mol / L phosphoric acid solution, mix well, shake at 100rpm for 24h at room temperature, wash with deionized water, filter until the filtrate is colorless and transparent, dry the solid at 90℃ to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain phosphoric acid modified biochar; (3) Add 100 mL of deionized water to 0.2 g of graphene and disperse evenly to obtain a graphene dispersion; add 10 g of bentonite to the graphene dispersion, heat the reactor at 400°C for 1.5 h, filter the product, wash with deionized water and filter until the filtrate is colorless and transparent, then dry the solid at 105°C to constant weight, pulverize again and pass through a 100-mesh sieve to finally obtain graphene-modified bentonite; (4) The final soil conditioner is obtained by mixing the phosphoric acid modified biochar from step (2) and the graphene modified bentonite from step (3) in a weight ratio of 1:1.

8.

9. The application of claims 1-8 in any of the following aspects: (1) Application in increasing the cation exchange capacity of saline-alkali soil; (2) Application in increasing soil moisture content; (3) Application in increasing the percentage content of water-stable aggregates; (4) Application in improving the physical and chemical properties of brown desert soil in sandy areas; (5) Application in increasing the vitamin C content, protein content and total sugar content of jujube fruit; (6) Application in increasing the transverse diameter of jujube fruit and the weight of a single fruit; (7) Application in reducing the organic acid content of jujube fruit.

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