Soil conditioner for improving soil fertility of orchard and application of soil conditioner

Abstract

The invention provides a soil conditioner for improving the soil fertility of an orchard and application of the soil conditioner, and belongs to the technical field of soil conditioners. The soil conditioner is prepared from the following raw materials: micro-activated humic acid raw powder, furfural residues and a functional synergist. The humic acid soil conditioner disclosed by the invention is applied in a furrow application mode for four consecutive years, so that the yield and the quality of apples are remarkably improved; the richness of soil species is enhanced, and relatively high soil microbial activity is shown; the physical and chemical key indexes of the soil are improved, and the fertility level of the soil is improved; the discharge of N2O in orchard soil can be reduced, and the soil conditioner is a low-carbon green soil conditioner.

Description

Technical Field

[0001] This invention relates to the field of soil conditioner technology, and in particular to a soil conditioner for improving orchard soil fertility and its application. Background Technology

[0002] As an important fruit tree economic crop, the development of apple industry is of great significance to agricultural economic growth and farmers' income increase. The dwarf rootstock high-density planting model, due to its advantages such as early fruiting, high yield, high quality, and ease of mechanized management, has become the mainstream development direction of the modern apple industry. However, in the vast apple-producing areas of northern my country, especially in mountainous and barren orchards, soil problems are becoming increasingly prominent, severely restricting the realization of the production potential of dwarf rootstock high-density apple orchards.

[0003] Currently, poor apple orchards generally suffer from low soil fertility, insufficient organic matter content, and deteriorated soil structure. In most orchards, the soil organic matter content is below 15g / kg, the supply of nutrients such as nitrogen, phosphorus, and potassium is unbalanced, the soil bulk density is high, and the porosity is low, resulting in poor water and fertilizer retention capacity and poor aeration and permeability. Simultaneously, long-term single-fertilization patterns and unreasonable field management have reduced soil microbial diversity and activity, and weakened soil carbon pool stability, further exacerbating soil degradation. These soil problems directly hinder apple growth and development, manifesting as low fruit yield, insufficient single fruit weight, and declining fruit quality, especially insufficient content of volatile aroma substances (such as esters and alcohols), affecting the flavor and commercial value of the apples.

[0004] In addition, the excessive application of chemical fertilizers in traditional orchard production in pursuit of yield has not only failed to effectively improve soil quality, but has also led to environmental problems such as increased soil acidification or salinization and nutrient loss. Among these problems, the increased emissions of greenhouse gases such as N2O from the soil have a potential impact on the ecological environment and do not meet the requirements for green and low-carbon agricultural development.

[0005] To address the aforementioned issues, soil conditioners have become an important means of improving orchard soil quality. Humic acid-based soil conditioners, rich in humic acid, organic matter, and various functional components, possess potential advantages in enhancing soil fertility, improving soil structure, and promoting crop growth, and have gradually attracted attention in agricultural production. However, existing research on the application of humic acid-based conditioners in dwarf rootstock densely planted apple orchards is not systematic, and there is insufficient optimization of specific formulations for infertile soils. The comprehensive regulatory mechanisms of conditioners on soil physical properties, chemical properties, and microbial community structure still need further clarification, and research on the synergistic optimization of conditioner dosage with apple yield, quality, and ecological effects (such as greenhouse gas emission reduction) is relatively lacking.

[0006] Therefore, developing a highly efficient humic acid soil conditioner suitable for densely planted apple orchards with poor dwarf rootstocks, clarifying its reasonable application methods and dosages, and achieving the organic unity of soil quality improvement, high-quality and high-yield apple production, and ecological environmental protection has become an urgent technical problem to be solved in the sustainable development of the apple industry. It also provides important practical needs and research directions for the research and development and application of related soil conditioners. Summary of the Invention

[0007] The purpose of this invention is to provide a soil conditioner for improving orchard soil fertility and its application, in order to solve the above-mentioned technical problems.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a soil conditioner for improving orchard soil fertility, comprising the following components in parts by weight: 50-60 parts of micro-activated humic acid raw powder; 20-30 parts of furfural residue; Functional synergist 10-30 parts.

[0009] Furthermore, the soil conditioner, calculated on a dry matter basis, contains ≥50% organic matter, ≥27.6% humic acid, ≥0.20 billion / g of viable bacteria, ≥4.0% total nitrogen, phosphorus, and potassium, ≥3% calcium oxide, ≤30.0% moisture, and pH 5.5~8.5.

[0010] Furthermore, the functional synergist comprises citric acid, malic acid, and seaweed extract, wherein the mass ratio of citric acid, malic acid, and seaweed extract is 20~25:15~20:10~15.

[0011] Furthermore, the micro-activated humic acid powder is derived from weathered coal alkali solution.

[0012] This invention also provides the application of the above-mentioned soil conditioner for improving orchard fertility in increasing fruit tree yield and quality.

[0013] The beneficial effects of this invention are: For four consecutive years, the application of the humic acid soil conditioner of this invention via trench application has significantly improved the yield and quality of apples; enhanced the richness of soil species and demonstrated high soil microbial activity; improved key physical and chemical indicators of the soil and increased soil fertility; and reduced N2O emissions from orchard soil, making it a low-carbon and green soil conditioner. Attached Figure Description

[0014] Figure 1 This is a comparison chart of apple yields at harvest time after application in Examples 1-3 and Comparative Example 1 of the present invention; Figure 2This is a comparison diagram of soil bulk density after treatment in the embodiments and comparative examples of the present invention; Figure 3 This is a comparison diagram of soil porosity after treatment in the embodiments and comparative examples of the present invention; Figure 4 This is a comparison diagram of soil field water holding capacity after treatment in the embodiments and comparative examples of the present invention; Figure 5 These are comparison images of soil CT scans after processing in the embodiments and comparative examples of the present invention; Figure 6 A comparison chart of soil organic matter and total nitrogen content at apple harvest after applying the soil conditioners of the embodiments and comparative examples of the present invention; Figure 7 This is a comparison chart of soil cation exchange capacity after treatment in the embodiments and comparative examples of the present invention; Figure 8 This is a comparison chart of soil species abundance after applying the soil conditioners of the embodiments and comparative examples of the present invention; Figure 9 This is a comparison chart showing the cumulative N2O emissions from the base fertilizer in apple orchard soils after applying the soil conditioners of the embodiments and comparative examples of this invention. Detailed Implementation

[0015] This invention provides a soil conditioner for improving orchard soil fertility, comprising the following components in parts by weight: 50-60 parts of micro-activated humic acid raw powder; 20-30 parts of furfural residue; Functional synergist 10-30 parts.

[0016] In this invention, the soil conditioner, calculated on a dry matter basis, contains ≥50% organic matter, ≥27.6% humic acid, ≥0.20 billion / g of viable bacteria, ≥4.0% total nitrogen, phosphorus and potassium, ≥3% calcium oxide, ≤30.0% moisture, and pH 5.5~8.5.

[0017] In this invention, the content of the micro-activated humic acid powder is preferably 52-58 parts by weight, and more preferably 54-56 parts by weight.

[0018] In this invention, the furfural residue content is preferably 22-28 parts by weight, and more preferably 24-26 parts by weight.

[0019] In this invention, the content of the functional synergist is preferably 15 to 25 parts by weight, and more preferably 20 parts by weight.

[0020] In this invention, the functional synergist comprises citric acid, malic acid and seaweed extract, wherein the mass ratio of citric acid, malic acid and seaweed extract is 20~25:15~20:10~15, preferably 20:15:10.

[0021] In this invention, the seaweed extract is a marine bioactive substance made by extracting active ingredients from seaweed using physical or chemical methods and then processing them through filtration, concentration, and other processes.

[0022] In this invention, the micro-activated humic acid powder is derived from weathered coal alkali solution.

[0023] This invention also provides the application of the above-mentioned soil conditioner for improving orchard fertility in increasing fruit tree yield and quality.

[0024] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0025] Experimental materials: The test crop was apple, the apple variety was Fuji, the tree age was 8 years, and the planting density was 4 m × 1.5 m.

[0026] Test location: Fuyu Industrial Park, Datai Township, Fuping County, Baoding City, Hebei Province, coordinates (114°19'E, 38°84'N).

[0027] Experimental Design: In a field plot trial, the soil conditioner product was a humic acid soil conditioner, denoted as Y in this trial. Three application rates of 750 kg / hm² were set up. 2 (Y1), 1500 kg / hm 2 (Y2) and 3000 kg / hm 2 (Y3); No control (CK) was added. There were a total of 4 treatments and 12 plots in total. Each plot had 15 apple trees and was arranged in a randomized block design.

[0028] In a field trial conducted in October 2021, the treatment was continued for four growing seasons. The conditioner was applied in furrows annually in autumn along with the basal fertilizer, and other management practices remained consistent with local standards. The nitrogen, phosphorus, and potassium application rates during the growing season were 150 kg / hm². 2 100kg / hm 2 150 kg / hm 2 .

[0029] Test conditions: The experimental site is located in Baiya Village, Datai Township, Fuping County, Baoding City, Hebei Province. The area has four distinct seasons: cold and snowless winters, dry and windy springs, hot and rainy summers, and cool and windy autumns. The average annual temperature is 12.6℃, and the average annual precipitation is 550mm. It has a warm temperate continental monsoon climate. The soil in the experimental garden is sandy loam with low fertility. When the field experiment was conducted in the autumn of 2021, the soil pH was 8.21, the soil organic matter was 11.35 g / kg, the total nitrogen was 0.85 g / kg, the available phosphorus was 5.68 mg / kg, and the available potassium was 87.58 mg / kg.

[0030] Test metrics

[0031] (1) Soil pH, organic matter, total nitrogen and CEC

[0032] Soil samples were collected after the autumn apple harvest, and pH, organic matter, total nitrogen, and CEC were measured in accordance with the requirements of the "Technical Specifications for Soil Testing and Fertilizer Recommendation".

[0033] (2) Soil bulk density and soil field water holding capacity

[0034] Uncirculated soil samples were collected at harvest time, and soil bulk density and field water holding capacity were determined by ring sampler method.

[0035] (3) Soil microbial biomass carbon and nitrogen and microbial diversity

[0036] Soil samples were collected during the fruit enlargement period. After collection, the samples were sealed in bags and placed in a refrigerator before being brought back to the laboratory for refrigeration. The chloroform fumigation method was used for analysis. Soil samples were also collected after fruit harvest, using a five-point sampling method to collect samples from the top 5-20 cm of soil. The five samples were thoroughly mixed to form a replicate and stored at -80℃. These samples were then sent to a professional company for microbial diversity analysis.

[0037] (4) Soil structure analysis - CT scan

[0038] Using a PVC tubular ring cutter, undisturbed soil samples were collected at depths of 0-20 cm and 20-40 cm. The soil pore distribution was determined by CT scanning. The scan was performed using an industrial CT Phoenix Visualization XS device, and the binary images were obtained using ImageJ software. The pore data were then extracted and calculated.

[0039] (5) Chemical structure of soil organic matter -- 13 C NMR spectroscopy analysis

[0040] The soil was treated with 10% hydrofluoric acid to remove paramagnetic compounds, rinsed with deionized water, dried at 40°C, ground and sieved (<0.15 mm), and then subjected to NMR analysis.

[0041] (6) Yield and quality determination

[0042] Apple yield was measured using a yield-by-yield method. At harvest, yield was measured per tree for each treatment, and the yield per unit area was calculated based on planting density. Single fruit weight (g) was determined using a 1 / 1000 scale. Firmness (kg / cm²) was determined using an LX-A type thermometer with Shore hardness. 2 The vitamin C content (mg / 100g) of the fruit was determined by titration with 2,6-dichlorophenolindophenol solution.

[0043] (7) Aroma substances (volatile substances)

[0044] Wipe the apple surface clean, do not peel, and chop it into pieces about 1cm in size with a stainless steel knife; weigh 80g into a fruit juicer, add an equal amount of NaCl and homogenize; weigh 10g into an SPME vial, add water to 10mL; add 100μL of cyclohexanone standard, and tighten the cap of the SPME vial; use an SPME autosampler (Shimadzu AOC 6000, Japan); perform chromatographic separation of the compounds (Shimadzu QP2010 Plus), and then use a mass spectrometer (Shimadzu, QP2010).

[0045] (8) Collection of gas samples

[0046] The static chamber-gas chromatography method was used. Gas samples were collected for 10 consecutive days after each fertilization and irrigation, and for 3 consecutive days after irrigation or significant rainfall (≥20 mm). Gas sampling was conducted from 9:00 AM to 11:00 AM daily, with samples taken every 10 minutes, for a total of 3 samplings. The chamber temperature was measured simultaneously. The collected gas was stored in 20 ml gas sample bottles, and the gas samples were analyzed using an Agilent-7890A gas chromatograph.

[0047] Example 1

[0048] The soil conditioner raw materials include: 58 parts of micro-activated humic acid powder, 26 parts of furfural residue, and 16 parts of functional synergists (7.1 parts of citric acid, 5.3 parts of malic acid, and 3.6 parts of seaweed extract); specific component contents: organic matter ≥50%, humic acid ≥27.6% (on a dry basis), effective viable bacteria count (CFU) ≥0.20 billion / g, total nutrients (nitrogen, phosphorus, potassium) (on a dry basis) ≥4.0%, calcium oxide ≥3%, moisture ≤30.0%, pH 6.5.

[0049] The application rate of soil conditioner is 750 kg / hm². 2 (Y1).

[0050] Example 2

[0051] Same as Example 1, except that the application rate of the soil conditioner is 1500 kg / hm. 2 (Y2).

[0052] Example 3

[0053] Same as Example 1, except that the application rate of the soil conditioner is 3000 kg / hm. 2 (Y3).

[0054] Comparative Example 1

[0055] As a control group, no soil conditioner of the present invention was applied (CK), but well-rotted pigeon manure was applied at a rate of 15,000 kg / hm². 2 After spreading the fertilizer, rotary tillage is carried out.

[0056] Experimental results: Production Figure 1 As shown, all embodiments showed increased yields compared to the control (CK), with the Y2 treatment exhibiting the highest yield at 44586.67 kg / hm², followed by the Y3 treatment (41622.9 kg / hm²). The apple fruit weight and firmness of all embodiments were significantly higher than those of the CK treatment; the higher glutamate-to-acid ratio resulted in a rich and pure sweetness; and the abundant vitamin C content significantly improved fruit nutrition (P > 0.05, Table 1).

[0057] Table 1 Apple Fruit Quality

[0058] Note: Different lowercase letters after the data in the charts indicate that the differences between different treatments are significant at the P<0.05 level; the same applies below.

[0059] Fruit volatile substances (fragrance substances): The eight main volatile components of apple fruit were analyzed (Table 2), including esters: 2-methylbutyl acetate, butyl acetate, and hexyl acetate; aldehydes: n-hexanal, trans-2-hexenal, and 2-hexenal; and alcohols: 2-methyl-1-butanol and n-hexanol. The ester contents of treatments Y1 and Y2 were 4.31 mg / kg and 3.56 mg / kg, respectively, significantly increased by 78.10% and 47.11% compared to the control (CK). The aldehyde content of treatment Y3 was 1.64 mg / kg, significantly increased by 16.31% compared to the CK. The alcohol contents of the three treatments significantly increased by 25.95%, 76.22%, and 100% compared to the CK, respectively. This indicates that the application of humic acid soil conditioner can increase the relative content of aroma compounds in the fruit.

[0060] Table 2. Classification and relative content of volatile components in fruits

[0061] Soil bulk density

[0062] like Figure 2As shown, in the 0-20cm soil layer, the soil bulk density of treatments Y1, Y2, and Y3 was significantly lower than that of the CK treatment (P<0.05), decreasing by 7.78%, 11.75%, and 16.17%, respectively; in the 20-40cm soil layer, there was no significant difference between the treatments and the CK.

[0063] Porosity

[0064] like Figure 3 As shown, in the 0-20cm soil layer, the total porosity of treatments Y1, Y2, and Y3 increased significantly compared to the control (CK), by 13.51%, 19.96%, and 27.47%, respectively. In the 20-40cm soil layer, there was no significant difference in total porosity among the treatments. Overall, the application of humic acid soil conditioner to the 0-20cm soil layer can increase the total porosity of the soil.

[0065] Soil field water holding capacity

[0066] like Figure 4 As shown, in the 0-20cm soil layer, the field water holding capacity of treatments Y1, Y2, and Y3 was significantly higher than that of the control (CK), increasing by 29.27%, 32.20%, and 29.41%, respectively. In the 20-40cm soil layer, Y2 had the highest field water holding capacity at 24.50%, with no significant differences among the treatments.

[0067] Soil structure analysis

[0068] Based on CT scan data analysis ( Figure 5 Applying soil conditioners can improve the soil pore microstructure, making it more complex and stable, and increasing soil pore connectivity, which is beneficial for the transport of water and nutrients in the soil.

[0069] pH

[0070] As shown in Table 3, the soil pH of the control and soils treated with humic acid soil conditioner was slightly higher than that before the experiment (basal soil sample); in the 0-20cm soil layer, the soil pH of the soil treated with humic acid soil conditioner was slightly higher than that of the control, while in the 20-40cm soil layer it was slightly lower than that of the control, but the differences were not significant.

[0071] Table 3 Soil pH

[0072] Organic matter and total nitrogen

[0073] like Figure 6 As shown, the organic matter content in the 0-20cm soil layer of treatments Y2 and Y3 increased significantly by 19.40% and 36.14% respectively compared with CK (P<0.05), while treatment Y1 showed no significant difference compared with CK (P>0.05); in the 20-40cm soil layer, all treatments showed a significant increase compared with CT (P<0.05).

[0074] In the 0-20cm soil layer, the total nitrogen in treatments Y2 and Y3 was significantly increased by 11.43% and 36.17% respectively compared to CT (P < 0.05). Figure 6 In the 20-40cm soil layer, the dosage of all three humic acid soil conditioners was significantly higher than that of the control (P<0.05), with the largest increase in treatment Y3 (37.13%) and the second largest increase in treatment Y2 (33.82%).

[0075] Cation exchange capacity

[0076] like Figure 7 As shown, in the 0-20cm soil layer, the cation exchange capacities of treatments Y1, Y2, and Y3 were 11.89, 12.16, and 13.00 cmol / L, respectively, significantly increasing by 18.90%, 21.60%, and 30.00% compared to the control (CK). In the 20-40cm soil layer, treatment Y1 significantly increased the cation exchange capacity by 16.48% compared to the CK, while treatments Y2 and Y3 showed no significant difference from the CK. Overall, the application of humic acid soil conditioner increased the cation exchange capacity in the 0-20cm soil layer.

[0077] Chemical structural characteristics of soil organic matter

[0078] The chemical structure of soil organic matter (SOM) is an important indicator for evaluating SOM quality. A high ratio of alkyl carbon, aromatic carbon, and hydrophobic carbon reflects a high degree of humification and greater stability of the SOM. Adding humic acid soil conditioners altered the molecular structure of SOM, increasing alkyl carbon by 9.77%-47.71% and aromatic carbon by 13.66-25.27%, respectively. It also increased the ratio of alkyl carbon to alkoxy carbon and hydrophobic carbon to hydrophilic carbon, significantly reducing aliphaticity and improving the aromaticity and hydrophobicity of the SOM. This resulted in more stable SOM, which is more conducive to carbon sequestration and soil fertility improvement (Table 4).

[0079] Table 4 13 The relative content of various functional groups of soil organic matter by C NMR spectroscopy

[0080] Soil microbial biomass carbon and nitrogen

[0081] Soil microbial biomass carbon in treatments Y1, Y2, and Y3 were significantly different from that in the control (CK) (P < 0.05, Table 5), indicating that the application of humic acid soil conditioner could significantly increase soil microbial biomass carbon in apple orchards. The three treatments Y1, Y2, and Y3 showed significant increases of 161.94%, 210.83%, and 72.13% respectively compared to the control (CK) (P < 0.05), indicating that the application of humic acid soil conditioner could significantly increase the relative content of soil microbial biomass nitrogen.

[0082] Table 5 Soil microbial biomass carbon and nitrogen

[0083] Soil species abundance

[0084] The top 10 species in terms of total abundance at the 0-20cm soil level, excluding other categories, are, from highest to lowest abundance: MND1 (Nitrosomonas), Sphingomonas, Ellin6067 (Acidobacteria), Microvirga, Subgroup_10, Gaiella, Blastococcus, Luteimonas, Gemmatimonas, and Nitrososphaera; the relative abundance rankings of species are basically consistent across the four treatments. Figure 8 a) The abundance of humic acid soil conditioner Y3 was the highest, and Sphingomonas had the highest abundance.

[0085] The top 10 most abundant species in the 20-40cm soil layer, excluding others, are MND1 (Nitrosomonas), Gaiella, Sphingomonas, Ellin6067 (Acidobacteria), Nitrososphaera, Gemmatimonas, IS-44, Tahibacter, Subgroup_10, and Dongia. Y2 and Y3 showed even higher bacterial abundance, with increased abundance of functional bacteria such as MND1, Sphingomonas, and Nitrososphaera, indicating more active metabolism and stronger functionality. Figure 8 b).

[0086] The soil microbial diversity is higher and more active when humic acid soil conditioner is applied in trenches.

[0087] The impact of soil conditioners on N2O emissions from orchard soils

[0088] Cumulative N2O emissions during the apple growing season Figure 9 As shown, the cumulative N2O emissions from the soil in the control treatment were significantly higher than those of the three dosages of humic acid soil conditioner, indicating that the application of humic acid soil conditioner can reduce N2O emissions from orchard soil.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A soil conditioner for improving orchard soil fertility, characterized in that, The components comprise the following parts by mass: 50-60 parts of micro-activated humic acid raw powder; 20-30 parts of furfural residue; Functional synergist 10-30 parts.

2. The soil conditioner for improving orchard fertility according to claim 1, characterized in that, The soil conditioner, calculated on a dry matter basis, contains ≥50% organic matter, ≥27.6% humic acid, ≥0.20 billion / g of viable bacteria, ≥4.0% total nitrogen, phosphorus, and potassium, ≥3% calcium oxide, ≤30.0% moisture, and pH 5.5~8.

5.

3. The soil conditioner for improving orchard fertility according to claim 1 or 4, characterized in that, The functional synergist comprises citric acid, malic acid, and seaweed extract, wherein the mass ratio of citric acid, malic acid, and seaweed extract is 20~25:15~20:10~15.

4. The soil conditioner for improving orchard fertility according to claim 5, characterized in that, The micro-activated humic acid raw material is derived from weathered coal alkali solution.

5. The application of the soil conditioner for improving orchard fertility as described in any one of claims 1 to 4 in increasing fruit tree yield and quality.

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