Compound fertilizer and application thereof in promoting growth of Chinese fir

Abstract

The invention relates to the technical field of forestry compound fertilizers, in particular to a compound fertilizer and application thereof in promoting growth of Chinese fir, the compound fertilizer comprises the following active ingredients: 972.26 mg.kg <-1 > of urea; 156.54 mg.kg <-1 > of monopotassium phosphate; 12.97 mg.kg <-1 > of manganese sulfate; 4.66 mg.kg <-1 > of zinc sulfate; 0.24 mg.kg <-1 > of sodium molybdate; the invention relates to a compound fertilizer, which comprises the following active ingredients: 970.10 mg.kg <-1 > of urea; 187.17 mg.kg <-1 > of magnesium sulfate; 158.42 mg.kg <-1 > of monopotassium phosphate; and 10.58 mg.kg <-1 > of manganese sulfate. According to the invention, a fertilizer formula is combined with a specific soil background and specific cultivated species, and different nutrients are provided for the cedarwood in a targeted manner according to different soils, so that the utilization efficiency of the fertilizer is improved, nutrient imbalance is corrected, and healthy growth of the cedarwood is promoted.

Description

Technical Field

[0001] This invention relates to the field of forestry compound fertilizer technology, and in particular to a compound fertilizer and its application in promoting the growth of Chinese fir. Background Technology

[0002] Chinese fir( Cunninghamia lanceolata Chinese fir (Cunninghamia lanceolata) is the most important timber species in southern my country. Data from the Ninth National Forest Resources Inventory shows that its plantations account for approximately 14.31% of the total planted forest area in the country. Not only does it play a significant role in safeguarding national timber security and supporting regional forestry economic development, but it also possesses irreplaceable ecological functions in enhancing forest carbon sequestration and addressing climate change.

[0003] The growth and development of Chinese fir are closely related to site conditions, with the parent rock being one of the key factors determining the physical and chemical properties of the soil. Granite and shale are two common types of parent rocks in the male Chinese fir producing areas, and their differences in mineral composition and weathering characteristics profoundly affect the growth of Chinese fir. Granite is an acidic intrusive rock, with quartz, feldspar, and mica as its main minerals. Due to its high content of quartz and potassium feldspar, it often presents a false impression of being "potassium-rich," but available phosphorus is easily fixed, and the soil is poor in organic matter and has a weak fertilizer retention capacity. On the other hand, heavy clay soils developed from shale parent material have strong water and fertilizer retention capacity and are relatively rich in nitrogen and phosphorus, but poor permeability of deep soil layers may limit root development.

[0004] Currently, general-purpose compound fertilizers are commonly used in the cultivation of Chinese fir. However, their nutrient formulations are not compatible with the background nutrient conditions of soils developed from different parent rocks (such as granite and shale). This lack of precise control over the soil's background nutrients not only leads to low fertilizer utilization efficiency but may also exacerbate soil fertility decline, thus adversely affecting the growth of Chinese fir. Summary of the Invention

[0005] In view of the shortcomings or problems existing in the prior art, this disclosure provides a compound fertilizer that can precisely regulate the background nutrients of granite or shale soil, thereby improving fertilizer utilization.

[0006] The technical solution adopted by this disclosure to solve the above-mentioned technical problems is as follows: In a first aspect, this application provides a compound fertilizer, the effective components of which are composed of the following components in appropriate amounts: Urea 972.26 mg·kg -1 ; Potassium dihydrogen phosphate 156.54 mg·kg -1 ; Manganese sulfate 12.97 mg·kg -1 ; Zinc sulfate 4.66 mg·kg -1; Sodium molybdate 0.24 mg·kg -1 .

[0007] It also includes an adhesive, the mass of which is 12% of the mass of the compound fertilizer.

[0008] The adhesive is an organic adhesive; preferably, it is corn pregelatinized starch.

[0009] Secondly, this application provides the application of a compound fertilizer in promoting the growth of Chinese fir in granite parent soil.

[0010] Thirdly, this application provides another compound fertilizer, the effective components of which are composed of the following components in appropriate amounts: Urea 970.10 mg·kg -1 ; Magnesium sulfate 187.17 mg·kg -1 ; Potassium dihydrogen phosphate 158.42 mg·kg -1 ; Manganese sulfate 10.58 mg·kg -1 .

[0011] It also includes an adhesive, the mass of which is 12% of the mass of the compound fertilizer.

[0012] The adhesive is an organic adhesive; preferably, it is corn pregelatinized starch.

[0013] Fourthly, this application provides the application of a compound fertilizer in promoting the growth of Chinese fir in shale parent soil.

[0014] Compared with the prior art, the beneficial effects of the present invention are: the present application links the fertilizer formula with the specific soil background and the specific cultivated species, and provides different nutrients to Chinese fir trees in a targeted manner according to different soils, thereby improving fertilizer utilization efficiency, correcting nutrient imbalance, and promoting the healthy growth of Chinese fir trees. Attached Figure Description

[0015] Figure 1 The effects of different element treatments on the relative biomass (%) of young Chinese fir trees; Figure 2 The effects of different fertilizer types on the growth of young Chinese fir forests; Figure 3 The effects of different fertilizer types on soil runoff phosphorus content in young Chinese fir forests; Figure 4 The effects of different fertilizer types on soil runoff nitrogen content in young Chinese fir forests; Figure 5 The effects of different fertilizer types on soil runoff potassium content in young Chinese fir forests; Figure 6 Effects of different fertilizers on the mixed concentration of nitrogen and phosphorus in soil runoff of young Chinese fir forest; Figure 7 Effects of different fertilizers on the mixed concentration of nitrogen, phosphorus and potassium in soil runoff of young Chinese fir forest. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure is described in detail, clearly and completely in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present disclosure and do not limit the present disclosure.

[0017] A compound fertilizer, the effective components of which are composed of the following components in the following amounts: urea 972.26 mg·kg -1 ; monopotassium phosphate 156.54 mg·kg -1 ; manganese sulfate 12.97 mg·kg -1 ; zinc sulfate 4.66 mg·kg -1 ; sodium molybdate 0.24 mg·kg -1 ; and corn pregelatinized starch adhesive, the mass of which is 12% of the mass of the compound fertilizer.

[0018] It should be noted that mg·kg -1 in the above units refers to the content of each component in per kilogram of soil, i.e. per kilogram of soil contains urea 972.26 mg, monopotassium phosphate 156.54 mg, manganese sulfate 12.97 mg, zinc sulfate 4.66 mg, and sodium molybdate 0.24 mg.

[0019] The above fertilizer is especially suitable for granite parent material soil.

[0020] A compound fertilizer, the effective components of which are composed of the following components in the following amounts: urea 970.10 mg·kg -1 ; magnesium sulfate 187.17 mg·kg -1 ; monopotassium phosphate 158.42 mg·kg -1 ; manganese sulfate 10.58 mg·kg -1 ; and corn pregelatinized starch adhesive, the mass of which is 12% of the mass of the compound fertilizer.

[0021] It should be noted that the above units mg·kg -1 It refers to the content of each component in per kilogram of soil, that is, per kilogram of soil contains urea 970.10 mg, magnesium sulfate 187.17 mg, potassium dihydrogen phosphate 158.42 mg, and manganese sulfate 10.58 mg.

[0022] The above-mentioned fertilizer is especially suitable for shale parent soil.

[0023] 1. The effect of the above two kinds of compound fertilizer on the growth and biomass of 1-year-old Chinese fir seedlings The test site is located in the Subtropical Forestry Experimental Center of China Forestry Science Research Institute in Fenyi County, Xinyu City, Jiangxi Province. The region belongs to the northern branch of Wugong Mountain of Loxia Mountain, low hilly landform, with an altitude of 72-1091.8 m. It belongs to subtropical monsoon humid climate, with an average annual temperature of 16.8 ℃, an average annual sunshine time of 1650 h, an average annual rainfall of 1656 mm, and an average annual evaporation of 1503 mm.

[0024] (1) General situation of the test site It was carried out in the seedling base of the tree garden of the Subtropical Forestry Experimental Center of China Forestry Science Research Institute. The base is equipped with a steel construction seedling greenhouse with a spray shading facility (greenhouse height 2.2 m). The greenhouse is equipped with a sprinkler system, and the top is covered with a shading net with a light transmittance of 70%.

[0025] (2) Test materials Growth healthy and uniform 1-year-old seedlings were selected from the second-generation seed orchard of the Subtropical Forestry Experimental Center. The test soil was collected from the 0-40 cm soil layer of the second-generation Chinese fir plantation in Dagangshan, Jiangxi Province, including two typical parent rock developed soils: granite weathered material (collected from Tongmu of Nianzhu Experimental Forest Farm) is sandy loam, pH 4.8-5.2; slate weathered material (collected from Changbu Experimental Forest Farm) is clay loam, pH 5.5-6.0. The soil was dried and sieved through a 2 mm sieve to remove stones and organic residues.

[0026] (3) Test design The test adopted a double-factor factorial design to investigate the effects of nutrient element level (A) and soil parent material type (B) on container seedling. Factor A is based on MS medium (Murashige and Skoog, 1962) to establish a gradient control system; factor B includes granite developed soil and slate developed soil. The specific treatment scheme is as follows: (1) Fertilizer amount calculation model The modified formula proposed by Qiu Yunliang (2010) was used to calculate the amount of nutrient elements added: MSr (modified concentration) = MS standard concentration - measured value of soil available nutrients Four gradient treatments were set up: a: full amount of missing group (MSr-x); b: half amount of missing group: 0.5 (MSr-x); c: single element supplement group (MSrx); d: half amount of single element supplement group: 0.5MSrx. Without adding exogenous nutrients as control (x represents the target element). (2) Target element screening By comparing the element content of MS medium with the measured value of soil available nutrients, the elements that need to be supplemented (difference <0 need to be added). The results showed that granite developed soil needed to supplement N, P, Mg, S, Mn, Zn, Mo, a total of 7 elements; slate developed soil needed to supplement N, P, Mg, S, Mn, Mo, a total of 6 elements (as shown in Table 1). Each element was added in the form of analytical pure reagent, and the specific reagent type and molecular formula are shown in Table 2.

[0027] Table 1 Comparison of mineral nutrient element requirements of different types of soil (mg·kg -1 )

[0028] Note: Difference in demand = MS standard value - measured value of soil; negative value indicates that the soil content is sufficient and does not need to be supplemented.

[0029] Table 2 Nutrient element supplement reagent type and chemical composition

[0030] Note: Each reagent is of analytical purity level, used to prepare nutrient supplement solutions for different treatments (Four) Test implementation During the implementation of the test, a completely randomized block design was used, with 27 treatments for granite matrix and 23 treatments for slate matrix (including blank controls), a total of 50 treatments (as shown in Tables 3-1 and 3-2). Each treatment was set up with 3 repetitions, 5 pots per repetition, and single plant planting method was used. Each pot was filled with 2.72 kg of soil (matrix preparation method: in late March 2023, the components were mixed manually, then stirred evenly with a mixer, and sieved through a 1 cm sieve before being placed in the pot), and a 0.5 mm aperture nylon mesh was placed at the bottom to prevent root penetration. In early April, the germinated Chinese fir seedlings were transplanted into the pots and placed in a nursery greenhouse equipped with shade nets, with the pots directly placed on the ground trays.

[0031] Fertilization management adopts a split application scheme: three times in September 2022 (vigorous growth period) and 2023 growth season (March germination period, May rapid growth period). Each treatment combination is prepared according to the test design (4°C light protection), and the target concentration is accurately diluted before application. The test period is unified to implement water management (keep the substrate moist) and pest control, and each group receives the same nursery care measures to ensure consistent environmental conditions. All treatments are numbered for observation and recording.

[0032] Table 3-1 Nutrient element treatment formula of granite substrate (unit: mg·kg -1 )

[0033] Table 3-2 Nutrient element treatment formula of slate substrate (unit: mg·kg -1 )

[0034] (Five) Data investigation In late November 2023, after the seedlings stopped growing, 20 plants were randomly selected from each treatment, and the seedling height and ground diameter were measured. Then the leaf and root scanning of the plants were performed using a root scanning instrument to obtain root functional traits (length, surface area, diameter, volume, and root tip) and leaf functional traits (leaf area, leaf circumference, leaf length, and leaf width) data. Finally, the seedlings were placed in a 105°C oven for 2 hours and then dried at 85°C to constant weight, and the root, stem, and leaf biomass were measured to calculate the root-shoot ratio (root biomass / aboveground biomass), specific root length (root length / root biomass), and root tissue density (root biomass / root volume), specific leaf area (leaf area / leaf dry weight).

[0035] (Six) Construction of comprehensive trait evaluation system for optimal formula combination Based on the growth characteristics of Chinese fir seedlings, a comprehensive evaluation system including three dimensions of growth, absorption, and photosynthesis was constructed. The mixed weight determination method combining analytic hierarchy process (AHP) and principal component analysis (PCA) was used, and the specific process was as follows: (1) Application of analytic hierarchy process (AHP): Constructing judgment matrix, using 1-9 scale method to quantify expert experience Calculating geometric mean to determine initial weight Consistency test (CR <0.1) Finally determine the dimension weight coefficient (2) Application of principal component analysis (PCA): Dimensionality reduction of standardized index data Extracting principal components with eigenvalues >1 Computing factor loading matrix Determining the weight of each index within the dimension Comprehensive evaluation method: Using membership function method to standardize index data Calculate the comprehensive score by weighted sum: Positive index: (X-Xmin) / (Xmax-Xmin) Negative index: (Xmax-X) / (Xmax-Xmin) Comprehensive score = Σ (index value x corresponding weight) This system realizes the organic combination of subjective experience and objective data through AHP-PCA hybrid model, providing a reliable basis for formula optimization. The evaluation system finally constructed meets the consistency requirement of CR <0.1 (granite CI = 0.038, slate CI = 0.043, RI = 0.580), and the weight values are standardized to ensure the scientificity of the evaluation results.

[0036] (Seven) Results and analysis (1) Growth characteristics of Cunninghamia lanceolata seedlings under different fertilization treatments The results showed that different fertilization treatments had significant effects on the growth of Cunninghamia lanceolata seedlings (P <0.01). In granite substrate, formulas 2, 5 and 13 showed the best growth characteristics, with seedling height (58.64-62.87 cm) and total biomass (44.73-48.33 g) significantly higher than other treatments; while in slate substrate, formulas 2, 5 and 10 showed the best growth, with formula 5 showing the most significant biomass increase (49.17 g). Root-shoot ratio analysis showed that formula 27 (0.59) in granite and formula 7 (0.55) in slate had stronger root development advantage.

[0037] Further analysis found that the average seedling height (51.92 cm) and biomass (34.47 g) of granite substrate were slightly better than those of slate (48.42 cm, 32.06 g). It is worth noting that the ground diameter of slate substrate (5.93-15.17 mm) was significantly larger than that of granite (7.16-7.78 mm), indicating that it was more sensitive to fertilization treatment. Comprehensive comparison showed that granite preferred formulas 2, 5 and 13 were suitable for fast-growing cultivation, while slate formulas 2, 5 and 10 grew well, but formula 5 had a lower root-shoot ratio (0.40) which might affect the stress resistance.

[0038] Table 4 Leaf functional traits of Cunninghamia lanceolata seedlings in granite soil type under different fertilization treatments

[0039] Table 5 Leaf functional traits of Cunninghamia lanceolata seedlings in different fertilization treatments

[0040] (2) Effects of different element treatments on the relative biomass of Cunninghamia lanceolata seedlings From Figure 1 It can be seen that the effects of different element treatments on the growth of Cunninghamia lanceolata seedlings were significantly different. In the single element supplement group, only the +0.5N treatment had a significant promoting effect on the growth of Cunninghamia lanceolata in slate soil, and the relative biomass increased by 10.57% compared with the control, while the addition of other elements had weak promoting effect or showed different degrees of inhibition on biomass. For example, +0.5Zn in granite soil and +0.5Mg in slate soil reduced the relative biomass by 26.25% and 22.98%, respectively.

[0041] In the multi-element supplement group, MSr and 0.5MSr element total addition treatments increased the relative biomass by more than 10% in both soil types. Under the condition of balanced fertilization based on MS medium, nitrogen and phosphorus elements were the main limiting factors for the biomass growth of Cunninghamia lanceolata in granite soil, and their absence treatments 0.5(MSr-N), 0.5(MSr-P), MSr-N, and MSr-P reduced the biomass by 6.57%-11.08%; while in slate soil, nitrogen element was the main limiting factor, and its absence treatments 0.5(MSr-N) and MSr-N reduced the biomass by 0.69%-12.95%. The absence of other elements could promote the increase of relative biomass to different degrees. MSr-Mg treatment in granite soil and MSr-Mo and MSr-Mg treatments in slate soil significantly increased the relative biomass to 42.4%, 77.38%, and 64.65%, respectively. This indicated that these elements might have strong antagonistic effect in balanced fertilization system.

[0042] (3) Comparison of root characteristics of Cunninghamia lanceolata seedlings under different fertilization treatments The results showed that different fertilization treatments had significant effects on the root morphological characteristics of Cunninghamia lanceolata seedlings (P < 0.05). In granite substrate, formulas 12-13 and 23 showed the best root development characteristics, with root length (3606.98-3693.03 cm), root surface area (819.12-940.96 cm 2 ), and root tip number (5749.33-6739.33) significantly higher than other treatments; while in slate substrate, formulas 3, 5, and 18 showed the best root characteristics, especially formula 5, with root volume (77.42 cm 3The maximum root length index showed that the root systems of granite formula 26 (386.03 m / g) and slate formula 22 (324.06 m / g) were the most elongated, which might have stronger nutrient absorption capacity.

[0043] Further analysis showed that the average root length (2765.64 cm) and root surface area (689.60 cm 2 ) of granite were slightly higher than those of slate (2464.30 cm, 636.98 cm 2 ), but there was no significant difference in root tissue density between the two types of substrates (average 0.29 g / cm 3 ). It is worth noting that the root volume of slate substrates varied greatly (43.67 cm 3 ), with formula 5 being particularly prominent (77.42 cm 3 ), indicating that the root system development under this substrate was more sensitive to fertilization treatment.

[0044] Table 6 Root traits of Chinese fir seedlings under different fertilization treatments in granite

[0045] Table 7 Leaf functional traits of Chinese fir seedlings under different fertilization treatments in slate

[0046] (4) Comparison of leaf functional traits of Chinese fir seedlings under different fertilization treatments The results showed (as shown in Tables 8 and 9) that different fertilization treatments had a significant impact on the leaf traits of Chinese fir seedlings, except for the leaf width index in granite soil type. In granite substrate, formula 5 showed the best leaf traits (leaf area 31.55 cm 2 , leaf length 13.79 cm); while in slate substrate, formula 20 and 23 showed the best leaf area (29.35-30.97 cm 2 ) and leaf length (12.38-12.00 cm). In terms of specific leaf area, formula 2, 7 (20.67-20.83 cm 2 / g) of granite and formula 8, 10 (19.97-20.13 cm 2 / g) of slate were higher than other treatments. Further analysis showed that the average leaf area of granite (23.95 cm 2 ) was slightly higher than that of slate (21.13 cm 2 ). The aspect ratio of leaf length of formula 5 (1.89) of granite and formula 8 (1.81) of slate was significantly higher than other treatments, indicating that specific fertilization programs could effectively regulate leaf shape.

[0047] Table 8 Leaf functional traits of Cunninghamia lanceolata seedlings under different fertilization treatments in granite substrate

[0048] Table 9 Leaf functional traits of Cunninghamia lanceolata seedlings under different fertilization treatments in slate substrate

[0049] (5) Comprehensive screening of optimal fertilizer formula combinations for Cunninghamia lanceolata Different formulas showed significant differences in growth, absorption, and photosynthesis indicators (Tables 10 and 11). In terms of growth indicators, formula 2 (0.5387) for granite and formula 5 (0.4361) for slate showed the best performance, indicating significant growth promotion and biomass accumulation. In terms of absorption indicators, formula 13 (0.3633) for granite and formula 8 (0.3110) for slate showed outstanding performance, indicating that they could effectively promote root development and nutrient absorption. In terms of photosynthesis indicators, formula 14 (0.4916) for granite and formula 10 (0.4805) for slate were the best, confirming that these formulas could significantly improve leaf photosynthetic efficiency. These results revealed the specific regulatory effects of different formulas on various physiological indicators.

[0050] Through comprehensive evaluation analysis, it was found that different formula combinations showed significant differences in growth, root, and leaf indicators of Cunninghamia lanceolata seedlings in granite and slate substrates. In the granite type, formula 2 showed the best performance (comprehensive score 0.5311), followed by formula 7 (0.5196) and formula 12 (0.5080), while formula 26 showed the worst performance (0.2585). In the slate type, formula 5 had the highest comprehensive score (0.4774), followed by formula 3 (0.3990) and formula 10 (0.3896), while formula 20 showed the weakest performance (0.2083).

[0051] Based on the research results, differentiated cultivation recommendations are proposed for different parent rock substrates: for granite substrates, preferentially use formula 2, 7, or 12, which can significantly improve seedling growth and photosynthetic efficiency; for slate substrates, recommend using formula 5, 3, or 10, which show excellent performance in promoting root development and enhancing photosynthetic performance. This differentiated selection strategy can maximize the advantages of each formula under different substrate conditions, achieving efficient cultivation of Cunninghamia lanceolata seedlings.

[0052] Table 10 Membership function evaluation of different formula combinations on growth, root, and leaf indicators of Cunninghamia lanceolata seedlings in granite substrate

[0053] Table 11 Membership function evaluation of different formula combinations on growth, absorption, and nutrition indicators of Cunninghamia lanceolata container seedlings in slate substrate

[0054] (6) Optimization and screening of compound fertilizer formula for Cunninghamia lanceolata seedling raising Construction of comprehensive evaluation system of compound fertilizer formula for Cunninghamia lanceolata seedling raising: Through the analysis of the comprehensive evaluation system of the fertilization formula of Cunninghamia lanceolata seedlings in granite and slate substrates (Table 12, Table 13), both types of substrates showed a dominant feature of growth dimension (weight 0.674), with a biomass index contribution rate of 100%, highlighting its core position in seedling evaluation. However, the absorption dimension showed obvious substrate specificity: granite emphasized root surface area (load 0.805, weight 0.087), while slate emphasized root tissue density (load 0.804, weight 0.086), which reflected the ecological adaptation strategies of porous structure promoting root expansion in granite and dense characteristics requiring root fixation in slate. The photosynthetic dimension showed high consistency in both substrates (load 0.71-0.73, weight 0.05), indicating that leaf functional traits were less affected by the substrate. Based on the reliable weight system (granite CI=0.038, slate CI=0.043) with CR<0.1, it is recommended to prioritize formulas that promote root expansion in granite substrates, and to strengthen root tissue development in slate substrates, but both types of substrates need to ensure the sustained accumulation of biomass as a common foundation.

[0055] Table 12 Comprehensive evaluation system of fertilization formula of Cunninghamia lanceolata seedlings in granite substrate

[0056] Table 13 Comprehensive evaluation system of fertilization formula of Cunninghamia lanceolata seedlings in slate substrate

[0057] In summary, the use of compound fertilizer according to the present application can significantly improve the growth and biomass of Cunninghamia lanceolata seedlings, optimize root structure and nutrient absorption efficiency, improve leaf photosynthetic performance, and improve the overall quality of seedlings.

[0058] Specifically, in terms of improving the growth and biomass of Cunninghamia lanceolata seedlings, the main performance is: 1) Increase in biomass: After applying the optimal formula (MSr-Mg) in granite soil, the total biomass of Cunninghamia lanceolata seedlings reached 48.33g, an increase of 42.39% compared with the control. After applying the optimal formula (MSr-Mo) in slate soil, the biomass increased by 77.60% (49.17g vs. 27.53g in the control).

[0059] 2) Height growth: After applying the preferred formula (MSr-Mg) to granite soil, the height of Chinese fir seedlings reached 58.64 cm, which was 17.28% higher than the control (50.0 cm). After applying the preferred formula (MSr-Mo) to slate soil, the height increased by 37.03% (57.73 cm vs. 42.13 cm in the control).

[0060] In terms of optimizing root structure and nutrient absorption efficiency, the main performance was: In granite substrate, the root surface area of formula (MSr-Mg) reached 792.27 cm 2 / plant, and the root tip number was 4968.17 per plant, which was significantly better than the control (771.58 cm 2 / plant, 4979.54 per plant). In slate substrate, the root surface area of formula (MSr-Mo) reached 911.83 cm 2 / plant, and the root tip number was 5646 per plant, which was significantly better than the control (610.55 cm 2 / plant, 3744 per plant).

[0061] In terms of improving leaf photosynthetic performance, the main performance was: The specific leaf area of granite preferred formula (MSr-Mg) was 20.67 cm 2 / g, which was 38.53% higher than the control (14.92 cm 2 / g), and the photosynthetic potential was significantly enhanced. The leaf area of slate formula (MSr-Mo) reached 28.86 cm 2 , which was more than 12.08% higher than the control (25.75 cm 2 ).

[0062] In terms of improving the overall quality of seedlings, the main performance was: The membership function for comprehensive evaluation of seedling quality (growth, absorption, photosynthesis) showed that the comprehensive score of granite optimization formula (MSr-Mg) was 0.5311, which was 17.58% higher than the control (0.4517); the comprehensive score of slate optimization formula (MSr-Mo) was 0.4774, which was 37.97% higher than the control (0.3460).

[0063] 2) The effect of the above two compound fertilizers on the growth of 2-year-old Chinese fir seedlings in granite (1) Test site The experiment was carried out in Tongmu of Changbu Experimental Forest Farm of Subtropical Forestry Experimental Center of Chinese Academy of Forestry. The base belongs to low hilly landform and granite soil type, and the previous crop is Chinese fir plantation. The reclamation of the whole land was carried out by machinery, and the remaining materials on the ground were cleaned.

[0064] (2) Test design In the spring of 2024, in the Tongmu area of Changbu Forest Farm, a randomized block experimental design was used, with three fertilization treatments: traditional fertilization, formula fertilization, and no fertilization (CK). Each treatment was repeated three times, for a total of 12 test plots. Each afforestation plot was 15m x 20m in size, with an initial planting density of 1.5m x 2m. Within each plot, a 5m x 15m runoff monitoring field was set up, and a rainfall automatic recorder was installed on the mountain top to continuously monitor surface runoff.

[0065] According to the root distribution pattern of Chinese fir young forest and MSr-Mg fertilization formula, the required amount of fertilizer was converted to the actual amount of corresponding soil volume per 0.24 m 2 of root area and 40 cm of soil depth. After conversion, the specific amounts were urea 1057.8 g / plot, potassium dihydrogen phosphate 170.32 g / plot, manganese sulfate tetrahydrate 14.12 g / plot, and zinc sulfate heptahydrate 5.08 g / plot. The traditional fertilization (100 kg / hm 2 urea, 50 kg / hm 2 superphosphate, 50 kg / hm 2 potassium chloride) treatment was converted to urea 3000 g / plot, superphosphate 1740 g / plot, potassium chloride 1410 g / plot, and no fertilization control (CK).

[0066] Fertilization was done in May 2024, 25-35 cm away from the young trees, with a strip trench dug, and the fertilizer was applied to the trench per tree, covered with topsoil. The fertilization time was in May.

[0067] (Three) Data investigation After fertilization, soil runoff water was collected under different rainfall intensities on June 3, 7.14, 6.29, and 8.10, 2024, for a total of four times. The nitrogen, phosphorus, and potassium contents in the water samples were detected. After the growing season, the tree height and ground diameter of each plant in the plot were investigated.

[0068] (Four) Sample detection The total nitrogen concentration in water was determined according to "SL / T 788-2019 Water Quality Determination of Total Nitrogen Continuous Flow Analysis-Spectrophotometric Method"; the total phosphorus concentration was analyzed according to "HJ 670-2013 Water Quality Determination of Phosphate and Total Phosphorus Continuous Flow-Ammonium Molybdate Spectrophotometric Method"; and the potassium content in water was determined according to "GB 11904-1989 Water Quality Determination of Potassium and Sodium Flame Atomic Absorption Spectrophotometric Method".

[0069] (Five) Data statistics and analysis The raw data were processed using Excel 2019 and then analyzed using SPSS 26 for ANOVA and Duncan's multiple comparisons.

[0070] (vi) Results and Analysis (1) Effects of different fertilizer types on the growth of young Chinese fir forests The effects of different fertilization treatments on the growth indicators of young Chinese fir forests were significantly different (p < 0.05), as shown in the following results. Figure 2 As shown, tree height, diameter at birth, and sectional area all exhibited the same pattern: the formulated fertilization (FF) treatment had the highest values, significantly higher than the conventional fertilization (CF) and no fertilization (CK) treatments, while the conventional fertilization treatment was significantly higher than the no fertilization treatment. Specifically, the average tree height, diameter at birth, and sectional area of ​​the FF treatment reached 2.29 m, 4.59 cm, and 0.32 cm, respectively. 2 Compared with the CF treatment, the FF treatment significantly increased tree height, ground diameter, and cross-sectional area by 9%, 15%, and 19%, respectively; compared with the CK treatment, these increases were significantly higher by 8.23%, 7.69%, and 15.92%, respectively. However, the average crown width varied among the treatments. The CF treatment had the largest average crown width (1.60 m), significantly greater than both the FF (1.44 m) and CK (1.41 m) treatments. This indicates that formulated fertilization most effectively promotes the growth of tree height and ground diameter in young Chinese fir trees.

[0071] (2) Effects of different fertilizer types on soil runoff nutrient content in young Chinese fir forests By monitoring and analyzing the concentrations of nitrogen, phosphorus, potassium, and mixed nutrients in soil runoff under different fertilization treatments (e.g., Figures 3-7The results showed that the phosphorus concentration in the runoff of each treatment was generally low, and there was no significant difference in different rainfall events, with a concentration of 0.01-0.03 mg / L, indicating that the phosphorus loss level was low, and the effect of fertilization treatment was limited. The nitrogen concentration fluctuated greatly under different treatments and rainfall conditions. Under the condition of heavy rain, the concentration of formula fertilization and non-fertilization treatment was higher, which was 3.33 mg / L and 3.26 mg / L, respectively, and the concentration of traditional fertilization treatment was only 1.91 mg / L; under the condition of moderate rain, the concentration of traditional fertilization and non-fertilization treatment was higher (about 2.18 mg / L), and the concentration of formula fertilization was lower (1.35 mg / L). It showed that the nitrogen loss was affected by rainfall intensity and fertilization method, but no consistent rule was formed. The potassium concentration also did not show a consistent rule among different treatments. Under the condition of heavy rain, the concentration of traditional fertilization treatment was the highest (2.28 mg / L), followed by formula fertilization (1.75 mg / L), and non-fertilization was the lowest (0.93 mg / L); while under the condition of light rain, the difference among the three was small (1.30-1.59 mg / L). The average value of nitrogen and phosphorus mixed concentration showed that the traditional fertilization was the highest (2.14 mg / L), followed by non-fertilization (1.99 mg / L), and formula fertilization was the lowest (1.52 mg / L). The average value of nitrogen and phosphorus mixed concentration, and the average value of nitrogen and phosphorus and potassium mixed concentration of formula fertilization were 28.86% and 28.33% lower than those of traditional fertilization, respectively. It showed that formula fertilization was beneficial to reduce the nutrient concentration in soil runoff water.

[0072] In summary, compared with traditional fertilization treatment, under the condition of granite parent rock soil, the average tree height, ground diameter and cross-sectional area of formula fertilization treatment reached 2.29 m, 4.59 cm and 0.32 cm 2 , which were 8.63%, 15.59% and 18.93% higher than those of traditional fertilization treatment, respectively; and were 8.94%, 8.31% and 44.18% higher than those of non-fertilization treatment, respectively. The average value of nitrogen and phosphorus and potassium mixed concentration of formula fertilization was 28.33% lower than that of traditional fertilization.

[0073] The above has carried out the detailed introduction to the application, the principle and implementation mode of the application have been described in this paper by applying specific examples, and the above example description is only used to help understand the application and core idea. It should be pointed out that for ordinary skilled persons in the technical field, some improvements and modifications can be made to the application without departing from the principle of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A compound fertilizer, characterized by, The effective component is composed of the following components in the following amount: Urea 972.26 mg kg -1 ; Potassium phosphate monobasic 156.54 mg·kg -1 ; Manganese sulfate 12.97 mg-kg -1 ; Zinc sulfate 4.66 mg / kg -1 ; Sodium molybdate 0.24 mg·kg -1 .

2. The compound fertilizer according to claim 1, characterized in that, Further comprising a binder, which is an organic binder, the mass of the binder accounting for 12% of the mass of the compound fertilizer.

3. The compound fertilizer according to any one of claims 1-2 for use in promoting the growth of Chinese fir in granite soil.

4. A compound fertilizer, characterized by The effective component is composed of the following components in the following amount: urea 970.10 mg-kg -1 ; Magnesium sulfate 187.17 mg-kg -1 ; Potassium phosphate monobasic 158.42 mg·kg -1 ; Manganese sulfate 10.58 mg-kg -1 .

5. The compound fertilizer according to claim 1, characterized in that, Further comprising a binder, which is an organic binder, the mass of the binder accounting for 12% of the mass of the compound fertilizer.

6. The compound fertilizer according to any one of claims 4-5 for use in promoting the growth of Chinese fir in slate soil.

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