Pineapple soil improvement method and special-purpose improver

Abstract

The present application relates to the technical field of soil improvement, and particularly relates to a pineapple planting soil improvement method and a special improver thereof. The pineapple planting soil improvement method comprises the following steps: before planting, spreading the special improver for pineapple planting soil on the soil, the spreading amount being 15-25 kg per mu, and then shallow ploughing after the spreading. The special improver for pineapple planting soil comprises the following raw materials in percentage by mass: activated carbon or loaded activated carbon 35-65%, cake fertilizer containing nematode inhibiting substances 30-60%, loaded pomegranate peel ethanol extract 0.5-5%, and the balance being a binder. The cake fertilizer containing nematode inhibiting substances (such as cottonseed meal and tea seed meal) used in the present application is an agricultural byproduct, and the raw materials are easy to obtain and low in cost. The activated carbon can be prepared by using agricultural and forestry wastes (such as coconut shell charcoal), which is in line with the circular economy. Meanwhile, the present application is friendly to the environment and ecology, biodegradable, free of chemical residues, and has the functions of killing insects and inhibiting bacteria.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, and in particular to a method for improving soil for pineapple cultivation and a special soil improver thereof. Background Technology

[0002] Pineapple (scientific name: Ananas comosus Pineapple (L.) Merr. is a tropical fruit. Its edible part mainly consists of a fleshy, enlarged inflorescence axis and spirally arranged flowers on the outer periphery. The flowers are usually non-fertile; the persistent perianth lobes form a cavity containing withered stamens and a style. The leaves have very strong fibers that can be used for weaving, rope making, net making, and papermaking. When eaten fresh, pineapple has golden-yellow flesh, a rich aroma, a sweet and sour taste, and is crisp and juicy.

[0003] However, the indiscriminate use of chemical fertilizers often leads to increasingly serious soil degradation problems in pineapple cultivation. Therefore, the research and application of soil conditioners are of great significance in preventing soil degradation. Existing soil conditioners on the market can be divided into four main categories: natural conditioners, synthetic conditioners, natural-synthetic copolymer conditioners, and biological conditioners. However, what farmers actually accept are mostly new, multifunctional soil conditioners developed using natural materials. These conditioners are characterized by their low price, wide availability of raw materials, and ability to provide a significant amount of organic matter. They are effective in solving soil compaction, mitigating soil salinity, regulating soil pH balance, and enhancing soil fertility and water retention. However, pineapples cannot effectively absorb organic matter and trace elements from the soil, preventing the conditioners from providing immediate results.

[0004] Meanwhile, root-knot nematodes also exist in the soil where pineapples are grown. These nematodes damage the vascular bundles of the roots, leading to stunted pineapple plants and reduced fruit yield. Their larvae can survive in the soil for 2-3 years and easily develop resistance to conventional nematicides (such as thiazophos). Current control methods rely on chemical drenching, which carries the risk of soil residue and cannot restore the soil microecology after nematode infestation, causing significant damage to the pineapple industry.

[0005] There is a need for a soil improvement method for pineapple cultivation that can both improve soil structure and provide long-lasting, slow-release control of pineapple root-knot nematodes. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for improving soil conditions for pineapple cultivation and a specific soil conditioner thereof.

[0007] A pineapple planting soil improvement method, before planting, a pineapple planting soil special improvement agent is applied to the soil, the application amount is 15-25 kg per mu, and shallow ploughing is performed after application; raw materials of the pineapple planting soil special improvement agent include, by mass percentage, 35-65% of activated carbon or loaded activated carbon, 30-60% of cake fertilizer containing nematode inhibiting substances, 0.5-5% of loaded pomegranate peel ethanol extract, and the balance of binder.

[0008] Preferably, the loaded pomegranate peel ethanol extract includes pomegranate peel ethanol extract, triptolide ketone, and carboxyl-terminated polyamide amine; the mass ratio of the pomegranate peel ethanol extract, triptolide ketone, and carboxyl-terminated polyamide amine is 1-10:1:2-4.

[0009] The pomegranate peel ethanol extract can be freely purchased from the market or self-made (after drying and crushing the pomegranate peel, adding anhydrous ethanol for soaking overnight, oscillating extraction on an oscillation machine for 12 h, filtering, and concentrating the filtrate to near dryness by a rotary evaporator and placing in a 4℃ refrigerator for storage).

[0010] Preferably, the cake fertilizer containing nematode inhibiting substances is at least one of cottonseed meal, tea seed meal, and tung seed meal.

[0011] Preferably, the cake fertilizer containing nematode inhibiting substances has a mesh number of 80-100 mesh.

[0012] Preferably, the binder is humic acid or / and diatomite.

[0013] Preferably, the loaded activated carbon is prepared by the following steps: adding activated carbon powder and a dispersing agent to an alkaline aqueous solution with pH=8-9 and stirring for 5-15 min, adding dopamine hydrochloride to continue stirring for 2-6 h, filtering, washing, and vacuum drying.

[0014] More preferably, the dispersing agent is polyvinylpyrrolidone or / and sodium dodecylbenzenesulfonate.

[0015] More preferably, the mass ratio of the activated carbon, the dispersing agent, and dopamine hydrochloride is 20-40:1:2-10.

[0016] More preferably, the activated carbon powder has a mesh number of 100 mesh.

[0017] More preferably, the alkaline aqueous solution is a sodium hydroxide solution.

[0018] A pineapple planting soil special improvement agent used in the above-mentioned pineapple planting soil improvement method.

[0019] A preparation method of the above-mentioned pineapple planting soil special improvement agent, including the following steps:

[0020] S1, mix activated carbon or loaded activated carbon with cake fertilizer containing nematode inhibiting substances, dry to a water content of ≤5%, to obtain a mixed substrate;

[0021] S2, add pomegranate peel ethanol extract, triptolide ketone, and carboxyl-terminated polyamide amine to an ethanol aqueous solution, stir for 10-30 min, to obtain a mixed solution containing loaded pomegranate peel ethanol extract; spray the mixed solution containing loaded pomegranate peel ethanol extract onto the mixed substrate, seal and stir at 60-70°C for 10-30 min, and vacuum dry; then mix and granulate with a binder.

[0022] Beneficial effects:

[0023] 1. The cake fertilizer (such as cottonseed meal, tea seed meal, and tung seed meal) containing nematode inhibiting substances used in the improved method of the present application is an agricultural byproduct, which is easy to obtain and low in cost; and the activated carbon can be prepared using agricultural and forestry waste (such as coconut shell charcoal), which is in line with the circular economy. At the same time, the present application is environmentally friendly, biodegradable, and has no chemical residues; and the cake fertilizer containing nematode inhibiting substances releases nitrogen, phosphorus, and potassium after decomposition, improves the soil organic matter content, and has soil improvement function.

[0024] 2. The obtained improver uses cake fertilizer containing nematode inhibiting substances and activated carbon or loaded activated carbon as a mixed substrate, which can provide organic matter to promote the proliferation of soil probiotics and improve soil structure, and is rich in gossypol, tea saponin and other plant-derived toxic substances, which can effectively inhibit nematode egg hatching; the activated carbon as a slow-release carrier can prolong the release time of nutrients, adsorb soil toxins to improve the microenvironment, prolong the inhibitory effect on nematodes (for more than 90 days), and enhance the insecticidal effect.

[0025] 3. The present application uses pomegranate peel ethanol extract, triptolide ketone, and carboxyl-terminated polyamide amine to form loaded pomegranate peel ethanol extract; triptolide ketone is a diterpene compound extracted from tripterygium, which has insecticidal activity, showing antifeeding, stomach toxicity and contact killing effect; pomegranate peel ethanol extract has high-efficiency contact killing property; and carboxyl-terminated polyamide amine is a dendrimer; the present application loads carboxyl-terminated polyamide amine into the mixed substrate, effectively enhances the loading stability of pomegranate peel ethanol extract and triptolide ketone in the mixed substrate, and enhances the killing effect of pomegranate peel ethanol extract and triptolide ketone on root-knot nematodes. The present application uses activated carbon or loaded activated carbon, cake fertilizer containing nematode inhibiting substances, and loaded pomegranate peel ethanol extract in combination, to realize synergistic effect through the triple mechanisms of slow release, killing, and improvement.

[0026] 4. This invention utilizes the oxidative self-polymerization of dopamine hydrochloride to form a three-dimensional network structure in the pore structure of activated carbon, thereby improving the adsorption and loading capacity of the supported activated carbon for pomegranate peel ethanol extract and triptolide, effectively reducing the loss of pomegranate peel ethanol extract and triptolide during application; and the terminal carboxyl polyamide amine can also combine with polydopamine in the supported activated carbon, further enhancing the loading stability of pomegranate peel ethanol extract and triptolide in the mixed matrix, with a lower degradation rate at room temperature (degradation rate ≤2% after 6 months).

[0027] 5. This invention utilizes a combination of pomegranate peel ethanol extract and activated carbon powder, which significantly prolongs the efficacy and extends the retention time in the soil. Field experiments have confirmed that it can reduce nematode density by 95% and achieve a control effect of over 90%. Attached Figure Description

[0028] Figure 1 Soil pH values ​​of Example 3, Example 4, Comparative Example 1, Comparative Example 2, Comparative Example 3 and the control group, and a comparison chart of soil organic matter growth rates of Example 3, Example 4, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[0029] Figure 2 The soil porosity of Example 3, Example 4, Comparative Example 1, Comparative Example 2, Comparative Example 3 and the control group are shown in the comparison chart of soil bulk density change rate of Example 3, Example 4, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[0030] Figure 3 The graph shows a comparison of the growth rate of soluble sugar content and yield of pineapples in Example 3, Example 4, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0031] Figure 4 The graph shows a comparison of the nematode density reduction rate and control effect among Example 3, Example 4, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Detailed Implementation

[0032] The present invention will be further explained below with reference to specific embodiments.

[0033] The coconut shell activated carbon used below has a mesh size of 100 and an average specific surface area of ​​857±43 m². 2 / g. The gossypol content in the cottonseed meal used below is 1.037 g / kg. The tea saponin content in the tea seed meal used below is 17.62%.

[0034] Example 1

[0035] A pineapple planting soil improvement method, before planting, a pineapple planting soil special improvement agent is applied to the soil, the application amount is 15 kg per mu, and shallow ploughing is performed after application.

[0036] The pineapple planting soil special improvement agent, raw materials of which include, by mass percentage, 35% of coconut shell activated carbon, 60% of 80-mesh tea seed meal, 0.5% of loaded pomegranate peel ethanol extract, and the balance of humic acid.

[0037] The loaded pomegranate peel ethanol extract includes pomegranate peel ethanol extract, triptolide ketone and 2.0-generation carboxyl-terminated polyamide amine, and the mass ratio of the pomegranate peel ethanol extract, the triptolide ketone and the carboxyl-terminated polyamide amine is 1:1:2.

[0038] The preparation method of the pineapple planting soil special improvement agent includes the following steps:

[0039] S1, the coconut shell activated carbon is mixed with the tea seed meal, dried at 60 DEG C until the water content is less than or equal to 5%, and a mixed substrate is obtained;

[0040] S2, the pomegranate peel ethanol extract, the triptolide ketone and the carboxyl-terminated polyamide amine are added to an ethanol aqueous solution with a mass fraction of 5% and stirred for 10 min at a stirring speed of 100 r / min, a mixed solution containing the loaded pomegranate peel ethanol extract is obtained, the mixed solution containing the loaded pomegranate peel ethanol extract is sprayed onto the mixed substrate, sealed and stirred for 10 min at a temperature of 60 DEG C, and vacuum dried at 60 DEG C, and then humic acid is added and mixed, and a particle size of 1-3 mm is formed through an extrusion granulator.

[0041] Example 2

[0042] A pineapple planting soil improvement method, before planting, a pineapple planting soil special improvement agent is applied to the soil, the application amount is 15 kg per mu, and shallow ploughing is performed after application.

[0043] The pineapple planting soil special improvement agent, raw materials of which include, by mass percentage, 63% of coconut shell activated carbon, 30% of 90-mesh cotton seed meal, 4% of loaded pomegranate peel ethanol extract, and the balance of diatomite.

[0044] The loaded pomegranate peel ethanol extract includes pomegranate peel ethanol extract, triptolide ketone and 2.0-generation carboxyl-terminated polyamide amine, and the mass ratio of the pomegranate peel ethanol extract, the triptolide ketone and the carboxyl-terminated polyamide amine is 1:1:2.

[0045] The preparation method of the pineapple planting soil special improvement agent includes the following steps:

[0046] S1, the coconut shell activated carbon is mixed with the tea seed meal, dried at 60 DEG C until the water content is less than or equal to 5%, and a mixed substrate is obtained;

[0047] S2, the pomegranate peel ethanol extract, triptolide ketone, carboxyl-terminated polyamide amine is added to the mass fraction of 7.5% ethanol solution and stirred for 30min, the stirring speed is 500r / min, the mixed solution containing the loaded pomegranate peel ethanol extract is obtained; the mixed solution containing the loaded pomegranate peel ethanol extract is sprayed to the mixed matrix, and is sealed and stirred for 30min at a temperature of 70 DEG C, and is vacuum dried at 60 DEG C; diatomite is added again and mixed, and a granule with a particle size of 1-3mm is formed by extrusion granulator.

[0048] Example 3

[0049] A pineapple planting soil improvement method, before planting, a pineapple planting soil special modifier is applied to the soil, the application amount is 20kg / mu, and shallow ploughing is performed after application.

[0050] The above-mentioned pineapple planting soil special modifier, raw materials thereof include, by mass percentage: activated carbon 55%, 100 mesh tea seed meal 40%, loaded pomegranate peel ethanol extract 3%, and the balance is diatomite.

[0051] The loaded pomegranate peel ethanol extract includes: pomegranate peel ethanol extract, triptolide ketone, 3.0 generation carboxyl-terminated polyamide amine; the mass ratio of pomegranate peel ethanol extract, triptolide ketone and carboxyl-terminated polyamide amine is 6:1:3.

[0052] The above-mentioned pineapple planting soil special modifier preparation method includes the following steps:

[0053] S1, the coconut shell activated carbon is mixed with the tea seed meal, and is dried at 60 DEG C until the water content is less than or equal to 5%, to obtain a mixed matrix;

[0054] S2, the pomegranate peel ethanol extract, triptolide ketone, carboxyl-terminated polyamide amine is added to the mass fraction of 7.5% ethanol solution and stirred for 30min, the stirring speed is 500r / min, the mixed solution containing the loaded pomegranate peel ethanol extract is obtained; the mixed solution containing the loaded pomegranate peel ethanol extract is sprayed to the mixed matrix, and is sealed and stirred for 30min at a temperature of 70 DEG C, and is vacuum dried at 60 DEG C; diatomite is added again and mixed, and a granule with a particle size of 1-3mm is formed by extrusion granulator.

[0055] Example 4

[0056] A pineapple planting soil improvement method, before planting, a pineapple planting soil special modifier is applied to the soil, the application amount is 20kg / mu, and shallow ploughing is performed after application.

[0057] The above-mentioned pineapple planting soil special modifier, raw materials thereof include, by mass percentage: activated carbon 55%, 100 mesh tea seed meal 40%, loaded pomegranate peel ethanol extract 3%, and the balance is diatomite.

[0058] The loaded pomegranate peel ethanol extract comprises: pomegranate peel ethanol extract, triptolide, and 3.0 generation carboxyl-terminated polyamide amine; the mass ratio of pomegranate peel ethanol extract, triptolide, and carboxyl-terminated polyamide amine is 6:1:3.

[0059] The loaded activated carbon was prepared by the following steps: 7.5 kg of coconut shell activated carbon and 0.25 kg of PVP-K30 were added to 50 kg of sodium hydroxide solution with pH=8.5 and stirred for 10 min at a stirring speed of 1000 r / min. 1.5 kg of dopamine hydrochloride was added and stirring was continued for 4 h. The mixture was then filtered, washed, and vacuum dried.

[0060] The above-mentioned method for preparing a soil conditioner specifically for pineapple cultivation includes the following steps:

[0061] S1. Mix the loaded activated carbon with tea seed meal and dry it at 60°C until the moisture content is ≤5% to obtain a mixed matrix;

[0062] S2. Add pomegranate peel ethanol extract, tripterygium lactone, and carboxyl-terminated polyamide amine to a 10% (w / w) ethanol aqueous solution and stir for 20 min at a stirring speed of 300 r / min to obtain a mixture containing pomegranate peel ethanol extract. Spray the mixture containing pomegranate peel ethanol extract onto a mixing matrix, seal and stir at 65℃ for 20 min, and vacuum dry at 60℃. Then add diatomaceous earth and mix, and form particles with a particle size of 1-3 mm using an extrusion granulator.

[0063] Comparative Example 1

[0064] A method for improving soil conditions for pineapple cultivation involves applying a special soil conditioner for pineapple cultivation to the soil before planting at a rate of 20 kg / mu, followed by shallow tilling.

[0065] The above-mentioned soil conditioner for pineapple cultivation contains the following raw materials by weight percentage: 55% loaded activated carbon, 40% 100-mesh tea seed meal, 3% loaded pomegranate peel ethanol extract, and the remainder is diatomaceous earth.

[0066] The loaded pomegranate peel ethanol extract comprises: pomegranate peel ethanol extract, triptolide, and 3.0 generation carboxyl-terminated polyamide amine; the mass ratio of pomegranate peel ethanol extract, triptolide, and carboxyl-terminated polyamide amine is 6:1:3.

[0067] The loaded activated carbon was prepared by the following steps: 1.5 kg of dopamine hydrochloride was added to 50 kg of sodium hydroxide solution with pH=8.5 and stirred for 4 hours at a stirring speed of 1000 r / min. 7.5 kg of coconut shell activated carbon was added and mixed evenly. The mixture was then filtered, washed, and vacuum dried.

[0068] The above-mentioned method for preparing a soil conditioner specifically for pineapple cultivation includes the following steps:

[0069] S1, mix the loaded activated carbon with tea seed meal, dry at 60℃ to a water content of ≤5%, to obtain a mixed substrate;

[0070] S2, add the pomegranate peel ethanol extract, triptolide ketone and carboxyl-terminated polyamide amine to an ethanol aqueous solution with a mass fraction of 10% and stir for 20 min at a stirring speed of 300 r / min, to obtain a mixed solution containing the loaded pomegranate peel ethanol extract; spray the mixed solution containing the loaded pomegranate peel ethanol extract onto the mixed substrate, seal and stir at a temperature of 65℃ for 20 min, and vacuum dry at 60℃; then mix with diatomite, and form granules with a particle size of 1-3 mm through an extrusion granulator.

[0071] Comparative Example 2

[0072] A pineapple planting soil improvement method, before planting, a pineapple planting soil special modifier is applied to the soil at an application amount of 20 kg per mu, and shallow ploughing is performed after application.

[0073] The pineapple planting soil special modifier, raw materials of which include, by mass percentage, 55% of loaded activated carbon, 40% of 100-mesh tea seed meal, 3% of loaded pomegranate peel ethanol extract, and the balance of diatomite.

[0074] The loaded pomegranate peel ethanol extract includes pomegranate peel ethanol extract and 3.0-generation carboxyl-terminated polyamide amine, and the mass ratio of the pomegranate peel ethanol extract, triptolide ketone and carboxyl-terminated polyamide amine is 2:1.

[0075] The loaded activated carbon is prepared by the following steps: adding 7.5 kg of coconut shell activated carbon and 0.25 kg of PVP-K30 to 50 kg of sodium hydroxide solution with pH=8.5 and stirring for 10 min at a stirring speed of 1000 r / min, adding 1.5 kg of dopamine hydrochloride thereto and continuing to stir for 4 h, filtering, washing, and vacuum drying.

[0076] The preparation method of the pineapple planting soil special modifier includes the following steps:

[0077] S1, mix the loaded activated carbon with tea seed meal, dry at 60℃ to a water content of ≤5%, to obtain a mixed substrate;

[0078] S2, add the pomegranate peel ethanol extract, triptolide ketone and carboxyl-terminated polyamide amine to an ethanol aqueous solution with a mass fraction of 10% and stir for 20 min at a stirring speed of 300 r / min, to obtain a mixed solution containing the loaded pomegranate peel ethanol extract; spray the mixed solution containing the loaded pomegranate peel ethanol extract onto the mixed substrate, seal and stir at a temperature of 65℃ for 20 min, and vacuum dry at 60℃; then mix with diatomite, and form granules with a particle size of 1-3 mm through an extrusion granulator.

[0079] Comparative Example 3

[0080] A pineapple planting soil improvement method, before planting, a pineapple planting soil special improvement agent is applied to the soil at an application amount of 20 kg per mu, and after application, shallow plowing is performed.

[0081] The pineapple planting soil special improvement agent described above, raw materials thereof include, by mass percentage: 55% of loaded activated carbon, 40% of 100-mesh tea seed meal, 3% of loaded pomegranate peel ethanol extract, and the balance of diatomite.

[0082] The loaded pomegranate peel ethanol extract includes pomegranate peel ethanol extract and triptolide ketone, and the mass ratio of the pomegranate peel ethanol extract to the triptolide ketone is 6:1.

[0083] The loaded activated carbon is prepared by the following steps: 7.5 kg of coconut shell activated carbon and 0.25 kg of PVP-K30 are added to 50 kg of sodium hydroxide solution with pH=8.5 and stirred for 10 min at a stirring speed of 1000 r / min, 1.5 kg of dopamine hydrochloride is added thereto and continues to be stirred for 4 h, filtered, washed, and vacuum dried.

[0084] The preparation method of the pineapple planting soil special improvement agent described above includes the following steps:

[0085] S1, the loaded activated carbon is mixed with the tea seed meal, dried at 60°C until the water content is ≤5%, and a mixed substrate is obtained;

[0086] S2, the pomegranate peel ethanol extract and the triptolide ketone are added to an ethanol aqueous solution with a mass fraction of 10% and stirred for 20 min at a stirring speed of 300 r / min to obtain a mixed solution containing the loaded pomegranate peel ethanol extract; the mixed solution containing the loaded pomegranate peel ethanol extract is sprayed onto the mixed substrate, sealed and stirred for 20 min at a temperature of 65°C, and vacuum dried at 60°C; diatomite is further added and mixed, and a granulator is used to form particles with a particle size of 1-3 mm.

[0087] The improvement methods of Example 3, Example 4, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are used for field tests in a nematode test area of an ecological agricultural pineapple planting base in Sanya, Hainan, the incidence of root-knot nematodes in this plot is 100%, and the previous crop is pineapple.

[0088] This place belongs to a tropical marine monsoon climate, the average annual temperature of the soil is 22-25°C, and the average annual rainfall is 1500-2200 mm. The basic physicochemical properties of the soil are as follows: pH value 4.37, organic matter 6.82 g / kg, alkali-hydrolyzable nitrogen 253.48 mg / kg, available phosphorus 141.95 mg / kg, and available potassium 29.03 mg / kg.

[0089] This time continues to plant pineapple (Tainong 17), set 6 groups, example 3 group, example 4 group, comparative example 1 group, comparative example 2 group and comparative example 3 group respectively adopt the modified method of example 3, example 4, comparative example 1, comparative example 2, comparative example 3, and the control group is to spray coconut shell activated carbon + rapeseed meal + diatomite (the mass ratio of the three is 55:40:2) to the soil before planting. The spraying amount of each group is 20 kg / mu, and the soil of each group is shallowly turned after spraying. Each group has 5 repetitions and is not adjacent to each other. The planting management of each group is the same as the general production (the agricultural tools of each group are independent of each other and are not mixed).

[0090] After the end of the pineapple harvest period, five-point sampling method is used to sample the 0-20 cm soil after harvesting of each group, and then the pH value, soil porosity, organic matter content and bulk density are determined, and the organic matter growth rate and soil bulk density change rate of each group are calculated.

[0091] The organic matter growth rate = (the organic matter content of the soil of the treatment group - the organic matter content of the soil of the control group) ÷ the organic matter content of the soil of the control group × 100%.

[0092] The soil bulk density change rate = (the soil bulk density of the control group - the soil bulk density of the treatment group) ÷ the soil bulk density of the control group × 100%.

[0093] As shown in Figure 1 The soil pH value of the control group is lower than that of the soil before planting, which shows that conventional fertilization can reduce the pH value of the pineapple planting soil and cause soil acidification; and the soil pH value of each treatment group is higher than that of the soil before planting and the soil pH value of the control group, which shows that the modifier obtained by the application can adjust the pH value of the pineapple planting soil and effectively alleviate the further acidification of the soil caused by conventional fertilization, but there is no significant difference between the treatment groups. At the same time, although the organic matter growth rate of example 3 group is the lowest, its organic matter growth rate has exceeded 20%, showing a good improvement effect on soil fertility; and the organic matter growth rate of example 4 group is the highest, which is better than the other groups (P<0.05).

[0094] As shown in Figure 2 The soil porosity of each treatment group is higher than that of the control group, which shows that the modifier obtained by the application can enhance the air permeability of the soil, and the soil porosity of example 4 group is the highest, which is better than the other groups (P<0.05). At the same time, although the soil bulk density change rate of example 3 group is the lowest, its soil bulk density change rate has reached 4.8%, showing a good improvement effect on the soil; and the soil bulk density change rate of example 4 group is the highest, which is better than the other groups (P<0.05).

[0095] The yield of each group of harvested pineapples is counted, and the soluble sugar content of the pineapple is determined to calculate the soluble sugar content growth rate and the yield increase rate of the pineapple.

[0096] The growth rate of soluble sugar content = (soluble sugar content of pineapple in the treatment group - soluble sugar content of pineapple in the control group) ÷ soluble sugar content of pineapple in the control group × 100%.

[0097] Pineapple yield increase rate = (Pineapple yield in treatment group - Pineapple yield in control group) ÷ Pineapple yield in control group × 100%.

[0098] like Figure 3 As shown, although the growth rate of soluble sugar content and the yield of pineapple in Example 3 were the lowest, the growth rate of soluble sugar content exceeded 7% and the yield of pineapple exceeded 20%, showing a good effect on improving the quality of pineapple and promoting the yield of pineapple; while the growth rate of soluble sugar content and the yield of pineapple in Example 4 were the highest, which were better than the other groups (P<0.05).

[0099] Simultaneously, after the pineapple harvest period, the nematode density and root knot number of each group were measured. Based on the control group, the nematode density reduction rate and control effect of Example 3 group, Example 4 group, Comparative Example 1 group, and Comparative Example 2 group were calculated.

[0100] Nematode density reduction rate = (control group nematode density - treatment group nematode density) ÷ control group nematode density × 100%.

[0101] Control effect = (Number of root knots in control group - Number of root knots in treatment group) ÷ Number of root knots in control group × 100%.

[0102] like Figure 4 As shown, although the nematode density reduction rate and control effect of the 3rd group were the lowest, its nematode density reduction rate exceeded 92% and its control effect exceeded 85%, which showed that it had an excellent control effect on root-knot nematodes in the soil; while the nematode density reduction rate and control effect of the 4th group were the highest, which were better than the other groups (P<0.05).

[0103] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for improving soil for growing pineapples, characterized by, Before planting, the pineapple planting soil special modifier is applied to the soil at an application amount of 15-25 kg per mu, and after application, shallow ploughing is performed; The raw materials of the pineapple planting soil special modifier include, by mass percentage, 35-65% of loaded activated carbon, 30-60% of cake fertilizer containing nematode inhibiting substances, 0.5-5% of loaded pomegranate peel ethanol extract, and the balance of binder; The loaded activated carbon is prepared by the following steps: activated carbon powder and dispersant are added to an alkaline aqueous solution with pH=8-9 and stirred for 5-15 min, hydrochloric acid dopamine is added thereto and continues to be stirred for 2-6 h, filtered, washed, and vacuum dried; The mass ratio of the activated carbon powder, the dispersant, and the hydrochloric acid dopamine is 20-40:1:2-10; the dispersant is polyvinylpyrrolidone or / and sodium dodecylbenzenesulfonate; the mesh number of the activated carbon powder is 100 mesh, and the alkaline aqueous solution is sodium hydroxide solution; The cake fertilizer containing nematode inhibiting substances is at least one of cottonseed meal, tea seed meal, and tung seed meal; The loaded pomegranate peel ethanol extract includes pomegranate peel ethanol extract, triptolide ketone, and carboxyl-terminated polyamide amine; the mass ratio of the pomegranate peel ethanol extract, the triptolide ketone, and the carboxyl-terminated polyamide amine is 1-10:1:2-4.

2. The pineapple soil improvement method according to claim 1, characterized by, The cake fertilizer containing nematode inhibiting substances has a mesh number of 80-100 mesh.

3. The pineapple soil improvement method according to claim 1, characterized by, The binder is humic acid or / and diatomite.

4. A special-purpose amendment for pineapple planting soil, characterized by comprising the following components: The pineapple planting soil special modifier used in the pineapple planting soil improvement method according to any one of claims 1-3. ​ 5. The method for preparing the special soil improver for pineapple planting soil according to claim 4, characterized in that, The method includes the following steps: S1, mixing the loaded activated carbon and the cake fertilizer containing nematode inhibiting substances, and drying to a water content of ≤5% to obtain a mixed substrate; S2, adding the pomegranate peel ethanol extract, the triptolide ketone, and the carboxyl-terminated polyamide amine to an ethanol aqueous solution and stirring for 10-30 min to obtain a mixed solution containing the loaded pomegranate peel ethanol extract; spraying the mixed solution containing the loaded pomegranate peel ethanol extract to the mixed substrate, stirring at 60-70°C for 10-30 min, and vacuum drying; and then adding the binder and mixing to granulate.

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