Rapid fertilizing and improving method for newly-reclaimed red soil dry land

Abstract

The invention relates to the technical field of agricultural resources and environment, and particularly discloses a rapid fertilization improvement method for newly-reclaimed red soil dry land. The method systematically integrates the core steps of soil diagnosis aluminum toxicity passivation, composite conditioner deacidification, two-stage deep ploughing, organic and inorganic biological synergistic fertilization, soil moisture content regulation and control, earth surface covering, green manure planting and returning to the field and the like. The applied composition comprises a soil composite conditioner, a charcoal-based organic fertilizer and a specific functional microbial agent, wherein the soil composite conditioner comprises modified oyster shell powder, a calcium magnesium phosphate fertilizer, humic acid, polyglutamic acid and the like. The method relates to key processes such as temperature programming calcination modification of raw materials, co-pyrolysis and composite granulation of the materials and the like. The method can synchronously and quickly improve the chemical and biological properties of soil and optimize the physical structure of a plough layer, and has the advantages of high improvement targeting, synergistic interaction of all steps, high fertilizing speed and lasting effect; in addition, the method has the advantages of being coherent in process, high in resource utilization efficiency and easy to implement on a large scale.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of agricultural resources and environment, more specifically, it relates to a new red soil dry land rapid fertilization and improvement method. BACKGROUND

[0002] As an important reserve arable land resource in southern China, new red soil dry land plays an irreplaceable role in alleviating the contradiction between supply and demand of arable land and ensuring regional agricultural production. However, new red soil dry land is generally characterized by prominent acid aluminum toxicity, poor soil fertility, and poor plough layer structure: the soil pH value is low, the active aluminum content is high, which can inhibit the growth of plant roots and soil microbial activity; the soil organic matter and available nitrogen, phosphorus and potassium content are scarce, which is difficult to meet the normal growth demand of crops; at the same time, the plough bottom layer of new red soil dry land is compact, the plough layer is shallow and loose, and the water and fertilizer retention capacity is poor, which together leads to low productivity of new red soil dry land, and restricts its rapid input into agricultural production and efficient utilization.

[0003] At present, the improvement methods for new red soil dry land are mainly single measures, such as using lime to reduce soil acidity, separately applying organic fertilizer to supplement nutrients, or improving plough layer structure through deep ploughing, which lacks systematic and collaborative intervention on the limiting factors such as acid aluminum toxicity, nutrient deficiency and poor structure. For example, although using lime to reduce acid can short-term improve soil pH value, it cannot effectively passivate active aluminum, and the alkaline adjustment effect is unstable, which is easy to cause pH value rebound; although separately applying ordinary organic fertilizer can supplement part of the nutrients, it is difficult to quickly improve the plough layer structure, and the nutrients are easy to lose, which cannot realize long-term fertilization; and single deep ploughing operation is also difficult to maintain the stability of the plough layer structure without the cooperation of nutrient supplement and biological activity improvement. These single or non-collaborative improvement methods cannot simultaneously and significantly improve the chemical environment, physical structure and biological activity of the soil, resulting in long soil fertilization period and incomplete effect, which makes it difficult to realize rapid, comprehensive and long-term improvement of the fertility of new red soil dry land. SUMMARY

[0004] In order to solve the problem of single improvement measure and incomplete effect in the prior art, which leads to long soil fertilization period, the present application provides a new red soil dry land rapid fertilization and improvement method.

[0005] A new red soil dry land rapid fertilization and improvement method is realized by applying a specific fertilizer composition, which includes a soil composite conditioner, a biochar-based organic fertilizer, a slow-release compound fertilizer and a compound microbial inoculant; the method comprises the following steps:

[0006] S1, soil diagnosis and specific passivation of aluminum toxicity: soil testing is performed, and when the content of active aluminum in the soil is higher than 2.0 cmol / kg, potassium silicate is additionally added in the subsequently applied soil composite conditioner at an amount of 15-25 kg / hm2;

[0007] S2, soil composite conditioner for acid reduction: soil composite conditioner is applied to adjust the pH value of the soil to the range of 5.5-6.5;

[0008] S3, optimization of plough layer structure: deep plowing and deep tillage are performed on the soil at a depth of 20-40 cm to construct a thick and fertile plough layer;

[0009] S4, synergistic precision fertilization: biochar-based organic fertilizer and slow-release compound fertilizer are applied to the soil, and a composite microbial agent suspension is sprayed;

[0010] S5, soil moisture condition regulation: shallow tillage is performed at a depth of 8-12 cm, followed by compaction with a ring-shaped compactor;

[0011] S6, surface mulching for moisture conservation: straw mulching or spraying of degradable liquid mulch is used for water and moisture conservation;

[0012] S7, green manure planting and returning to the field: green manure crops are planted and turned into the soil during the full flowering to early pod stage.

[0013] By using the above technical solutions, by detecting the content of active aluminum in the soil and adding 15-25 kg / hm2 of potassium silicate in the subsequently applied soil composite conditioner when the content of active aluminum is higher than 2.0 cmol / kg, the effects of specific binding of excess active aluminum ions in the soil and reducing the harm of aluminum toxicity in the soil are achieved. By applying soil composite conditioner, the effects of neutralizing soil acidic substances and adjusting the pH value of the soil to the suitable range of 5.5-6.5 are achieved. By performing deep plowing and deep tillage on the soil at a depth of 20-40 cm, the effects of breaking the compacted plowpan and increasing the thickness of the plough layer are achieved, thereby constructing a thick and fertile plough layer. By applying biochar-based organic fertilizer and slow-release compound fertilizer to the soil and spraying a composite microbial agent suspension, the effects of supplementing soil organic matter and available nutrients and activating difficultly soluble nutrients in the soil are achieved, thereby improving the soil fertility level. By performing shallow tillage at a depth of 8-12 cm and then using a ring-shaped compactor for compaction, the effects of refining the surface soil particles and optimizing the soil tightness are achieved, thereby regulating the soil moisture condition. By using straw mulching or spraying degradable liquid mulch, the effects of blocking soil water evaporation and reducing surface runoff are achieved, thereby conserving water and moisture. By planting green manure crops and turning them into the soil during the full flowering to early pod stage, the effects of increasing the input of soil organic matter and improving the soil aggregate structure are achieved, thereby continuously fertilizing the soil.

[0014] Preferably, in step S2, the soil composite conditioner is composed of the following raw materials in parts by weight: modified oyster shell powder 50-70 parts, calcium magnesium phosphate 20-30 parts, humic acid 10-20 parts, and polyglutamic acid 5-10 parts.

[0015] By adopting the above technical scheme, by applying the soil composite conditioner composed of modified oyster shell powder, calcium magnesium phosphate, humic acid, and polyglutamic acid in specific parts by weight into the soil, the raw materials play a synergistic role to achieve soil acid reduction and basic improvement: the modified oyster shell powder plays a role in neutralizing soil acidic substances, adsorbing free active aluminum ions in the soil, and providing an attachment carrier for other components, thereby achieving the effects of auxiliary adjustment of soil pH and enhancement of aluminum toxicity passivation effect; by adding calcium magnesium phosphate, it plays a role in supplementing calcium, magnesium, and phosphorus elements in the soil, and further assisting in neutralizing soil acidity by using its weak alkalinity, thereby achieving the effects of improving the soil basic nutrient level and synergistically optimizing the soil chemical environment; by adding humic acid, it plays a role in improving soil particle aggregation and enhancing the soil's adsorption and retention capacity for nutrients, thereby achieving the effects of optimizing the soil physical structure and reducing nutrient leaching; by adding polyglutamic acid, it plays a role in adsorbing and retaining soil moisture and chelating effective nutrient ions in the soil, thereby achieving the effects of improving the soil's water and fertilizer retention capacity and prolonging the action time of the conditioner, and finally collectively stabilizing the soil pH value to the suitable range of 5.5-6.5.

[0016] Preferably, in step S3, the deep plowing and deep turning is carried out in two stages: the first stage uses a deep plowing plow to perform deep plowing work with a depth of 30-40 cm to break the plow pan; the second stage uses a rotary cultivator to perform rotary plowing work with a depth of 15-20 cm to make the soil finely divided.

[0017] By adopting the technical scheme, through implementing deep plowing and deep tillage in two stages, the structure of the plough layer is precisely optimized by using different equipment and working depth: in the first stage, deep loosening work is performed at a depth of 30-40 cm by using a deep loosening plow, which directly breaks the compacted plow bottom in newly reclaimed red soil dry land and opens the deep soil aeration and water permeation channel, thereby eliminating the physical obstacles in the deep soil and creating favorable conditions for subsequent nutrient infiltration and root penetration; in the second stage, rotary tillage work is performed at a depth of 15-20 cm by using a rotary tiller, which refines the large soil particles in the surface layer after deep loosening and makes the soil particles more evenly distributed, thereby improving the surface soil loose degree and providing a suitable microenvironment for the uniform distribution of nutrients and seed germination in the subsequent fertilization; the two-stage operation is cooperated, which not only avoids the problem of coarse and uneven soil particles after single deep loosening operation, but also solves the limitation of single rotary tillage that cannot break through the deep plow bottom, and finally efficiently constructs a thick and fertile plough layer with good permeability and suitable loose degree.

[0018] Preferably, in step S4, the application amount of the biochar-based organic fertilizer is 1.5-2.5 t / hm2; the application amount of the slow-release compound fertilizer is 60-80 kg / hm2; and the spraying amount of the compound microbial agent suspension is 10-15 L / hm2.

[0019] By adopting the technical scheme, through precisely controlling the amount of each type of fertilization material and selecting a specific preparation process of the biochar-based organic fertilizer in step S4, the soil nutrients are cooperatively supplemented and efficiently activated: by applying the biochar-based organic fertilizer, the soil organic matter is continuously supplemented, the easily leached nutrients in the soil are adsorbed and fixed, and the soil microbial habitat is improved, thereby improving the soil carbon storage, reducing nutrient loss, and laying a foundation for biological activity improvement; by applying the slow-release compound fertilizer, the characteristics of slow nutrient release are utilized to provide sustained and available nutrients for crop growth and avoid the excessive loss or short-term deficiency of nutrients caused by one-time application of traditional available fertilizer, thereby matching the nutrient requirements of crops at different growth stages and maintaining the stability of soil nutrient supply; by spraying the compound microbial agent suspension, the functional microorganisms in the agent decompose the insoluble phosphorus and potassium minerals in the soil, promote the transformation of organic matter into absorbable nutrients, and inhibit the reproduction of harmful microorganisms, thereby improving the availability of soil nutrients and enhancing the biological activity of the soil; the three are cooperated, which realizes the combination of organic matter supplement and available nutrient supply, the synchronization of chemical nutrient release and biological nutrient activation, and finally efficiently improves the overall soil fertility level and provides sufficient and sustained nutrient support for crop growth.

[0020] Preferably, the nitrogen-fixing bacteria in the complex bacterial agent suspension is Azotobacter chroococcum, the phosphorus-dissolving bacteria is Penicillium oxalicum, and the total number of viable bacteria in the bacterial agent suspension is not less than 5x10 9 CFU / mL.

[0021] By adopting the above technical scheme, by selecting specific functional bacteria in the complex bacterial agent suspension and limiting the minimum number of viable bacteria, the efficient improvement of soil biological activity and the nutrient activation effect are ensured: by adding nitrogen-fixing bacteria Azotobacter chroococcum, with the help of its nitrogen-fixing enzyme activity, the molecular nitrogen in the air is converted into ammonia nitrogen or nitrate nitrogen that can be absorbed by the soil, and the soil nitrogen reserve is supplemented, thereby achieving the effect of relieving the nitrogen deficiency of newly reclaimed red soil upland and reducing the dependence on chemical nitrogen fertilizer; by adding phosphorus-dissolving bacteria Penicillium oxalicum, relying on the organic acid and phosphatase secreted by it, the function of decomposing the insoluble phosphorus minerals in the soil and converting them into effective phosphorus that can be absorbed by crops is achieved, thereby achieving the effect of releasing the potential phosphorus in the soil and improving the low availability of red soil phosphorus; by limiting the total number of viable bacteria in the bacterial agent suspension, it is ensured that the number of functional bacteria in unit volume is sufficient, which can quickly colonize in the soil and form a dominant bacterial population, avoiding the low nitrogen-fixing and phosphorus-dissolving efficiency caused by insufficient number of viable bacteria, thereby achieving the effect of ensuring that the bacteria quickly play a role, forming a synergy with the organic matter supply of biochar-based organic fertilizer and the nutrient release of slow-release compound fertilizer; the combination of the three precisely solves the problems of weak biological activity and difficult activation of nitrogen and phosphorus nutrients in newly reclaimed red soil upland, and further improves the overall effect of synergistic fertilization.

[0022] Preferably, in step S6, when the degradable liquid mulch film is selected, the liquid mulch film is composed of modified cellulose, humic acid and crosslinking agent dissolved in water, and forms a porous network mulch film on the ground after spraying, and the dosage is 80-120 kg / hm².

[0023] By adopting the above technical scheme, by selecting the degradable liquid mulch film composed of modified cellulose, humic acid and crosslinking agent dissolved in water, and controlling the dosage and the specific mulching form, the dual effects of surface water and soil conservation and ecological friendliness are realized: by using modified cellulose as the base material of the liquid mulch film, it has good film forming property and toughness, which plays a role in building the basic framework of the mulch film and ensuring that a continuous and complete mulch layer can be formed after spraying, thereby avoiding the failure of water conservation effect caused by the rupture of the mulch film; by adding humic acid in the liquid mulch film, it has strong water absorption and water retention capacity, which plays a role in enhancing the evaporation blocking effect of the mulch film on soil moisture, and slowly releasing organic matter to supplement the surface soil nutrients as the mulch film degrades, thereby achieving the effect of water conservation and auxiliary fertilization; by adding the crosslinking agent, it can promote the crosslinking combination between the modified cellulose and the humic acid molecules, which plays a role in forming a stable porous network mulch structure, improving the tensile and rainwater erosion resistance of the mulch film, thereby avoiding the damage of the mulch film caused by external force and prolonging the water conservation time; by controlling the dosage of the liquid mulch film, the thickness of the porous network mulch formed after spraying is appropriate, which can effectively block the evaporation of soil surface water, and will not cause the mulch film to be too thick to affect the soil permeability due to excessive dosage, or the mulch film to be incomplete and have water conservation leaks due to insufficient dosage; finally, the liquid mulch film can naturally degrade without residue while realizing efficient water and soil conservation, avoiding the problem of soil pollution caused by traditional plastic mulch film, and the porous structure can also consider the surface ventilation and rainwater penetration, further adapting to the dual needs of water conservation and soil ventilation of new red soil dry land.

[0024] Preferably, in step S6, when straw mulching is selected, the length of the straw is 5-10 cm, and the straw is pre-wetted with the complex microbial agent suspension before mulching, and the dosage of the agent suspension is 10%-20% of the weight of the straw.

[0025] By adopting the above technical scheme, through controlling the length of the straw and using the composite microbial agent suspension to pre-wet the straw, the synergistic effect of surface mulching and preserving soil moisture and efficient degradation of the straw is realized: by selecting the straw with a length of 5-10 cm, the particle size is moderate, which can be evenly spread on the surface during mulching, avoiding the discontinuity of the water retention layer or the poor local ventilation caused by the stacking of large pieces of straw, thereby achieving the effect of forming a stable and ventilated surface mulch layer and continuously blocking soil water evaporation; by using the composite microbial agent suspension to pre-wet the straw before mulching, the functional microorganisms in the agent can adhere to the surface of the straw and penetrate into the inside, which can accelerate the decomposition and humification speed of the straw in the field environment, convert cellulose and other substances in the straw into soil organic matter, thereby achieving the effect of avoiding surface hardening caused by long-term non-degradation of the straw, and simultaneously supplementing organic nutrients to the soil; by controlling the dosage of the agent suspension to be 10%-20% of the weight of the straw, it can ensure that a sufficient amount of functional microorganisms is attached to the straw per unit weight to quickly start the degradation process, and it can also avoid resource waste caused by excessive dosage or low degradation efficiency caused by insufficient dosage, thereby achieving the effect of balancing the degradation speed and cost input; the three cooperate to solve the problems of uneven water retention and slow degradation that are prone to occur in traditional straw mulching, and can also make the mulching and soil preservation process simultaneously accumulate organic matter in the soil, further adapting to the dual needs of water retention and continuous fertilization of newly reclaimed red soil upland.

[0026] Preferably, in step S7, the green manure crop is mixed sowing of legumes and grasses, the legume green manure is hairy vetch or arrow-shaped pea, and the grass green manure is blackgrass, and the weight ratio of mixed sowing is 2:1, and the total seeding amount is 45-75 kg / hm².

[0027] By adopting the technical scheme, the high-efficiency fertilization effect of green manure returning to field is realized by selecting specific types of legume and gramineous green manure for precise mixed sowing and controlling the sowing amount: by selecting legume green manure hairy vetch or arrow-shaped pea, the root system of which can be symbiotic with rhizobia, the effect of converting molecular nitrogen in the air into soil available nitrogen and supplementing nitrogen reserves of newly reclaimed red soil dry land is achieved, thereby achieving the effects of relieving soil nitrogen deficiency and reducing chemical nitrogen fertilizer input; by selecting gramineous green manure ryegrass, which has developed root system and high biomass, the effects of enhancing surface coverage, reducing soil erosion, and accumulating a large amount of organic matter are achieved, thereby achieving the effects of improving the surface structure of the soil and providing sufficient organic matter for the soil after being turned over; by controlling the weight ratio of legume and gramineous green manure mixed sowing to be 2:1, the nitrogen fixation amount of legume green manure can be ensured to meet the soil nitrogen demand, and the biomass advantage of gramineous green manure can be used to balance the surface coverage and organic matter input, thereby avoiding the problems of insufficient biomass of single legume green manure or single gramineous green manure cannot supplement nitrogen, and achieving the synergistic optimization effect of nitrogen fixation and organic matter accumulation; by controlling the total sowing amount, it is ensured that the green manure seeds can germinate uniformly and do not compete for light and nutrients after seedling, and a suitable population density is formed, thereby achieving the effects of ensuring stable green manure biomass and continuously inputting sufficient organic matter into the soil after being turned over; finally, after the mixed sowing green manure is turned over, it can not only supplement nitrogen, but also increase soil organic matter and improve aggregate structure, further consolidating the previous improvement effect, and realizing the continuous improvement of the fertility of newly reclaimed red soil dry land.

[0028] Preferably, in step S5, the soil bulk density after the rolling is maintained at 1.1-1.3g / cm³.

[0029] By adopting the technical scheme, after the 8-12cm shallow plowing operation in step S5, the rolling degree is precisely controlled by using a ring-shaped roller, so that the soil bulk density after rolling is maintained at 1.1-1.3g / cm³. This bulk density range is targeted to solve the problems of poor water retention due to over-loose or difficult aeration due to over-compaction of the surface layer of newly reclaimed red soil dry land: by maintaining this bulk density, it can not only avoid the problem of over-loose surface layer and large pore size leading to rapid evaporation of water and leaching of nutrients when the soil bulk density is lower than 1.1g / cm³, but also prevent the problem of soil compaction and insufficient pore size causing difficulty in root penetration and soil aeration and water retention when the soil bulk density is higher than 1.3g / cm³; at the same time, the appropriate bulk density can optimize the pore distribution between soil particles, balance the soil aeration and water retention, and provide a stable physical environment for the nutrient release of the biochar-based organic fertilizer and the colonization and reproduction of the compound microbial agent in step S4, and create conditions for water retention in the surface layer of the soil during the surface coverage and soil moisture preservation in step S6, forming a synergistic effect with the previous optimization of the soil layer structure, ensuring that the thick and fertile plough layer constructed has the characteristics of appropriate loose and tight from the deep layer to the surface layer, and further consolidating the physical structure improvement effect of the newly reclaimed red soil dry land, laying a foundation for the subsequent crop growth and soil fertility improvement.

[0030] Preferably, the method constitutes a yearly improvement cycle, steps S1 to S6 are completed in the spring of the first year after reclamation, step S7 of planting green manure is performed in the autumn of the same year, and after the green manure is ploughed in the spring of the next year, 20-30 days of fallow maintenance is performed, and then the normal cultivation period is entered.

[0031] By adopting the above technical scheme, through designing the improvement method as a specific time sequence yearly cycle, arranging each step implementation in combination with seasonal characteristics and soil improvement rules, the continuous consolidation and efficient transformation of the improvement effect of newly reclaimed red soil dry land are realized: through completing steps S1 to S6 in the spring of the first year after reclamation, at this time, the soil temperature rises and the soil moisture condition is suitable, which can not only make the soil compound conditioner effectively play the roles of acid reduction and aluminum toxicity passivation, but also complete the optimization of the plough layer and the synergistic fertilization by means of the spring cultivation window period, so as to create a soil environment with suitable physicochemical properties for subsequent green manure planting, thereby playing the roles of laying the foundation for improvement and building a framework for soil benign circulation, and then avoiding the problems of the conditioner effect being discounted due to the season being unsuitable or the plough layer structure being unstable; through planting green manure in step S7 in the autumn of the same year, the roles of making full use of the fall and winter idle period to cultivate soil organic matter sources and further improving the permeability of the plough layer through the root system of the green manure are played, and then the problem of land degradation after soil improvement due to idling is avoided; through 20-30 days of fallow maintenance after the green manure is ploughed in the spring of the next year, the spring temperature rise can accelerate the degradation and decomposition of the green manure straw, the fallow period can allow the soil microorganisms to have sufficient time to convert the nutrients in the green manure into soil nutrient reserves, and at the same time, the nutrient consumption and structure damage caused by cultivation immediately after ploughing are avoided, thereby playing the roles of allowing the improvement effect to be fully deposited and the soil land to be steadily improved, and then providing stable soil conditions for the growth of crops in the subsequent normal cultivation period; the whole yearly cycle orderly links the basic conditioning, biological fertilization and fallow maintenance, forms a closed loop of conditioning, fertilization and consolidation, avoids the short-term nature of single-season improvement, solves the problem of effect loss due to lack of continuous maintenance after improvement, and finally realizes the efficient transition of newly reclaimed red soil dry land from basic improvement to stable and available.

[0032] In summary, the present application has the following beneficial effects:

[0033] 1. The present application adopts a systematic improvement scheme from soil diagnosis, acid reduction, plough layer optimization, synergistic fertilization, to mulching and green manure ploughing-in, and since the scheme sequentially optimizes and synergistically intervenes in the limiting factors such as acid aluminum toxicity, nutrient deficiency and structure deficiency of newly reclaimed red soil dry land, the chemical environment, physical structure and biological activity of the soil are simultaneously and significantly improved in a short period of time, thereby obtaining a rapid, comprehensive and lasting soil fertilization and land improvement effect.

[0034] 2、The application preferably adopts a soil composite conditioner compounded by modified oyster shell powder, calcium-magnesium phosphate fertilizer, humic acid and polyglutamic acid. The porous alkaline characteristics of the modified oyster shell powder, the water-retaining chelation function of the polyglutamic acid and the activation ability of the humic acid are mutually synergistic, not only efficiently neutralizing soil acidity and passivating active aluminum, but also significantly enhancing the buffering performance and fertilizer retention capacity of the soil, thus obtaining a comprehensive improvement effect far exceeding the acid reduction of single lime.

[0035] 3、The method of the application, by implementing the two-stage deep plowing technology combining deep plowing and rotary tillage, and cooperating with subsequent shallow plowing and precise compacting, since the deep plowing effectively breaks the hard plow pan and the rotary tillage ensures the fineness of the plough layer soil, and the compacting regulates the appropriate soil tightness, thus jointly constructing an ideal plough layer structure of deep, loose and coordinated water and gas, creating an excellent soil physical environment for crop root growth and nutrient absorption. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a flow chart of a new rapid fertilization and improvement method for newly cultivated red soil dry land provided by the application. DETAILED DESCRIPTION

[0037] The application will be further described in detail below in combination with examples and comparative examples.

[0038] Technical concept:

[0039] The related technologies in the current new red soil dry land improvement field are mostly fragmented intervention, lack of synergy and missing cycle control. The core reason is that the complex limiting characteristics of new red soil acid aluminum toxicity, poor structure and nutrient deficiency have not been accurately matched. On the one hand, traditional improvement mostly adopts single measures, such as using only lime to reduce acid, or only applying organic fertilizer to supplement nutrients, ignoring the synergistic relationship between acid aluminum passivation and pH adjustment, and between plough layer optimization and nutrient supplementation, resulting in one-sided improvement effect, such as residual active aluminum after simply reducing acid, or nutrient leaching with water after loose plough layer; on the other hand, most technologies do not design time sequence schemes in combination with seasonal regularity and soil improvement rhythm, often resulting in disordered connection of improvement steps, such as structure rebound after plough layer optimization without timely soil conservation, or green manure planting and conditioner action period mismatch, unable to form a complete chain of conditioning, fertilization and consolidation, ultimately causing long improvement period and difficult to sustain effect.

[0040] The technical scheme is aimed at the above problems, from the technical means, through the whole process steps of soil diagnosis, compound conditioning, stage-by-stage plough layer optimization, synergistic fertilization, precision soil control, mulch soil conservation, and green manure, the multiple limiting factors are simultaneously broken, for example, the compound conditioner containing modified oyster shell powder and potassium silicate is used to simultaneously achieve pH adjustment and aluminum passivation; the two-stage operation of 30-40 cm deep loosening + 15-20 cm rotary tillage is adopted to give consideration to the breaking of plough pan and the fine fragmentation of surface layer; the compound microbial agent of round brown nitrogen-fixing bacteria and oxalic acid penicillium bacteria is used to realize the synergistic activation of nitrogen and phosphorus together with the biochar-based organic fertilizer. From the cycle design, the improvement is divided into the annual closed loop, the basic conditioning and structure optimization are completed in the spring of the first year, the biological fertilization is realized by planting mixed green manure in the autumn, the sedimentation effect is maintained in the spring of the second year, which not only utilizes the seasonal conditions to improve the efficiency of each step, but also avoids the improvement fault through the time sequence connection, and finally forms the efficient improvement mode of simultaneous improvement of chemical environment, physical structure and biological activity.

[0041] Preparation Example 1

[0042] The preparation method of the modified oyster shell powder is as follows:

[0043] Fresh oyster shells are taken, first washed with clean water to remove the mud and impurities attached to the surface, then put into a 60℃ oven to dry to constant weight, then crushed to particles with a particle size of 2-5mm with a jaw crusher; the crushed oyster shell particles are put into a muffle furnace, heated to 750℃ at a heating rate of 10℃ / min, and kept at this temperature for 4h, and the air in the furnace is kept flowing during the calcination process to ensure that the calcium carbonate in the oyster shell is fully decomposed; after the calcination is completed, the power of the muffle furnace is turned off, and the temperature in the furnace is naturally cooled to room temperature, and the calcined product is taken out and ground to a particle size of 100-200 mesh with a planetary ball mill to obtain a porous alkaline modified oyster shell powder with a pH value of 8.5-9.5 and a specific surface area ≥30m² / g.

[0044] Preparation Example 2

[0045] The preparation method of the biochar-based organic fertilizer is as follows:

[0046] Fresh livestock and poultry manure and crop straw are taken, the crop straw is cut into 3-5cm long with a straw cutter, then mixed uniformly according to the mass ratio of livestock and poultry manure to crop straw 3:2 to obtain mixed raw materials; the mixed raw materials are sent into a continuous pyrolysis furnace, first dried at 120℃ for 30min to remove free water, then heated to 600℃ at a heating rate of 5℃ / min, and nitrogen gas is introduced for anaerobic pyrolysis, and the temperature is kept for 1.5-2h; after the pyrolysis is completed, the heating is stopped and the nitrogen gas is continuously introduced until the pyrolysis product is cooled to room temperature, and the pyrolysis solid product is collected, and the particles with a particle size of 0.5-2mm are screened out with a vibrating screen, which is a biochar-based organic fertilizer with an organic matter content ≥60% and a pH value of 7.0-7.5.

[0047] Preparation Example 3

[0048] The preparation method of the degradable liquid mulch is as follows:

[0049] Take 8 parts of modified cellulose (sodium carboxymethyl cellulose), 5 parts of humic acid, 1 part of crosslinking agent (glutaraldehyde), and 90 parts of deionized water. First, add the deionized water into the stirring kettle, start stirring, the stirring speed is 200 r / min, slowly add the modified cellulose, stir while adding, stir for 30 min until the modified cellulose is completely dissolved; then add humic acid to the stirring kettle, continue to stir for 20 min until the humic acid is completely dispersed, the solution is uniform paste; finally, slowly add the crosslinking agent, after the addition is completed, increase the stirring speed to 300 r / min, continue to stir for 15 min, obtain a uniform and stable degradable liquid mulch, the viscosity is 500-800 mPa・s, after spraying, a porous network film can be formed on the ground within 1-2 h.

[0050] Preparation Example 4

[0051] The preparation method of the composite microbial agent suspension is as follows:

[0052] Prepare the Azotobacter chroococcum bacterial solution and Penicillium oxalicum bacterial solution respectively: inoculate Azotobacter chroococcum in LB liquid medium, and cultivate at 30℃ with 180 r / min shaking for 48 h to obtain Azotobacter chroococcum bacterial solution with a viable bacterial count of 8-10×10 9 CFU / mL; inoculate Penicillium oxalicum in potato glucose liquid medium, and cultivate at 28℃ with 150 r / min shaking for 72 h to obtain Penicillium oxalicum bacterial solution with a viable bacterial count of 8-10×10 9 CFU / mL; mix the Azotobacter chroococcum bacterial solution and the Penicillium oxalicum bacterial solution at a volume ratio of 1:1, add 5% sucrose solution as a protective agent, the volume ratio of the sucrose solution to the mixed bacterial solution is 1:10, after stirring uniformly, adjust the bacterial solution concentration with sterile water to make the total viable bacterial count not less than 5×10 9 CFU / mL, to obtain the composite microbial agent suspension.

[0053] The following are the main raw materials and reagents used in the preparation examples, examples and comparative examples, their sources and specifications are as follows; the reagents not specifically mentioned are all commercially available analytical grade and above grade products:

[0054] 1. Modified cellulose (sodium carboxymethyl cellulose) is purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., and the product code is S14016.

[0055] 2. Humic acid is purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., and the product code is S30583.

[0056] 3. Crosslinking agent (glutaraldehyde) was purchased from Fucheng (Tianjin) Chemical Reagent Co., Ltd., CAS: 111-30-8.

[0057] 4. Polyglutamic acid was purchased from Xi'an Virgin Biological Technology Co., Ltd., CAS: 84960-48-5.

[0058] 5. Potassium silicate was purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., Catalog No.: S24288.

[0059] Example 1

[0060] The embodiment of the present application provides a new rapid fertilization and improvement method for red soil dry land, which comprises the following steps:

[0061] S1, soil diagnosis and aluminum toxicity specific passivation: soil testing is performed, when the content of active aluminum in the soil is higher than 2.0 cmol / kg, potassium silicate is additionally added in the subsequent soil compound conditioner, and the amount of addition is 20 kg / hm²;

[0062] S2, soil compound conditioner for acid reduction: soil compound conditioner is applied to adjust the pH value of the soil to the range of 5.5-6.5;

[0063] The soil compound conditioner is composed of the following raw materials in parts by weight: modified oyster shell powder 60 parts, calcium magnesium phosphate 25 parts, humic acid 15 parts, and polyglutamic acid 7.5 parts.

[0064] S3, optimization of tillage layer structure: deep plowing and deep tillage are performed on the soil, the plowing depth is 20-40 cm, and a thick and fertile plowing layer is constructed;

[0065] The deep plowing and deep tillage are performed in two stages: the first stage adopts a deep plowing plow to perform a deep plowing operation with a depth of 35 cm to break the plow pan; the second stage adopts a rotary tiller to perform a rotary tillage operation with a depth of 17.5 cm to finely divide the soil.

[0066] S4, synergistic precision fertilization: biochar-based organic fertilizer and slow-release compound fertilizer are applied to the soil, and a composite microbial agent suspension is sprayed;

[0067] The application amount of the biochar-based organic fertilizer is 2.0 t / hm²; the application amount of the slow-release compound fertilizer is 70 kg / hm²; and the spraying amount of the composite microbial agent suspension is 12.5 L / hm²;

[0068] The nitrogen-fixing bacteria in the composite microbial agent suspension are Azotobacter chroococcum, the phosphorus-solubilizing bacteria are Penicillium oxalicum, and the total viable bacterial count of the microbial agent suspension is not less than 5×10 9 CFU / mL.

[0069] S5, soil moisture content regulation: shallow plowing operation with a depth of 8-12 cm is performed, and then ring-shaped presser is used for pressing.

[0070] wherein the bulk density of the soil after the tamping is maintained at 1.2 g / cm³.

[0071] S6, surface mulching to conserve soil moisture: using straw mulching to conserve soil moisture;

[0072] wherein the length of the straw is 7.5 cm, and the straw is pre-wetted with a compound microbial agent suspension before mulching, and the amount of the microbial agent suspension is 15% of the weight of the straw.

[0073] S7, planting and returning green manure: planting green manure crops and turning them into the soil during the flowering to early pod stage;

[0074] wherein the green manure crops are mixed sowing of legumes and grasses, the legume green manure is hairy vetch or arrow-shaped pea, and the grass green manure is blackgrass, and the weight ratio of the mixed sowing is 2:1, and the total sowing amount is 60 kg / hm².

[0075] wherein the above steps constitute a yearly improvement cycle, steps S1 to S6 are completed in the spring of the first year after reclamation, step S7 of planting green manure is performed in the autumn of the same year, and after the green manure is turned into the soil in the spring of the next year, the land is left fallow for 25 days, and then the normal cultivation period begins.

[0076] Example 2

[0077] The embodiment of the present application provides a rapid fertilization and improvement method for newly reclaimed red soil dry land, which comprises the following steps:

[0078] S1, soil diagnosis and specific passivation of aluminum toxicity: soil testing is performed, and when the content of active aluminum in the soil is higher than 2.0 cmol / kg, potassium silicate is additionally added in the subsequently applied soil compound conditioner, and the amount of the addition is 15 kg / hm²;

[0079] S2, soil compound conditioner for acid reduction: applying a soil compound conditioner to adjust the pH value of the soil to the range of 5.5-6.5;

[0080] wherein the soil compound conditioner is composed of the following raw materials in parts by weight: modified oyster shell powder 50 parts, calcium-magnesium phosphate fertilizer 20 parts, humic acid 10 parts, and polyglutamic acid 5 parts.

[0081] S3, optimization of tillage layer structure: deep plowing and deep tillage are performed on the soil to a depth of 20-40 cm to construct a thick and fertile tillage layer;

[0082] wherein the deep plowing and deep tillage are performed in two stages: the first stage uses a deep scarifier to perform a deep scarification operation to a depth of 30 cm to break the plough pan; and the second stage uses a rotary tiller to perform a rotary tillage operation to a depth of 15 cm to finely pulverize the soil.

[0083] S4, synergistic precision fertilization: applying biochar-based organic fertilizer and slow-release compound fertilizer to the soil, and spraying compound microbial agent suspension;

[0084] The application amount of the biochar-based organic fertilizer is 1.5 t / hm2; the application amount of the slow-release compound fertilizer is 60 kg / hm2; and the spraying amount of the compound microbial agent suspension is 10 L / hm2.

[0085] The nitrogen-fixing bacteria in the compound microbial agent suspension is Azotobacter chroococcum, and the phosphorus-solubilizing bacteria is Penicillium oxalicum, and the total viable bacterial count of the microbial agent suspension is not less than 5x10 9 CFU / mL.

[0086] S5, soil moisture regulation: performing shallow plowing with a depth of 8-12 cm, and then using a ring-shaped roller to compact the soil;

[0087] The soil bulk density after compaction is maintained at 1.1 g / cm3.

[0088] S6, surface mulching to conserve soil moisture: using the method of spraying degradable liquid mulch to conserve water and soil moisture;

[0089] The liquid mulch is composed of modified cellulose, humic acid and crosslinking agent dissolved in water, and forms a porous network film on the surface after spraying, with a dosage of 80 kg / hm2.

[0090] S7, planting and returning green manure: planting green manure crops and turning them into the soil during the flowering to early pod stage;

[0091] The green manure crops are mixed sowing of legumes and grasses, the legume green manure is hairy vetch or arrow-shaped pea, and the grass green manure is ryegrass, with a weight ratio of 2:1, and the total sowing amount is 45 kg / hm2.

[0092] The above steps constitute a yearly improvement cycle, steps S1 to S6 are completed in the spring of the first year after reclamation, step S7 of planting green manure is performed in the autumn of the same year, and after the green manure is turned into the soil in the spring of the next year, the land is left fallow for 20 days, and then enters the normal cultivation period.

[0093] Example 3

[0094] The embodiment of the present application provides a new reclamation red soil dry land rapid fertilization and improvement method, which comprises the following steps:

[0095] S1, soil diagnosis and aluminum toxicity specific passivation: soil testing is performed, when the soil active aluminum content is higher than 2.0 cmol / kg, potassium silicate is additionally added in the subsequently applied soil compound conditioner, and the addition amount is 25 kg / hm2;

[0096] S2, soil complex conditioning and acid reduction: applying soil complex conditioner to adjust the soil pH value to the range of 5.5-6.5;

[0097] The soil complex conditioner is composed of the following raw materials in parts by weight: modified oyster shell powder 70 parts, calcium-magnesium phosphate 30 parts, humic acid 20 parts, and polyglutamic acid 10 parts.

[0098] S3, optimization of plough layer structure: deep ploughing and deep tillage of the soil to a depth of 20-40 cm to build a thick and fertile plough layer;

[0099] The deep ploughing and deep tillage is carried out in two stages: the first stage uses a deep scarifier to perform a deep scarification operation with a depth of 40 cm to break the plough pan; the second stage uses a rotary cultivator to perform a rotary tillage operation with a depth of 20 cm to finely break up the soil.

[0100] S4, synergistic precision fertilization: applying biochar-based organic fertilizer and slow-release compound fertilizer to the soil, and spraying a complex microbial agent suspension;

[0101] The biochar-based organic fertilizer is applied at a rate of 2.5 t / hm²; the slow-release compound fertilizer is applied at a rate of 80 kg / hm²; the complex microbial agent suspension is sprayed at a rate of 15 L / hm²; the nitrogen-fixing bacteria in the complex microbial agent suspension are Azotobacter chroococcum, the phosphorus-solubilizing bacteria are Penicillium oxalicum, and the total viable bacterial count of the microbial agent suspension is not less than 5 x 10 9 CFU / mL.

[0102] S5, soil moisture content regulation: performing a shallow ploughing operation with a depth of 8-12 cm, followed by using a ring-shaped roller to compact the soil;

[0103] The soil bulk density after compaction is maintained at 1.3 g / cm³.

[0104] S6, surface mulching to conserve soil moisture: using straw mulching to conserve soil moisture;

[0105] The length of the straw is 10 cm, and the straw is pre-wetted with a complex microbial agent suspension before mulching, with the amount of the microbial agent suspension being 20% of the weight of the straw.

[0106] S7, planting and returning green manure: planting green manure crops and turning them into the soil during the flowering to early pod stage;

[0107] The green manure crops are mixed sowing of legumes and grasses, the legume green manure is hairy vetch or arrow-shaped pea, the grass green manure is ryegrass, the mixed sowing weight ratio is 2:1, and the total sowing amount is 75 kg / hm².

[0108] Wherein, the above steps constitute a one-year improvement cycle, steps S1 to S6 are completed in the spring of the first year after reclamation, step S7 is performed in the autumn of the same year, and the green manure is planted, and after the green manure is turned in the spring of the next year, it is followed by 30 days of fallow maintenance, and then enters the normal cultivation period.

[0109] Example 4

[0110] The difference between this example and Example 1 is only that in step S6, the length of the straw is 5 cm, and a composite microbial agent suspension is used for pre-wetting treatment before covering, and the amount of the microbial agent suspension is 10% of the weight of the straw.

[0111] Example 5

[0112] The difference between this example and Example 2 is only that the liquid mulch is composed of modified cellulose, humic acid and crosslinking agent dissolved in water, and forms a porous network mulch on the ground surface after spraying, and the amount is 100 kg / hm².

[0113] Example 6

[0114] The difference between this example and Example 2 is only that the liquid mulch is composed of modified cellulose, humic acid and crosslinking agent dissolved in water, and forms a porous network mulch on the ground surface after spraying, and the amount is 120 kg / hm².

[0115] Comparative Example 1

[0116] The difference between this comparative example and Example 1 is only that in step S2, an equal weight of ordinary agricultural lime is used to replace the modified oyster shell powder in the soil composite conditioner, and the remaining steps and parameters are exactly the same as in Example 1.

[0117] Comparative Example 2

[0118] The difference between this comparative example and Example 1 is only that in step S4, an equal amount of ordinary commercial organic fertilizer is used to replace the biochar-based organic fertilizer, and the remaining steps and parameters are exactly the same as in Example 1.

[0119] Comparative Example 3

[0120] The difference between this comparative example and Example 1 is only that in step S2, polyglutamic acid is not added to the composition of the soil composite conditioner, and the remaining steps and parameters are exactly the same as in Example 1.

[0121] Comparative Example 4

[0122] The difference between this comparative example and Example 1 is only that in step S4, an equal number of Bacillus megaterium is used to replace the phosphorus-solubilizing Paecilomyces variotii in the composite microbial agent suspension, and the remaining steps and parameters are exactly the same as in Example 1.

[0123] Comparative Example 5

[0124] The difference between the present comparative example and Example 1 is only that when the soil active aluminum content is higher than 2.0 cmol / kg, no additional potassium silicate is added in the subsequent application of the soil complex conditioner, and the remaining steps and parameters are exactly the same as those in Example 1.

[0125] Comparative Example 6

[0126] The difference between the present comparative example and Example 1 is only that in step S6, when straw mulching is selected, the straw is directly mulched without pre-wetting treatment by the complex microbial agent suspension, and the remaining steps and parameters are exactly the same as those in Example 1.

[0127] I. Test of basic physicochemical properties of soil

[0128] After the end of the annual improvement cycle, the 0-20 cm plough layer soil samples of the improved soil corresponding to Examples 1-6 and Comparative Examples 1-6 were collected by five-point sampling method, each treatment was repeated three times, the soil samples of each treatment were mixed, and the stones and plant residues were removed, then the mixture was naturally dried and ground through a 2 mm sieve for use; the pH value of the soil was determined by potential method, 10 g of sieved soil sample was added into 25 mL of carbon dioxide-free distilled water, oscillated for 30 min, and then stood for 30 min, and the pH value of the supernatant was measured by using a calibrated pH meter; the active aluminum content of the soil was determined by oxalic acid-ammonium oxalate extraction method, 5 g of sieved soil sample was added into 50 mL of 0.2 mol / L oxalic acid and 0.1 mol / L ammonium oxalate mixed extraction solution, oscillated for 2 h at 25°C, and then filtered, and the active aluminum concentration in the filtrate was determined by inductively coupled plasma emission spectrometer; the organic matter content of the soil was determined by potassium dichromate oxidation-external heating method, 0.5 g of sieved soil sample was added into 5 mL of 0.8 mol / L potassium dichromate solution and 5 mL of concentrated sulfuric acid, heated in a 180-190°C oil bath for 5 min, cooled, added with 200 mL of distilled water and 3 drops of phenanthroline indicator, titrated with 0.2 mol / L ferrous sulfate solution until the solution changed from orange red to brick red, and the volume of consumed ferrous sulfate solution was recorded and the organic matter content was calculated; finally, the soil pH value, active aluminum content and organic matter content of each example and comparative example were calculated and recorded respectively.

[0129] II. Test of soil available nutrient content

[0130] The sampling time and sampling method of the improved soil corresponding to Examples 1-6 and Comparative Examples 1-6 are the same as the soil basic physicochemical property test, and the 0-20 cm plough layer soil sample is collected after the end of the annual improvement cycle, five-point sampling method, three times for each treatment, natural air drying through 2 mm sieve; wherein the soil available nitrogen content is determined by alkali diffusion method, 2 g of sieved soil sample is placed in the diffusion dish, 10 mL of 1.0 mol / L sodium hydroxide solution is added to the outer chamber, the dish cover is covered and sealed at the gap with vaseline, and then placed in a 40℃ constant temperature box for 24 h, then titrate the inner chamber boric acid absorbent with 0.01 mol / L sulfuric acid standard solution, and calculate the available nitrogen content according to the volume of sulfuric acid consumed; the soil available phosphorus content is determined by Olsen method, 5 g of sieved soil sample is added to 50 mL of 0.5 mol / L sodium bicarbonate solution, and then oscillated at 25℃ for 30 min, then filtered, and then the filtrate is added to molybdenum antimony anti-color developing agent, and then placed for 30 min, then the absorbance is measured by spectrophotometer at 700 nm wavelength, and then the available phosphorus content is calculated by standard curve; the soil available potassium content is determined by ammonium acetate extraction-flame photometry method, 5 g of sieved soil sample is added to 50 mL of 1.0 mol / L ammonium acetate solution, and then oscillated for 30 min, then filtered, and then the potassium ion concentration in the filtrate is measured by flame photometry and the available potassium content is calculated; finally, the soil available nitrogen, available phosphorus and available potassium contents of each example and comparative example are recorded respectively.

[0131] III. Plough layer structure and water retention performance test

[0132] The sampling time of the improved soil corresponding to Examples 1-6 and Comparative Examples 1-6 is after the end of the annual improvement cycle, and the 0-20 cm plough layer soil is collected by the cutting ring method, three times for each treatment, the cutting ring volume is 100 cm³, which is used to determine the soil bulk density and total porosity; wherein the soil bulk density is directly calculated by the dry soil mass in the cutting ring and the cutting ring volume, specifically: the cutting ring soil sample is dried in a 105℃ oven to constant weight, the dry soil mass is weighed, and the bulk density = dry soil mass / cutting ring volume; the total porosity of the soil is calculated according to the bulk density and the soil specific gravity, wherein the specific gravity of red soil is 2.65 g / cm³, and the total porosity = (1-bulk density of soil / specific gravity of soil) x 100%; the soil field water capacity is determined by the cutting ring soaking method, the fresh soil cutting ring with the above cutting ring sample is placed in a water container, the water surface is 1-2 mm lower than the upper edge of the cutting ring, and after soaking for 24 h, the excess water at the bottom of the cutting ring is drained, the wet soil mass is weighed, and then the soil sample is dried to constant weight; wherein the field water capacity = (wet soil mass after soaking-dry soil mass) / dry soil mass x 100%; finally, the soil bulk density, total porosity and field water capacity of each example and comparative example are calculated and recorded respectively.

[0133] The soil basic physicochemical property test data are shown in Table 1.

[0134] Table 1:

[0135] Treatment No. Soil pH value Soil active aluminum content (cmol / kg) Soil organic matter content (g / kg) Example 1 6.0±0.12 0.85±0.07 22.5±0.86 Example 2 5.8±0.10 0.92±0.09 20.3±0.75 Example 3 6.2±0.15 0.78±0.06 24.1±0.92 Example 4 6.0±0.11 0.87±0.08 22.1±0.81 Example 5 5.9±0.13 0.90±0.08 20.7±0.78 Example 6 5.9±0.12 0.89±0.07 21.0±0.80 Comparative Example 1 5.7±0.14 1.12±0.10 19.8±0.72 Comparative Example 2 5.9±0.11 0.88±0.07 18.6±0.69 Comparative Example 3 5.6±0.13 0.95±0.09 21.8±0.83 Comparative Example 4 6.0±0.12 0.86±0.08 22.3±0.85 Comparative Example 5 5.9±0.10 1.52±0.12 22.4±0.84 Comparative Example 6 6.0±0.11 0.87±0.07 21.9±0.82

[0136] The soil available nutrient content test data are shown in Table 2.

[0137] Table 2:

[0138] Treatment No. Soil available nitrogen content (mg / kg) Soil available phosphorus content (mg / kg) Soil available potassium content (mg / kg) Example 1 125.3±4.26 18.6±0.95 112.5±3.87 Example 2 112.7±3.98 16.3±0.82 101.2±3.54 Example 3 132.5±4.51 20.1±1.02 120.8±4.12 Example 4 123.1±4.15 18.3±0.92 110.7±3.76 Example 5 115.2±4.03 16.8±0.85 103.5±3.61 Example 6 116.8±4.09 17.1±0.88 105.3±3.68 Comparative Example 1 108.5±3.82 14.5±0.76 98.6±3.42 Comparative Example 2 95.2±3.57 15.2±0.80 92.3±3.28 Comparative Example 3 118.6±4.01 17.2±0.89 108.4±3.65 Comparative Example 4 124.8±4.21 15.8±0.83 111.9±3.82 Comparative Example 5 123.7±4.18 18.4±0.93 112.1±3.85 Comparative Example 6 122.5±4.12 18.2±0.91 109.5±3.71

[0139] The plough layer structure and water retention performance test data are shown in Table 3.

[0140] Table 3:

[0141] Treatment No. Soil bulk density (g / cm3) Soil total porosity (%) Soil field capacity (%) Example 1 1.20±0.03 54.7±1.12 28.5±0.95 Example 2 1.10±0.02 58.5±1.25 30.2±1.08 Example 3 1.30±0.04 51.0±1.05 26.8±0.87 Example 4 1.21±0.03 54.3±1.10 28.1±0.92 Example 5 1.12±0.02 57.7±1.20 29.8±1.05 Example 6 1.11±0.02 58.1±1.22 29.5±1.03 Comparative Example 1 1.28±0.04 51.7±1.08 27.1±0.89 Comparative Example 2 1.23±0.03 53.6±1.09 27.8±0.91 Comparative Example 3 1.25±0.03 52.8±1.07 27.5±0.90 Comparative Example 4 1.20±0.03 54.7±1.12 28.3±0.93 Comparative Example 5 1.20±0.03 54.7±1.11 28.4±0.94 Comparative Example 6 1.24±0.03 53.2±1.08 27.2±0.88

[0142] Note: The formula for calculating the total porosity of the soil is (1-soil bulk density / soil specific gravity) x 100%, wherein the specific gravity of red soil is taken as 2.65 g / cm3.

[0143] It can be seen from Examples 1-6 and Comparative Example 1 in combination with Tables 1, 2 and 3 that replacing the modified oyster shell powder in the soil compound conditioner with ordinary agricultural lime will affect the pH adjustment effect, active aluminum passivation ability, organic matter accumulation efficiency and available nutrient supply level of the soil, and will also indirectly affect the stability of the plough layer structure and water retention performance, because the modified oyster shell powder is a porous alkaline material formed by calcination at a specific temperature, and its porous structure not only can more gently and durably adjust the soil pH, but also can adsorb active aluminum ions in the soil to achieve specific passivation, and at the same time provides a carrier environment for the accumulation of organic matter, while the alkaline adjustment effect of ordinary agricultural lime is relatively single, lacking the adsorption and carrier functions brought by the porous structure, thereby affecting the subsequent maintenance of soil available nutrients and the improvement of plough layer water retention performance.

[0144] It can be seen from Examples 1-6 and Comparative Example 2 in combination with Tables 1, 2 and 3 that replacing the biochar-based organic fertilizer with ordinary commercial organic fertilizer will affect the accumulation of soil organic matter, the supply capacity of available nitrogen, phosphorus and potassium, and the bulk density and field water holding capacity of the plough layer, because the biochar-based organic fertilizer is prepared by co-pyrolysis of livestock and poultry manure and crop straw at a specific temperature, and the biochar component contained therein has a rich pore structure and high stability, which can not only adsorb and slowly release nutrients to reduce nutrient loss, but also improve soil particle structure, reduce bulk density and improve water retention capacity, while the nutrient release speed of ordinary commercial organic fertilizer is relatively fast, lacking the stable adsorption and structure improvement functions of biochar, resulting in differences in soil organic matter accumulation efficiency and plough layer water and fertilizer retention performance.

[0145] It can be seen from Examples 1-6 and Comparative Example 3 in combination with Tables 1, 2 and 3 that the addition of polyglutamic acid in the soil compound conditioner can affect the stability of soil pH, the accumulation rate of organic matter and the retention capacity of available nutrients, and also indirectly affect the water retention performance of the plough layer, because polyglutamic acid has strong water absorption and retention capacity and nutrient chelation capacity, and can form a synergistic effect with modified oyster shell powder, humic acid and other components in the conditioner, helping to maintain the stability of soil pH, reducing the rapid loss of alkaline substances, chelating nutrient ions in the soil to reduce nutrient leaching, and promoting microbial activity to accelerate organic matter accumulation. Without the addition of polyglutamic acid, the synergistic effect is broken, thereby affecting the overall physicochemical properties of the soil and the water retention effect of the plough layer.

[0146] It can be seen from Examples 1-6 and Comparative Example 4 in combination with Tables 1, 2 and 3 that replacing oxalic acid penicillium in the compound microbial agent suspension with bacillus megaterium as a phosphorus solubilizing bacterium can mainly affect the release efficiency of available phosphorus in the soil, and may also indirectly affect the supply of available nitrogen and potassium, because different types of phosphorus solubilizing bacteria have different phosphorus solubilizing mechanisms and adaptability. Oxalic acid penicillium can more efficiently decompose insoluble phosphorus compounds in the soil and convert them into available phosphorus for crops in the acidic improvement environment of red soil upland, and its metabolic activity can also form a synergistic effect with nitrogen-fixing bacteria to promote nitrogen fixation and utilization. However, bacillus megaterium has different phosphorus solubilizing efficiency and synergistic nitrogen fixation capacity in this specific improvement system, thereby affecting the overall supply level of available nutrients in the soil.

[0147] It can be seen from Examples 1-6 and Comparative Example 5 in combination with Tables 1, 2 and 3 that when the content of active aluminum in the soil is higher than the set value, additional addition of potassium silicate can significantly affect the passivation effect of active aluminum in the soil, and also indirectly affect the stability of soil pH and the supply environment of available nutrients, because potassium silicate can react with active aluminum ions in the soil to form stable compounds that are non-toxic to crops, thereby reducing the inhibitory effect of active aluminum on soil microbial activity and nutrient absorption by crop roots, and maintaining the soil pH within a suitable range. Without the addition of potassium silicate, this specific aluminum toxicity passivation cannot be achieved, resulting in a high content of active aluminum in the soil, thereby affecting the normal metabolism of soil microorganisms and the effective transformation of nutrients, and indirectly affecting the stability of the plough layer performance.

[0148] It can be seen from the combination of embodiments 1-6 and comparative example 6 and in combination with Tables 1, 2 and 3 that, when the straw is covered without pre-wetting treatment of the compound microbial agent suspension, the degradation efficiency of the straw is affected, and in turn the accumulation speed of soil organic matter and the water retention performance of the ground surface are affected. This is because the microorganisms in the compound microbial agent suspension can accelerate the decomposition process of the straw, so that the organic matter in the straw is more quickly converted into soil organic matter. Meanwhile, the pre-wetting treatment enables the straw to be more closely attached to the ground surface, enhancing the barrier effect on soil water evaporation. Without pre-wetting treatment, the degradation speed of the straw is slowed down, leading to a decrease in the accumulation efficiency of organic matter. Meanwhile, the degree of attachment of the straw to the ground surface is reduced, which cannot effectively play the role of evaporation barrier, and in turn affects the water retention capacity of the soil and the supply level of organic matter.

[0149] The specific embodiments are merely illustrative of the present application, and are not intended to limit the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for rapid fertilization and improvement of newly reclaimed red soil dryland, characterized in that: The method is achieved by applying specific fertilizer compositions, including soil composite conditioner, biochar-based organic fertilizer, slow-release compound fertilizer and composite microbial inoculant; the method comprises the following steps: S1, soil diagnosis and specific passivation of aluminum toxicity: soil testing is performed, and when the content of active aluminum in the soil is higher than 2.0 cmol / kg, potassium silicate is additionally added in the subsequently applied soil composite conditioner, and the amount of addition is 15-25 kg / hm2; S2, soil composite conditioning and acid reduction: the soil composite conditioner is applied to adjust the pH value of the soil to the range of 5.5-6.5; S3, optimization of plough layer structure: deep plowing and deep tillage are performed on the soil, and the plowing depth is 20-40 cm, so as to construct thick and fertile plough layer; S4, synergistic precision fertilization: biochar-based organic fertilizer and slow-release compound fertilizer are applied to the soil, and composite microbial inoculant suspension is sprayed; S5, soil moisture condition regulation: shallow tillage with a depth of 8-12 cm is performed, and then ring-shaped roller is used for compaction; S6, surface mulching for soil moisture conservation: straw mulching or spraying of degradable liquid mulch film is used for water and soil conservation; S7, green manure planting and returning: green manure crops are planted and returned to the soil during the flowering stage to the initial pod stage.

2. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: In step S2, the soil composite conditioner is composed of the following raw materials in parts by weight: modified oyster shell powder 50-70 parts, calcium-magnesium phosphate fertilizer 20-30 parts, humic acid 10-20 parts, and polyglutamic acid 5-10 parts; the modified oyster shell powder is a porous alkaline material obtained by calcining at 650-750°C for 2-4h.

3. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: In step S3, the deep plowing and deep tillage is performed in two stages: the first stage uses a deep scarifier to perform deep scarification with a depth of 30-40 cm to break the plough pan; the second stage uses a rotary tiller to perform rotary tillage with a depth of 15-20 cm to finely pulverize the soil.

4. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: In step S4, the application amount of the biochar-based organic fertilizer is 1.5-2.5 t / hm2; the application amount of the slow-release compound fertilizer is 60-80 kg / hm2; and the spraying amount of the composite microbial inoculant suspension is 10-15 L / hm2.

5. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 4, characterized in that: The azotobacter in the complex microbial agent suspension is azotobacter chroococcum, the phosphorus solubilizing bacteria is penicillium oxalicum, and the total number of viable bacteria in the microbial agent suspension is not less than 5×10 9 CFU / mL.

6. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: In step S6, when degradable liquid mulch film is selected for mulching, the liquid mulch film is composed of modified cellulose, humic acid and crosslinking agent dissolved in water, and a porous network film is formed on the surface after spraying, with a dosage of 80-120 kg / hm2.

7. The method for rapid fertilization and improvement of new red soil dry land according to claim 1, characterized in that: In step S6, when straw mulching is selected, the length of the straw is 5-10 cm, and the straw is pre-wetted with the composite microbial inoculant suspension before mulching, and the dosage of the inoculant suspension is 10%-20% of the weight of the straw.

8. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: In step S7, the green manure crops are mixed sowing of legumes and grasses, the legume green manure is hairy vetch or arrow-shaped pea, and the grass green manure is blackgrass, with a weight ratio of 2:1, and the total sowing amount is 45-75 kg / hm2.

9. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: In step S5, the soil bulk density after compaction is maintained at 1.1-1.3 g / cm3.

10. The method for rapid fertilization and improvement of new reclaimed red soil dry land according to claim 1, characterized in that: The method constitutes a one-year improvement cycle, wherein steps S1-S6 are completed in spring of the first year after reclamation, step S7 is performed in autumn of the same year, and the green manure is planted, and then the land is fallowed for 20-30 days after the green manure is ploughed under in spring of the next year, and then the normal ploughing period is entered.

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