Search

CN-122010638-A - Coastal saline-alkali soil crop growth promoting modifier with pH response release characteristic, and preparation method and application thereof

CN122010638ACN 122010638 ACN122010638 ACN 122010638ACN-122010638-A

Abstract

The invention belongs to the technical field of saline-alkali soil improvement, and particularly relates to an intelligent pH response controlled release crop growth-promoting soil improver for coastal saline-alkali soil and a preparation method and application thereof. The modifier is a biochar-based composite microsphere, the inner core is formed by compounding biochar, silicon quantum dots and nitrogen, phosphorus and potassium compound fertilizer, and the outer layer is coated with a pH response coating formed by chitosan, so that an environment sensing-release regulation-accurate fertilizer supply integrated system is constructed. After the soil is applied, the coating layer swells under the rhizosphere micro-domain acidic condition, so that the nutrient diffusion is intelligently regulated, and the leaching loss and volatilization are reduced. The porous structure of biochar adsorbs and fixes salt ions, improves the agglomeration body and ventilation water permeability, enhances water retention and fertilizer retention, the silicon quantum dots promote photosynthetic efficiency and enhance oxidation resistance, and the compound fertilizer is continuously supplied with nitrogen, phosphorus and potassium. The components synergistically improve the soil microstructure and water-salt migration, relieve salt ion toxicity, improve nutrient utilization and crop salt tolerance, promote yield increase and stable yield, and are suitable for saline-alkali soil restoration.

Inventors

  • LUO XIANXIANG
  • ZHENG HAO
  • WANG TIANWEN
  • LI FENGMIN
  • Li Peichong
  • LIU QIANG

Assignees

  • 中国海洋大学

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. The littoral saline-alkali soil crop growth promoting modifier with pH response release characteristic is characterized in that the soil modifier is a biochar-based microsphere formed by combining biochar, silicon quantum dots and nitrogen-phosphorus-potassium compound fertilizer, and the biochar-based composite microsphere is prepared from alginate and nitrogen-phosphorus-potassium compound fertilizer And the pH response coating layer swells or contracts under different pH conditions, so that the release rate of nutrients in the microsphere is regulated.
  2. 2. The littoral saline-alkali soil crop growth promoting modifier with pH response release characteristics as claimed in claim 1, wherein: the fertilizer comprises, by weight, 100-300 parts of biochar, 1-10 parts of silicon quantum dots and 1-10 parts of nitrogen-phosphorus-potassium compound fertilizer.
  3. 3. The littoral saline-alkali soil crop growth promoting modifier with pH response release characteristics as claimed in claim 1, wherein: The particle size of the silicon quantum dot is 2-4 nm, and the particle size of the biochar-based microsphere is 3-5 mm.
  4. 4. The littoral saline-alkali soil crop growth promoting modifier with pH response release characteristics as claimed in claim 1, wherein: the molar ratio of the nitrogen, phosphorus and potassium compound fertilizer is N:P:K=17:16:19.
  5. 5. The method for preparing the littoral saline-alkali soil crop growth-promoting modifier with pH response release characteristics according to any one of claims 1 to 4, which is characterized in that the preparation step comprises, (1) Preparation of biochar Corn straw is used as a raw material, and is prepared by adopting an anaerobic slow pyrolysis method; (2) Preparation of silicon Quantum dots Preparing silicon quantum dots by using ascorbic acid and N- [3- (trimethoxysilyl) propyl ] ethylenediamine; (3) Preparation of biochar-based microspheres Fully stirring and uniformly mixing biochar, silicon quantum dots and nitrogen, phosphorus and potassium compound fertilizer according to a proportion, adding the mixture into sodium alginate solution, performing ultrasonic dispersion to form mixed solution, dripping the mixed solution into CaCl 2 solution, crosslinking alginate and Ca 2+ to form biochar-based microspheres, and naturally air-drying to constant weight; (4) Preparation of chitosan coating And dissolving the chitosan solution in acetic acid solution, adding the air-dried biochar-based microspheres into the chitosan solution, and forming a coating layer on the surfaces of the microspheres by using chitosan to obtain the soil conditioner microspheres with pH response release characteristics.
  6. 6. The method for preparing the littoral saline-alkali soil crop growth-promoting modifier with pH response release characteristics according to claim 5, which is characterized in that: the specific steps of the (1) comprise: Drying corn stalk in oven to constant weight, pulverizing to powder, sieving with 2mm standard sieve, weighing pretreated waste biomass material, placing in tubular furnace, introducing nitrogen gas, discharging air, heating to 500 deg.C, maintaining at 3h, naturally cooling to room temperature under nitrogen protection after pyrolysis, air drying, pulverizing, and sieving with 1mm sieve.
  7. 7. The method for preparing the littoral saline-alkali soil crop growth-promoting modifier with pH response release characteristics according to claim 5, which is characterized in that: The specific steps of the (2) comprise: Weighing 2.3 g ascorbic acid, dissolving in 8 mL ultrapure water, adding 2mL N- [3- (trimethoxysilyl) propyl ] ethylenediamine, heating and stirring at 80 ℃ for 8h, transferring the solution into a dialysis bag of 1000 Da, and dialyzing in the ultrapure water for 48 h, wherein the water phase solution collected is the silicon quantum dots.
  8. 8. The method for preparing the littoral saline-alkali soil crop growth-promoting modifier with pH response release characteristics according to claim 5, which is characterized in that: In the step (3), the mass fraction of the sodium alginate solution is 2% -5%, the mass fraction of the CaCl 2 solution is 2%, and 1-3 mL of the sodium alginate solution is added into each gram of uniformly mixed solid mixture of biochar, silicon quantum dots and nitrogen-phosphorus-potassium compound fertilizer; in the step (4), the mass fraction of the chitosan solution is 1% -5%, and the concentration of the acetic acid solution is 20%.
  9. 9. The method for preparing the littoral saline-alkali soil crop growth-promoting modifier with pH response release characteristics according to claim 6, which is characterized in that: In the step (1), the drying temperature is 95 ℃, the nitrogen gas introducing rate is 500 mL min -1 , the time is 20 min, and the heating rate is 5 ℃ min -1 .
  10. 10. The use of the littoral saline-alkali soil crop growth promoting modifier with pH response release characteristics according to any one of claims 1 to 4, wherein the soil modifier is used for improving saline-alkali soil and promoting plant growth.

Description

Coastal saline-alkali soil crop growth promoting modifier with pH response release characteristic, and preparation method and application thereof Technical Field The invention belongs to the technical field of saline-alkali soil improvement, and particularly relates to a coastal saline-alkali soil crop growth-promoting modifier with pH response release characteristics, and a preparation method and application thereof. Background Soil salinization is one of important obstacles restricting the sustainable development of global agriculture, particularly in coastal areas, the high-salinity environment leads to the weakness of the soil ecosystem, and seriously threatens the growth of crops and the grain safety. The coastal saline-alkali soil has the problems of poor water holding capacity, deficient organic matters, high salt content and the like. The high-salt environment obviously inhibits the growth and development of plants through mechanisms such as osmotic stress, ion poisoning, nutrient imbalance, oxidative damage, inhibition of cell division, metabolic activity and the like, so that the yield and quality of crops are reduced, and the ecological safety and the agricultural development of a region are further affected. Therefore, the development of the high-efficiency and environment-friendly coastal saline-alkali soil improvement technology has important significance. Currently, saline-alkali soil improvement mainly depends on physical, chemical and biological methods, such as soil replacement, leaching desalination, application of an improver or planting of salt-tolerant crops and the like. Although the traditional methods can partially relieve salt damage of soil, the problems of long improvement period, higher cost, complex operation, possibility of secondary pollution and the like generally exist. In recent years, the research and development of functional soil amendments become a new direction of saline-alkali soil treatment, and the core of the functional soil amendments is that the synergistic effect of soil structure optimization, salinity regulation and plant growth promotion is realized through material innovation. However, existing improvers still have the following significant limitations: 1. the functions are single, the synergy is insufficient, common materials are designed aiming at a certain problem of saline-alkali soil, and system integration is lacked. For example, biochar can improve soil structure and raise water holding capacity, but has limited selective adsorption capacity for salt ions and weak direct raising effect on plant physiological resistance, silicon quantum dots (Si-QDs) can enhance plant oxidation resistance and photosynthetic efficiency, but the improvement effect on soil physicochemical property is not obvious, and conventional compound fertilizer can supplement nutrients, but has low utilization rate due to leaching or fixation in saline-alkali soil. These materials are used alone or simply compounded, and it is difficult to synchronously realize the multi-objective synergistic effect of soil improvement, stress relief and growth promotion. 2. The coastal saline-alkali soil has the unique environment of high salt and high pH, and most of the modifying agents have poor stability and easily attenuated functions under the condition, or cannot realize intelligent response according to the change of soil environment. For example, common fertilizers or active ingredients are released too quickly in alkaline soil and are easy to run off or lose efficacy, the adsorption function of biochar is possibly weakened under alkaline conditions, and the traditional embedding materials lack of pH responsiveness, so that the release of nutrients on demand is difficult to realize, and the improvement effect is not durable and the pertinence is not strong. Therefore, developing a novel composite material which can adapt to the coastal saline-alkali soil environment, improve the integrated structure, regulate and control the salinity, intelligently release the nutrients, promote the plant resistance and other multiple functions into a whole becomes a key technical problem to be broken through in the field. Biochar is widely used for soil improvement due to the porous structure, high specific surface area and rich surface functional groups, and can effectively improve the water holding capacity of saline-alkali soil, adsorb salt ions and promote microbial activity. As a novel nano material, the silicon quantum dots (Si-QDs) have excellent biocompatibility and light modulation and control characteristics, and can relieve salt stress by enhancing the antioxidant capacity and photosynthetic efficiency of plants. Compared with other nano particles, the nano particles have smaller volume, better water solubility and stability and good biocompatibility, so that the nano particles can enter plant tissues better, influence physiological activities of plants, and show good application prospects in t