Aqueous triggered controlled-release saline-alkali soil conditioner and preparation method therefor

Abstract

Disclosed in the present invention are an aqueous triggered controlled-release saline-alkali soil conditioner and a preparation method therefor. The aqueous triggered controlled-release saline-alkali soil conditioner comprises agent A. The agent A comprises a water-soluble polymer and controlled-release suspended particles. The controlled-release suspended particles comprise alginate / anti-reverse regulator composite particulates. The alginate / anti-reverse regulator composite particulates are obtained by sequentially subjecting an alginate to two-step gel cross-linking by means of a cationic anti-reverse regulator and a high-valent metal ion-containing cross-linking agent. In the present invention, the alginate used as a main material is subjected to charged regulator-based high-speed dispersion for primary gelation and high-valent metal-based secondary gelation, thereby preparing a micron-nano powder and suspension, and incorporating a solvable organic polymer material, the functions of graded release and intelligent regulation of a product are achieved. The incorporation of an organic acid and a phosphoric acid material can not only prevent a micro-irrigation device from scaling but can also achieve triggered controlled-release of the material on demand and in a timely manner, thereby achieving the effects of multi-particle-size dispersion and precise release of the product in soil.

Description

Aqueous trigger-controlled release saline-alkali soil improver and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the field of agricultural planting, and particularly relates to an aqueous trigger-controlled release saline-alkali soil improver and a preparation method thereof. BACKGROUND

[0002] Saline-alkali soil is a common term for saline soil and alkaline soil. Soil containing more than 0.2% salt or soil colloids adsorbing a certain amount of exchangeable sodium, with an alkalization degree of more than 15%-20%, is harmful to the normal growth of crops and belongs to the saline-alkali soil type. Saline soil refers to a soil type in which a large amount of neutral salts accumulates to a certain concentration (salt content is greater than 0.5%-2%, salt composition is different, and the lower limit of salt content is different), and the main salt composition is sodium chloride and sodium sulfate. Alkaline soil is a soil type formed under the influence of sodium bicarbonate, sodium carbonate, etc., in which the sodium ion reaches a certain amount in the exchangeable complex, and the soil properties deteriorate (alkalization degree > 30%, pH > 9.0, and salt content < 0.5%). According to the results of the 2019 national "three surveys", there are 115 million mu of saline-alkali land (referring to unused land) in China, which is an important reserve of arable land resources. Among them, 110 million mu (96%) of saline-alkali land in the northwest inland area includes the western part of Inner Mongolia, Ningxia, Gansu, Qinghai, and most of Xinjiang. 3.68 million mu (3%) of saline-alkali land in the northeast soda area is mainly distributed in the Songnen Plain and is one of the three largest soda saline-alkali lands in the world. 770,000 mu (1%) of saline-alkali land in the eastern coastal area is distributed along the coastline and is relatively scattered. Reasonable development and utilization of these saline-alkali land resources is of great significance to guarantee national food security, promote sustainable agricultural development, improve the ecological environment, and promote the coordinated development of regional economy and society.

[0003] Since the 1990s, research on high polymer saline-alkali land improvers has gradually emerged and attracted widespread attention. Current saline-alkali land improvement mainly involves high polymer improvers, application amount, and their effects on soil properties, crop emergence and growth, and fertilizer uptake. Existing technologies have reported that different material types of improvers such as gypsum, calcareous fertilizer, and humic acid have also been applied to saline-alkali land improvement.

[0004] The current chemical improvement measures for saline-alkali soil in China mainly add various types of chemical improvers, natural mineral resources (such as zeolite, peat, etc.), agricultural and industrial wastes (organic fertilizer, straw, coal gangue, black vitriol, phosphogypsum, desulfurization gypsum, etc.) to the saline-alkali soil, which causes ion exchange or complexation reaction with the salt-forming ions in the soil, so that the salt-forming ions are separated from the soil particles and dissolved or dispersed in the irrigation water and then discharged, thereby achieving the purpose of reducing the soil salt content. Chemical improvement has the characteristics of short-term significant effect, but its application needs to increase the agronomic process, which is time-consuming and costly, and the economic cost is high. In addition, long-term use of some chemical improvers has certain harm to the soil and environmental pollution risk. Traditional saline-alkali soil improvers have the problems of large application amount, limited application time, short duration, high transportation and labor cost, high preparation cost of new biological agents, large application limitations, few application tests, and imperfect environmental safety evaluation.

[0005] With the development of science and technology, the chemical improvement materials for saline-alkali soil are continuously developed, and various factors such as the improvement performance of raw materials, economic cost and environmental cost are comprehensively considered. The current research and invention of saline-alkali soil improvers mainly focus on water-retaining agents to improve soil structure (CN201310069798); traditional phosphogypsum and other ion balance regulators to supplement nutrient elements (CN201210400569, CN201310386417); biological agents (CN201110209123). The current technical products for saline-alkali soil have a large input amount (0.2-2 tons per mu), and the improvement cost per mu is generally higher than 1000 yuan per mu, which has high cost, and the water amount for washing salt is generally 300 m 3 / mu, which increases the improvement threshold and implementation difficulty. The inventors have a series of product patents, such as CN201510460886, CN201710320323, CN201910192704, which use microcapsule or controlled release technology to improve the utilization efficiency of effective components. However, the agricultural effect in the arid and rainy areas of saline-alkali soil region still needs to be improved.

[0006] For arid and rainy areas, agriculture has the characteristics of water-saving agriculture in arid areas, and agricultural film mulching and micro-irrigation under film are widely popularized, the water and fertilizer integration degree is high, the irrigation water amount is small, and the application amount of traditional improvers is large, the efficiency is low, and the cost is high, so it is urgent to develop an improver suitable for arid and rainy saline-alkali soil.

[0007] SUMMARY

[0008] The present application aims at the fact that the performance of existing saline-alkali soil improvers in arid and less rainy areas still needs to be improved, and provides a water-based trigger controlled-release saline-alkali soil improver and a preparation method thereof, which is suitable for water and fertilizer integration technology and has the characteristics of saving fertilizer, labor and water, and can be applied in current agricultural scenarios such as drip irrigation, soil application, flushing application and seed treatment with irrigation water.

[0009] A water-based trigger controlled-release saline-alkali soil improver comprises an A agent, the A agent comprises a water-soluble polymer and a controlled-release suspended particle; the controlled-release suspended particle comprises alginate / anti-stress regulator composite microparticles, and the alginate / anti-stress regulator composite microparticles are obtained by two-step gel crosslinking of alginate, cationic anti-stress regulator and high-valence metal ion-containing crosslinking agent in sequence.

[0010] Further, the alginate is selected from at least one of sodium alginate, potassium alginate and ammonium alginate with a molecular weight of 200,000-2,000,000; the cationic anti-stress regulator is selected from at least one of chlormequat, mepiquat, choline chloride, choline, lysine and arginine; and the high-valence metal ion-containing crosslinking agent contains at least one of divalent and higher metal ions such as Ca 2+ , Fe 3+ , Al 3+ , Mg 2+ , Zn 2+ and Mn 4+ , and examples can include but are not limited to at least one of calcium chloride, calcium lactate, calcium sulfate, calcium gluconate, iron chloride, ferrous sulfide, ferrous sulfate, aluminum chloride, aluminum sulfate, magnesium chloride, zinc chloride and manganese chloride.

[0011] Further, the surface Zeta potential of the alginate / anti-stress regulator composite microparticles is 0-+10 mV. Generally, the surface Zeta potential of particles dispersed in water is above-10 mV, and in the present application, the surface of the composite microparticles is neutral to positive due to neutralization of negative charges by cationic crosslinking.

[0012] Further, the mass ratio of the alginate, the cationic anti-stress regulator and the high-valence metal ion-containing crosslinking agent is 1:2-5:0.1-1, and preferably 1:2-3:0.12-0.4.

[0013] Further, the mass ratio of the water-soluble polymer and the controlled-release suspended particle is 5-7:3-5.

[0014] Further, the alginate / anti-stress regulator composite microparticle has a micro / nano structure, and the particle size is 300 nm-100 μm, preferably 500 nm-50 μm; more preferably 500 nm-10 μm; the micro / nano level particle size helps to stably disperse in water and soil system. If the particle size is too small, such as <300 nm, the preparation cost will be greatly increased; and if the particle size is too large, such as >100 μm, the dispersion performance will be reduced, causing pipe blockage and affecting the field effect.

[0015] Further, the D50 of the alginate / anti-stress regulator composite microparticle is 0.3-2 μm.

[0016] Further, the alginate / anti-stress regulator composite microparticle is prepared by a two-step gel preparation method, specifically by the preparation method comprising the following steps:

[0017] S1) preparing a cationic anti-stress regulator aqueous solution under high-speed stirring, and then adding an alginate aqueous solution to prepare an alginate dispersion gel system;

[0018] S2) adding a high-valence metal ion crosslinking agent aqueous solution to the sodium alginate dispersion gel system, mechanically stirring, washing and drying to obtain a controlled-release suspended particle.

[0019] Further, in step S1), the concentration of the cationic anti-stress regulator aqueous solution is 10-20 wt%, the high-speed stirring speed is 3000-20000 rpm, and the high-speed stirring equipment includes but is not limited to a high-speed shearing machine; the concentration of the alginate aqueous solution is 2-10 wt%, and the heating temperature is 60-80°C; in step S2), the concentration of the high-valence metal ion crosslinking agent aqueous solution is 10-30 wt%, the mechanical stirring speed is 500-1000 rpm, and the stirring time is 1-3 h. The washing and drying are not particularly limited and are well known in the art, such as a washing method of centrifugal water washing and a drying method of vacuum drying, oven drying, spray drying and freeze drying.

[0020] The alginate is added to the anti-stress regulator solution, and electrostatic interaction occurs between the molecules. The alginate shows slow solubility, which helps to realize the micro / nano preparation and drug loading at the same time under the action of high-speed shearing force. After completion, a high-valence metal ion crosslinking agent is added for further crosslinking to form alginate-cationic anti-stress regulator-high-valence metal crosslinking agent gel beads. The high-valence cation in the gel can be replaced under acidic conditions to form a coordination, so that the gel is dissolved and the active ingredient is released.

[0021] Further, the water-soluble polymer is selected from at least one of polyglutamic acid, polyaspartic acid, calcium polyaspartate, polylysine, chitosan, chitooligosaccharide, water-soluble starch, microcrystalline cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, potassium fulvate, sodium fulvate, potassium alginate, potassium lignosulfonate; the water-soluble natural polymer can be absorbed by soil particles, and has the functions of water retention, soil conditioning and biological regulation. The molecular weight of the natural polymer satisfies sufficient water solubility, and a too large molecular weight leads to a decrease in water solubility, which is well known to those skilled in the art.

[0022] Preferably, the A agent further comprises a water-soluble surfactant. The water-soluble surfactant is added when the triggered controlled-release saline-alkali soil amendment is a water-based dispersion system and a wettable powder preparation, so as to maintain the stability and uniformity of the system; when the triggered controlled-release saline-alkali soil amendment is a powder, the water-soluble surfactant is not required.

[0023] Further, the water-soluble surfactant is selected from at least one of an anionic emulsifier, a cationic emulsifier and a non-ionic emulsifier; wherein the anionic emulsifier is preferably selected from at least one of sulfonate, C1-C20 carboxylic acid, succinate, sodium alkylbenzenesulfonate, sodium polyoxyethylene nonyl phenyl ether sulfonate, sodium stearate, sodium dodecyl sulfonate and sodium dodecyl benzene sulfonate; the cationic emulsifier is preferably selected from at least one of fatty amine salt, quaternary ammonium salt and alkyl pyridine salt; and the non-ionic emulsifier is selected from at least one of polysorbate, polyoxyethylene alcohol, nonylphenol polyoxyethylene ether and alkylphenol polyoxyethylene ether. If the water-soluble surfactant exists, the mass ratio of the water-soluble polymer, the controlled-release suspended particle and the water-soluble surfactant is 5-7:3-5:0.1-1.

[0024] Further, the controlled-release suspended particle further comprises a non-water-soluble alginate salt, such as at least one of calcium alginate, zinc alginate and iron alginate. Further, the non-water-soluble alginate salt accounts for 10-70wt%, preferably 30%-50% in the controlled-release suspended particle.

[0025] Further, the non-water-soluble alginate salt is prepared by sand mill wet grinding, specifically including the following steps: a water-dispersed solution of the non-water-soluble alginate salt with a concentration of 10-50wt% is circularly ground for 3-6h using a sand mill at a rotation speed of 1000-1500rpm, and then washed and dried to obtain the non-water-soluble alginate salt.

[0026] The non-water-soluble alginate salt is also a touch control component. Compared with the alginate salt / anti-stress regulator composite microparticles, the non-water-soluble alginate salt particles have a larger particle size, which is 2-100 μm. The dispersion and effective component release and migration performance of the two different particle sizes are different. The non-water-soluble alginate salt particles have a stronger effect between soil aggregates. The alginate salt / anti-stress regulator composite microparticles can act within the soil aggregates. The non-water-soluble alginate salt particles bridge the soil aggregates to form aggregates. The alginate salt / anti-stress regulator composite microparticles act within the aggregates to release the active substances.

[0027] Fig. 1 is a chemical reaction formula of the triggered controlled release saline-alkali soil conditioner. Reaction formula (1) is a triggered release reaction of the triggered controlled release saline-alkali soil conditioner. The insoluble alginate salt is dissolved to form water-soluble alginate salt, precipitated metal salt and metal coordination compound. Reaction formula (2) is that the water-soluble alginate salt combines with high-valence metal cations in the soil to form hydrogel in situ, which plays a role in soil particle bonding and water retention. Reaction formula (3) is that the insoluble alginate salt and alginate hydrogel exchange ions in the saline-alkali soil, and slowly take effect.

[0028] In a preferred technical scheme of the present application, the triggered controlled release saline-alkali soil conditioner further comprises B agent, and the B agent comprises a touch control agent.

[0029] Further, the touch control agent is at least one selected from pyrophosphoric acid, potassium tripolyphosphate, sodium tripolyphosphate, polyepoxysuccinic acid (PESA), citric acid, silicon phosphorus crystals, maleic acid, maleic anhydride, acrylic acid, and acrylic acid / acrylate copolymer. The addition of the touch control agent in the B agent can prevent the scaling of the micro-irrigation equipment, solve the scaling problem of the micro-irrigation system caused by the high-valence salt contained in the A agent, further control the release of the material, and activate the soil to provide nutrients.

[0030] Fig. 2 is a schematic diagram of the mechanism of the combined use of the A agent and the B agent of the triggered controlled release saline-alkali soil conditioner. After the addition of the B agent, the alginate salt / anti-stress regulator composite microparticles and the non-water-soluble alginate salt particles are triggered to release the active substances. The B agent can activate the N and P nutrient ions in the soil.

[0031] Further, the B agent further comprises a stabilizer, and the stabilizer is at least one selected from glycerol, pentaerythritol, ethylene glycol, propylene glycol, butanediol, hexanediol, polyethylene glycol, polyvinyl alcohol, xylitol, and sorbitol. In the B agent, the touch control agent accounts for 10-90 wt%, and preferably 30-70 wt%. The stabilizer needs to be added when the storage and transportation time is long and when the seed treatment agent is used.

[0032] The trigger controlled release saline-alkali soil improver of the present application can be used alone as A agent or together with B agent.

[0033] The method of using A agent alone or A agent and B agent jointly is as follows: during the whole growth period of crops, preferably seedling stage, the application mode of the trigger controlled release saline-alkali soil improver includes scattering with basal fertilizer, seed treatment, flushing with irrigation water or micro-irrigation with water.

[0034] Further, when A agent and B agent are jointly applied, the sequence of micro-irrigation with water is to use A agent first and then B agent, and the interval time is 2-48h, preferably 12-24h; the amount of micro-irrigation with water ranges from 30kg to 450kg / hm 2 of A agent powder and 1-15kg / hm 2 of B agent powder, preferably 150-188kg / hm 2 of A agent powder and 3-5kg / hm 2 of B agent powder; when the application mode is seed treatment, A agent and B agent are mixed to configure seed soaking liquid or seed dressing, and 0.1-1kg of A agent powder and 0-0.5kg of B agent powder per hectare of crop seeds are applied, preferably 0.15-0.3kg of A agent powder and 0.1-0.15kg of B agent powder per hectare of crop seeds are applied. If it is not in the form of powder, it is converted to solid content.

[0035] When the trigger controlled release saline-alkali soil improver of the present application is applied in the form of seed dressing agent, A agent is preferably used jointly with B agent, and the mass ratio of A agent to B agent is 1:1 to 5:1. Compared with micro-irrigation with water, the amount of B agent is increased when it is applied in seed dressing because B agent contains stabilizer, and the stabilizer is necessary for seed dressing agent.

[0036] The trigger controlled release saline-alkali soil improver of the present application takes alginate as the main material, is prepared by primary gel high-speed dispersion with charged regulator and secondary gel with high-valence metal, obtains micron-nanometer level powder and suspension, realizes product grading release and intelligent control function in combination with soluble organic high molecular material, has dissolution and cation coordination effect on calcium and high-valence metal insoluble salt, can prevent micro-irrigation equipment from scaling, and can realize product multi-particle size dispersion and precise release effect in soil.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] 1) The saline-alkali soil improver of the present application is water-soluble or water-dispersible, is suitable for micro-irrigation system in arid areas, A agent is micron-nanometer level powder and suspension product, and B agent solves the problem of scaling and plugging of micro-irrigation pipeline.

[0039] 2) The alginate / anti-stress regulator composite microparticles have a touch-controlled release function, multi-stage release of effective components, multi-level dispersion in the environment, and the characteristics of saving fertilizer, labor and water. The alginate / anti-stress regulator composite microparticles and non-water-soluble alginate particles can be compounded to introduce various cations, adjust the release curve, and broaden the application range.

[0040] 3) The raw material natural polymer material is used as the main body, the material is biodegradable, and the degradation metabolites can be used as nutrients, fertilizer synergists, soil conditioners, water retention agents and plant growth regulators, so that multiple effects are achieved and the yield of crops in saline-alkali soil is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a touch-controlled release and soil improvement chemical reaction formula of the touch-controlled release saline-alkali soil improver according to the present application;

[0042] Figure 2 is a mechanism diagram of the combined use of A agent and B agent of the touch-controlled release saline-alkali soil improver according to the present application;

[0043] Figure 3 is a scanning electron microscope image of the chlormequat chloride-calcium alginate controlled release microparticle / nanoparticle dry powder of Example 1;

[0044] Figure 4 is a chlormequat chloride touch-controlled release effect diagram of the chlormequat chloride-calcium alginate controlled release microparticle / nanoparticle of Example 1;

[0045] Figure 5 is a Ca 2+ Touch-controlled release simulation effect diagram;

[0046] Figure 6 is a soil aggregate distribution diagram of the potting soil treated by the touch-controlled release saline-alkali soil improver of Example 2;

[0047] Figure 7 is a soil improvement cation exchange capacity diagram of Example 3;

[0048] Figure 8 is a soil improvement pH and EC diagram of Example 3;

[0049] Figure 9 is a soil improvement root water content diagram of Example 3;

[0050] Figure 10 is a corn aboveground fresh weight diagram of Example 3;

[0051] Figure 11 is a soil dehydrogenase activity diagram of the root system of Example 3;

[0052] Figure 12 is a germination experiment effect of the corn seed treated by the touch-controlled release saline-alkali soil improver of Example 5 under salt stress. DETAILED DESCRIPTION

[0053] The method of the present application will be described below through specific examples, but the present application is not limited thereto.

[0054] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0055] Example 1 Preparation of Triggered Controlled Release Salt-alkali Soil Conditioner

[0056] 1) 50 g of sodium alginate (molecular weight 50,000) was slowly added to 1 L of deionized water at 60°C, and dissolved for 1 h with mechanical stirring at 300 rpm as the dispersed phase. 500 ml of deionized water was added to a 500 ml beaker, and 100 g of paclobutrazol was added and dissolved with stirring as the continuous phase. A high-speed shear emulsification head was inserted into the dispersed phase, and stirred at 10,000 rpm. At this time, a 50 ml syringe was used, with a 0.15 mm inner diameter needle, and the dispersed phase was slowly injected into the continuous phase, and high-speed shearing was maintained for 10 min, to prepare a sodium alginate dispersion gel system. Another container was prepared with 30 ml of a 20 wt% calcium chloride solution, which was slowly added to the sodium alginate dispersion gel system, and mechanical stirring was maintained at 300 rpm for 1 h, to prepare a paclobutrazol-calcium alginate controlled release micro / nano particle suspension. After centrifugal washing with water three times, freeze-drying was performed to obtain paclobutrazol-calcium alginate controlled release micro / nano particle dry powder. The scanning electron microscope photograph is shown in Figure 3, which shows that the paclobutrazol-calcium alginate controlled release micro / nano particle particle size is about 1 μm.

[0057] 2) A 50% (w / w) water dispersion of water-insoluble calcium alginate (molecular weight 20,000) was prepared in 200 ml of water. A sand mill was used to maintain a 1,500 rpm rotation speed for 3 h of cyclic grinding, and the discharge was prepared to obtain a calcium alginate micro / nano particle suspension. After centrifugal washing with water three times, freeze-drying was performed to obtain calcium alginate micro / nano particle dry powder.

[0058] 3) 5 g of the paclobutrazol-calcium alginate controlled release micro / nano particle dry powder prepared in step 1) was mixed with 10 g of the calcium alginate micro / nano particle dry powder prepared in step 2), and 15 g of polyglutamic acid, 1 g of sodium dodecylbenzenesulfonate was mixed to obtain A agent.

[0059] 4) 2 g of pyrophosphoric acid was mixed with 1 g of glycerol to obtain B agent.

[0060] A agent and B agent are solid powders, and can be dissolved and uniformly dispersed in an aqueous phase.

[0061] The chlormequate-alginate calcium controlled release micro / nanoparticle water chlormequate trigger release effect is shown in Figure 4, using A agent (TA group) alone treatment: 1 g of A agent is placed in a 500 Dalton dialysis bag, and after sealing, it is placed in 50 ml of deionized water, 2 ml of supernatant is taken at 1 h, 3 h, 6 h, 12 h, 24 h, 36 h, 48 h, and the solution is supplemented with water to 50 ml, and the chlormequate in the solution is quantified by sodium tetraphenylborate precipitation method. The control group (CK group) is 50 ml of deionized water added with 0.05 g of chlormequate, and A agent and B agent are used in combination (TAB group) with the same treatment method as the TA group, the difference is that 0.1 g of B agent is added by micro-irrigation at 6 h, and the TAB group shows a chlormequate burst release phenomenon after 6 h, and the subsequent release is accelerated, proving that the chlormequate-alginate calcium controlled release micro / nanoparticle has a trigger release effect.

[0062] Chlormequate-alginate calcium controlled release micro / nanoparticle salt water Ca 2+ The trigger release effect is shown in Figure 5, and the salt water simulation trigger release test is set as follows: 1 g of A agent is placed in a 500 Dalton dialysis bag, and after sealing, it is placed in 50 ml of 0.5% NaCl aqueous solution, a total of 12 (3 treatments, 1 control; 3 replicates each). T1, T2, T3 treatments are added with 0.1 g, 0.2 g, 0.3 g of B agent at 6 h, and the CK treatment is not added with B agent, 2 ml of supernatant is taken at 1 h, 3 h, 6 h, 12 h, 24 h, 36 h, 48 h, and the Ca 2+ ion concentration (flame absorption method), and the converted release amount. It can be seen that the Ca 2+ ion concentration of the T3 group is more than 50% at 24 h, and the CK group has a slow release due to ion exchange, and the Ca 2+ ion concentration is 16% at 48 h. It is proved that the chlormequate-alginate calcium controlled release micro / nanoparticle has a slow release and trigger release effect in saline-alkali environment.

[0063] Example 2 Trigger release saline-alkali land improvement agent micro-irrigation soil pot culture test

[0064] Using the prepared sample of the modifier of Example 1, 100 kg of soil of 0-40 cm soil layer was taken from the corn land of the 33rd regiment of the 2nd division of Xinjiang Bayinguoleng, mixed and air-dried to obtain the salt-alkali soil air-dried soil, the soil properties were tested as shown in Table 1, a 20 cm diameter and 20 cm high flowerpot was used to pack 6 kg of salt-alkali soil air-dried soil 1#, 0.4 g of A sample was dissolved in 3 kg of deionized water. The A agent solution / water dispersion was micro-irrigated into the flowerpot with a micro-irrigation device, and after 8 h of culture at 25℃, 1 kg of 0.001 wt% B agent aqueous solution was added by irrigation with a micro-irrigation device, and after 24 h of culture at 25℃, 100 g of 0-10 cm soil sample was taken as Tb, Ta group according to the Tb step, the difference is that no B agent is added, and an equal amount of deionized water is used instead, and after the culture is completed, 100 g of 0-10 cm soil sample is taken as Ta. The control group does not add the agent, and the same process is used to add an equal amount of water instead, and after the common culture is completed, 100 g of soil is finally taken as CK.

[0065] 50 g of soil sample was taken and tested by wet sieving method to test soil aggregate, the results are shown in Figure 6, Ta has increased 0.02 mm-2 mm aggregate compared with CK, the proportion of small aggregate is reduced. After using B agent, Tb group has significantly increased large aggregate compared with Ta group, which shows that A agent+B agent combination has triggered the improvement of soil. The test results of soil pH, EC are shown in Table 2, A agent+B agent combination has reduced pH by 1.67 and EC by 2.27 mS / cm compared with the control soil.

[0066] Table 1 Soil properties of the corn land of the 33rd regiment of the 2nd division of Xinjiang Bayinguoleng

[0067] Table 2 Soil pH, EC of treatment and control

[0068] Example 3 Triggered controlled release salt-alkali land modifier field application

[0069] 1) In a 2000L reaction kettle, 950L of deionized water was added, heated to 70℃, 50kg of sodium alginate(molecular weight 20,000) was slowly added to the water, and the mechanical stirring was dissolved for 1h as the dispersed phase. In a 2000L reaction kettle, 200L of deionized water was added, 100kg of chlormequat was added and stirred to dissolve as the continuous phase, the high-speed shearing machine emulsification head was inserted into the dispersed phase, the speed was 10000rpm, the dispersed phase was slowly injected into the continuous phase with peristaltic pump, and the high-speed shearing was maintained for 30min, the sodium alginate dispersion gel system was prepared. Another container was configured with 30L of 20% calcium chloride solution, slowly added into the sodium alginate dispersion gel system, and maintained 500rpm mechanical stirring for 1h, the chlormequat-calcium alginate controlled release micro / nano particle suspension was prepared, after centrifugation and washing with water for three times, the calcium alginate micro / nano particle dry powder was obtained by spraying.

[0070] 2) 100 L of 10 wt% water-insoluble calcium alginate (molecular weight 100,000) aqueous dispersion was prepared. The sand mill was used to keep the rotation speed at 1500 rpm for 3 h of circulating grinding, and the outlet was prepared to obtain the calcium alginate micro / nano-particle suspension.

[0071] 3) After mixing 10 kg of chlormequat-chloride-calcium alginate controlled-release micro / nano-particle dry powder with 100 L of calcium alginate micro / nano-particle suspension, 20 kg of polyglutamic acid and 2 kg of sodium dodecylbenzenesulfonate were added to obtain A agent.

[0072] 4) 20 kg of pyrophosphoric acid was mixed with 10 kg of glycerol to obtain B agent.

[0073] The test site was located in the newly reclaimed farmland of Yutian County, Hetian City, Xinjiang Uygur Autonomous Region, and the crop was corn. The corn variety selected was Beinong Qingcun 208, and the soil properties are shown in Table 3.

[0074] Table 3 Soil properties

[0075] The treatment is shown in Table 4, and the area of each treatment is 0.067 hm 2 First, the phosphorus and potassium fertilizers and urea were applied as base fertilizer at the beginning of sowing by means of a dropper into the soil. During the whole growth period, there were 5 times of drip irrigation, and the seedling water was irrigated twice. The first time was to add A agent, and the irrigation was 750 m 3 The second time was to add B agent, and the irrigation was 150 m 3 The interval between the two irrigations was 24 h. Except for the seedling water, the other four times of drip irrigation were 450 m 3 .

[0076] Table 4 Field test setting table

[0077] At the corn seedling stage, jointing stage, silking stage, filling stage, and milk ripening stage, the agronomic trait indicators of corn were sampled and investigated. The root system soil was collected by the shaking root method. When collecting, the soil tightly attached to the root system was brushed off, and the rhizosphere soil was obtained. The collected root system soil was immediately put into a self-sealing bag to mix the soil samples. A part of the soil samples was stored at low temperature, and a part of the soil was placed in a well-ventilated place for natural air drying and grinding for screening, which was used to determine the soil chemical properties and related enzyme activity.

[0078] The change of soil cation exchange capacity (CEC) is shown in Figure 7. After using the modifier, the CEC of treatments 1 and 2 at the seedling stage decreased significantly, which was caused by the washing away of Na + from the soil. From the silking stage to the milk ripening stage, the CEC of CK was significantly higher than that of treatments 1 and 2. Due to the Ca 2+The ions are released to produce effects. The changes of soil pH and EC are shown in Figure 8, and the pH and EC are significantly lower than CK, the pH decreases from 9.3 to below 8, and the EC decreases by more than half, indicating that the main ions causing salinity and alkalinity are leached out with water, and the root soil is improved and desalinated. The soil moisture content of the root system is shown in Figure 9, and the soil moisture content of the 20 cm soil layer of the CK group is less than 0.04%, and after improvement, it is increased to more than 0.1%, proving that the modifier has water retention performance. The fresh weight of the aboveground part of the silage corn at each growth stage is shown in Figure 10, and the improved group is better than the control group at each period, and the average fresh weight of the aboveground part of the improved group 1 at the milk stage is 655.83g, the average fresh weight of the aboveground part of the improved group 2 is 675.34g, and the average fresh weight of the aboveground part of the control group is 503.15g. Compared with the control group, the improved group 1 and the improved group 2 are increased by 30.2% and 34.1% respectively. The actual yield of the test field is 44481.15kg / hm 2 , the improved group 2 is 49385.7kg / hm 2 , and the control group is 30852.9kg / hm 2 , and the fresh weight of the improved group 1 and the improved group 2 is increased by 44.18% and 60.11% respectively. The dehydrogenase activity of the improved root system soil is shown in Figure 11, and the change is not significant at the seedling stage, but the modifier can significantly improve the dehydrogenase activity at the corn filling stage and the milk stage, which can reflect the amount of active microorganisms in the soil system and its degradation activity to organic matter.

[0079] Example 4 Triggered controlled release saline-alkali soil modifier field application

[0080] The triggered controlled release saline-alkali soil modifier sample prepared in Example 3 is applied to plant corn in a saline-alkali soil in Xinjiang Hetian 225 team, and the corn variety is selected as Xin Yu 68, and the treatment is 300kg of A agent and 7.5kg of B agent per hectare. 750m 3 / hm 2 of water is irrigated after germination, and 600m 3 / hm 2 , 150m 3 / hm 2 of water is irrigated twice, and the interval is 24h, A agent is applied with the first irrigation, and B agent is applied with the second irrigation. The whole growth period is irrigated 5 times, and 450m 3 / hm 2 of water is irrigated after the seedling water, and the other field management conditions such as fertilization and pesticide application are the same.

[0081] The yield test shows that the fresh weight of the improved corn is 85.9T / hm 2 , the fresh weight of the control field is 64.9T / hm 2 , and the yield is increased by 32.35%; the ear weight is 26.8T / hm 2 , and the equal water irrigation control is 20.1T / hm2 , the yield is increased by 33.82%, and the growth period of the improved corn is advanced by 10 days.

[0082] Example 5 Preparation of the trigger controlled release saline-alkali soil conditioner for seed treatment

[0083] 1) In a 500ml reaction bottle, 200ml of deionized water was added, and the water was heated to 80℃. 20g of sodium alginate (molecular weight 100,000) was slowly added to the water, and the solution was dissolved for 1h with mechanical stirring at 600rpm as the dispersed phase. 80ml of deionized water was added to chlormequat chloride 60g, and the solution was stirred and dissolved as the continuous phase. A high-speed shearing machine emulsification head was inserted into the dispersed phase, and stirring was carried out at a speed of 5000rpm. At this time, a 50ml syringe was used, and a needle with an inner diameter of 0.15mm was installed. The dispersed phase was slowly injected into the continuous phase, and high-speed shearing was maintained for 30min to prepare a sodium alginate dispersion gel system. Another container was configured with 40ml of 20% iron chloride solution, which was slowly added to the sodium alginate dispersion gel system, and mechanical stirring was maintained at 700rpm for 1h to prepare a chlormequat chloride-ferric alginate controlled release micro / nano particle suspension. After centrifugal washing three times, chlormequat chloride-ferric alginate controlled release micro / nano particle dry powder was obtained by freeze-drying.

[0084] 2) A powder A was prepared by mixing 21g of potassium fulvic acid, 1g of polyoxyethylene glycol (number average molecular weight 3000), and 15g of chlormequat chloride-ferric alginate controlled release micro / nano particles.

[0085] 3) A powder B was prepared by mixing 3g of potassium tripolyphosphate and 7g of polyvinyl alcohol 1788.

[0086] 4) Salt stress seed germination experiment: corn seeds were selected as the subject, and three treatments were set up: CK: the same amount of deionized water; T1: 2kg of corn seeds were placed in 5g of A agent and 5g of B agent and 200ml of water for seed treatment; T2: 2kg of corn seeds were placed in 10g of A agent and 5g of B agent and 200ml of water for seed treatment. Three concentrations of salt stress were set up in total, and NaCl and Na2SO4 were mixed in a molar ratio of 9:1 to configure salt water. The concentrations of the salt water were 0, 2.5, and 5g / L, respectively. One filter paper was placed in each petri dish, and 10 full corn seeds (provided by the Agricultural University Corn Center) were placed on the filter paper. Each treatment was set up with 3 repeated experiments, and 10ml of water and salt solution was added to each treatment. Then, the petri dishes were placed in a constant temperature incubator at 25℃ for culture. During the culture, 1ml of water was added every day to keep the filter paper moist. After 7 days, the number of germinated seeds was counted. The amount of corn seeds used was 60kg per hectare.

[0087] Germination rate (%) = (number of germinated seeds / total number of seeds) x 100%

[0088] Figure 12 is the effect of seed treatment with the triggered controlled release saline-alkali soil conditioner sample in Example 5 on the emergence rate of corn seeds. As can be seen from the water treatment group, seed treatment at two concentrations had no significant inhibitory effect on germination. Under 5‰ salt stress, the germination rate of T1 treated seeds reached 80%, significantly better than the 50% of the control treatment, proving that seed treatment with the triggered controlled release saline-alkali soil conditioner of the present application has the effect of resisting stress and improving germination rate. Example 6 Preparation of Triggered Controlled Release Saline-Alkaline Soil Conditioner Suspension Concentrate / Water Soluble Powder

[0089]

[0090] 1) In a 500ml reaction bottle, add 200ml deionized water, heat the water to 70℃, slowly add 10g sodium alginate (molecular weight 100,000) to the water, mechanically stir at 700rpm for 2h as the dispersed phase. In a 500ml open beaker, add 200ml deionized water, add 20g choline chloride, stir to dissolve as the continuous phase, insert the high-speed shear emulsification head into the dispersed phase, stir at 10,000rpm, at this time, use a 50ml syringe, install a 0.15mm inner diameter needle, slowly inject the dispersed phase into the continuous phase, keep high-speed shearing for 10min, prepare the sodium alginate dispersion gel system. Another container is configured with 20ml of 20% mass concentration of ferric chloride solution, slowly add to the sodium alginate dispersion gel system, keep mechanically stirring at 700rpm for 1h, prepare the choline chloride-ferric alginate controlled release micro / nano particle suspension.

[0091] 2) Add 15g potassium lignosulfonate, 1g polyoxyethylene glycol to the choline chloride-ferric alginate controlled release micro / nano particle suspension to prepare A agent.

[0092] 3) Mix 4g potassium tripolyphosphate with 2g pentaerythritol to obtain B agent.

[0093] A agent suspension concentrate and B agent water soluble powder sample preparation is completed.

[0094] ​Using the A agent suspension and B agent water soluble powder type sample prepared in this embodiment, the soil sample uses the 0-40 cm soil layer soil of the corn field of the 33th regiment of the Xinjiang Bayinguoleng farm 2nd division, mixes and dries to test the soil properties, and uses an aluminum box to load 200 g of dry saline soil. The treatment group T1 is that the A agent sample is added with 0.0005 g, dispersed with 100 ml of deionized water, and then irrigated into the flowerpot with the micro-irrigation equipment, cultured at 25°C for 8 h, then irrigated with 10 ml of 0.001 wt% B agent aqueous solution with the micro-irrigation equipment, cultured at 25°C for 24 h, and then 5 g of soil sample was taken to test the soil pH and EC; the remaining soil sample was used for seed culture test, using Nongda 778 corn seeds, 10 seeds were sown in each aluminum box, three parallel tests were conducted for each treatment, and the seed germination rate was calculated by counting every day in the 25°C incubator for 7 days, and irrigated with 5 ml of water every day. The treatment group T2 and the treatment group T1 are the same, except that no B agent aqueous solution is added; the control group does not add the agent, and the same process is used to add an equal amount of water instead, and the other operations are the same, and the control group is denoted as CK.

[0095] Table 5 Soil culture test data of example 6

[0096] From the soil culture data, it can be seen that the soil pH value is significantly reduced by the modifier treatment. The effect of T1 group is better than that of T2 group, and the use of A agent alone can obviously alleviate and inhibit the salt stress of soil, but the effect of the combination of A agent and B agent is better.

[0097] Example 7 Preparation of trigger-controlled release saline-alkali soil modifier suspension / water agent

[0098] 1) In a 200 ml reaction bottle, 100 ml of deionized water was added, and the water was heated to 60°C, 5 g of sodium alginate (molecular weight 100,000) was slowly added to the water, and the mechanical stirring was dissolved for 1 h as the dispersed phase. In a 500 ml open beaker, 100 ml of deionized water was added, 10 g of mepiquat chloride was added, and the stirring was dissolved as the continuous phase. The high-speed shearing machine emulsification head was inserted into the dispersed phase, and the stirring was carried out at 5000 rpm. At this time, a 10 ml syringe was installed with a 0.15 mm inner diameter needle, and the dispersed phase was slowly injected into the continuous phase, and the high-speed shearing was maintained for 30 min to prepare the sodium alginate dispersion gel system. Another container was configured with 20 ml of 10% calcium citrate solution, which was slowly added to the sodium alginate dispersion gel system, and the mechanical stirring was maintained at 300 rpm for 1 h to prepare the mepiquat chloride-calcium alginate controlled release micro / nano particle suspension. After centrifugal washing three times, the mepiquat chloride-calcium alginate controlled release micro / nano particle dry powder was obtained by freeze-drying.

[0099] 2) 100 ml water solution, 10% (w / w) water insoluble ferric alginate (molecular weight 50,000) aqueous dispersion was prepared. The sand mill was used to keep the speed of 1500 rpm for 3 h, and the discharge was prepared to obtain the ferric alginate micro / nanoparticle suspension.

[0100] 3) 5 g of mepiquat chloride-alginate controlled release micro / nanoparticle dry powder was added to 50 ml of ferric alginate micro / nanoparticle dry powder, then 10 g of water-soluble starch and 1 g of nonylphenol polyoxyethylene ether were added and stirred to dissolve / disperse to obtain the A agent suspension.

[0101] 4) 2 g of pyrophosphate, 1 g of citric acid and 1 g of glycerol were mixed and dissolved in 100 ml of water to obtain the B agent water agent.

[0102] The A agent suspension and B agent water agent type sample preparation was completed.

[0103] The A agent suspension and B agent water agent type sample prepared by using the present embodiment, the soil sample was used in Yutian County, Hotan City, Xinjiang, mixed and dried, and the soil properties were tested, as shown in Table 6, using a 9 cm diameter flowerpot to pack 600 g of the aforementioned dried soil, 0.0010 g of A agent sample was added, and 300 ml of deionized water was dispersed and used to micro-irrigate into the flowerpot, 25℃ incubated for 8 h, then irrigated with 100 ml of 0.005wt% B agent aqueous solution, 25℃ incubated for 24 h, then 25 g of soil sample was taken to test the soil pH and EC, the remaining soil sample was used for seed culture test, using Nongda 778 corn seeds, 10 seeds were sown in each flowerpot, three parallel tests were set for each treatment, 25℃ incubator incubation for 7 days, 20 ml of water was irrigated every day, the seventh day was counted to calculate the seed germination rate, the treatment group was recorded as T3; the control group did not add the agent, the same process was used to add the same amount of water instead, and the other operations were the same, and the control group was recorded as CK.

[0104] Table 6 Soil culture test data of Example 7

[0105] From the soil culture data, it can be seen that the amendment treatment significantly reduces the soil pH value, and from the seed germination test, it can be seen that the amendment has obvious alleviating and inhibiting effect on soil salt stress.

Claims

1. An aqueous trigger-release saline soil amendment, characterized in that, The A agent comprises a water-soluble polymer and a controlled-release suspending particle; the controlled-release suspending particle comprises alginate / anti- stress regulator composite microparticles, which are obtained by two-step gel crosslinking of alginate with a cationic anti-stress regulator and a high-valence metal ion-containing crosslinking agent in sequence; the cationic anti-stress regulator is selected from at least one of chlormequat, mepiquat, choline, lysine and arginine; the alginate / anti-stress regulator composite microparticles have a particle size of 300 nm to 100 μm and a D50 of 0.3 to 2 μm; the alginate is selected from at least one of sodium alginate, potassium alginate and ammonium alginate with a molecular weight of 200,000 to 2,000,000; and the water-soluble polymer is selected from at least one of polyglutamic acid, polyaspartic acid, calcium polyaspartate, polylysine, chitosan, chitooligosaccharide, water-soluble starch, microcrystalline cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, potassium fulvic acid, sodium fulvic acid, potassium alginate and potassium lignosulfonate.

2. The aqueous trigger-release saline soil amendment of claim 1, wherein, The high-valence metal ion-containing crosslinking agent contains divalent and higher metal ions.

3. The aqueous trigger-release saline soil amendment of claim 2, wherein, The divalent and higher metal ions are selected from at least one of Ca 2+ , Fe 3+ , Al 3+ , Mg 2+ , Zn 2+ , Mn 4+ .

4. The aqueous trigger-release saline soil amendment of claim 2, wherein, The high-valence metal ion-containing crosslinking agent comprises calcium chloride, calcium lactate, calcium sulfate, calcium gluconate, ferric chloride, ferrous sulfide, ferrous sulfate, aluminum chloride, aluminum sulfate, magnesium chloride, zinc chloride or manganese chloride.

5. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The alginate / anti-stress regulator composite microparticles have a surface Zeta potential of 0 to +10 mV.

6. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The mass ratio of the alginate, the cationic anti-stress regulator and the high-valence metal ion-containing crosslinking agent is 1:2-5:0.1-1.

7. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The mass ratio of the alginate, the cationic anti-stress regulator and the high-valence metal ion-containing crosslinking agent is 1:2-3:0.12-0.

4.

8. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The mass ratio of the water-soluble polymer and the controlled-release suspending particle is 5-7:3-5.

9. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The alginate / anti-stress regulator composite microparticles are prepared by a preparation method comprising the following steps: S1) preparing a cationic anti-stress regulator aqueous solution under high-speed stirring, and then adding an alginate aqueous solution to prepare an alginate dispersion gel system; S2) adding a high-valence metal ion-containing crosslinking agent aqueous solution to the sodium alginate dispersion gel system and mechanically stirring and washing drying to obtain the controlled-release suspending particle.

10. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The A agent further comprises a water-soluble surfactant; and the mass ratio of the water-soluble polymer, the controlled-release suspending particle and the water-soluble surfactant is 5-7:3-5:0.1-1.

11. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The controlled-release suspending particle further comprises a non-water-soluble alginate, which is selected from at least one of calcium alginate, zinc alginate and iron alginate; and the non-water-soluble alginate accounts for 10-70 wt% in the controlled-release suspending particle.

12. The aqueous trigger-release saline soil amendment of claim 11, wherein, The non-water-soluble alginate accounts for 30-50 wt% in the controlled-release suspending particle.

13. The aqueous trigger-controlled release saline soil amendment of claim 11, wherein, The non-water-soluble alginate is prepared by wet grinding with a sand mill and comprises the following steps: a water-insoluble alginate aqueous dispersion with a concentration of 10-50 wt% is cyclically ground at a speed of 1,000-1,500 rpm for 3-6 h with a sand mill, and then washed and dried to obtain the non-water-soluble alginate.

14. The aqueous trigger-controlled release saline soil amendment of claim 1, wherein, The triggered controlled-release saline-alkali soil improver further comprises a B agent, and the B agent comprises a trigger control agent, and the trigger control agent accounts for 10-90 wt% of the total weight of the B agent.

15. The aqueous trigger-controlled release saline soil amendment of claim 14, wherein, The touch agent includes pyrophosphoric acid, potassium tripolyphosphate, sodium tripolyphosphate, polyepoxysuccinic acid, citric acid, silicon phosphorus crystal, maleic acid, maleic anhydride, acrylic acid or acrylic acid / acrylate copolymer; the touch agent accounts for 30-70wt% of the total weight of the B agent.

16. The water-based trigger controlled release saline soil amendment of claim 14, wherein, The B agent further includes a stabilizer, which includes glycerol, pentaerythritol, ethylene glycol, propylene glycol, butanediol, hexanediol, polyethylene glycol, polyvinyl alcohol, xylitol or sorbitol.

17. A method of using the water triggered controlled release saline soil improver of any one of claims 1 to 16, characterized in that, The dosage form of the A agent includes powder or suspension; in the case of including the B agent, the dosage form of the B agent includes water or powder.

18. The method of use of claim 17, wherein, The aqueous triggered controlled-release saline-alkali soil improver is the aqueous triggered controlled-release saline-alkali soil improver of claim 14, the A agent and the B agent are jointly applied, and the application mode includes application with basal fertilizer, seed treatment, application with irrigation water or micro-irrigation with water; When the composition is applied with irrigation water or micro-irrigation, the order of use is to apply A agent first, and then B agent, with an interval of 2-48 hours; A agent powder 150-188 kg / hm 2 , B agent powder 3-5 kg / hm 2 ; when the composition is applied for seed treatment, A agent and B agent are mixed to prepare seed soaking liquid or seed dressing, with A agent powder 0.15-0.3 kg per hectare of crop seeds, and B agent powder 0.1-0.15 kg per hectare of crop seeds; if the application form is not powder, the solid content is converted.

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