CN111234833B

CN111234833B - Saline-alkali soil water-retention granules and preparation method thereof

Info

Publication number: CN111234833B
Application number: CN202010052664.8A
Authority: CN
Inventors: 刘永红; 汪波; 蒯婕; 任奕林; 周广生
Original assignee: Huazhong Agricultural University
Current assignee: Huazhong Agricultural University
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2021-05-28
Anticipated expiration: 2040-01-17
Also published as: CN111234833A

Abstract

The invention provides saline-alkali soil water-retention granules and a preparation method thereof, wherein the method comprises the following steps of 1, preparing a phase A mixture: adding water into a macromolecular water-absorbing material to prepare a colloidal mixture; adding biochar into the obtained colloidal mixture to prepare a phase A mixture; step 2, preparing a B-phase mixture: uniformly stirring and mixing bentonite and attapulgite to obtain a phase B mixture; the mass ratio of the bentonite to the attapulgite is 1-3: 1; step 3, mixing the phase A and the phase B according to a mass ratio of 1: 8-15, uniformly stirring, and granulating to obtain the saline-alkali soil water-retention granules. The saline-alkali soil water-retention granules have the effects of water absorption, water retention and saline-alkali resistance, can improve the water-saving and drought-resistant capacity of rape production in the northwest saline-alkali dry land in China, and improve the planting benefit.

Description

Saline-alkali soil water-retention granules and preparation method thereof

Technical Field

The invention relates to the technical field of saline-alkali soil improvement, in particular to saline-alkali soil water-retention granules and a preparation method thereof.

Background

Saline-alkali soil is a soil type with accumulated salts, and refers to a soil type in which the normal growth of crops is affected by the salts contained in the soil. The saline-alkali soil comprises saline soil and alkaline earth, the saline soil mainly refers to saline soil with high chloride or sulfate content, and the soil is alkalescent. The alkaline earth refers to the soil containing carbonate or heavy phosphate, the pH value is higher, and the soil is alkaline. The area of the saline-alkali soil all over the world is 9.544 hundred million hectares, and the area of the saline-alkali soil is 9913 million hectares in China. The saline-alkali soil has low organic matter content, low soil fertility and poor physical and chemical properties, and the saline-alkali soil is often accompanied by drought, so that the crop yield is low and even the crop production is not suitable. In arid and semiarid regions in northwest and north China, the precipitation amount is small, the evaporation amount is large, the salt dissolved in water is accumulated on the surface layer of soil, and the seasonal change of the soil salt is not obvious. In the areas, because of large transpiration, small rainfall and high soil salinity, thick and hard salt crusts are formed on the ground surface, so that the soil profile has high salinity measurement, low crop yield and even is not suitable for crop production.

The existing water-retaining agent in the market has poor water-retaining and drought-resisting capability and basically has no saline-alkali resisting effect, and is not suitable for being used as a water-retaining agent for saline-alkali soil. Therefore, the development of a water-retaining agent with the effects of water absorption, water retention and saline-alkali resistance is an urgent technical problem to be solved.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides saline-alkali soil water-retention granules and a preparation method thereof.

The invention is realized by the following steps:

one of the purposes of the invention is to provide a preparation method of saline-alkali soil water-retention granules, which comprises the following steps:

step 1, preparing a phase A mixture: adding water into the macromolecular water-absorbing material mixture to prepare a colloidal mixture; adding biochar into the obtained colloidal mixture to prepare a phase A mixture;

step 2, preparing a B-phase mixture: uniformly stirring and mixing bentonite and attapulgite to obtain a phase B mixture; the mass ratio of the bentonite to the attapulgite is 1-3: 1;

step 3, mixing the phase A and the phase B according to a mass ratio of 1: 8-15, uniformly stirring, and granulating to obtain the saline-alkali soil water-retention granules.

Preferably, the high molecular water absorption material comprises one or more of polyethylene glycol, polypropylene glycol and polyacrylamide. More preferably, the mass ratio of the polyethylene glycol to the polypropylene glycol to the polyacrylamide is 1: 1: 1.

preferably, the mass concentration of the high molecular water absorbing material in the colloidal mixture in the step 1 is 8-15%.

Preferably, the biochar in the step 1 comprises biochar prepared at 300 ℃ (BC300) or biochar prepared at 500 ℃ (BC 500). The weight of the 300 ℃ modified biochar (BC300) is 1-3% (preferably 2%) of the weight of the colloidal mixture.

Preferably, the mass ratio of the bentonite to the attapulgite in the step 2 is 2: 1.

preferably, the mass ratio of the mixture of the phase A and the phase B in the step 3 is 1: 10. the particle size of the granulated saline-alkali soil water-retaining granules is 2-5 mm.

The invention also aims to provide the saline-alkali soil water-retaining granules prepared by the method.

The invention has the beneficial effects that:

1. the invention provides saline-alkali soil water-retaining granules, which are prepared by adding water into a macromolecular water-absorbing material to prepare a colloidal mixture and adding biochar into the colloidal mixture, and mixing the organic phase with an inorganic phase (bentonite and attapulgite in a mass ratio of 1-3: 1) according to a mass ratio of 1: 8-15, compounding to prepare composite water-retaining agent particles; humate formed by the organic phase degradation can promote the formation of soil aggregate structure, increase the porosity and enhance the water permeability, thus being beneficial to leaching salt and inhibiting salt return; the inorganic phase can absorb the moisture in the environment under a certain condition, so that the minerals are swelled to store the moisture, and when the inorganic phase and the organic phase are compounded, more organic-inorganic aggregates can be formed, and the storage of the moisture and the storage of nutrients in the soil are facilitated.

2. The saline-alkali soil water-retention granule provided by the invention has the effects of water absorption, water retention and saline-alkali resistance, and the water-retention agent is applied when the saline-alkali dry land is sowed, so that the saline-alkali stress can be effectively relieved, the irrigation water consumption is reduced, the water-saving and drought-resistant capability and the germination rate of crops and the quality of rape seedlings are improved, and the planting benefit is improved.

Detailed Description

The technical solution of the present invention will be described in detail with reference to examples. The following examples are merely illustrative of the present invention and should not be construed as limiting thereof. The specific techniques or conditions not mentioned in the examples are all performed according to the literature in the field or the conventional technical means in the field.

Example 1

The embodiment provides saline-alkali soil water-retention granules, and a preparation method thereof comprises the following steps:

selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of 10% of the high polymer material. Biochar (BC300) prepared at 300 ℃ was added to the gummy mixture in a portion of 2.0% of the gummy mixture, this is organic term a; the inorganic mineral item B is prepared from the following components in a mass ratio of 1: 1 bentonite and attapulgite mixture. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 10, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-1.

Example 2

selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of 10% of the high polymer material. Biochar (BC300) prepared at 300 ℃ was added to the gummy mixture in a portion of 2.0% of the gummy mixture, this is organic term a; the inorganic mineral item B is prepared from the following components in a mass ratio of 2: 1 bentonite and attapulgite mixture. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 10, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-2.

Example 3

selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of 10% of the high polymer material. Biochar (BC300) prepared at 300 ℃ was added to the gummy mixture in a portion of 2.0% of the gummy mixture, this is organic term a; the inorganic mineral item B is prepared from the following components in a mass ratio of 3: 1 bentonite and attapulgite mixture. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 10, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-3.

Example 4

selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of 8% of the high polymer material. Adding biochar (BC300) prepared at 300 ℃ to the gummy mixture in a fraction of 1% of the gummy mixture, this is organic term A; the inorganic mineral item B is prepared from the following components in a mass ratio of 1: 1 bentonite and attapulgite mixture. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 8, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-6.

Example 5

selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of the high polymer material of 12%. Biochar (BC300) prepared at 300 ℃ was added to the gummy mixture in 3% of the gummy mixture, this is organic term a; the inorganic mineral item B is prepared from the following components in a mass ratio of 1: 1 bentonite and attapulgite mixture. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 15, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-7.

Comparative example 1

Selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of 10% of the high polymer material. Biochar (BC300) prepared at 300 ℃ was added to the gummy mixture in a portion of 2.0% of the gummy mixture, this is organic term a; the inorganic mineral item B is bentonite. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 10, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-4.

Comparative example 2

Selecting an organic matter mixture (polyethylene glycol, polypropylene alcohol and polyacrylamide with the mass ratio of 1: 1: 1), and adding a certain amount of water to prepare a colloidal mixture with the mass concentration of 10% of the high polymer material. Biochar (BC300) prepared at 300 ℃ was added to the gummy mixture in a portion of 2.0% of the gummy mixture, this is organic term a; the inorganic mineral B is attapulgite. The organic item A and the inorganic item B are mixed according to the mass ratio of 1: 10, mixing, dispersing the mixture, granulating, controlling the particle size to be 2-5mm, and drying at the constant temperature of 50 ℃ to obtain the water-retaining agent BS-5.

Application examples

And in 2018, a saline-alkali land block of a big spring ditch in Shihuzi city is selected in the Uygur autonomous region in Xinjiang for testing. The pH value of the soil of the test field is 7.43, the total organic carbon content is 13.66g/kg, the organic matter content is 2.38%, the contents of quick-acting potassium, quick-acting phosphorus and quick-acting nitrogen are 285.2, 19.74 and 178.7mg/kg respectively, the content of the soil total salt is 0.077%, the content of carbonate is 88.17g/kg, the alkalization degree is 2.67%, and water-soluble sulfate is absent.

A rape variety 62 rich in Chinese thorowax oil is selected as a test material, ditching and drilling are carried out on the rape variety 8 months and 30 days in 2018, the row distance of each row is 25cm, the length of each row is 150cm, and 150 seeds are sowed in each row. When the rape is sowed, each water-retaining agent is divided into two doses (39 and 58 kg/mu) which are repeated for three times, the granular water-retaining agents and seeds are uniformly mixed and sowed, and the same rape sowing amount and the same granular water-retaining agent using amount are adopted in each row. And applying 45kg of compound fertilizer (15 percent of nitrogen, phosphorus and potassium respectively) per mu before sowing (applying fertilizer in 24 days in 7 months). The seedlings of the rapes are not thinned, the number of seedlings in each row is counted after 16 days of sowing, and the results are shown in table 1. 25 plants were randomly sampled at 20 days in 10 months, and the indexes of root system and overground part of the plant, such as root length, seedling height, fresh weight and dry weight, are measured, and the results are shown in Table 2.

TABLE 1 statistics of emergence after 16 days of sowing (150cm length, unit: plant)

As can be seen from the table 1, after the water-retaining agent is applied, the emergence rate of the saline-alkali soil shows a trend of increasing, the emergence rates of the BS-1, BS-2 and BS-3 series water-retaining agents are higher than those of the control, the increase rate is between 11% and 320%, and significant differences exist, which indicate that different water-retaining agents have different influences on the germination of rapes in the saline-alkali soil. However, the emergence rates of the water-retaining agents BS-4 and BS-5 are obviously lower than those of other series and lower than that of a control, which shows that the compounding effect of the inorganic filler in the water-retaining agent is important for improving the water-retaining capacity of the water-retaining agent. Meanwhile, the water-retaining agents are different in dosage and have larger difference in germination rate, the 39 kg/mu dosage of the water-retaining agent is more favorable for rape germination, and the high-dosage (58 kg/mu) water-retaining agent can inhibit rape germination. In addition, the effect of the water-retaining agent BS-2 is best, the effect of the water-retaining agent BS-3 is slightly inferior, but the emergence rate is far higher than that of the contrast, the water-retaining agent BS-1 is slightly poor, the effects of BS-4 and BS-5 are the worst, and the effects of BS-6 and BS-7 are poor. In practical application, the low-dosage inorganic mineral composite water-retaining agent is more reasonable.

TABLE 2-survey of rape seedling growth 50 days after sowing (random 25 plants analysis)

TABLE 3-survey of rape seedling growth 50 days after sowing (random 25 plants analysis)

As can be seen from tables 2-3, after the water-retaining agent is applied, the later growth of the rape is obviously different. After 50 days of sowing, compared with a control, the plant height growth rate of the rape is 16-65%, and the difference is large; the root length increase rate is between 2% and 46%, and great difference exists; the amount of the water retention agent is increased, and the plant height and the root length growth rate of the rape plants are changed greatly. After the water-retaining agent is applied, the fresh weight increment of the rape root system is between 20 and 360 percent, and the obvious difference exists; the water retention agent dosage is increased, and the growth change rate of the water retention agent is different. After the water-retaining agent is applied, the overground fresh weight increment of rape plants is 22-159%, and a significant difference exists; while the difference between different material treatments is obvious between 53 percent and 121 percent of the dry weight of the rape. The amount of the water-retaining agent is increased, and the overground fresh weight and the plant dry weight of the rape plant are reduced, although the amount is increased compared with the control. The results show that different water-retaining agents have different influences on the growth of the rapes in the saline-alkali soil. Meanwhile, the water-retaining agents with different dosages have larger difference in the growth of the rapes, and the water-retaining agents with the dosages lower than 39 kg/mu have better influence on the growth and development of the rapes.

As is clear from tables 1 and 2, the emergence rates of BS1, BS-2 and BS-3 (the B phase mixture is bentonite and attapulgite in a mass ratio of 1-3: 1) were higher and the growth vigor of rape seedlings was better than those of BS-4 (the B phase mixture is bentonite) and BS-5 (the B phase mixture is attapulgite).

As can be seen from tables 1 and 3, the emergence rates of BS1, BS-2 and BS-3 are higher and the growth vigor of rape seedlings is better than those of BS-6 and BS-7; the mass ratio of the mixture of the phase A and the phase B is shown to influence the water-saving drought resistance, the germination rate and the quality of rape seedlings, and the mass ratio of the organic phase to the inorganic phase is 1: 8-15, more organic-inorganic aggregates can be formed, and the prepared composite water-retaining agent particles are more beneficial to preservation of water and storage of nutrients in soil.

The invention is not to be considered as limited to the particular embodiments shown, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of saline-alkali soil water-retention granules is characterized by comprising the following steps:

step 1, preparing a phase A mixture: adding water into a macromolecular water-absorbing material to prepare a colloidal mixture; adding biochar into the obtained colloidal mixture to prepare an A-phase mixture, wherein the high-molecular water-absorbing material comprises polyethylene glycol, polyallyl alcohol and polyacrylamide, and the mass ratio of the polyethylene glycol to the polyallyl alcohol to the polyacrylamide is 1: 1: 1, the biochar comprises biochar BC300 prepared at 300 ℃;

2. The method for preparing the saline-alkali soil water-retaining granules according to claim 1, wherein the mass concentration of the polymer water-absorbing material in the colloidal mixture in the step 1 is 8-15%.

3. The method for preparing the saline-alkali soil water-retaining granules according to claim 2, wherein the weight of the biochar BC300 prepared at 300 ℃ in the step 1 is 1-3% of the weight of the colloidal mixture.

4. The method for preparing the saline-alkali soil water-retaining granules according to claim 1, wherein the mass ratio of the bentonite to the attapulgite in the step 2 is 2: 1.

5. the method for preparing the saline-alkali soil water-retaining granules according to claim 1, wherein the mass ratio of the mixture of the phase A and the phase B in the step 3 is 1: 10.

6. the method for preparing the saline-alkali soil water-retaining granules according to claim 1, wherein the particle size of the saline-alkali soil water-retaining granules after granulation in the step 3 is 2-5 mm.

7. The saline-alkali soil water-retaining granules prepared by the method of any one of claims 1 to 6.