Water-locking and fertilizer-preserving sponge particle as well as preparation method and application thereof

Abstract

The invention provides a water-retaining and fertilizer-retaining sponge particle and a preparation method and application thereof.The preparation method comprises the steps that straw and decomposed cow dung are mixed according to the mass ratio of 15: 1, the water content is adjusted to 40% with a 0.1% CMC solution, then the mixed material is put into a growth base preparation device, and the sponge particle is prepared; when the prepared sponge particles are applied to farmland, growth of weeds can be reduced to a certain extent, the surface temperature can be reduced when the sponge particles are applied to the surface of sand land, and the risk that seedlings grow in the sand land and are burnt is reduced; in addition, after covering the earth surface soil, the sponge particles can absorb moisture and reduce soil moisture evaporation, meanwhile, the underwater infiltration depth is shallower than that of bare land, the intensity of solar radiation reaching the earth surface is reduced, and the soil temperature difference is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of soil wind erosion control and improvement, and particularly relates to a water-locking and fertilizer-preserving sponge granule, a preparation method thereof and an application thereof. Background Art

[0002] In arid and semi-arid grassland degradation areas, drought, less rainfall, low soil fertility and serious soil wind erosion are the main reasons for ecological degradation. In recent years, in view of the ecological degradation problems in arid and semi-arid areas, a large number of ecological restoration projects based on the planting of restoration species have been carried out. However, there are phenomena such as "planting trees every year but not seeing forests" and "stunted trees", and the problems of soil water and fertilizer and soil wind erosion have not been fundamentally solved, and the ecological restoration effect is relatively low. Changing the surface cover method is one of the important ways to solve soil water and fertilizer and soil wind erosion. The purpose is to improve the soil water storage and moisture conservation capacity, soil nutrient content, improve the soil structure, and at the same time achieve the purpose of soil and fertilizer conservation by adopting optimized surface cover technology. Regarding the application effects of various surface coverings, a large number of studies have been carried out at home and abroad, mainly focusing on the effects of surface coverings on soil moisture, soil structure and nutrients, soil temperature, erosion resistance, plant growth, etc. The advantages and disadvantages of various covering materials are significantly different. For example, the prior art often evenly spreads crop straws (such as corn straws, wheat straws, etc.) on the soil surface to form a protective layer. This layer of covering can effectively block the direct contact between the wind and the soil, reduce the starting and movement of soil particles, and can reduce the wind erosion intensity, but it cannot effectively improve soil fertility and maintain soil moisture. Summary of the Invention

[0003] In order to solve the above problems, the present invention produces water-locking and fertilizer-preserving sponge granules, which have the advantages of water storage and moisture conservation, improving soil structure and nutrients, and wind erosion resistance, and provide theoretical and technical support for ecological restoration practice in arid and semi-arid areas.

[0004] The preparation method of the water-locking and fertilizer-preserving sponge granule is to mix straw and decomposed cow dung in a mass ratio of 15:1, and adjust the moisture content with a CMC solution, and then put the mixed material into a growth medium preparation device to obtain sponge granules.

[0005] The growth medium preparation device is the growth medium preparation device described in the patent application with the patent number 201821615117.0. The specific method for the growth medium preparation device to prepare sponge granules refers to "Design and Test of Straw Nutrient Growth Medium Molding Device", authors Tian Meirong, Gao Jixi, Liang Hui and Niu Jianhui.

[0006] Preferably, the mass concentration of the CMC solution is 0.1%.

[0007] Preferably, the moisture content is adjusted to 40%.

[0008] Preferably, the straw is crushed into straw filaments of 1 cm - 5 cm and then mixed.

[0009] Preferably, the method for preparing the decomposed cow dung is to compost cow dung with a moisture content of 50%-65% for 1 month at a fermentation temperature of 55-70° C. and turn the pile every 4 days to obtain the decomposed cow dung.

[0010] The application method of the water-locking and fertilizer-retaining sponge particles in soil ecological restoration is to cover the soil surface with the water-locking and fertilizer-retaining sponge particles, with a coverage rate of 20%-70%.

[0011] The present invention has the following advantages:

[0012] (1) Strong water retention capacity

[0013] The water-locking and fertilizer-retaining sponge particles can efficiently absorb and store water, with a water absorption rate of several times its own weight. In arid and semi-arid areas, this characteristic can significantly reduce the evaporation and loss of soil moisture, improve the soil's water utilization efficiency, and ensure that plants can still obtain a stable water supply under drought conditions.

[0014] (2) Efficient fertilizer retention function

[0015] The water-locking and fertilizer-retaining sponge particles can not only absorb water, but also adsorb and slowly release nutrients, promoting the decomposition of organic matter and the release of nutrients. This feature can effectively reduce fertilizer loss, improve soil fertility, reduce the frequency and amount of fertilization, thereby saving resources and reducing environmental pollution. In ecological restoration, this fertilizer-retaining function helps improve soil quality and promote the recovery and growth of vegetation.

[0016] (3) Significant anti-wind erosion effect

[0017] The porous structure and high strength of the water-locking and fertilizer-retaining sponge particles enable them to form a stable protective layer on the soil surface, effectively resisting wind erosion. Its granular form can increase the roughness of the soil and reduce the force of wind speed on soil particles, thereby reducing wind erosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0019] Figure 1 The soil moisture content at a depth of 0-10cm changes under different covering conditions.

[0020] Figure 2The effects of different sponge particles on the available nutrients in soil at different soil depths (in the figure, H1, H2, and H3 are the sample numbers for three samplings at 10-day intervals, and CK is the control group).

[0021] Figure 3 The wind erosion amount of sandy soil under different sponge particle coverings. Specific implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment 1

[0024] Step 1: Crush rice straw into straw filaments with lengths ranging from 1 cm to 5 cm.

[0025] Step 2: Compost cow dung with a moisture content of 50%-65% for 1 month at a fermentation temperature of 55-70%. Turn the pile every 4 days and adjust the moisture content until the compost is fully decomposed.

[0026] Step 3: Mix the straw and decomposed cow dung in a mass ratio of 15:1, and adjust the moisture content to 40% with a 0.1% CMC solution by mass concentration. Then, put the mixed material into a growth medium preparation device to obtain sponge particles. The sponge particles are in the shape of hexagonal slices, with a bottom diameter of 9 cm and a thickness of 1.5 cm. The growth medium preparation device is the growth medium preparation device described in the patent application with the patent number 201821615117.0, and a forming mechanism 9 with a hexagonal cross-section of the internal cavity is selected. For the specific method of preparing sponge particles by the growth medium preparation device, refer to "Design and Experiment of Straw Nutrient Growth Medium Molding Device" by Tian Meirong, Gao Jixi, Liang Hui, and Niu Jianhui.

[0027] Test Example 1

[0028] For the water retention test of sponge particles, two treatments are designed. The first group of treatments adopts the bare land mode of the growth pond (control CK), and the second group adopts the sponge particle full-coverage growth pond mode. The test areas are 1 m 2 .

[0029] Water both groups of growth ponds with 10.4 kg of water at the same time. In the evening, use a ring knife to sample the topsoil of 0-10 cm of the two growth ponds three times. Use the drying method to measure the soil moisture content and test the soil moisture content of the two treatments. The results are as Figure 1 .

[0030] There is Figure 1It can be seen that since the evapotranspiration capacity of the bare soil layer is greater than that of the soil layer covered with sponge particles, the sponge particles form a protective isolation layer for the soil, reducing solar radiation and lowering the evaporation efficiency. At the same time, part of the water absorbed by the sponge particles can infiltrate into the soil to supplement soil moisture; on the 7th day, due to the higher air humidity than that on the 6th day, the water content of the topsoil under the uncovered condition is 1.05% higher than that on the 6th day, resulting in a slower decrease in the water content of the topsoil covered with sponge particles.

[0031] Experimental Example 2

[0032] For the fertilizer retention property of sponge particles, when no sponge particles were covered in the experiment, the first sampling of 0-10 cm and 10-20 cm was carried out on September 9 as the control group (CK). The sponge particles were treated according to the experimental design and watered twice, 10.4 kg of water was applied on September 9 and September 11 respectively. The first, second, and third samplings (codes are H1, H2, and H3 respectively) of the 0-10 cm and 10-20 cm soil covered with sponge particles were carried out on September 10, September 12, and September 24 to analyze the available nitrogen, available phosphorus, and available potassium in the soil. Among them, the diffusion distillation method was used for the determination of soil available nitrogen, the sodium bicarbonate extraction solution-ammonium molybdate spectrophotometry was used for the determination of soil available phosphorus, the ammonium acetate extraction-atomic absorption spectrophotometer method was used for the determination of soil available potassium, and the pH meter method was used for the determination of soil pH value. The results are as Figure 2 .

[0033] It can be seen from Figure 2 that the available nitrogen in H3 is the largest in 0-10 cm, and the available nitrogen content in H1 is the largest in 10-20 cm; the available phosphorus content in H1 is the largest in both 0-10 cm and 10-20 cm. The available potassium content in H3 is the largest in 0-10 cm, and the available potassium content in H2 is the largest in 10-20 cm.

[0034] Experimental Example 3

[0035] Flaky sponge particles with a hexagon of about 67 cm 2 were evenly covered on the soil tray to simulate the effect of sponge particle coverage on the wind erosion resistance of the soil. The sandy soil was placed in a soil tray with a size of 1 m 2 ×m 2 , and a height of 7 cm. An industrial electric blower was used to simulate blowing, and a Kestrel 4500 handheld anemometer was used to measure and record the instantaneous wind speed. The sponge particle coverage = sponge particle area / soil tray area × 100. The sponge particle coverage was set to: 0%, 20%, 30%, 40%, 50%, 60%, 70% for a total of 7 treatments, and each treatment was repeated 3 times. The eroded materials within 1 m × 1.6 m in front of the soil tray were collected.

[0036] For the determination of the wind erosion resistance of the sponge granule cover, when the water content of the sandy soil in the soil tray is 4% and the sponge granule cover is 0%, the wind erosion starting velocity of the bare land is measured to be 4.5 m / s. When the set wind speed is 7 m / s, the erosion amount of the sandy soil is measured. The measurement method is to place an empty tray of 1 m × 1.6 m in front of the erosion soil tray to collect the eroded materials in the soil tray, and then weigh them with a balance. The results are as Figure 3 .

[0037] It can be Figure 3 seen that with the increase of the sponge granule cover, the wind erosion amount of the sandy soil shows a downward trend. When the cover is 20%, the wind erosion amount decreases by 74.95% compared with the case without cover. When the cover is 40%, it decreases by 63.65% compared with the 20% cover. When the cover is 70%, it decreases by 27.25% compared with the 40% cover. And when the cover is 50%, the wind erosion amount increases by 36.09% compared with the 40% cover, indicating that when the cover degree exceeds 40%, increasing the cover degree has no significant effect on the wind erosion resistance. When the cover degrees are 20%, 30%, 40%, 50%, 60%, and 70%, the erosion amounts are 25.05%, 18.14%, 9.11%, 12.39%, 9.48%, and 6.62% of the erosion amount without cover respectively. Through experimental observation, it mainly depends on the sponge granule cover situation at the near-air inlet of the soil tray. Considering comprehensively, the cover degree of 20% is the most suitable coverage degree.

[0038] For the water-locking and fertilizer-preserving sponge granules prepared by the present invention, the water retention capacity of the sponge granules for the soil is at most 4.9% higher than that of the control group, increasing the soil water content. At the same time, the sponge granules contain a certain amount of water, and in the later stage, the soil water content decreases more slowly than that of the control group, which can effectively reduce the number of artificial watering times and ensure sufficient water for crop growth; the coverage of the sponge granules has a certain influence on the infiltration of water in the soil. In the experiment, when the sponge granules are 100% covered, the measured infiltration depth of water at the soil covered by the sponge granules is about 5 cm less than that of the control group. The sponge granules have strong fertilizer-preserving properties and can improve the soil nutrients relatively quickly.

[0039] For the wind prevention and sand fixation performance of the sponge granules, the simulation test research shows that after the sponge granules are covered, the soil erosion amount shows an "L"-shaped downward characteristic. When the coverage is 20%, the erosion amount is 25.05% of the erosion amount without coverage, and the reduction of the erosion amount is obvious.

[0040] After the sponge granules are applied to the field, rainwater or artificial drip irrigation is required for leaching, which is convenient for the quick-acting components of the sponge granules to enter the soil through leaching, accelerating the rate of the sponge granules to improve the soil nutrient structure. Applying the sponge granules to the farmland can reduce the growth of weeds to a certain extent; applying them to the sandy land surface can reduce the surface temperature and reduce the risk of seedling growth burns on the sandy land. In addition, after the sponge granules cover the soil surface, the infiltration depth of water is shallower than that of the bare land, reducing the intensity of solar radiation reaching the ground surface and reducing the soil temperature difference.

[0041] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a water-locking and fertilizer-retaining sponge granule, characterized in that, It includes the following steps: mixing straw and decomposed cow dung in a mass ratio of 15:1, adjusting the moisture content with a CMC solution, and then putting the mixed material into a growth medium preparation device to obtain sponge pellets.

2. The preparation method of a water-locking and fertilizer-retaining sponge granule according to claim 1, wherein The mass concentration of the CMC solution is 0.1%.

3. The preparation method of a water-locking and fertilizer-retaining sponge granule according to claim 1, characterized in that, Adjust the moisture content to 40%.

4. The preparation method of a water-locking and fertilizer-retaining sponge granule according to claim 1, characterized in that, Crush the straw into straw filaments of 1 cm - 5 cm and then mix.

5. The preparation method of a water-locking and fertilizer-preserving sponge granule according to claim 1, characterized in that, The preparation method of the decomposed cow dung is: compost and ferment cow dung with a moisture content of 50% - 65% for 1 month at a fermentation temperature of 55 - 70 °C, and turn the pile once every 4 days to obtain decomposed cow dung.

6. The water-locking and fertilizer-retaining sponge pellets prepared by the method according to any one of claims 1 - 5.

7. The application of the water-locking and fertilizer-retaining sponge pellets according to any one of claims 1 - 6 in soil ecological restoration.

8. The application according to claim 7, characterized in that, The application method is: covering the soil surface with the water-locking and fertilizer-retaining sponge pellets, and the coverage rate is 20% - 70%.

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