A straw compound fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of fertilizers, and in particular to a straw compound fertilizer and a preparation method thereof, wherein the preparation method comprises spraying liquid onto a compound fertilizer of mass a and in a discrete state, so that the surface of the compound fertilizer is damp and mutually adheres to obtain the compound fertilizer in an aggregated solidified state; secondly spraying liquid onto the compound fertilizer in the aggregated solidified state, so as to obtain the compound fertilizer in an aggregated solidified state with a moist surface; then placing the compound fertilizer in the aggregated solidified state with a moist surface in straw powder of mass b, so as to obtain the compound fertilizer with the straw powder adhered to the surface; and finally drying the compound fertilizer with the straw powder adhered to the surface, so as to obtain the straw compound fertilizer; wherein a:b is 1:0.25-1, and when the straw compound fertilizer prepared by the invention is stored, the straw powders abut against each other, so as to avoid the straw compound fertilizer from adhering to each other in a humid environment, and no anti-caking agent is required to be sprayed on the surface of particles, and the straw compound fertilizer is directly and slowly released under the rhizomes of plants, so as to avoid the dispersion of particles and the reduction of fertilizer utilization rate.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizers, and in particular to a straw compound fertilizer and a preparation method thereof. Background Art

[0002] The solid fertilizers currently used on the market are generally granular fertilizers with a diameter between 2-2.5mm. The small particles and large specific surface area result in a large contact area between the fertilizer particles, making the fertilizer more susceptible to moisture and caking. Currently, the method of spraying anti-caking agents on the surface of the particles is usually adopted, which will lead to a waste of anti-caking agents. In addition, small particles and large specific surface area will also lead to a large dispersion of granular fertilizers after they are applied to the soil, and the probability of fertilizer nutrients being fixed by the soil instead of being absorbed by plants is high, reducing the utilization rate of the fertilizer. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a straw compound fertilizer and a preparation method thereof, which is used to solve the problem that the solid fertilizer used on the market has a large specific surface area, which leads to a large dispersion of granular fertilizer after being applied to the soil, and a high probability that the fertilizer nutrients are fixed by the soil instead of being absorbed by plants, resulting in a reduced utilization rate of the fertilizer.

[0004] The present invention provides a straw compound fertilizer, comprising compound fertilizer and straw powder;

[0005] Wherein, the straw powder is bonded to the outer surface of the compound fertilizer;

[0006] The mass ratio of the straw powder to the compound fertilizer is 0.25-1:1.

[0007] Preferably, the mass ratio of the straw to the compound fertilizer is 0.25:1.

[0008] Preferably, the straw powder is obtained by crushing the straw and passing it through a 60-mesh sieve.

[0009] Preferably, the compound fertilizer is a 45% compound fertilizer with N:P:K=15:15:15;

[0010] Among them, the straw compound fertilizer is in a spherical shape with a diameter of 3-4cm.

[0011] The present invention also provides a method for preparing a straw compound fertilizer, comprising:

[0012] Step 1: spraying liquid onto the compound fertilizer of mass a in a discrete state, so that the surface of the compound fertilizer is dampened and adheres to each other, thereby obtaining the compound fertilizer in an aggregated and solidified state;

[0013] Step 2: spraying liquid onto the aggregated solidified compound fertilizer to obtain the aggregated solidified compound fertilizer with a moist surface;

[0014] Step 3: placing the compound fertilizer in a wet aggregated solidified state in straw powder of mass b to obtain a compound fertilizer with straw powder adhered to the surface;

[0015] Step 4: drying the compound fertilizer with straw powder adhered to the surface to obtain straw compound fertilizer;

[0016] Among them, a:b is 1:0.25-1.

[0017] Preferably, the liquid is water.

[0018] Preferably, the straw is rice straw.

[0019] Beneficial effects:

[0020] 1. When storing the above straw compound fertilizer, the straw powders are in contact with each other to avoid direct contact between the compound fertilizer particles. Thus, in a humid environment, the straw compound fertilizer will not be bonded together, and there is no need to spray an anti-caking agent on the particle surface.

[0021] 2. When the straw compound fertilizer is in a humid environment, water first reaches the compound fertilizer through the straw powder. At this time, the surface of the compound fertilizer is moist and melted, and the compound fertilizer slowly moves toward the outer straw and contacts the plant roots. Under the action of microorganisms in the soil, the straw powder is gradually corroded into nutrients and absorbed by the plant roots together with the compound fertilizer. In this way, large-particle straw compound fertilizer can realize the slow release of fertilizer directly under the plant roots, avoiding the dispersion of particles and reducing the fertilizer utilization rate, and avoiding direct contact between the compound fertilizer and the plant root system, which may cause the plant root system to be burned.

[0022] 3. Deep burial of straw and return to the field + reduced application of chemical fertilizers can promote the growth and quality of crops. At the same time, it can also increase soil porosity, increase the number of soil microbial populations and other land-saving benefits. In addition, mixing straw with inorganic fertilizers can accelerate straw decomposition and improve fertilizer efficiency.

[0023] 4. A spherical straw compound fertilizer can provide the nutrients needed for the entire growth process of crops, and the application of spherical straw compound fertilizer can achieve the effect of reducing the amount of chemical fertilizer and increasing its efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : A schematic diagram of the spherical straw compound fertilizer covered with rhizomes dug out after harvesting corn in the present invention;

[0025] Figure 2 : A schematic diagram of the surface of the spherical straw compound fertilizer densely covered with bacterial colonies after corn is harvested in the present invention;

[0026] Figure 3 : It is a schematic diagram of the cross section of the spherical straw compound fertilizer after corn is harvested in the present invention;

[0027] Figure 4 : It is a schematic diagram of the spherical straw compound fertilizer which is almost wrapped by the rhizome after the corn is harvested in the present invention. DETAILED DESCRIPTION

[0028] Embodiment 1:

[0029] A straw compound fertilizer comprises compound fertilizer and straw powder; wherein the straw powder is adhered to the outer surface of the compound fertilizer; and the mass ratio of the straw powder to the compound fertilizer is 0.25-1:1.

[0030] Exemplarily, the mass ratio of straw to compound fertilizer is 0.25:1.

[0031] The straw powder is obtained by crushing rice straw and passing it through a 60-mesh sieve, and the compound fertilizer is a 45% compound fertilizer with N:P:K=15:15:15; the straw compound fertilizer is in a spherical shape with a diameter of 3-4 cm.

[0032] Example 2

[0033] A method for preparing the straw compound fertilizer described in Example 1 comprises:

[0034] Step 1: spraying atomized water onto the compound fertilizer of mass a in a discrete state, so that the surface of the compound fertilizer is dampened and adheres to each other, thereby obtaining the compound fertilizer in an aggregated and solidified state;

[0035] Step 2: spraying atomized water onto the aggregated solidified compound fertilizer to obtain the aggregated solidified compound fertilizer with a moist surface;

[0036] Step 3: placing the compound fertilizer in a wet aggregated solidified state in straw powder of mass b to obtain a compound fertilizer with straw powder adhered to the surface;

[0037] The straw powder is adhered to the surface of the compound fertilizer by adopting a layered multiple adhesion method.

[0038] Specifically, after a layer of straw powder is adhered to the surface of the compound fertilizer, the compound fertilizer is dried at a drying temperature of 60-80°C, exemplarily 70°C. After drying, the compound fertilizer adhered with the straw powder is sprayed with armed water, and then the dry straw powder is continued to contact the wet surface of the compound fertilizer adhered with the straw powder to continue bonding until all the straw with a weight of b is adhered to the surface of the compound fertilizer.

[0039] Among them, a:b is 1:0.25-1, and illustratively, a:b is 1:1.

[0040] Step 4: Dry the compound fertilizer with straw powder adhered to the surface to obtain straw compound fertilizer.

[0041] The drying temperature is 60-80°C, and 70°C is exemplary.

[0042] Comparative Example 1

[0043] A method for preparing a straw compound fertilizer, which differs from Example 2 in that:

[0044] The compound fertilizer solution and straw powder are mixed and dried to prepare a spherical compound fertilizer.

[0045] The mass ratio of compound fertilizer solution to straw powder is 1:1.

[0046] Among them, the straw powder is not sieved.

[0047] Comparative Example 2

[0048] A method for preparing a straw compound fertilizer, which differs from Example 2 in that:

[0049] The straw was not sieved.

[0050] Comparative Example 3

[0051] A method for preparing a straw compound fertilizer, which differs from Example 2 in that:

[0052] The material bonded to the surface of the compound fertilizer is composed of matrix soil and unscreened straw powder.

[0053] Among them, the ratio of matrix soil: straw powder: compound fertilizer is 0.5:0.5:1.

[0054] The method comprises the following steps: firstly, mixing the matrix soil and the straw powder uniformly, and then bringing the surface-moistened compound fertilizer into contact with and bonded with the mixture of the matrix soil and the straw powder.

[0055] Comparative Example 4

[0056] A method for preparing a straw compound fertilizer, which differs from Example 2 in that:

[0057] The material bonded to the surface of the compound fertilizer is composed of matrix soil and 60-mesh sieved straw powder.

[0058] Among them, the ratio of matrix soil: straw powder: compound fertilizer is 0.5:0.5:1.

[0059] The method comprises the following steps: firstly, mixing the matrix soil and the straw powder uniformly, and then bringing the surface-moistened compound fertilizer into contact with and bonded with the mixture of the matrix soil and the straw powder.

[0060] Performance testing and analysis:

[0061] 1. Roundness index (K)

[0062] Take 20 spherical straw compound fertilizers after drying, and use a vernier caliper to measure their diameters in the x, y, and z directions in the Cartesian coordinate system. The number of the three diameter data with a maximum difference of no more than 3 mm is recorded as n, and the roundness index K=n / 20.

[0063] 2. Drop strength index (Δ)

[0064] Take 20 ball-like straw compound fertilizer samples and drop them repeatedly at a height of 200 mm, up to 20 times, and record the average number of times without breakage as the drop strength index of the ball-like straw compound fertilizer, with the unit of times / grain (n / p).

[0065] Among them, the roundness index and drop strength index test results are shown in Table 1 below:

[0066] Table 1 Roundness index and drop strength index test results:

[0067] K Δ(times / particle) Example 2 1 19.8 Comparative Example 1 0.1 1.4 Comparative Example 2 0.7 6.1 Comparative Example 3 0.85 18.4 Comparative Example 4 1 20

[0068] It can be seen that Example 2 and Comparative Example 4 are better formed and have a higher drop strength index, but the density and volume of the spherical straw compound fertilizer in Comparative Example 4 are relatively large, which may be inconvenient to transport. It is confirmed that straw and traditional fertilizers can be mixed to make spherical organic-inorganic compound fertilizers with good strength.

[0069] 3. Analysis of the influence of the mass ratio of straw powder to compound fertilizer on straw compound fertilizer

[0070] In order to further reduce the volume of spherical straw compound fertilizer, molding experiments with different proportion gradients were set up.

[0071] Specifically, the process of Example 2 was used to set the ratio gradient of inorganic nutrient weight of compound fertilizer to straw weight to be 1:1, 1:0.5, 1:0.25, and 1:0.125, respectively. After rolling the balls, they were dried and the drop strength Δ was tested.

[0072] The test results are shown in Table 2 below:

[0073] Table 2 Experimental results

[0074] Inorganic nutrient quality: straw quality Δ(times / particle) 1:1(A1) 19.8 1:0.5(A2) 19.9 1:0.25(A3) 20 1:0.125(A4) Basically shapeless

[0075] It can be seen that based on 20g of 45% (15-15-15) compound fertilizer, the diameter of the spherical straw compound fertilizer made according to the ratio of A3 is between 3 and 5cm, which preliminarily meets the expectations and can be used for field cultivation trials.

[0076] 4. Analysis of the impact of straw compound fertilizer on corn growth cycle

[0077] On the basis of Example 2, the effects of spherical straw compound fertilizer and common 45% compound fertilizer on the whole growth cycle of corn were further compared under the premise of equal amount of inorganic nitrogen.

[0078] Specifically, the processing technology includes:

[0079] Prepare spherical straw compound fertilizer according to 13.2kg of pure nitrogen per mu, and weigh the same inorganic compound fertilizer.

[0080] T1: 13.2kg pure nitrogen per mu, one-time basal fertilizer application;

[0081] T2: 13.2kg pure nitrogen per mu, one-time basal fertilizer hole application;

[0082] T3: 13.2 kg of pure nitrogen per mu is converted into 22 g of 45% inorganic fertilizer per corn plant, and a spherical straw compound fertilizer is prepared according to the process of Example 2 at a ratio of 1:0.25 for hole application.

[0083] See the following table 3 for the germination results:

[0084] Table 3 Seedling results

[0085]

[0086] The mid-term corn plant height is shown in Table 4 below:

[0087] Table 4 Plant height of corn in mid-term

[0088]

[0089] The height of corn plants in the later period is shown in Table 5 below:

[0090] Table 5 Plant height of corn in late stage

[0091]

[0092] The diameter of corn stalks in the later period is shown in Table 6 below:

[0093] Table 6 Diameter of corn stalk in late stage

[0094]

[0095] The chlorophyll content of corn leaves in the later period is shown in Table 7 below:

[0096] Table 7 Chlorophyll content of leaves in late stage

[0097]

[0098] The final results are shown in Table 8 below:

[0099]

[0100]

[0101] Harvest or dig out straw compound fertilizer, such as attached Figure 1-4 As shown in Table 3-8, it can be seen that deep burial of straw and reduced application of chemical fertilizers can promote the growth and quality of crops. At the same time, it can also increase soil porosity, increase the number of soil microbial populations and other land-saving benefits. In addition, mixing straw with inorganic fertilizers can accelerate straw decomposition and improve fertilizer efficiency.

[0102] In addition, large-particle straw compound fertilizer can slowly release fertilizer directly under the roots of plants, avoiding the dispersion of particles and reducing fertilizer utilization, and preventing compound fertilizer from directly contacting plant roots and causing plant roots to be burned.

Claims

1. A method for preparing a straw compound fertilizer, characterized in that: include: Step 1: spraying liquid onto the compound fertilizer of mass a in a discrete state, so that the surface of the compound fertilizer is dampened and adheres to each other, thereby obtaining the compound fertilizer in an aggregated and solidified state; Step 2: spraying liquid onto the aggregated solidified compound fertilizer to obtain the aggregated solidified compound fertilizer with a moist surface; Step 3: placing the compound fertilizer in a wet aggregated solidified state in straw powder of mass b to obtain a compound fertilizer with straw powder adhered to the surface; Step 4: drying the compound fertilizer with straw powder adhered to the surface to obtain straw compound fertilizer; Among them, a:b is 1:0.25-1; The liquid is water; The straw powder is obtained by crushing the straw and passing it through a 60-mesh sieve; the compound fertilizer is a 45% compound fertilizer with N:P:K=15:15:15; Among them, the straw compound fertilizer is in a spherical shape with a diameter of 3-4cm.

2. The method according to claim 1, characterized in that: The straw is rice straw.

3. The straw compound fertilizer prepared by the method according to claim 2, characterized in that: Including compound fertilizer and straw powder; Wherein, the straw powder is bonded to the outer surface of the compound fertilizer; The mass ratio of the straw powder to the compound fertilizer is 0.25:1; The straw powder is obtained by crushing the straw and passing it through a 60-mesh sieve; the compound fertilizer is a 45% compound fertilizer with N:P:K=15:15:15; Among them, the straw compound fertilizer is in a spherical shape with a diameter of 3-4cm.

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