A calculation method for the maximum safe phosphorus reserve in red soil profile of sloping paddy fields

Abstract

The invention discloses a method for calculating the maximum safe phosphorus reserve of a red soil profile of a sloping paddy field, comprising the following steps: determining the concentration of water-soluble phosphorus in the soil; determining the phosphorus saturation in the soil; performing linear fitting on the concentration value of the water-soluble phosphorus in the soil and the phosphorus saturation value in the soil, and obtaining an inflection point as the phosphorus saturation threshold value in the soil; calculating the soil phosphorus storage capacity by using the obtained soil phosphorus saturation threshold value; calculating the soil residual phosphorus reserve, and then obtaining the soil safe phosphorus reserve by adding the calculated soil residual phosphorus reserve and the soil phosphorus storage capacity; while judging whether the soil has a loss risk, estimating and clarifying the maximum safe phosphorus reserve of the red soil paddy field profile, and making judgments and predictions for the effective evaluation of the soil residual phosphorus reserve and its biological effectiveness and environmental safety.

Description

Technical Field

[0001] The invention relates to the field of agricultural soil phosphorus loss assessment, and specifically to a method for calculating the maximum safe phosphorus reserve in a red soil profile of a sloping paddy field. Background Art

[0002] Phosphorus is an essential nutrient for plant growth and an important pollutant in the aquatic environment. The long-term application of exogenous phosphate fertilizer is an important way to improve soil quality and enhance soil fertility, but the exogenous phosphorus that enters the soil will quickly combine with iron, aluminum and other ions in the soil to form insoluble phosphate precipitates, or adsorb and fix on soil colloidal particles, thereby reducing the biological effectiveness of soil phosphorus. Therefore, long-term and large-scale application of phosphate fertilizers is required in agricultural production to ensure high and stable crop yields, but at the same time, it also increases the amount of primary sequestration and loss risk of soil residual phosphorus. The alternating water management mode of "flooding-drying-rewatering" in rice fields increases the risk of soil phosphorus migration and loss at the profile scale. Therefore, effectively estimating the safe reserves of soil phosphorus in rice field profiles and its loss potential are of great significance to the efficient management of soil phosphorus in rice fields. Summary of the invention

[0003] In order to solve the deficiencies mentioned in the above background technology, the purpose of the present invention is to provide a method for calculating the maximum safe phosphorus reserve in the red soil profile of sloping paddy fields.

[0004] The object of the present invention can be achieved by the following technical scheme: a method for calculating the maximum safe phosphorus reserve of a red soil profile in a sloping paddy field, the method comprising the following steps:

[0005] Determine the concentration of water-soluble phosphorus CaCl2-P in the soil;

[0006] Determine the phosphorus saturation PSR in soil;

[0007] The CaCl2-P value and PSR value of the soil are linearly fitted, and the inflection point obtained is the PSR threshold ThresholdPSR;

[0008] The obtained Threshold PSR is used to calculate the soil phosphorus storage capacity ∑SPSC;

[0009] Calculate the soil residual phosphorus reserve ∑TP, and then add the calculated soil residual phosphorus reserve ∑TP and soil phosphorus storage capacity ∑SPSC to obtain the soil safe phosphorus reserve ∑SSPR.

[0010] Preferably, the process of determining the concentration of water-soluble phosphorus CaCl2-P in soil comprises the following steps:

[0011] Weigh 4 g of air-dried soil passed through a 2 mm sieve, place it in a 100 mL conical flask, add 40 mL of 0.01 mol L-1 CaCl2 solution, place it at room temperature of 25±2°C, oscillate with a reciprocating oscillator for 1 hour, centrifuge, and filter with a filter membrane to obtain the use solution. The solubility of phosphorus in the solution is determined by the molybdenum blue colorimetry.

[0012] Preferably, the process of determining the phosphorus saturation PSR in soil comprises the following steps:

[0013] Weigh 1.00 g of air-dried soil that has passed through a 0.149 mm sieve, place it in a 100 mL conical flask, and add 50 mL of 0.2 mol L -1 The ammonium oxalate extract was sealed with a rubber stopper at the mouth of the triangular flask, placed in a black cloth bag to prevent photochemical reaction, placed at room temperature of 25±2℃, shaken with a reciprocating oscillator for 2h, centrifuged, and filtered with a filter membrane to obtain the stock solution; 1ml of the stock solution was taken, diluted 10 times, and the contents of P, Fe and Al in the sample solution were determined with an inductively coupled plasma spectrometer; PSR was calculated;

[0014] The calculation formula is as follows:

[0015]

[0016] Where P ox , Fe ox 、Al ox are the contents of phosphorus, iron and aluminum extracted by acidic ammonium oxalate, and 31, 56 and 27 are the atomic masses of phosphorus, iron and aluminum respectively.

[0017] Preferably, the pH of the ammonium oxalate extract is 3.0.

[0018] Preferably, the pore size of the filter membrane is 0.45 μm.

[0019] Preferably, the process of calculating the soil phosphorus storage capacity ΣSPSC using the obtained Threshold PSR comprises the following steps:

[0020]

[0021] Soil PSR is the phosphorus saturation rate in soil: Fe ox is the iron content extracted by acidic ammonium oxalate, Al ox The content of aluminum extracted by acidic ammonium oxalate;

[0022]

[0023] Where i is the i-th occurrence layer; n is the total number of occurrence layers; BD is the soil bulk density, and D is the thickness of the occurrence layer.

[0024] Preferably, the process of calculating the soil residual phosphorus reserve ∑TP comprises the following steps:

[0025] Weigh 1.0g of air-dried soil that has passed through a 0.149mm sieve, place it in a 50mL Erlenmeyer flask, add 8ml of sulfuric acid, leave it overnight, add 10 drops of perchloric acid and boil it down. The boiled solution is determined using the molybdenum antimony colorimetric method.

[0026] The calculation formula is as follows:

[0027]

[0028] Where i is the i-th occurrence layer; n is the total number of occurrence layers; BD is the soil bulk density, and D is the thickness of the occurrence layer.

[0029] Preferably, the calculation process of the soil safe phosphorus reserve ΣSSPR is:

[0030] ∑SSPR=∑SPSC+∑TP.

[0031] Preferably, a device comprises:

[0032] one or more processors;

[0033] A memory for storing one or more programs;

[0034] When one or more of the programs are executed by one or more of the processors, the one or more processors implement the method for calculating the maximum safe phosphorus reserves in the red soil profile of sloping rice fields as described above.

[0035] Preferably, a storage medium comprising computer executable instructions, wherein the computer executable instructions, when executed by a computer processor, are used to execute the method for calculating the maximum safe phosphorus reserve in a red soil profile of a sloping rice field as described above.

[0036] Beneficial effects of the present invention:

[0037] While judging whether the soil has the risk of loss, the present invention estimates and clarifies the maximum safe reserve of phosphorus in the red soil paddy field profile, and makes judgments and predictions for the effective evaluation of soil residual phosphorus reserves and its biological effectiveness and environmental safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1This is a diagram showing changes in safe phosphorus reserves in a red soil profile of a sloping cultivated land according to an embodiment of the present invention;

[0040] Figure 2 This is a graph showing changes in water-soluble phosphorus content in a red soil profile of a sloping cultivated land in an embodiment of the present invention;

[0041] Figure 3 This is a graph showing changes in phosphorus saturation content in a red soil profile of a sloping cultivated land according to an embodiment of the present invention;

[0042] Figure 4 is a fitting diagram of the phosphorus saturation rate threshold value of the red soil profile of the sloping cultivated land in the embodiment of the present invention;

[0043] Figure 5 is a graph showing changes in total phosphorus reserves in a red soil profile of a sloping cultivated land in an embodiment of the present invention;

[0044] Figure 6 This is a graph showing changes in phosphorus storage capacity in a red soil profile of a sloping cultivated land according to an embodiment of the present invention;

[0045] Figure 7 It is a diagram of the division of red soil profile layers in sloping cultivated land in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] like Figure 1 As shown, a method for calculating the maximum safe phosphorus reserve in a red soil profile of a sloping paddy field comprises the following steps:

[0048] Determine the concentration of water-soluble phosphorus CaCl2-P in the soil;

[0049] Determine the phosphorus saturation PSR in soil;

[0050] The CaCl2-P value and PSR value of the soil are linearly fitted, and the inflection point obtained is the PSR threshold ThresholdPSR;

[0051] The obtained Threshold PSR is used to calculate the soil phosphorus storage capacity ∑SPSC;

[0052] Calculate the soil residual phosphorus reserve ∑TP, and then add the calculated soil residual phosphorus reserve ∑TP and soil phosphorus storage capacity ∑SPSC to obtain the soil safe phosphorus reserve ∑SSPR.

[0053] It should be noted that the process of determining the concentration of water-soluble phosphorus CaCl2-P in soil includes the following steps:

[0054] Weigh 4g of air-dried soil that has passed through a 2mm sieve, place it in a 100mL conical flask, add 40mL of 0.01mol L-1CaCl2 solution, place it at room temperature of 25±2℃, shake it with a reciprocating shaker for 1h, centrifuge it, and filter it with a filter membrane to obtain the working solution. The solubility of phosphorus in the solution is determined by the molybdenum blue colorimetry.

[0055] It should be noted that, in this implementation process, the process of determining the phosphorus saturation PSR in soil includes the following steps:

[0056] Weigh 1.00 g of air-dried soil that has passed through a 0.149 mm sieve, place it in a 100 mL conical flask, and add 50 mL of 0.2 mol L -1 The ammonium oxalate extract was sealed with a rubber stopper at the mouth of the triangular flask, placed in a black cloth bag to prevent photochemical reaction, placed at room temperature of 25±2℃, shaken with a reciprocating oscillator for 2h, centrifuged, and filtered with a filter membrane to obtain the stock solution; 1ml of the stock solution was taken, diluted 10 times, and the contents of P, Fe and Al in the sample solution were determined with an inductively coupled plasma spectrometer; PSR was calculated;

[0057] The calculation formula is as follows:

[0058]

[0059] Where P ox , Fe ox 、Al ox are the contents of phosphorus, iron and aluminum extracted by acidic ammonium oxalate, and 31, 56 and 27 are the atomic masses of phosphorus, iron and aluminum respectively.

[0060] It should be noted that the pH of the ammonium oxalate extract is 3.0.

[0061] The pore size of the filter membrane is 0.45 μm.

[0062] The process of calculating the soil phosphorus storage capacity ΣSPSC using the obtained Threshold PSR comprises the following steps:

[0063]

[0064] Soil PSR is the phosphorus saturation rate in the soil, Fe ox is the iron content extracted by acidic ammonium oxalate, Al ox The content of aluminum extracted by acidic ammonium oxalate;

[0065]

[0066] Where i is the i-th occurrence layer; n is the total number of occurrence layers; BD is the soil bulk density, and D is the thickness of the occurrence layer.

[0067] It should be noted that the process of calculating the soil residual phosphorus reserve ∑TP includes the following steps:

[0068] Weigh 1.0g of air-dried soil that has passed through a 0.149mm sieve, place it in a 50mL Erlenmeyer flask, add 8ml of sulfuric acid, leave it overnight, add 10 drops of perchloric acid and boil it down. The boiled solution is determined using the molybdenum antimony colorimetric method.

[0069] The calculation formula is as follows:

[0070]

[0071] Where i is the i-th occurrence layer; n is the total number of occurrence layers; BD is the soil bulk density, and D is the thickness of the occurrence layer.

[0072] It should be noted that the calculation process of the soil safe phosphorus reserve ∑SSPR is as follows:

[0073] ∑SSPR=∑SPSC+∑TP.

[0074] It needs to be further explained that in the specific implementation process:

[0075] 1. Sample collection

[0076] In November 2020, three rice fields with a planting period of 50 to 60 years were selected for sample collection in the typical red soil watershed of Sunjia according to the slope changes. They were located on the top slope (MP-T), in the middle slope (MP-M) and below the slope (MP-B). A vertical downward section with a length, width and depth of 2m×1m×1.1m was dug in the middle of each field. The sunny side was vertically trimmed as the observation surface, and the soil layers were divided according to the texture, color and compactness of the soil (Table 1). The original soil samples of each layer were collected from bottom to top in a hard lunch box, and 5 to 8 soil samples were collected from each layer and mixed. The soil samples were brought back to the room to remove small stones and plant and animal residues, and then naturally air-dried and sieved through a 2mm sieve for storage. At the same time, samples of the profile layers on both sides of the observation surface were collected as repeats.

[0077] Table 1 Division and description of red soil layers in paddy fields at different slope positions

[0078]

[0079]

[0080] 2. Test indicators and methods

[0081] Soil bulk density (BD) was determined using the ring knife method; soil water-soluble phosphorus (CaCl2-P) was measured using 0.01 mol L -1 After CaCl2 extraction, the content was determined by molybdenum blue colorimetry; soil total phosphorus (TP) was determined by molybdenum antimony colorimetry; amorphous iron oxide (a-Fe2O3) and amorphous aluminum oxide (a-Al2O3) were extracted with acidic ammonium oxalate solution (pH = 3.17), and the iron and aluminum concentrations in the above extracts were determined by inductively coupled plasma spectrometer (ICP-OES).

[0082] 3. Clarify the changes in water-soluble phosphorus (CaCl2-P) in different layers of red soil paddy field profiles on sloping cultivated land

[0083] Depend on Figure 1 It can be seen that the content of soil CaCl2-P is the highest in the Ap1 layer, but it tends to decrease gradually with the increase of the depth of the occurrence layer. Compared with the Ap1 layer, the CaCl2-P content of the bottom soil in the MP-T, MP-M and MP-B profiles decreased significantly by 34.2% to 92.8%, 52.9% to 77.7% and 66.0% to 96.4%. With the decrease of slope position, compared with the MP-T profile, the CaCl2-P content of the MP-M soil decreased by 9.38%, while the CaCl2-P content of the MP-B profile increased significantly by 17.2%.

[0084] 4. Clarify the changes in phosphorus saturation rate (PSR) of different layers in red soil paddy field profiles on sloping cultivated land

[0085] Depend on Figure 2 It can be seen that the phosphorus saturation rate (PSR) of different rice field profiles is the highest in the Ap1 layer, and with the increase of the depth of the occurrence layer, the PSR shows a trend of first decreasing and then increasing. Compared with the Ap1 layer, the PSR of the bottom soil of the MP-T, MP-M and MP-B profiles decreased significantly by 41.7% to 67.9%, 26.1% to 57.0% and 34.7% to 74.2%. With the decrease of slope position, compared with the MP-T profile, the PSR of the MP-M and MP-B profiles increased significantly by 47.2% and 33.3%, respectively.

[0086] 5. Clarify the PSR thresholds of different occurrence layers in the red soil paddy field profile of sloping cultivated land (Threshold PSR)

[0087] Depend on Figure 3 It can be seen that the PSR values ​​calculated from the phosphorus, iron and aluminum extracted by the acidic ammonium oxalate solution and CaCl2-P all show a significant piecewise linear relationship, that is, there are changing "inflection point" values. The soil PSR value corresponding to the "inflection point" obtained by the acidic ammonium oxalate method is 0.11, and the corresponding soil CaCl2-P content is 0.76 mg kg-1. The "inflection point" is divided into "slow increase" and "sharp increase" stages.

[0088] 6. Clarify the changes in total phosphorus storage (∑TP) in different layers of red soil paddy field profiles on sloping cultivated land

[0089] Depend on Figure 4 It can be seen that the total phosphorus storage (∑TP) of the red soil profile of paddy fields at different slopes is 130.8 kg hm -2 ~2163.6kghm -2 , in the order of MP-B>MP-M>MP-T, and they all decreased first and then increased with the increase of the depth of the occurrence layer. Compared with the Ap1 layer, the ∑TP of the bottom soil of the MP-T, MP-M and MP-B profiles increased significantly by 9.59% to 14.1%, 8.07% to 51.3% and decreased significantly by 30.0% to 81.1%, respectively. Compared with the MP-B profile, the total ∑TP of the MP-T and MP-M profiles decreased significantly by 24.1% and 4.85%, respectively.

[0090] 7. Clarify the changes in phosphorus storage capacity of different layers in red soil paddy field profiles on sloping cultivated land (∑SPSC)

[0091] Depend on Figure 5 It can be seen that the variation range of ∑SPSC in red soil profiles of paddy fields at different slope positions is -650.9 kg hm -2 ~1083.1kg hm -2 , and with the increase of the depth of the occurrence layer, the ∑SPSC of the MP-T and MP-M sections gradually increases, while that of the MP-B section first increases and then decreases ( Figure 3 ). The ∑SPSC of the Ap layer in MP-T (except Ap2 layer), MP-M and MP-B profiles are all negative, which means they are soil "phosphorus sources" and there is a risk of phosphorus loss; while the ∑SPSC of the B layer and C layer in each profile are all positive, which means they are soil "phosphorus sinks" and there is no risk of phosphorus loss. Figure 3 It can be seen that the SPSC reserves in the B layer of the MP-T and MP-B profiles are the largest, while the reserves in the C layer of the MP-M profile are the largest.

[0092] 8. Clarify the soil safe phosphorus reserve (SSPR) of different layers in the red soil paddy field profile of sloping cultivated land

[0093] Depend on Figure 6 It can be seen that the soil safe phosphorus reserve can be calculated based on ∑SPSC and ∑TP. It is known that ∑SPSC is the soil phosphorus storage capacity reserve of a certain layer in the soil profile, which can be used to determine whether there is phosphorus loss in this layer; and ∑TP is the total phosphorus reserve of a certain layer in the soil profile, which is used to determine the phosphorus content in the soil. The sum of the two can determine the phosphorus reserve that a certain layer of the soil can continue to accommodate. Figure 5It can be seen that all the occurrence layers in each profile have the ability to continue to accommodate exogenous phosphorus, but the content of exogenous phosphorus that the Ap2 layer in each profile can continue to accommodate is the smallest.

[0094] Based on the same inventive concept, the present invention also provides a computer device, which includes: one or more processors, and a memory for storing one or more computer programs; the program includes program instructions, and the processor is used to execute the program instructions stored in the memory. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is used to implement one or more instructions, specifically for loading and executing one or more instructions in a computer storage medium to implement the above method.

[0095] It needs to be further explained that, based on the same inventive concept, the present invention also provides a computer storage medium, on which a computer program is stored, and the computer program is executed by a processor to execute the above method. The storage medium can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electrical, magnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure may have various changes and improvements, and these changes and improvements fall within the scope of the present disclosure to be protected.

Claims

1. A method for calculating the maximum safe phosphorus reserve in red soil profile of sloping paddy fields, characterized in that: The method comprises the following steps: Determine the concentration of water-soluble phosphorus CaCl2-P in the soil; Determine the phosphorus saturation PSR in soil; The process of determining the phosphorus saturation PSR in soil comprises the following steps: Weigh 1.00 g of air-dried soil that has passed through a 0.149 mm sieve, place it in a 100 mL conical flask, and add 50 mL of 0.2 mol L -1 The ammonium oxalate extract was sealed with a rubber stopper at the mouth of the triangular flask, placed in a black cloth bag to prevent photochemical reaction, placed at room temperature of 25±2℃, shaken with a reciprocating oscillator for 2h, centrifuged, and filtered with a filter membrane to obtain the stock solution; 1ml of the stock solution was taken, diluted 10 times, and the contents of P, Fe and Al in the sample solution were determined with an inductively coupled plasma spectrometer; PSR was calculated; The calculation formula is as follows: Where P ox , Fe ox 、Al ox are the contents of phosphorus, iron and aluminium extracted with acidic ammonium oxalate, 31, 56 and 27 are the atomic masses of phosphorus, iron and aluminium respectively; The CaCl2-P value and PSR value of the soil are linearly fitted, and the inflection point obtained is the PSR threshold Threshold PSR; The obtained Threshold PSR is used to calculate the soil phosphorus storage capacity ∑SPSC; The process of calculating the soil phosphorus storage capacity ΣSPSC using the obtained Threshold PSR comprises the following steps: SoilPSR is the soil phosphorus saturation rate, Fe ox is the iron content extracted by acidic ammonium oxalate, Al ox The content of aluminum extracted by acidic ammonium oxalate; Where i is the i-th occurrence layer; n is the total number of occurrence layers; BD is the soil bulk density, D is the occurrence layer thickness, SPSC i is the soil phosphorus storage capacity of the i-th layer; BD i is the soil bulk density of the i-th layer, D i is the thickness of the i-th generation layer; Calculate the soil residual phosphorus reserve ∑TP, and then add the calculated soil residual phosphorus reserve ∑TP and soil phosphorus storage capacity ∑SPSC to obtain the soil safe phosphorus reserve ∑SSPR; The process of calculating the soil residual phosphorus reserve ∑TP comprises the following steps: Weigh 1.0g of air-dried soil that has passed through a 0.149mm sieve, place it in a 50mL Erlenmeyer flask, add 8ml of sulfuric acid, leave it overnight, add 10 drops of perchloric acid and boil it down. The boiled solution is determined using the molybdenum antimony colorimetric method. The calculation formula is as follows: Where i is the i-th occurrence layer; n is the total number of occurrence layers; BD is the soil bulk density, D is the occurrence layer thickness, TP i is the total phosphorus content of soil in the i-th occurrence layer; The calculation process of the soil safe phosphorus reserve ∑SSPR is as follows: ∑SSPR=∑SPSC+∑TP.

2. The method for calculating the maximum safe phosphorus reserve in the red soil profile of a sloping paddy field according to claim 1, characterized in that: The process of measuring the concentration of water-soluble phosphorus CaCl2-P in soil comprises the following steps: Weigh 4 g of air-dried soil passed through a 2 mm sieve, place it in a 100 mL conical flask, add 40 mL of 0.01 mol L-1 CaCl2 solution, place it at room temperature of 25±2°C, oscillate with a reciprocating oscillator for 1 hour, centrifuge, and filter with a filter membrane to obtain the use solution. The solubility of phosphorus in the solution is determined by the molybdenum blue colorimetry.

3. The method for calculating the maximum safe phosphorus reserve in red soil profile of sloping paddy fields according to claim 1, characterized in that: The pH of the ammonium oxalate extract is 3.

0.

4. The method for calculating the maximum safe phosphorus reserve in the red soil profile of a sloping paddy field according to claim 1, characterized in that: The pore size of the filter membrane is 0.45 μm.

5. A device, characterized in that: include: one or more processors; A memory for storing one or more programs; When one or more of the programs are executed by one or more of the processors, one or more of the processors implement a method for calculating the maximum safe phosphorus reserve in the red soil profile of a sloping rice field as described in any one of claims 1-4.

6. A storage medium containing computer executable instructions, characterized in that: The computer executable instructions, when executed by a computer processor, are used to execute a method for calculating the maximum safe phosphorus reserve in a red soil profile of a sloping rice field as described in any one of claims 1-4.

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