An algorithm for determining the amount of phosphorus fertilizer to be applied based on quantifying the turnover amount of phosphorus bio-activation in the rhizosphere soil of crops

Abstract

The application discloses a kind of algorithm based on quantification crop rhizosphere soil phosphorus biological activation turnover quantity determines the phosphorus fertilizer application amount;Including: determine the phosphorus requirement of crop target yield;Determine the activation turnover flux of crop rhizosphere microbial quantity phosphorus;Determine the phosphorus fertilizer availability loss rate of fertilization plot soil;Establish quantitative phosphorus application algorithm.The recommended amount of phosphorus fertilizer calculated by the quantitative phosphorus application algorithm provided by the application is reduced compared with the amount recommended by the constant monitoring technology based on soil available phosphorus level under the premise of ensuring crop yield, so that the fertilizer phosphorus input of farmland and the amount of crop taken away are basically balanced.

Description

Technical Field

[0001] This invention belongs to the field of phosphorus application technology for crops, specifically an algorithm for determining the amount of phosphate fertilizer to be applied based on the quantitative turnover of phosphorus bioactivation in crop rhizosphere soil. Background Technology

[0002] Phosphorus is closely related to grain production. Phosphate fertilizer applied to the field must go through three processes to participate in crop yield formation: (1) Soil fixation process: Phosphate ions in phosphate fertilizer readily react with Ca in the soil solution. 2+ Fe 2+ Fe 3+ And Al 3+ When metal cations undergo precipitation reactions, insoluble phosphate compounds are formed, causing phosphorus to be fixed in the soil solid phase and temporarily lose its effectiveness. (2) Bioactivation process: There are a large number of functional microbial communities in the rhizosphere of crops. They can activate phosphorus not only by releasing protons, organic acid anions, iron carriers and various phosphatases, but also by activating phosphorus through microbial biomass turnover. The turnover of soil microbial biomass phosphorus (MBP) pool is not only an important source of available phosphorus in the soil, but also a quantifiable indicator of soil phosphorus bioactivation. (3) Absorption process: For mycorrhizal crops (e.g., corn, wheat, cotton, etc.), they have two phosphorus absorption and utilization pathways: roots and mycorrhizae. Fully exploring the biological potential of efficient phosphorus utilization in the rhizosphere of crops is a sustainable way to improve the efficiency of phosphate fertilizer utilization in crops.

[0003] Determining the optimal phosphate fertilizer application rate is crucial for promoting healthy crop growth and increasing yield, extending the lifespan of phosphorus resources, and reducing non-point source pollution of phosphorus in agriculture. Currently, methods for determining recommended phosphate fertilizer application rates can be broadly categorized into two types: one is based on soil available phosphorus levels, known as soil testing-based fertilization; the other uses field fertilizer effect experiments and mathematical models to simulate the relationship between phosphorus application rate and crop yield, thereby obtaining the optimal recommended phosphate fertilizer rate. However, both of these methods focus more on the crop yield response and neglect the biological potential for efficient phosphorus utilization in the rhizosphere, leading to recommended phosphate fertilizer application rates that are often higher than the actual phosphorus requirements of crops, resulting in excess phosphate fertilizer accumulating in the soil. Summary of the Invention

[0004] To address the problems existing in the background technology, this invention provides an algorithm for determining the application rate of phosphate fertilizer based on the quantitative turnover of phosphorus bioactivation in crop rhizosphere soil. The technical solution includes:

[0005] 1) Determine the target crop phosphorus requirement (PD);

[0006] 2) Determine the activation turnover flux M of crop rhizosphere microbial biomass phosphorus;

[0007] 3) Determine the phosphate fertilizer availability loss rate f of the fertilized soil;

[0008] 4) Establish a quantitative phosphorus application algorithm

[0009] The method for determining the target crop phosphorus requirement (PD) is as follows: the average yield of crops in the past three years is set as the target yield of the fertilized crop, and the corresponding phosphorus uptake is taken as the target yield phosphorus requirement (PD) of the crop in the next season for that plot.

[0010] The method for determining the activation turnover flux M of rhizosphere microbial biomass phosphorus in the fertilized plot is as follows: The microbial biomass phosphorus content (MBP) and soil bulk density (ρ) of the topsoil during the crop's growth period are measured monthly or weekly. The activation turnover flux M of rhizosphere microbial biomass phosphorus in the fertilized plot is calculated as: M = ρ × V × ∑ΔMBP, where V is the volume of topsoil per unit area.

[0011] The method for determining the phosphorus fertilizer availability loss rate f in the fertilized soil is as follows: Crops are planted in experimental plots with consistent basic phosphorus levels. Two treatments are established: no phosphorus application and phosphorus application. Nitrogen and potassium fertilizers are applied according to the normal growth requirements of the crops, while phosphorus fertilizer is applied at a level higher than the crop's phosphorus requirement, so as to significantly change the soil's available phosphorus level. After crop harvest, the Olsen-P content A0 and phosphorus uptake U0 in the topsoil of the no-phosphorus treatment and the Olsen-P content A0 in the topsoil of the phosphorus-approved treatment are measured. p and phosphorus absorption U p Phosphate availability loss rate in fertilized soil

[0012] After establishing the quantitative phosphorus application algorithm, when it is needed, the following steps are performed: calculate the optimal amount of phosphorus fertilizer and apply fertilizer according to the optimal amount of phosphorus fertilizer.

[0013] The beneficial effects of this invention are as follows:

[0014] 1. The quantitative phosphorus application model provided by this invention calculates a recommended phosphorus fertilizer application rate that, while ensuring crop yield, reduces the application rate by 25.3% compared to the rate recommended by constant-quantity monitoring technology based on soil available phosphorus levels. Figure 2 This ensures that the amount of phosphorus input into farmland is basically balanced with the amount removed by crops.

[0015] 2. For the first time, the quantitative analysis of the loss of phosphate fertilizer availability in the soil and the soil biological activation process is incorporated into the phosphate fertilizer management system, which enables more precise application of phosphate at the regional or plot scale. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating an embodiment of an algorithm for determining the amount of phosphate fertilizer to be applied based on the quantitative turnover of phosphorus bioactivation in crop rhizosphere soil according to the present invention.

[0017] Figure 2 This invention presents a comparison of the recommended phosphate fertilizer application rates between a quantitative phosphorus bio-activation turnover-based phosphate application technology and a constant-quantity monitoring technology based on soil available phosphorus levels. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings. We provide three embodiments.

[0019] Example 1: Example under suitable phosphorus supply intensity conditions (available phosphorus level of 15 mg / kg) -1 )

[0020] like Figure 1 The embodiment of the present invention shown includes the following steps:

[0021] Step 1: Set the average yield of the local fertilized plots over the past 3 years as the target yield, and use the corresponding phosphorus uptake as the target yield phosphorus requirement (PD) at that yield level; specifically, select farmland plots in the Shangzhuang area of ​​Beijing that have been planted with corn for 3 consecutive years (available phosphorus level is 14.6 mg / kg). -1 Apply nitrogen, phosphorus, and potassium fertilizers according to the normal requirements of the crop. 10.2 t / ha of corn was obtained. -1 The phosphorus requirement at the target output is 34.8 kg P ha -1 (Table 1)

[0022] Table 1. Corn yield per 10 t ha in Shangzhuang area of ​​Beijing -1 Phosphorus demand at target output

[0023]

[0024] Step 2: Determine the activation turnover flux M of rhizosphere microbial biomass phosphorus in the fertilized plot. The method for determining the activation turnover flux M is as follows: Measure the microbial biomass phosphorus content (MBP) and soil bulk density (ρ) of the topsoil during the crop's growth period on a monthly or weekly basis. The activation turnover flux M of rhizosphere microbial biomass phosphorus in the fertilized plot is calculated as: M = ρ × V × ∑ΔMBP, where V is the volume of topsoil per unit area. Specifically, the measured activation turnover flux M of microbial biomass phosphorus in the rhizosphere soil of maize in this area is 27.6 kg P ha -1 (Table 2).

[0025] Table 2. Crop rhizosphere soil microbial biomass and phosphorus pool turnover flux in fertilized plots in Shangzhuang area, Beijing.

[0026]

[0027] Step 3: Determine the phosphorus availability loss rate f of the fertilized soil. The method for determining the phosphorus availability loss rate of the fertilized soil is as follows: Crops are planted in experimental plots with consistent basic phosphorus levels. Two treatments are set up: no phosphorus application and phosphorus application. Nitrogen and potassium fertilizers are applied according to the normal growth requirements of crops, while phosphorus fertilizer is applied at a level higher than the crop's phosphorus requirement, so as to significantly change the available phosphorus level in the soil. After crop harvest, the Olsen-P content A0 and phosphorus uptake U0 of the topsoil in the no-phosphorus treatment and the Olsen-P content A0 of the topsoil in the phosphorus-approved treatment are measured. p and phosphorus absorption U p The rate of phosphorus fertilizer availability loss in the fertilized soil is f = Specifically, the measured loss rate f of phosphate fertilizer availability in the soil of the phosphate-applied plots in this region was 74.7% (Table 3).

[0028] Table 3. Phosphate fertilizer availability loss rate in fertilized soil plots in Shangzhuang area, Beijing.

[0029]

[0030] Step 4: Establish a quantitative phosphorus application model

[0031] Step 5: Calculate the optimal recommended application rate of phosphate fertilizer based on the quantitative phosphate application algorithm in Step 4; specifically, the available phosphorus level in the soil of the Shangzhuang area in Beijing was measured to be 14.6 mg / kg. -1 10.2 t ha of corn -1 The optimal phosphate fertilizer application rate for the target yield is 31.1 kg Pha. -1 .

[0032] Example 2: Example under phosphorus-deficient soil conditions (available phosphorus level of 10 mg / kg) -1 )

[0033] The available phosphorus in the soil is 10 mg / kg. -1 Corn was planted on the plot, and nitrogen, phosphorus, and potassium fertilizers were applied according to the normal crop requirements. 9 tons of corn were obtained. -1 The phosphorus requirement at the target output is 30 kg P ha -1 Under this soil phosphorus supply intensity, the microbial phosphorus pool turnover flux in the maize rhizosphere soil was 15.4 kg P ha -1 The phosphate fertilizer availability loss rate was 73.2%, and the calculated recommended phosphate fertilizer application rate was 54.5 kg P ha -1 .

[0034] Example 3: Example under the condition that soil phosphorus supply intensity exceeds the agronomic threshold (available phosphorus level > 40 mg / kg) -1 )

[0035] Soil available phosphorus levels are greater than 40 mg / kg -1 Corn was planted on the plot, and nitrogen, phosphorus, and potassium fertilizers were applied according to the normal crop requirements. 9 tons of corn were obtained. -1 The phosphorus requirement at the target output is 36.5 kg P ha -1 Under this soil phosphorus supply intensity, the microbial phosphorus pool turnover flux in the maize rhizosphere is 20 kg P ha. -1 The loss rate of phosphate fertilizer availability was 85.1%, and the calculated recommended application rate of phosphate fertilizer was 110.7 kg P ha -1 This is because high phosphorus conditions inhibit the ability of soil microorganisms to activate and recycle soil phosphorus, and the soil phosphorus supply intensity is far higher than the agronomic threshold range for available phosphorus in maize. Therefore, this algorithm cannot be used to recommend phosphate fertilizer application rates in scenarios where available phosphorus is far above the agronomic threshold. Based on experience, a small amount of phosphate fertilizer (4-6 kg P ha) is recommended in this scenario. -1 As a starting phosphorus, it is applied as a seed fertilizer when corn is planted.

Claims

1. An algorithm for determining the amount of phosphatic fertilizer to be applied based on quantifying the phosphorus bio-activation turnover quantity of the rhizosphere soil of a crop, characterized by, Comprise: 1) determine the crop target yield phosphorus requirement PD; 2) determine the fertilization plot crop rhizosphere microbial amount phosphorus activation turnover flux M; 3) determine the soil of fertilization plot phosphorus fertilizer availability loss rate f; 4) Establish quantitative phosphorus application algorithm FP = ; The method for determining the loss rate f of the phosphorus fertilizer effectiveness of the soil of the fertilized plot is: planting crops in the test plot with consistent soil base phosphorus level, setting two treatments of no phosphorus application and phosphorus application, applying nitrogen and potassium fertilizers according to the normal growth demand of the crops, and applying phosphorus fertilizer according to the phosphorus demand of the crops, so that the soil available phosphorus level changes obviously; after the crops are harvested, the Olsen-P content A0 and the phosphorus absorption U0 of the plough layer soil of the treatment without phosphorus application and the Olsen-P content A p and the phosphorus absorption U p of the plough layer soil of the treatment with phosphorus application are determined; wherein the Olsen-P is available phosphorus. where f is the rate of loss of phosphorus fertilizer effectiveness of the soil of the fertilized plot ; wherein, is the amount of phosphorus applied.

2. The algorithm for determining the amount of phosphatic fertilizer to be applied based on the quantification of the phosphorus bio-activation turnover quantity in the rhizosphere soil of the crop according to claim 1, characterized in that, The method for determining the crop target yield phosphorus requirement PD is: setting the average yield of the crops in the farmland in the past 3 years as the target yield of the fertilized crops, and taking the corresponding phosphorus absorption amount as the target yield phosphorus requirement PD of the plot for the next season of the crops.

3. The algorithm for determining the amount of phosphatic fertilizer to be applied based on the quantification of the phosphorus bio-activation turnover in the rhizosphere soil of the crop according to claim 1, characterized in that, The method for determining the activated turnover flux M of the microbial biomass phosphorus in the crop rhizosphere of the fertilized plot is: the microbial biomass phosphorus content MBP and the soil bulk density p of the plough layer soil in the growth period of the crop in the fertilized plot are determined monthly or weekly; the activated turnover flux M of the microbial biomass phosphorus in the crop rhizosphere of the fertilized plot is p x V x , and V is the volume of the plough layer soil per unit area.

4. The algorithm for determining the amount of phosphatic fertilizer to be applied based on the quantification of the phosphorus bio-activation turnover in the rhizosphere of the crop according to claim 1, characterized in that, After the establishment of the quantitative phosphorus application algorithm, when it is needed to be applied, the best phosphorus fertilizer amount is calculated, and fertilization is carried out according to the best phosphorus fertilizer amount.

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