Sodium fumarate regulation-based soil phosphorus activation synergistic method and application thereof

Abstract

The invention discloses a soil phosphorus activation synergistic method based on sodium fumarate regulation and application thereof, by adding sodium fumarate, insoluble phosphorus in soil is effectively activated, the utilization rate of phosphorus is increased, the application amount of phosphate fertilizer is reduced, and the risk of environmental pollution is reduced. The method is easy to operate, remarkable in effect and especially suitable for fertility improvement and agricultural sustainable management of soil with high phosphorus fixity and low phosphorus effectiveness, and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural soil improvement and plant nutrition, and particularly relates to a method for activating and enhancing soil phosphorus and its application. Background Art

[0002] Phosphorus is a key nutrient essential for plant growth, but the availability of phosphorus in soils is generally low globally. Phosphorus in soils mainly exists in the forms of inorganic phosphorus and organic phosphorus, and usually inorganic phosphorus accounts for about 80% of the total soil phosphorus. Among them, 99% of the inorganic phosphorus exists in the form of insoluble inorganic phosphates (such as calcium phosphate, iron phosphate, aluminum phosphate), and its biological availability is extremely low, making it difficult for plants to directly absorb and utilize, resulting in a current-season utilization rate of phosphate fertilizers of less than 20%. Long-term low-efficiency input of phosphate fertilizers not only exacerbates resource waste but also causes non-point source pollution (such as water eutrophication) caused by phosphorus loss. Therefore, developing efficient and low-cost soil phosphorus activation technologies is one of the core requirements for agricultural sustainable development and ecological protection.

[0003] The excessively low availability of phosphorus in farmland soils has become one of the main limiting factors for crop production. To increase crop yields, a large amount of chemical phosphate fertilizers are often applied to agricultural soils. Although the application of traditional phosphate fertilizers (such as superphosphate, diammonium phosphate) can increase the content of available phosphorus in the soil in the short term, the large application of phosphate fertilizers not only directly causes the gradual depletion of phosphate rock resources, but long-term application will lead to an excess of phosphorus in the soil. Most of the applied phosphorus is fixed in the soil and becomes iron / aluminum-bound phosphorus (Fe / Al-P), calcium-bound phosphorus (Ca-P), and occluded phosphorus (Res-P) that are difficult for plants to absorb and utilize, resulting in a gradual increase in the content of insoluble phosphorus in the soil and a decrease in the soil phosphorus activation rate. Moreover, it will also cause a series of high-risk environmental problems, such as soil acidification, increased phosphorus fixation, and phosphorus resource shortage.

[0004] Currently, the mainstream phosphorus activation methods include chemical activation, biological activation, and physical-chemical coupling methods. Activating insoluble phosphorus in soils with organic acids (such as citric acid, oxalic acid) or microbial inoculants has disadvantages such as high cost, poor stability, and obvious environmental pollution. Sodium fumarate (C 4 H 3 NaO 4 ) is a non-toxic and highly efficient organic acid salt, which has multiple functions such as regulating soil pH, promoting microbial activity, and enhancing plant stress resistance. The molecule contains two α-carboxylic acid groups, and the complexation constants (logK) for Ca 2+ , Fe 3+ , Al 3 + reach 3.5, 11.2, and 8.7 respectively, which are significantly higher than those of citric acid, and can complex with metal ions in the soil (such as Ca 2+ , Fe 3+ , Al3+ ) form stable complexes, thereby releasing the fixed phosphorus. Currently, there is little research on the application of sodium fumarate in soil phosphorus activation, and there is a lack of systematic technical solutions and application data. Summary of the Invention

[0005] Technical problems to be solved: Provide a method for enhancing soil phosphorus activation regulated by sodium fumarate and its application. By optimizing the application concentration, application method and treatment time of sodium fumarate, significantly increase the content of available phosphorus in the soil, promote the absorption and utilization of phosphorus by crops, reduce the application amount of phosphate fertilizers, and reduce agricultural production costs and environmental risks.

[0006] Technical solution: A method for enhancing soil phosphorus activation regulated by sodium fumarate and its application. The phosphorus activator is sodium fumarate, including the steps: preparation of sodium fumarate solvent, dilution of the solvent, spraying of the solvent, and soil standing. For solvent preparation, accurately weigh 100 g of sodium fumarate and dissolve it in 1 L of deionized water. Stir with a glass rod and then sonicate for 10 min to make the sodium fumarate evenly and fully mixed. After solvent preparation, dilute the solvent according to requirements and then mix well. Fill the diluted sodium fumarate solution into a sprayer, and evenly apply the sodium fumarate solution in the form of water mist to the soil in the crop root zone. After solvent spraying, let the soil stand for 1 day to allow sodium fumarate to react fully with metal ions in the soil, release the fixed phosphorus, and thus improve the availability of soil phosphorus.

[0007] Specific application method:

[0008] 1. The application concentration is related to the soil phosphorus activation coefficient. The lower the soil phosphorus activation coefficient, the higher the application concentration. When the soil phosphorus activation coefficient ≤ 5%, the application concentration is 0.8 g / L, and the spraying amount is 5 L / mu; when the soil phosphorus activation coefficient ≥ 5%, the application concentration is 0.2 g / L, and the spraying amount is 5 L / mu.

[0009] 2. The application method is spraying. Fill the diluted sodium fumarate solution into a sprayer, and evenly apply the sodium fumarate solution in the form of water mist to the soil in the crop root zone.

[0010] 3. The application frequency is related to the soil phosphorus activation coefficient. When the soil phosphorus activation coefficient ≤ 5%, the application frequency is 3 - 4 times a year; when the soil phosphorus activation coefficient ≥ 5%, the application frequency is 2 - 3 times a year.

[0011] 4. The application time varies depending on the crops planted. Before planting crops (such as corn, wheat, rice), treat the soil according to the above method. Before planting fruit trees (such as apples, citrus) or during the fruit growth period, treat the orchard soil according to the above method. In greenhouse cultivation (such as tomatoes, cucumbers), treat the cultivation substrate according to the above method.

[0012] Advantages of the present invention:

[0013] As a natural organic acid derivative, sodium fumarate contains carboxyl groups that can complex elements such as calcium, iron, and aluminum in the soil, release phosphates fixed by these metal elements, and convert them into readily available phosphorus that can be absorbed by plants. The innovation of this invention lies in: for the first time, sodium fumarate is proposed as a soil phosphorus activator, and its application method, application concentration, and application frequency are clarified. This method can greenly and efficiently improve the availability of soil phosphorus, and is simple to prepare and convenient to apply.

[0014] 1. High-efficiency phosphorus activation. The method of this invention can effectively release the insoluble phosphorus fixed by elements such as calcium, iron, and aluminum in the soil. The organic acid root ions in sodium fumarate can form stable complexes with cations such as Fe 3+ 、Al 3+ 、Ca 2+ in the soil, reduce the fixation of these cations on phosphate ions, and convert them into readily available phosphorus that can be absorbed by plants. The available phosphorus content in the soil can be increased by up to 80% within 24 hours.

[0015] 2. Long-lasting activation ability. The organic acid root ions (C 4 H 3 O 4 - ) in sodium fumarate can compete with phosphate ions (PO 4 3- ) for adsorption sites on the surface of soil colloids. Due to the strong affinity of organic acid root ions for soil colloids, they can replace the adsorbed phosphate ions and release them into the soil solution, thereby improving the availability of phosphorus. The method of this invention can improve the availability of soil phosphorus in the long term, and the available phosphorus content in the soil is still increasing on the 45th day after application.

[0016] 3. Environmentally friendly and alleviating non-point source pollution. The degradation products of sodium fumarate used in the method of this invention are non-toxic to the soil, and the sodium fumarate activator reduces the application amount of phosphate fertilizers by improving the availability of phosphorus, thereby reducing the surplus and leaching risk of soil phosphorus.

[0017] 4. Enhancing soil biological activity. Sodium fumarate used in the method of this invention can also regulate microbial activities, promote their metabolic activities, and accelerate the mineralization of organic phosphorus and the dissolution of inorganic phosphorus.

[0018] 5. Multiple synergistic effects. It has the functions of regulating soil pH and enhancing the stability of soil organic matter, can reduce soil compaction, enhance the water and fertilizer retention capacity of the soil, and improve the crop growth environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the drawings.

[0020] Figure 1 Variation of available phosphorus content during soil cultivation in Example 1.

[0021] Figure 2 Variation of the contents of various forms of soil inorganic phosphorus during soil cultivation in Example 1.

[0022] Figure 3 Variation of available phosphorus content in the soil of Example 2. Specific implementation mode

[0023] The following specific examples are further descriptions of the present invention, and it is not considered that the content of the present invention is limited to the scope of the examples given.

[0024] At the same time, in the experimental methods described in the following examples, unless otherwise specified, they are all conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial channels.

[0025] Example 1:

[0026] The soil sample was collected from the typical mine - abandoned site of Guobayan in Baoxing County, Sichuan Province. The soil type is sierozem and the texture is sandy soil. The original surface soil (0 - 20 cm) sample was collected (first removing the surface sediment and then collecting the original soil). After the soil sample was transported back to the laboratory, it was naturally air - dried, passed through a 100 - mesh sieve, and then stored in a sealed room at room temperature in a dry and cool place.

[0027] Table 1 Basic physical and chemical properties of the soil in Example 1

[0028]

[0029] The main implementation steps are as follows:

[0030] (1) Filling soil. Take 500 g of the treated soil sample and add it to a biochemical basin. The size of the biochemical basin is selected as: 10.2 cm×18 cm×11 cm, and a total of three parallels are set.

[0031] (2) Preparation of sodium fumarate solution. Accurately weigh 0.2 g of sodium fumarate and dissolve it in 1 L of deionized water. Stir with a glass rod and then ultrasonicate for 10 min to make the sodium fumarate evenly and fully mixed.

[0032] (3) Incubate at a constant temperature. Two control groups were set up. One group was added with sodium fumarate solution, and the other group was a blank control group. 80 ml of sodium fumarate solution with a concentration of 0.2 g / L was sprayed into the culture bottles of the sodium fumarate treatment group, and no other treatment was done to the blank group. The soil culture bottles were placed in an artificial climate incubator at a temperature of 20 °C and a relative humidity of 60%. During this period, the soil water content was kept constant by the weighing method, and deionized water was regularly added to keep the soil water content at about 17%. A 60-day soil cultivation experiment was carried out. During this period, the mass was weighed every other day, the water released was calculated from the mass difference, and the corresponding mass of deionized water was used to supplement it.

[0033] (4) Soil sampling. One soil sample was taken with an undisturbed sampler on the 1st, 10th, 20th, 30th, 45th, and 60th days after cultivation. After natural air drying, it was ground and passed through a 100-mesh sieve and then bagged for standby, which was used for the determination and analysis of soil available phosphorus, inorganic phosphorus forms, and various basic physical and chemical properties of the soil.

[0034] The measurement results showed that applying sodium fumarate solution could effectively increase the soil available phosphorus content, and a significant increase in phosphorus availability could be achieved in the short term. The available phosphorus content in the sodium fumarate group increased by 3.5 mg / kg on the first day, with an increment of 63.6%. On the 45th day, the soil available phosphorus content was still in the rising stage, and the phosphorus activation effect was persistent and efficient.

[0035] There are significant differences in the contributions of different forms of inorganic phosphorus to soil phosphorus availability and soil phosphorus cycling. Among them, Ca 2 -P is considered a directly available phosphorus source, Ca 8 -P, Fe-P, and Al-P are considered moderately active phosphorus sources, while O-P and Ca 10 -P are regarded as potential phosphorus sources. The changes in the contents of various inorganic phosphorus forms in the soil during the cultivation period are shown in Figure 2 . On the 1st day of soil cultivation, the inorganic phosphorus forms in the soil with sodium fumarate added changed significantly compared with the blank group. The main change was that the content of Ca 10 -P decreased rapidly by 52 mg / kg. The content of Fe-P increased from 17 mg / kg to 25 mg / kg, an increase of 8 mg / kg; the content of Al-P increased from 2 mg / kg to 11 mg / kg, an increase of 9 mg / kg; the content of Ca 2 -P increased from 3.2 mg / kg to 4.7 mg / kg, an increase of 1.5 mg / kg. The contents of Ca 8 -P and O-P were almost the same as those in the blank group on the first day. During the 60-day soil cultivation experiment period, the Ca 2-P gradually increased in a parabolic shape and then leveled off, rising from 4.7 mg / kg on the first day to 6.7 mg / kg, an increase of 2 mg / kg, while the content in the blank group (CK) remained stable within the range of 3.2 mg / kg to 3.5 mg / kg. The Ca 8 -P content in the sodium fumarate group continuously increased during the cultivation period, while the Ca 8 -P in the blank group first increased and then decreased during the cultivation period. The Fe-P in the blank group fluctuated within a small range during the cultivation period, and the Fe-P with high-concentration sodium fumarate addition gradually increased during the fluctuation and reached the maximum value of 27.7 mg / kg on the 45th day. The content of soil O-P was hardly affected by sodium fumarate, and the O-P contents in both the sodium fumarate group and the blank group fluctuated within a small range between 2 and 4 mg / kg. The Ca10-P in the soil with sodium fumarate addition gradually decreased and then leveled off, and reached the minimum value of 462 mg / kg on the 45th day. The directly available phosphorus source first showed a parabolic increase and finally leveled off during the entire cultivation period, the moderately active phosphorus source gradually increased and finally leveled off during the entire cultivation period, and the potential phosphorus source first fluctuated and then gradually decreased. As described above, the sodium fumarate solution significantly improved the activity of inorganic phosphorus sources.

[0036] Example 2:

[0037] The implementation site is located in the farmland near Guobayan, Baoxing County, Sichuan Province, and the soil type is brown soil. The main implementation steps are as follows: Evenly spray the sodium fumarate solution on the soil, with the application concentration of 0.6 g / L and the application amount of 8 L / acre. After spraying, let it stand for 1 day, and measure the soil physical and chemical properties on the 60th day.

[0038] Table 2 Changes in soil physical and chemical properties during the cultivation period of Example 2

[0039]

[0040] The change in the available phosphorus content in the soil during the cultivation period is shown in Figure 3 . The test results show that the available phosphorus content in the soil with sodium fumarate solution addition increased rapidly within the first 10 days, and the available phosphorus content increased from 5.92 mg / kg to 10.25 mg / kg, with an increase of 73.14%. From the 20th day to the 60th day, the available phosphorus content was stable at about 7.8 mg / kg, an increase of 41.84% compared with the blank group.

[0041] Example 3:

[0042] The implementation plot is located in the farmland of Qingyi Town, Mianyang City, Sichuan Province. The basic physical and chemical properties of the soil are as follows: The pH value is 8.2, the organic matter content is 1.2%, the total phosphorus content is 1.05 g / kg, the available phosphorus is 25.6 mg / kg, the soil texture is clay loam, the main phosphorus fixation form is calcium phosphate, the soil type is sierozem, and the texture is sandy soil.

[0043] The main implementation steps are as follows: Apply sodium fumarate solution 7 days before wheat sowing, with an application concentration of 0.4 g / L and an application rate of 10 L / acre. Two control groups are set up, CK1: conventional phosphate fertilizer, CK2: no phosphate fertilizer applied (only nitrogen and potassium fertilizers are applied). The test results show that the available phosphorus content in the sodium fumarate group increased by 148% compared with the CK2 group, and was significantly higher than that in the CK1 group; the phosphorus fertilizer utilization rate increased by 59% compared with the CK1 group, and the phosphate fertilizer input was reduced by 40%; mild soil acidification (pH decreased by 0.3) is beneficial to alleviating phosphorus fixation in calcareous soil.

[0044] Table 3 Soil physical and chemical properties of each treatment in Example 3

[0045]

[0046]

[0047] Table 4 Wheat yield and phosphorus fertilizer utilization rate in Example 3

[0048]

[0049] Example 4:

[0050] The test plot is an orange orchard in Danling County, Meishan City, Sichuan Province. The soil type is cinnamon soil, the soil pH is 6.5, and the initial available phosphorus content is 12.4 mg / kg. Uniformly spray 0.2 g / L sodium fumarate solution on the soil around the roots of the fruit trees, with a spraying amount of 50 ml per fruit tree, and let it stand for 3 days. The test results show that the available phosphorus content in the soil on the 30th day increased to 15.8 mg / kg, an increase of 27.4% compared with the blank control group. When the fruit is ripe, the fruit sugar content in the group sprayed with sodium fumarate solution increased by 8.6% compared with the blank control group.

[0051] Example 5:

[0052] The test plot is a greenhouse base in Zhaozhen, Jintang County, Sichuan Province. The soil type is yellow soil, the soil pH is 6.2, and the initial available phosphorus content is 15.6 mg / kg. Uniformly spray 0.4 g / L sodium fumarate solution on the soil in the root zone, with a dosage of 6 L / acre, and let it stand for 2 days. The experimental results show that the available phosphorus content in the soil on the 30th day increased to 19.2 mg / kg, an increase of 23.1% compared with the blank group; when the crops are mature, the crop yield in the group sprayed with sodium fumarate solution increased by 6.7% compared with the blank control group.

Claims

1. A soil phosphorus activation and synergistic method based on sodium fumarate regulation, characterized in that: The soil phosphorus activator is sodium fumarate.

2. The soil phosphorus activation and synergistic method according to claim 1, characterized in that: The phosphorus activator used in the method is dissolved in water and then evenly sprayed on the soil in the crop root zone through a sprayer.

3. The soil phosphorus activation and synergistic method as claimed in claim 1, comprising the steps of: preparing sodium fumarate solution, diluting with solvent, spraying with solvent, and allowing the soil to stand.

4. The soil phosphorus activation and synergistic method according to claim 1, characterized in that: The concentration of sodium fumarate solution is 0.2g / L, and the economical and effective spraying amount of this phosphorus activator is 5L / mu.

5. The soil phosphorus activation and synergistic method according to claim 1, characterized in that: It is widely used to increase the effective phosphorus content in various types of soils such as farmland, orchards and greenhouse cultivation. It is especially suitable for soils with high phosphorus fixation and areas with low phosphorus fertilizer utilization rate in facility agriculture; it has a long effect period, which can last for more than 2 months.

6. The method for activating and enhancing soil phosphorus based on sodium fumarate regulation according to any one of claims 1 to 5, characterized in that: It can effectively dissolve mineral phosphorus in the soil that is difficult for plants to absorb and utilize, and increase the effective phosphorus content in the soil.

Images