A method for quantitative application of biochar in dryland wheat fields

Abstract

This invention relates to the field of soil fertility improvement technology, specifically disclosing a method for quantitatively applying biochar to dryland wheat fields. The method includes calculating the amount of exogenous carbon required to increase soil organic carbon per hectare based on soil bulk density, soil topsoil thickness, and the difference between the target and current organic carbon content. Then, using the ratio of exogenous carbon to the total carbon content of biochar, a coefficient for straw treatment methods, and a biochar application adjustment coefficient for sandy loam, the required amount of biochar to be applied per hectare is calculated and applied to the soil surface. This method for quantitatively applying biochar can quantitatively calculate the required biochar content based on the target soil organic carbon content, avoiding the problems of excessively high soil pH and resource waste caused by excessive biochar application, and also avoiding the problem of insufficient biochar application leading to poor soil organic carbon enhancement.

Description

Technical Field

[0001] This invention relates to the field of soil fertility improvement technology, specifically to a method for quantitative application of biochar in dryland wheat fields. Background Technology

[0002] Soil organic carbon is one of the key indicators of soil quality. It is crucial to soil structure, properties and nutrient cycling. Increasing soil organic carbon content can improve soil structure, increase soil water and fertilizer retention capacity, and help improve farmland productivity and promote sustainable agricultural development.

[0003] Biochar is a stable solid carbon fixation product obtained by thermal decomposition of agricultural and forestry plant waste biomass such as crop straw at 400 ℃ to 700 ℃ under anaerobic or limited oxygen supply conditions.

[0004] Wheat, as a major food crop, is widely cultivated in China. Improving soil organic carbon content and enriching the soil through the rational application of biochar is one of the important measures to promote the management of low- and medium-yield farmland, increase wheat production and quality, and drive the green and efficient development of dryland agriculture.

[0005] Applying biochar can effectively increase soil organic carbon content, and applying a small amount (<4 t / hm) is even better. 2 ) and excessive (>45 t / hm) 2 Biochar has no significant impact on soil fertility or crop growth, and may even have negative effects on the soil-crop system. However, most discussions on biochar application rates are qualitative, and the application rate is largely determined empirically, which is highly subjective. Therefore, the actual impact of biochar application on soil is unclear. Previous studies have failed to provide a quantitative and convenient method for calculating biochar application rates, leading to widespread irrational biochar application. Therefore, there is an urgent need to provide a quantitative method for biochar application. Summary of the Invention

[0006] To develop a quantitative method for biochar application, this invention provides a method for quantitatively applying biochar to dryland wheat fields. The quantitative biochar application method provided by this invention can quantitatively calculate the required amount of biochar to be applied based on the target organic carbon content of the soil, avoiding the problems of excessive soil pH and resource waste caused by excessive biochar application, and also avoiding the problem of insufficient biochar application leading to poor soil organic carbon enhancement.

[0007] This invention provides a method for quantitative application of biochar in dryland wheat fields, comprising the following steps:

[0008] Based on soil bulk density, soil topsoil thickness, and the difference between the target soil organic carbon content and the current organic carbon content, the amount of exogenous carbon required to increase soil organic carbon per hectare was calculated.

[0009] The amount of biochar required per hectare of soil is calculated by using the ratio of exogenous carbon application to the total carbon content of biochar, the coefficient of straw treatment method, and the biochar application adjustment coefficient for sandy loess. The straw treatment method includes straw return to the field or straw removal from the field.

[0010] Then, based on the calculated biochar dosage, the biochar is evenly applied to the soil surface, and then the biochar is turned into the soil, completing the process of quantitative application of biochar in dryland wheat fields.

[0011] This invention calculates the amount of exogenous carbon required to increase soil organic carbon per hectare based on soil bulk density, soil topsoil thickness, and the difference between the target and current soil organic carbon content. It then uses the ratio of exogenous carbon to the total carbon content of biochar, a coefficient for straw treatment methods, and an adjustment coefficient for biochar application in sandy loam to calculate the required amount of biochar to be applied per hectare. This method provides a quantitative application of biochar in dryland wheat fields. This invention can quantitatively calculate the required biochar content based on the target soil organic carbon content, avoiding the problems of excessively high soil pH and resource waste caused by excessive biochar application, while also avoiding the problem of insufficient biochar application leading to poor soil organic carbon enhancement.

[0012] Furthermore, the formula for calculating the amount of exogenous carbon is: C input = BD T D 10;

[0013] In the formula, C input represents the amount of exogenous carbon used, t / hm. 2 BD represents soil bulk density, g / cm³ 3 T represents the soil topsoil thickness, in meters; D represents the difference between the target organic carbon content and the current organic carbon content, in g / kg; 10 represents the first unit conversion factor.

[0014] Furthermore, the formula for calculating the amount of biochar required per hectare of soil is as follows:

[0015] Biochar Amount=(C input / TC) SR 1.1 100;

[0016] In the formula, Biochar Amount represents the amount of biochar used, in t / hm². 2; TC represents the total carbon content of biochar, %; SR represents the coefficient of straw treatment method, which includes straw returning to the field or straw removal from the field. When straw is returned to the field, the coefficient of straw treatment method is 0.7, and when straw is removed from the field, the coefficient of straw treatment method is 1; 1.1 represents the adjustment coefficient for biochar dosage in sandy loess; 100 represents the conversion coefficient for the second unit.

[0017] Furthermore, the biochar is incorporated into the soil at a depth of 20 cm to 30 cm.

[0018] Furthermore, after applying biochar, apply neutral or physiologically acidic fertilizer as seed fertilizer at sowing time.

[0019] Furthermore, the application rates of the seed fertilizer are as follows: nitrogen (N) 6.0 kg / mu to 12.0 kg / mu, phosphorus (P2O5) 2.0 kg / mu to 4.0 kg / mu, and potassium (K2O) 1.0 kg / mu to 2.5 kg / mu.

[0020] Furthermore, the amount of fertilizer applied is determined according to the target organism, as follows:

[0021] For wheat fields with a yield of 300-400 kg / mu, apply nitrogen (N) at 9.0-12.0 kg / mu, phosphorus (P2O5) at 3.0-4.0 kg / mu, and potassium (K2O) at 2.0-2.5 kg / mu.

[0022] For wheat fields with a yield of 250-300 kg / mu, apply nitrogen (N) at 7.5-9.0 kg / mu, phosphorus (P2O5) at 2.5-3.0 kg / mu, and potassium (K2O) at 1.5-2.0 kg / mu.

[0023] For wheat fields with a yield of 200-250 kg per mu, apply 6.0-7.5 kg of nitrogen (N), 2.0-2.5 kg of phosphorus (P2O5), and 1.0-1.5 kg of potassium (K2O).

[0024] Furthermore, the seed fertilizer is any one or a combination of several of urea, monoammonium phosphate, and potassium chloride.

[0025] Furthermore, the application rate of urea is 20 kg / mu, the application rate of monoammonium phosphate is 15 kg / mu, and the application rate of potassium chloride is 5.0 kg / mu.

[0026] Furthermore, the soil texture on which the biochar is applied is sandy loam.

[0027] Furthermore, the soil properties of the sandy loam are as follows: bulk density is 1.22 g / cm³. 3 The pH was 8.18, the organic carbon content was 8.73 g / kg, the total nitrogen content was 0.81 g / kg, the mineral nitrogen content was 15.9 mg / kg, the available phosphorus content was 5.4 mg / kg, and the available potassium content was 139.9 mg / kg.

[0028] Furthermore, the biochar is Grade I biochar.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention provides a method for quantitatively increasing soil organic carbon by applying biochar in sandy loam wheat fields. The method can quantitatively calculate the required amount of biochar to be applied based on the target organic carbon content of the soil, avoiding the problems of excessive soil pH and resource waste caused by excessive application of biochar, as well as the problem of poor soil organic carbon increase caused by insufficient biochar application. This provides theoretical support for the scientific application of biochar for soil improvement and fertilization in wheat fields.

[0031] This invention considers the good permeability and rapid turnover of sandy loam loess. Based on the results of previous field trials on biochar gradients, the biochar application rate adjustment coefficient for sandy loam loess is set at 1.1. Simultaneously, considering the exogenous organic carbon brought in by straw return to the field, the biochar application rate adjustment coefficient is set at 0.7 when straw is returned to the field. By considering specific soil and agronomic management conditions, the biochar application rate is optimized through adjustment coefficients to efficiently and rapidly increase soil organic carbon. This invention can calculate the reasonable application rate of biochar in sandy loam loess without using complex technologies such as high-throughput sequencing and quantitative real-time PCR; it only requires basic information such as soil bulk density. It has the advantages of quantification, rationalization, and simplification, and is highly operable. Detailed Implementation

[0032] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0033] This invention provides a method for quantitative application of biochar in dryland wheat fields, comprising the following steps:

[0034] Based on soil bulk density, soil topsoil thickness, and the difference between the target organic carbon content and the current organic carbon content, the amount of exogenous carbon required to increase soil organic carbon per hectare is calculated according to formula (1).

[0035] The amount of exogenous carbon used is calculated and combined with formula (2) to calculate the amount of biochar to be applied.

[0036] Then, using the biochar amount calculated by formula (2) as the standard, the biochar is evenly applied to the surface and then turned into the soil.

[0037] Formula (1) is: C input = BD T D 10;

[0038] In the formula, C input represents the amount of exogenous carbon used, t / hm. 2 BD represents soil bulk density, g / cm³ 3 T represents the soil topsoil thickness, in meters; D represents the difference between the target organic carbon content and the current organic carbon content, in grams per kilogram; 10 represents the unit conversion factor.

[0039] Formula (2) is: Biochar Amount = (C input / TC) SR 1.1 100;

[0040] In the formula, Biochar Amount represents the amount of biochar used, in t / hm². 2 ; TC represents the total carbon content of biochar, %; SR represents a value of 0.7 when straw is returned to the field and a value of 1 when straw is removed from the field; 1.1 represents the adjustment coefficient for biochar usage in sandy loess; 100 represents the unit conversion coefficient.

[0041] The method for quantitative application of biochar provided by this invention can quantitatively calculate the amount of biochar to be applied based on the target organic carbon content of the soil, avoiding the problems of excessive soil pH and resource waste caused by excessive application of biochar, and also avoiding the problem of poor effect in increasing soil organic carbon due to insufficient application of biochar.

[0042] Example 1: A method for quantitative application of biochar in dryland wheat fields.

[0043] I. Experimental Materials and Methods

[0044] 1. Selection of experimental materials and experimental fields

[0045] Grade I biochar was selected, and the specific technical requirements are shown in Table 1.

[0046] Table 1 Technical Requirements for Grade I Biochar

[0047]

[0048] Note: a: Heavy metals and heavy metal-like arsenic are calculated based on total elemental content; b: Moisture content is based on factory inspection data; c: Moisture content is based on fresh samples, while other indicators are based on dried samples.

[0049] The soil in the experimental field was sandy loam with a bulk density of 1.22 g / cm³. 3 The soil composition was as follows: pH 8.18, organic carbon 8.73 g / kg, total nitrogen 0.81 g / kg, mineral nitrogen 15.9 mg / kg, available phosphorus 5.4 mg / kg, and available potassium 139.9 mg / kg. The experimental field did not undergo straw return treatment. The total carbon content of the biochar was 60%, the topsoil thickness was 0.20 m, and the soil organic carbon content was 10 g / kg.

[0050] 2. Experimental methods and results

[0051] Biochar application should be done from September 10th to September 20th, choosing a windless day. Spread the biochar evenly on the soil surface and use a rotary tiller to incorporate it into the soil to a depth of 25 cm. Sowing should be done from September 25th to October 5th, applying a seed fertilizer consisting of urea, monoammonium phosphate, and potassium chloride, mixed in the following proportions: urea 20 kg / mu, monoammonium phosphate 15 kg / mu, and potassium chloride 5.0 kg / mu.

[0052] The amount of biochar used is denoted as Biochar Amount, expressed in t / hm. 2 It is stated that the target soil organic carbon content is set at 12 g / kg, and the difference between the target soil organic carbon content and the current organic carbon content is 2 g / kg, which is calculated according to the following formula.

[0053] C input=BD T D 10;

[0054] Where: BD—soil bulk density, g / cm³ 3 T—Soil topsoil thickness, m; D—Difference between target and current organic carbon content, g / kg; 10—Unit conversion factor.

[0055] Taking into account factors such as biochar quality, whether straw is returned to the field, and soil texture, the biochar amount is calculated using the following formula, expressed in t / hm². 2 express.

[0056] Biochar Amount=(C input / TC) SR 1.1 100;

[0057] Where: TC—total carbon content of biochar, %; SR—value of 0.7 when straw is returned to the field, and value of 1 when straw is removed from the field; 1.1—adjustment coefficient for biochar usage in sandy loess; 100—unit conversion coefficient.

[0058] Substituting the parameters from this embodiment into the above formula yields the following results:

[0059]

[0060] Therefore, the biochar dosage in this embodiment is 9.5 t / hm. 2 .

[0061] Example 2: A method for quantitative application of biochar in dryland wheat fields.

[0062] The experimental materials and experimental field selection for Example 2 are the same as those for Example 1. The specific steps are as follows:

[0063] Biochar should be applied from September 10th to September 20th, choosing a windless day. Spread the biochar evenly on the soil surface and use a rotary tiller to incorporate it into the soil to a depth of 25 cm. After applying the biochar, apply seed fertilizer at sowing time. The seed fertilizer consists of urea, monoammonium phosphate, and potassium chloride, with the following dosages: urea 20 kg / mu, monoammonium phosphate 15 kg / mu, and potassium chloride 5.0 kg / mu.

[0064] The amount of biochar used is denoted as Biochar Amount, expressed in t / hm. 2 It is stated that the target soil organic carbon content is set at 13 g / kg, and the difference between the target soil organic carbon content and the current organic carbon content is 3 g / kg, which is calculated according to the following formula.

[0065] C input=BD T D 10;

[0066] Where: BD—soil bulk density, g / cm³ 3 T—Soil topsoil thickness, m; D—Difference between target and current organic carbon content, g / kg; 10—Unit conversion factor.

[0067] Taking into account factors such as biochar quality, whether straw is returned to the field, and soil texture, the biochar amount is calculated using the following formula, expressed in t / hm².2 express.

[0068] Biochar Amount=(C input / TC) SR 1.1 100;

[0069] Where: TC—total carbon content of biochar, %; SR—value of 0.7 when straw is returned to the field, and value of 1 when straw is removed from the field; 1.1—adjustment coefficient for biochar usage in sandy loess; 100—unit conversion coefficient.

[0070] Substituting the parameters from this embodiment into the above formula yields the following results:

[0071]

[0072] Therefore, the biochar return rate in this embodiment is 14.3 t / hm². 2 .

[0073] Example 3: A method for quantitative application of biochar in dryland wheat fields.

[0074] The experimental materials and experimental field selection for Example 3 are the same as those for Example 1. The specific steps are as follows:

[0075] The experimental method is as follows: Biochar was applied from September 10th to September 20th, on windless days. The biochar was evenly spread on the soil surface and then tilled into the soil using a rotary tiller to a depth of 25 cm. After applying the biochar, seed fertilizer was applied at sowing time. The seed fertilizer consisted of urea, monoammonium phosphate, and potassium chloride, with the following dosages: urea 20 kg / mu, monoammonium phosphate 15 kg / mu, and potassium chloride 5.0 kg / mu.

[0076] The amount of biochar used is denoted as Biochar Amount, expressed in t / hm. 2 It is stated that the target soil organic carbon content is set at 14 g / kg, and the difference between the target soil organic carbon content and the current organic carbon content is 4 g / kg, which is calculated according to the following formula.

[0077] C input=BD T D 10;

[0078] Where: BD—soil bulk density, g / cm³ 3 T—Soil topsoil thickness, m; D—Difference between target and current organic carbon content, g / kg; 10—Unit conversion factor.

[0079] Taking into account factors such as biochar quality, whether straw is returned to the field, and soil texture, the biochar amount is calculated using the following formula, expressed in t / hm². 2 express.

[0080] Biochar Amount=(C input / TC) SR 1.1 100;

[0081] Where: TC—total carbon content of biochar, %; SR—value of 0.7 when straw is returned to the field, and value of 1 when straw is removed from the field; 1.1—adjustment coefficient for biochar usage in sandy loess; 100—unit conversion coefficient.

[0082] Substituting the parameters from this embodiment into the above formula yields the following results:

[0083]

[0084] Therefore, the biochar return rate in this embodiment is 19.1 t / hm². 2 .

[0085] The soil organic carbon content was measured before and after the application of biochar in Examples 1 to 3. The results are shown in Table 2.

[0086] Table 2 Soil organic carbon content before and after biochar application

[0087]

[0088] Note: The data in this table comes from Shilipu Village, Changwu County, Shaanxi Province (measured in 2024).

[0089] As shown in Table 2, the soil organic carbon content increased after the application of biochar, and the increase in organic carbon content in Examples 1-3 was close to the theoretical value, which proves the rationality of the biochar return formula involved in this invention.

[0090] Although preferred embodiments of the invention have been described, those skilled in the art, once they have learned the basic inventive concept, can make other changes and modifications to these embodiments.

[0091] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for quantitatively applying biochar to dryland wheat fields, characterized in that, Includes the following steps: Based on soil bulk density, soil topsoil thickness, and the difference between the target soil organic carbon content and the current organic carbon content, the amount of exogenous carbon required to increase soil organic carbon per hectare was calculated. The formula for calculating the amount of external carbon used is: C input = BD T D 10; In the formula, C input represents the amount of exogenous carbon used, t / hm. 2 BD represents soil bulk density, g / cm³ 3 T represents the thickness of the topsoil layer, in meters. D represents the difference between the target organic carbon content and the current organic carbon content in the soil, in g / kg; 10 represents the conversion factor for the first unit. The required biochar application rate per hectare was calculated using the ratio of exogenous carbon application to the total carbon content of biochar, a coefficient for straw treatment methods, and an adjustment coefficient for biochar application in sandy loam. The straw treatment methods included straw return to the field or straw removal from the field. The formula for calculating the required biochar application rate per hectare is as follows: Biochar Amount=(C input / TC) SR 1.1 100; In the formula, Biochar Amount represents the amount of biochar used, in t / hm². 2 ; TC represents the total carbon content of biochar, %; SR represents the coefficient for straw treatment methods, which include straw return to the field or straw removal from the field. When straw is returned to the field, the coefficient for straw treatment methods is 0.7; when straw is removed from the field, the coefficient for straw treatment methods is 1; 1.1 represents the adjustment coefficient for biochar usage in sandy loess; 100 represents the conversion coefficient for the second unit. Then, based on the calculated biochar dosage, the biochar is evenly applied to the surface and then turned into the soil, completing the process of quantitative application of biochar in dryland wheat fields.

2. The method for quantitative application of biochar in dryland wheat fields according to claim 1, characterized in that, The biochar is incorporated into the soil at a depth of 20 cm to 30 cm.

3. The method for quantitative application of biochar in dryland wheat fields according to claim 1, characterized in that, After applying biochar, apply neutral or physiologically acidic fertilizer as seed fertilizer at the time of sowing.

4. The method for quantitative application of biochar in dryland wheat fields according to claim 3, characterized in that, The application rates of the seed fertilizer are as follows: nitrogen 6.0 kg / mu to 12.0 kg / mu, phosphorus 2.0 kg / mu to 4.0 kg / mu, and potassium 1.0 kg / mu to 2.5 kg / mu.

5. The method for quantitative application of biochar in dryland wheat fields according to claim 4, characterized in that, The amount of fertilizer applied is determined based on the target organism, as follows: For wheat fields with a yield of 300-400 kg / mu, apply nitrogen at 9.0-12.0 kg / mu, phosphorus at 3.0-4.0 kg / mu, and potassium at 2.0-2.5 kg / mu. For wheat fields with a yield of 250-300 kg / mu, apply nitrogen at 7.5-9.0 kg / mu, phosphorus at 2.5-3.0 kg / mu, and potassium at 1.5-2.0 kg / mu. For wheat fields with a yield of 200-250 kg / mu, apply 6.0-7.5 kg / mu of nitrogen, 2.0-2.5 kg / mu of phosphorus, and 1.0-1.5 kg / mu of potassium.

6. The method for quantitative application of biochar in dryland wheat fields according to claim 5, characterized in that, The fertilizer is any one or a combination of several of urea, monoammonium phosphate, and potassium chloride.

7. The method for quantitative application of biochar in dryland wheat fields according to claim 1, characterized in that, The soil texture on which the biochar was applied was sandy loam.

8. The method for quantitative application of biochar in dryland wheat fields according to claim 7, characterized in that, The soil properties of the sandy loam are as follows: bulk density is 1.22 g / cm³. 3 The pH was 8.18, the organic carbon content was 8.73 g / kg, the total nitrogen content was 0.81 g / kg, the mineral nitrogen content was 15.9 mg / kg, the available phosphorus content was 5.4 mg / kg, and the available potassium content was 139.9 mg / kg.

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