Method for quantitatively applying biochar to dry wheat field

Abstract

The invention relates to the technical field of soil fertility improvement, and particularly discloses a method for quantitatively applying biochar to a dry wheat paddy.The method comprises the steps that the amount of exogenous carbon needed for increasing organic carbon of soil per hectare is calculated based on the soil bulk density, the soil plough layer thickness and the difference value between the soil target organic carbon content and the current organic carbon content; calculating to obtain the amount of biochar needing to be applied to each hectare of soil by utilizing the ratio of the amount of exogenous carbon to the total carbon content of the biochar, the coefficient of a straw treatment field mode and the adjustment coefficient of the amount of sandy loam loess biochar, and applying the biochar to the earth surface. According to the method for quantitatively applying the biochar, the content of the biochar needing to be applied can be quantitatively calculated according to the content of the target organic carbon in the soil, the problems that the pH of the soil is too high and resources are wasted due to excessive application of the biochar are solved, and the problem that the effect of improving the organic carbon in the soil is poor due to insufficient use amount of the biochar is also solved.

Description

Technical Field

[0001] The invention relates to the technical field of soil fertilization, and in particular to a method for quantitatively applying biochar in a dryland wheat field. Background Art

[0002] Soil organic carbon is one of the key indicators of soil quality and is crucial to soil structure, properties and nutrient cycles. Increasing the 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 refers to a stable solid carbon-fixing product obtained by thermal cracking of agricultural and forestry plant waste biomass such as crop straw at 400℃ to 700℃ under anaerobic or limited oxygen supply conditions.

[0004] As a major food crop, wheat is widely planted in China, and the stable increase of wheat yield is directly related to national food security. Proper application of biochar to increase soil organic carbon content and fertilize the soil is one of the important measures to promote the management of medium and low-yield fields, promote wheat production, quality and efficiency, and promote the green and efficient development of dryland agriculture.

[0005] The application of biochar can effectively increase the content of soil organic carbon, and the application of small amounts (<4t / hm 2 ) and excessive (>45t / hm 2 ) Biochar has no significant effect on soil fertility and crop growth, and may even have a negative effect on the soil-crop system. However, most of the discussions on the application amount of biochar are qualitative, and the application amount of biomass is mostly determined based on experience. The empirical method is highly subjective, so the actual impact of biochar application on soil is not clear. Previous studies have failed to quantify and provide a simple method for calculating the amount of biochar, resulting in widespread irrational application of biochar. Therefore, there is an urgent need to provide a quantitative biochar application method. Summary of the invention

[0006] In order to develop a quantitative biochar application method, the present invention provides a method for quantitatively applying biochar in dryland wheat fields. The method for quantitatively applying biochar provided by the present invention can quantitatively calculate the amount of biochar required to be applied according to the target organic carbon content of the soil, thereby avoiding the problem of excessively high soil pH and waste of resources caused by excessive application of biochar, and also avoiding the problem of insufficient application of biochar resulting in poor effect of increasing soil organic carbon.

[0007] The present invention provides a method for quantitatively applying biochar to dryland wheat fields, comprising the following steps:

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

[0009] The amount of biochar required to be applied per hectare of soil is calculated using the ratio of the amount of exogenous carbon to the total carbon content of the biochar, the coefficient of the straw treatment method for the field, and the adjustment coefficient of the biochar amount for sandy loam loess; the straw treatment method for the field includes returning the straw to the field or removing the straw from the field;

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

[0011] The present invention calculates the amount of exogenous carbon required to increase soil organic carbon per hectare based on soil bulk density, soil tillage layer thickness, and the difference between the target soil organic carbon content and the current organic carbon content; uses the ratio of the exogenous carbon amount to the total carbon content of biochar, the coefficient of the straw treatment field method, and the sandy loam loess biochar amount adjustment coefficient to calculate the amount of biochar required to be applied per hectare of soil, and applies it on the surface, thereby providing a method for quantitatively applying biochar in dryland wheat fields. The present invention can quantitatively calculate the biochar content required to be applied according to the target soil organic carbon content, thereby avoiding the problem of excessive soil pH and waste of resources caused by excessive application of biochar, and also avoids the problem of poor effect of increasing soil organic carbon caused by insufficient biochar application.

[0012] Furthermore, the calculation formula of the exogenous carbon dosage is: C input = BD × T × D × 10;

[0013] In the formula, C input represents the amount of external carbon, t / hm 2 ; BD represents soil bulk density, g / cm 3 ; T represents the thickness of the soil tillage layer, m; D represents the difference between the target soil organic carbon content and the current soil organic carbon content, g / kg; 10 represents the first unit conversion coefficient.

[0014] Furthermore, the amount of biochar required per hectare of soil is calculated as:

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

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

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

[0018] Furthermore, after applying the biochar, a neutral or physiologically acidic fertilizer is applied as a seed fertilizer at the time of sowing.

[0019] Furthermore, the amount of seed fertilizer applied is: 6.0kg / mu to 12.0kg / mu of nitrogen (N), 2.0kg / mu to 4.0kg / mu of phosphorus (P2O5), and 1.0kg / mu to 2.5kg / mu of potassium (K2O).

[0020] Furthermore, the amount of the seed fertilizer applied is determined according to the application object, as follows:

[0021] For wheat fields with an acreage yield of 300kg to 400kg, apply nitrogen (N) at 9.0kg to 12.0kg per acre, phosphorus (P2O5) at 3.0kg to 4.0kg per acre, and potassium (K2O) at 2.0kg to 2.5kg per acre.

[0022] For wheat fields with an acreage yield of 250kg to 300kg, apply nitrogen (N) at 7.5kg to 9.0kg per acre, phosphorus (P2O5) at 2.5kg to 3.0kg per acre, and potassium (K2O) at 1.5kg to 2.0kg per acre.

[0023] For wheat fields with an acreage yield of 200kg to 250kg, apply 6.0kg / acre to 7.5kg / acre of nitrogen (N), 2.0kg / acre to 2.5kg / acre of phosphorus (P2O5), and 1.0kg / acre to 1.5kg / acre of potassium (K2O).

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

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

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

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

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

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a method for quantitatively increasing soil organic carbon by applying biochar in sandy loam loam wheat fields. The method can quantitatively calculate the biochar content that needs to be applied according to the target organic carbon content of the soil, thereby avoiding the problems of excessive soil pH and waste of resources caused by excessive application of biochar, and also avoiding the problem of poor effect of improving soil organic carbon due to insufficient biochar use, thereby providing theoretical support for the scientific application of biochar in wheat field soil for soil improvement and fertilization.

[0031] The present invention takes into account the characteristics of good air permeability of sandy loam loess and fast turnover of added biochar, and based on the results of previous biochar gradient field tests, the biochar dosage adjustment coefficient of sandy loam loess is set to 1.1; at the same time, the exogenous organic carbon brought in by the returned straw is taken into account, and the biochar dosage adjustment coefficient is set to 0.7 when the straw is returned to the field. By considering the specific soil and agronomic management conditions, the biochar application amount is optimized in the form of an adjustment coefficient to efficiently and quickly increase soil organic carbon. The present invention can calculate the reasonable application amount of sandy loam loess biochar without using complex technologies such as high-throughput sequencing technology and fluorescent quantitative PCR technology, and only needs to master basic information such as soil bulk density. It has the advantages of quantification, rationalization, light simplification, etc., and has strong operability. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0033] The present invention provides a method for quantitatively applying biochar to dryland wheat fields, comprising the following steps:

[0034] Based on soil bulk density, soil tillage layer thickness and the difference between the target soil organic carbon content and the current soil 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 biochar required is calculated using the calculated amount of exogenous carbon combined with formula (2);

[0036] Then, the biochar is evenly applied to the surface based on the biochar dosage calculated by formula (2), and then the biochar is turned into the soil.

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

[0038] In the formula, C input represents the amount of external carbon, t / hm 2 ; BD represents soil bulk density, g / cm 3 ; T represents the thickness of the soil tillage layer, m; D represents the difference between the target soil organic carbon content and the current soil organic carbon content, g / kg; 10 represents the unit conversion coefficient.

[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, t / hm 2 ; TC represents the total carbon content of biochar, %; SR represents the value of 0.7 when the straw is returned to the field and the value of 1 when the straw is removed from the field; 1.1 represents the biochar dosage adjustment coefficient for sandy loam; 100 represents the unit conversion coefficient.

[0041] The method for quantitatively applying biochar provided by the present invention can quantitatively calculate the amount of biochar required to be applied according to the target organic carbon content in the soil, thereby avoiding the problem of excessive soil pH and waste of resources caused by excessive application of biochar, and also avoiding the problem of poor effect of improving soil organic carbon due to insufficient biochar application.

[0042] Example 1: A method for quantitatively applying biochar to dryland wheat fields.

[0043] 1. Experimental Materials and Methods

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

[0045] The biochar used is grade I biochar, and the specific technical index requirements are shown in Table 1.

[0046] Table 1 Technical index requirements for Class I biochar

[0047] project Level I Level II Total carbon (C), % ≥60 ≥30 Fixed carbon (FC), % ≥50 ≥25 Arsenic (as As) a, mg / kg ≤13 ≤15 Cadmium (measured in Cd)a, mg / kg ≤0.3 ≤3 Lead (Pb)a, mg / kg ≤50 ≤50 Chromium (as Cr)a, mg / kg ≤90 ≤150 Mercury (in Hg)a, mg / kg ≤0.5 ≤2 Copper (Cu)a, mg / kg ≤50 ≤200 Zinc (as Zn)a, mg / kg ≤200 ≤300 <![CDATA[Moisture (H2O) bc, %]]> ≤30 ≤30

[0048] Note: a: Heavy metals and quasi-heavy metal arsenic are calculated based on the total amount of elements; b: Moisture content is based on factory inspection data; c: Moisture content is calculated based on fresh samples, and other indicators are calculated based on drying basis.

[0049] The soil in the experimental field is sandy loam with a bulk density of 1.22 g / cm 3 , pH is 8.18, organic carbon is 8.73g / kg, total nitrogen is 0.81g / kg, mineral nitrogen is 15.9mg / kg, available phosphorus is 5.4mg / kg, and available potassium is 139.9mg / kg. The experimental field was not treated with straw return, the total carbon content of the biochar was 60%, the tillage layer thickness was 0.20m, and the soil organic carbon content was 10g / kg.

[0050] 2. Experimental methods and results

[0051] The biochar application time is from September 10 to September 20, and the application is selected in windless weather. The biochar is evenly spread on the surface and turned into the soil with a rotary tiller, with a tillage depth of 25 cm. The sowing time is from September 25 to October 5, and seed fertilizer is applied during sowing. The seed fertilizer is urea, monoammonium phosphate and potassium chloride. The three fertilizers are mixed and applied in proportion, and the amount of each fertilizer is: urea 20kg / mu, monoammonium phosphate 15kg / mu, potassium chloride 5.0kg / mu.

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

[0053] C input = BD × T × D × 10;

[0054] Where: BD——soil bulk density, g / cm 3 ; T——soil tillage layer thickness, m; D——the difference between the target soil organic carbon content and the current soil organic carbon content, g / kg; 10——unit conversion coefficient.

[0055] Taking into account the quality of biochar, whether the straw is returned to the field, soil texture and other conditions, the biochar amount is calculated according to the following formula, in t / hm 2 express.

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

[0057] In the formula: TC is the total carbon content of biochar, %; SR is 0.7 when the straw is returned to the field and 1 when the straw is removed from the field; 1.1 is the adjustment coefficient of biochar dosage for sandy loam; 100 is the unit conversion coefficient.

[0058] Substituting the parameters in this embodiment into the above formula, the results are as follows:

[0059]

[0060] Therefore, the amount of biochar used in this example is 9.5 t / hm 2 .

[0061] Example 2: A method for quantitatively applying biochar to dryland wheat fields.

[0062] The experimental materials and test fields of Example 2 were selected in the same manner as those of Example 1. The specific steps are as follows:

[0063] The biochar application time is from September 10 to September 20, and the application is selected in windless weather. The biochar is evenly spread on the surface and turned into the soil with a rotary tiller. The tillage depth is 25 cm. After the biochar is applied, seed fertilizer is applied during sowing. The seed fertilizer is urea, monoammonium phosphate and potassium chloride, and the amount of each fertilizer is: urea 20kg / mu, monoammonium phosphate 15kg / mu, and potassium chloride 5.0kg / mu.

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

[0065] C input = BD × T × D × 10;

[0066] Where: BD——soil bulk density, g / cm 3 ; T——soil tillage layer thickness, m; D——the difference between the target soil organic carbon content and the current soil organic carbon content, g / kg; 10——unit conversion coefficient.

[0067] Taking into account the quality of biochar, whether the straw is returned to the field, soil texture and other conditions, the biochar amount is calculated according to the following formula, in t / hm 2 express.

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

[0069] In the formula: TC is the total carbon content of biochar, %; SR is 0.7 when the straw is returned to the field and 1 when the straw is removed from the field; 1.1 is the adjustment coefficient of biochar dosage for sandy loam; 100 is the unit conversion coefficient.

[0070] Substituting the parameters in this embodiment into the above formula, the results are as follows:

[0071]

[0072] Therefore, the amount of biochar returned to the field in this example is 14.3t / hm 2 .

[0073] Example 3: A method for quantitatively applying biochar to dryland wheat fields.

[0074] The experimental materials and test fields of Example 3 were selected in the same manner as those of Example 1. The specific steps are as follows:

[0075] The experimental method is as follows: the biochar application time is from September 10 to September 20, and the application is selected in windless weather. The biochar is evenly spread on the surface, and the biochar is turned into the soil using a rotary tiller, and the tillage depth is 25 cm. After the biochar is applied, seed fertilizer is applied during sowing, and the seed fertilizer is urea, monoammonium phosphate and potassium chloride, wherein the amount of each fertilizer is: urea 20kg / mu, monoammonium phosphate 15kg / mu, potassium chloride 5.0kg / mu.

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

[0077] C input = BD × T × D × 10;

[0078] Where: BD——soil bulk density, g / cm 3 ; T——soil tillage layer thickness, m; D——the difference between the target soil organic carbon content and the current soil organic carbon content, g / kg; 10——unit conversion coefficient.

[0079] Taking into account the quality of biochar, whether the straw is returned to the field, soil texture and other conditions, the biochar amount is calculated according to the following formula, in t / hm 2 express.

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

[0081] In the formula: TC is the total carbon content of biochar, %; SR is 0.7 when the straw is returned to the field and 1 when the straw is removed from the field; 1.1 is the adjustment coefficient of biochar dosage for sandy loam; 100 is the unit conversion coefficient.

[0082] Substituting the parameters in this embodiment into the above formula, the results are as follows:

[0083]

[0084] Therefore, the amount of biochar returned to the field in this example is 19.1t / hm 2 .

[0085] The soil organic carbon content was tested 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 measured data in this table are from Shilipu Village, Changwu County, Shaanxi Province (measured in 2024).

[0089] It can be seen from Table 2 that after applying biochar, the soil organic carbon content increased, and the organic carbon content increase values ​​of Examples 1-3 were all close to the theoretical set values, which proves the rationality of the biochar return amount formula involved in the present invention.

[0090] Although preferred embodiments of the present invention have been described, additional changes and modifications may occur to these embodiments once those skilled in the art are aware of the basic inventive concepts.

[0091] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for quantitatively applying biochar to dryland wheat fields, characterized in that: The steps include: Based on soil bulk density, soil tillage layer thickness, and the difference between the target soil organic carbon content and the current soil organic carbon content, the amount of exogenous carbon required to increase soil organic carbon per hectare is calculated; The amount of biochar required to be applied per hectare of soil is calculated using the ratio of the amount of exogenous carbon to the total carbon content of the biochar, the coefficient of the straw treatment method for the field, and the adjustment coefficient of the amount of biochar for sandy loam loess; the straw treatment method for the field includes returning the straw to the field or removing the straw from the field; Then, the biochar is evenly applied to the surface based on the calculated biochar dosage, and then the biochar is turned into the soil to complete the process of quantitative application of biochar in dryland wheat fields.

2. The method for quantitatively applying biochar to dryland wheat fields according to claim 1, characterized in that: The calculation formula of the exogenous carbon dosage is: Cinput = BD × T × D × 10; In the formula, C input represents the amount of external carbon, t / hm 2 ; BD represents soil bulk density, g / cm 3 ; T represents the thickness of the soil tillage layer, m; D represents the difference between the target soil organic carbon content and the current soil organic carbon content, g / kg; 10 represents the first unit conversion coefficient.

3. The method for quantitatively applying biochar to dryland wheat fields according to claim 1, characterized in that: The formula for calculating the amount of biochar required per hectare of soil is: Biochar Amount=(Cinput / TC)×SR×1.1×100; In the formula, Biochar Amount represents the amount of biochar used, t / hm 2 ; TC represents the total carbon content of biochar, %; SR represents the coefficient of the straw treatment field method, which includes returning straw to the field or removing straw from the field. When returning straw to the field, the coefficient of the straw treatment field method is 0.7, and when removing straw from the field, the coefficient of the straw treatment field method is 1; 1.1 represents the adjustment coefficient of sandy loess biochar dosage; 100 represents the second unit conversion coefficient.

4. The method for quantitatively applying biochar to dryland wheat fields according to claim 1, characterized in that: The tillage depth of the biochar into the soil is 20 cm to 30 cm.

5. The method for quantitatively applying biochar to 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.

6. The method for quantitatively applying biochar to dryland wheat fields according to claim 5, characterized in that: The amount of seed fertilizer applied is: 6.0kg / mu to 12.0kg / mu of nitrogen, 2.0kg / mu to 4.0kg / mu of phosphorus, and 1.0kg / mu to 2.5kg / mu of potassium.

7. The method for quantitatively applying biochar to dryland wheat fields according to claim 6, characterized in that: The amount of the seed fertilizer to be applied is determined according to the application object, as follows: For wheat fields with an acreage yield of 300kg to 400kg, apply nitrogen at 9.0kg to 12.0kg per acre, phosphorus at 3.0kg to 4.0kg per acre, and potassium at 2.0kg to 2.5kg per acre. For wheat fields with an acreage yield of 250kg to 300kg, apply 7.5kg to 9.0kg of nitrogen per acre, 2.5kg to 3.0kg of phosphorus per acre, and 1.5kg to 2.0kg of potassium per acre. For wheat fields with an per-acre yield of 200kg to 250kg, apply 6.0kg / mu to 7.5kg / mu of nitrogen, 2.0kg / mu to 2.5kg / mu of phosphorus, and 1.0kg / mu to 1.5kg / mu of potassium.

8. The method for quantitatively applying biochar to dryland wheat fields according to claim 7, characterized in that: The seed fertilizer is any one of urea, monoammonium phosphate and potassium chloride or a combination of several of them.

9. The method for quantitatively applying biochar to dryland wheat fields according to claim 1, characterized in that: The soil texture to which the biochar is applied is sandy loam.

10. The method for quantitatively applying biochar to dryland wheat fields according to claim 9, characterized in that: The soil properties of the sandy loam are: bulk density is 1.22 g / cm 3 , pH is 8.18, organic carbon is 8.73g / kg, total nitrogen is 0.81g / kg, mineral nitrogen is 15.9mg / kg, available phosphorus is 5.4mg / kg, and available potassium is 139.9mg / kg.

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