An evaluation method for the activity function of livestock and poultry manure compost and its application

Abstract

The present invention relates to a method for evaluating the active function of livestock and poultry manure compost and its application, and belongs to the technical field of organic waste treatment. The method for evaluating the active function of livestock and poultry manure compost of the present invention comprises the following steps: determining the humic acid content and the relative content of humic acid functional groups in the livestock and poultry manure compost, and calculating the alkylation index and E4 / E6 value; evaluating and / or characterizing the functional activity of the livestock and poultry manure compost according to the humic acid content, the relative content of carboxyl carbonyl carbon, the alkylation index and the E4 / E6 value. The evaluation method of the present invention includes a variety of evaluation indicators that are correlated with active functions such as promoting crop growth, promoting nutrient absorption, and reducing soil ammonia volatilization, and has the advantages of strong comprehensiveness, strong systematicity, high accuracy, and relative perfection.

Description

Technical Field

[0001] The invention relates to the technical field of organic waste treatment, in particular to an evaluation method for the active function of livestock and poultry manure compost and an application thereof. Background Art

[0002] With the development of the livestock and poultry farming industry, the amount of livestock and poultry manure produced has been increasing, reaching an average annual output of 420 million tons. Livestock and poultry manure is rich in organic matter, nitrogen, phosphorus, potassium, and other nutrients. It is estimated that in 2019, the nitrogen, phosphorus, and potassium production from livestock and poultry manure reached 928,000 tons, 604,000 tons, and 686,000 tons, respectively. However, due to untimely and unscientific treatment of livestock and poultry manure, a massive amount of manure has accumulated and been wasted, causing environmental pollution, including eutrophication of water bodies and soil acidification.

[0003] Aerobic composting is an important way to utilize livestock and poultry manure as fertilizer. The compost obtained after aerobic composting of livestock and poultry manure has the characteristics of long-lasting fertilizer effect and comprehensive nutrients. Long-term application can effectively increase the content of soil organic matter, improve the physical and chemical properties of the soil, promote crop growth and nutrient absorption, and can also reduce the volatilization of soil ammonia through adsorption, complexation, etc., and reduce nitrogen loss in farmland. At present, there are many evaluation indicators for the maturity of livestock and poultry manure compost, such as humic acid structure, spectral characteristics of soluble organic carbon, etc., but there are few indicators for predicting and evaluating the functional activity of compost, and the existing technology has not yet disclosed an evaluation method that can comprehensively and systematically characterize the functional activity of livestock and poultry manure compost. Summary of the Invention

[0004] The purpose of the present invention is to address the defects in the above-mentioned prior art and provide a method for evaluating the activity function of livestock and poultry manure compost and its application, so as to solve the problem that the prior art cannot comprehensively and systematically evaluate and / or characterize the functional activity of livestock and poultry manure compost.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for evaluating the activity function of livestock and poultry manure compost, comprising the following steps:

[0007] (1) Determination of humic acid content in livestock and poultry manure compost;

[0008] (2) Determination of the relative content of humic acid functional groups in livestock and poultry manure compost;

[0009] The relative content of the humic acid functional groups includes the relative content of alkyl carbon, the relative content of alkoxy carbon, and the relative content of carboxyl carbonyl carbon;

[0010] (3) calculating the alkylation index according to the relative content of alkyl carbon and the relative content of alkoxy carbon described in step (2);

[0011] (4) Determine the absorbance of soluble organic carbon in livestock and poultry manure compost at 465 nm and 665 nm, and calculate the E4 / E6 value;

[0012] (5) Evaluate and / or characterize the functional activity of livestock and poultry manure compost based on the humic acid content, relative content of carboxyl carbonyl carbon, alkylation index and E4 / E6 value of livestock and poultry manure compost.

[0013] Preferably, the method for determining the humic acid content in step (1) is sodium hydroxide extraction-loss on ignition method.

[0014] Preferably, the method for determining the relative content of humic acid functional groups in step (2) is: 13 C cross-polarization / magic angle spinning-NMR method.

[0015] Preferably, the calculation formula of the alkylation index in step (3) is: alkylation index = relative content of alkyl carbon / relative content of alkoxy carbon.

[0016] Preferably, the absorbance value in step (4) is determined by ultraviolet-visible spectrophotometry.

[0017] Preferably, when the humic acid content of the livestock and poultry manure compost is ≥100 g / kg, 1.5<E4 / E6 value<2.0, and alkylation index>1.4, the livestock and poultry manure compost has the function of promoting crop growth and nutrient absorption;

[0018] When the humic acid content of the livestock and poultry manure compost is ≥100 g / kg and the relative content of carboxyl carbonyl carbon is >19%, the livestock and poultry manure compost has the function of reducing soil ammonia volatilization.

[0019] Preferably, the livestock and poultry manure compost is obtained by aerobic fermentation;

[0020] The aerobic fermentation method is windrow aerobic fermentation, tank aerobic fermentation or reactor composting aerobic fermentation.

[0021] The present invention also provides application of the evaluation method in evaluating and / or characterizing the functional activity of livestock and poultry manure compost.

[0022] The present invention has the following technical effects and advantages:

[0023] The present invention studies the changing characteristics of humic acid and soluble organic carbon in livestock and poultry manure compost through multiple batches of composting experiments. Specifically, the changing characteristics of the humic acid functional group structure and soluble organic carbon spectroscopic parameters in different batches of livestock and poultry manure compost are compared. The correlation between the quality indicators of livestock and poultry manure compost and its active functions such as promoting crop growth, promoting nutrient absorption, and reducing soil ammonia volatilization is analyzed, providing a scientific basis for screening, evaluating, and / or characterizing indicators for the functional activity of livestock and poultry manure compost.

[0024] The present invention establishes a comprehensive and reasonable evaluation method for the active function of livestock and poultry manure compost, covering multiple evaluation indicators such as humic acid content, relative content of carboxyl carbonyl carbon, alkylation index, E4 / E6 value, etc., effectively avoiding the deviation that may exist and be caused by using a single evaluation indicator. It has the advantages of strong comprehensiveness, strong systematicity, high accuracy, and relative perfection, and can provide theoretical support for the high-value utilization of livestock and poultry manure compost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the seed germination index of each batch of livestock manure compost;

[0026] Figure 2 The humic acid content of each batch of livestock manure compost;

[0027] Figure 3 is the soil NH3 volatilization rate of each compost. DETAILED DESCRIPTION

[0028] The present invention provides a method for evaluating the activity function of livestock and poultry manure compost, comprising the following steps:

[0029] (1) Determination of humic acid content in livestock and poultry manure compost;

[0030] (2) Determination of the relative content of humic acid functional groups in livestock and poultry manure compost;

[0031] The relative content of the humic acid functional groups includes the relative content of alkyl carbon, the relative content of alkoxy carbon, and the relative content of carboxyl carbonyl carbon;

[0032] (3) calculating the alkylation index according to the relative content of alkyl carbon and the relative content of alkoxy carbon described in step (2);

[0033] (4) Determine the absorbance of soluble organic carbon in livestock and poultry manure compost at 465 nm and 665 nm, and calculate the E4 / E6 value;

[0034] (5) Evaluate and / or characterize the functional activity of livestock and poultry manure compost based on the humic acid content, relative content of carboxyl carbonyl carbon, alkylation index and E4 / E6 value of livestock and poultry manure compost.

[0035] In the present invention, the method for determining the humic acid content in step (1) is sodium hydroxide extraction-loss on ignition method.

[0036] In the present invention, the method for determining the relative content of humic acid functional groups in step (2) is as follows: 13 C cross-polarization / magic angle spinning-NMR method.

[0037] In the present invention, the calculation formula of the alkylation index in step (3) is: alkylation index = relative content of alkyl carbon / relative content of alkoxy carbon.

[0038] In the present invention, the absorbance value in step (4) is determined by ultraviolet-visible spectrophotometry.

[0039] In the present invention, when the humic acid content of the livestock and poultry manure compost is ≥100 g / kg, 1.5<E4 / E6 value<2.0, and alkylation index>1.4, the livestock and poultry manure compost has the function of promoting crop growth and nutrient absorption;

[0040] When the humic acid content of the livestock and poultry manure compost is ≥100 g / kg and the relative content of carboxyl carbonyl carbon is >19%, the livestock and poultry manure compost has the function of reducing soil ammonia volatilization.

[0041] In the present invention, the livestock and poultry manure compost comprises livestock and poultry manure and auxiliary materials;

[0042] The mass ratio of the livestock and poultry manure to the auxiliary material is 8-20:2-6, preferably 12.2:5.

[0043] In the present invention, the livestock and poultry manure includes one or more of chicken manure, pig manure and cow manure;

[0044] The auxiliary materials include one or more of rice straw, wheat straw, vegetable straw, rice husk, rice husk, mushroom residue, sawdust and kitchen waste.

[0045] In the present invention, the livestock and poultry manure compost is obtained by aerobic fermentation;

[0046] The aerobic fermentation method is windrow aerobic fermentation, tank aerobic fermentation or reactor compost aerobic fermentation;

[0047] The aerobic fermentation time is 49 to 70 days, preferably 56 days.

[0048] In the present invention, the aerobic fermentation method is intermittent forced ventilation combined with timed turning;

[0049] The ventilation rate of the intermittent forced ventilation is 0.3 to 0.8 L / (kg·min), preferably 0.5 L / (kg·min); the ventilation interval of the intermittent forced ventilation is 10 to 30 minutes of rest every 20 to 40 minutes of ventilation, preferably 20 minutes of rest every 20 to 40 minutes of ventilation, and more preferably 20 minutes of rest every 30 minutes of ventilation;

[0050] The time interval of the regular turning and tossing is 5 to 10 days, preferably 7 days.

[0051] The present invention also provides application of the evaluation method in evaluating and / or characterizing the functional activity of livestock and poultry manure compost.

[0052] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] The pilot fermentation workshop of the present invention is located in Jiangsu Academy of Agricultural Sciences;

[0054] Among the test materials of the present invention, the tested Chinese cabbage variety was Nanjing Aijiaohuang, purchased from Nanjing Wanbang Seed Co., Ltd.; the tested watermelon variety was Qilin, purchased from Shangrao Ganfeng Seed Co., Ltd.; the tested soil was paddy soil with a loam texture, collected from Jiangsu Academy of Agricultural Sciences;

[0055] In the apparatus and equipment of the present invention, the closed reactor was purchased from Jiangsu Zhongke New Ecological Technology Co., Ltd., Kjeltec TM The 8400 automatic nitrogen analyzer was purchased from Foss, Sweden.

[0056] Example 1: Preparation of livestock and poultry manure compost

[0057] Livestock and poultry manure, such as pig manure, chicken manure, and cow manure, and auxiliary materials such as rice straw, wheat straw, vegetable straw, rice husks, rice husk husks, and kitchen waste were used as raw materials for livestock and poultry manure composting. The raw material combinations for livestock and poultry manure composting were set according to the compatibility and dosage shown in Table 1. A total of 12 batches, A1 to A12, were set up. Aerobic fermentation was carried out in a closed reactor in a pilot fermentation workshop. Intermittent forced ventilation combined with timed turning and tossing was used during the fermentation process. The ventilation rate was 0.5 L / (kg·min) and the ventilation interval was 30 min per ventilation and 20 min intermittently. Turning and tossing were performed once a week. Fermentation was completed for a total of 56 d, resulting in 12 batches of livestock and poultry manure compost.

[0058] Table 1 Raw materials for each batch of livestock and poultry manure composting

[0059] batch Livestock and poultry manure (wet weight) Excipients (wet weight) A1 15.5kg pig manure 3.3kg rice straw A2 Pig manure 14.0kg 3.5kg wheat straw A3 13kg pig manure 5.5kg rice straw A4 18.5kg chicken manure 5.9kg rice straw A5 17kg chicken manure Rice husk 4.5kg A6 20kg chicken manure 2kg rice husk A7 13kg pig manure Rice husk 1.5kg + rice straw 3.5kg A8 5kg pig manure + 9kg cow manure 5kg rice straw A9 6kg chicken manure + 6.7kg pig manure 4kg rice husks A10 8kg chicken manure 2kg kitchen waste + 4kg rice straw A11 10kg pig manure 3kg rice straw + 3kg vegetable straw A12 5.5kg chicken manure + 6.7kg cow manure Rice husk 3kg + rice straw 2kg

[0060] Example 2: Determination of indicators for livestock and poultry manure composting

[0061] Seed germination index (GI) is an indicator for evaluating the maturity of livestock and poultry manure compost. The GI of each batch of livestock and poultry manure compost prepared in Example 1 was determined according to the method disclosed in "Organic Fertilizer NY / T 525-2021", and the maturity of each batch of livestock and poultry manure compost was evaluated in combination with the evaluation criteria. The evaluation criteria are: GI>50% indicates that the livestock and poultry manure compost is basically mature; GI>70% indicates that the livestock and poultry manure compost is completely mature. The results are as follows: Figure 1 shown.

[0062] Humic acid is an active functional product during the composting and fermentation process of livestock and poultry manure. The humic acid content is an indicator for evaluating the quality of livestock and poultry manure compost. The humic acid content of each batch of livestock and poultry manure compost prepared in Example 1 was determined by sodium hydroxide extraction-loss on ignition method according to the literature published by Tu Qiaoping (Tu Qiaoping. Study on the Effect and Mechanism of Biochar Addition on Humification of Pig Manure Compost [D]. Zhejiang University, 2014). The results are as follows: Figure 2 shown.

[0063] Alkyl carbon, alkoxy carbon, aromatic carbon, and carboxyl carbonyl carbon are the main humic acid functional groups in organic matter in livestock and poultry manure compost. The relative content of humic acid functional groups is an indicator for evaluating the composting activity of livestock and poultry manure. 13 C-NMR) analyses during composting of olive mill wastes plus straw[J].Bioresource Technology, 2004, 93(3):285-290) 13 C cross-polarization / magic angle spinning-NMR method ( 13 The humic acid functional group content of each batch of livestock manure compost prepared in Example 1 was determined by CCP / MAS-NMR, wherein the NMR spectrum of alkyl carbon was located at 0-45 ppm, the NMR spectrum of alkoxy carbon was located at 45-110 ppm, the NMR spectrum of aromatic carbon was located at 110-160 ppm, and the NMR spectrum of carboxyl carbonyl carbon was located at 160-200 ppm. Then, the peak area of each humic acid functional group was fitted using MestReNova software to obtain the relative content of each humic acid functional group (including the relative content of alkyl carbon, the relative content of alkoxy carbon, the relative content of aromatic carbon, and the relative content of carboxyl carbonyl carbon), and the hydrophobicity index (HB / HI), alkylation index (A / OA), and aromatization index (ARM) were calculated. The results are shown in Table 2.

[0064] The calculation formula for HB / HI is:

[0065] The calculation formula of A / OA is:

[0066] The calculation formula for ARM is:

[0067]

[0068] The E2 / E3 value is used to track the relative molecular size and aromaticity of organic matter in livestock and poultry manure compost, and is negatively correlated with the molecular weight of organic matter, the number of aromatic structures, and the degree of humification. The E4 / E6 value is the humification coefficient, which is used to represent the condensation degree of humic acid and the aromatization degree of aromatic components in the organic matter of livestock and poultry manure compost, and is negatively correlated with the condensation degree and aromatization degree of organic matter. Each batch of livestock and poultry manure compost prepared in Example 1 was mixed with 0.05 mol / L sodium bicarbonate solution according to a solid-to-liquid ratio of 1:10, and a compost extract was obtained after filtration through a 0.45 μm filter membrane. The absorbance values of the soluble organic carbon of each compost extract at 254 nm, 365 nm, 465 nm, and 665 nm were determined by ultraviolet-visible spectrophotometry, and the E2 value, E3 value, E4 value, and E6 value were obtained accordingly, and the E2 / E3 value and E4 / E6 value were calculated. The results are shown in Table 2.

[0069] Table 2 Quality indicators of each batch of livestock and poultry manure compost

[0070]

[0071]

[0072] The results showed that the GI of each batch of livestock and poultry manure compost was independently higher than 70%, indicating that the 12 batches of livestock and poultry manure compost prepared in Example 1 were all fully decomposed and met the organic fertilizer implementation standard; the humic acid content of each batch of livestock and poultry manure compost was 110-160 g / kg, that is, the humic acid content of the 12 batches of livestock and poultry manure compost was independently greater than 100 g / kg; the relative content of alkyl carbon in each batch of livestock and poultry manure compost was 13%-46%, the relative content of alkoxy carbon was 18%-47%, the relative content of aromatic carbon was 22%-43%, the relative content of carboxyl carbonyl carbon was 3%-20%, the E2 / E3 value was 1.44-2.67, and the E4 / E6 value was 1.17-4.95.

[0073] Example 3: Evaluation of the Function of Livestock Manure Compost in Promoting Crop Growth and Nutrient Absorption

[0074] Each batch of livestock manure compost prepared in Example 1 was added to peat at a ratio of 1%, mixed thoroughly, and then transferred to a plug tray. Nanjing dwarf yellow cabbage seeds were sown in each plug tray and watered every 2 days after emergence. A plug tray containing only peat was used as a control. 45 days after sowing the cabbage seeds, the aboveground fresh weight and root fresh weight of the cabbage seedlings were measured; another cabbage seedling was digested with sulfuric acid and hydrogen peroxide using Kjeltec TM The total nitrogen content (TN) of pakchoi seedlings was determined using an 8400 automatic nitrogen analyzer. The total phosphorus content (TP) and total potassium content (TK) of pakchoi seedlings were determined using the molybdenum antimony colorimetric method and flame photometer method published by Bao Shidan et al. in Soil Agrochemical Analysis, respectively. The results are shown in Table 3. The correlation between the physiological indicators of pakchoi seedlings and the quality indicators of each batch of poultry and livestock manure compost was analyzed, and the results are shown in Table 4.

[0075] Table 3 Physiological indicators of Chinese cabbage cultivated with livestock manure compost in different batches

[0076]

[0077] Table 4 Correlation between physiological parameters of pakchoy seedlings and quality parameters of each batch of livestock manure compost

[0078]

[0079] In the table, * indicates significant correlation at the P < 0.05 level, and ** indicates extremely significant correlation at the P < 0.01 level.

[0080] The results showed that, under the treatment of various batches of livestock manure composting, the aboveground fresh weight and root fresh weight of Chinese cabbage seedlings were higher than those of the control to varying degrees; compared with the control, the aboveground fresh weight increased by 0.6% to 101%, the root fresh weight increased by 25.8% to 100%, and TN, TP, and TK increased by an average of 29.7%, 31.0%, and 19.2%, respectively; this indicates that the livestock manure composting of the present invention has a more obvious effect on promoting the growth and development of crop roots, and can also promote the accumulation of nitrogen and phosphorus nutrients in the aboveground part of crops.

[0081] The results of correlation analysis showed that the aboveground fresh weight and root fresh weight of pakchoy seedlings were negatively correlated with the E2 / E3 value, E4 / E6 value, relative content of alkoxy carbon, relative content of aromatic carbon, and ARM of each batch of poultry and livestock manure compost, among which the E4 / E6 value showed a significant negative correlation; the aboveground fresh weight and root fresh weight of pakchoy seedlings were positively correlated with the relative content of alkyl carbon, relative content of carboxyl carbonyl carbon, HB / HI, and A / OA of each batch of poultry and livestock manure compost, among which the A / OA showed a significant positive correlation. Among them, the E4 / E6 values of livestock manure composts in batches A9, A10, and A12 were independently greater than 1.5 and less than 2.0, and the A / OA values were independently greater than 1.4. The aboveground fresh weight and root fresh weight of pakchoy seedlings cultured with livestock manure composts in batches A9, A10, and A12 were both larger, indicating that when the humic acid content of livestock manure compost is ≥100 g / kg, the E4 / E6 value is 1.5 < 2.0, and the alkylation index is >1.4, the livestock manure compost has the function of promoting crop growth and nutrient absorption.

[0082] Example 4: Evaluation of the Function of Livestock Manure Compost in Reducing Soil Ammonia Volatilization

[0083] 1.0000 g of each batch of livestock manure compost prepared in Example 1 was respectively evenly spread on a micro-electronic balance weighing pan, and then 40 mL of 25% NH 3 · H 2 O solution was placed in a micro-electronic balance and positioned outside the weighing pan. The micro-electronic balance was sealed for 60 min, and the mass of each batch of livestock manure compost was recorded after the micro-electronic balance reading stabilized. Each batch of livestock manure compost without NH 3 · H 2 O solution was used as a corresponding control, and NH 3 adsorption capacity was calculated. The results are shown in Table 5. Simultaneously, the NH 3 adsorption capacity (q ) of each batch of livestock manure compost was analyzed. e ) and the correlation between the quality indicators, the results are shown in Table 6.

[0084] q e The calculation formula is:

[0085] Where: m1 is the initial mass of each batch of livestock manure compost (1.0000 g), and m0 is the mass of each batch of livestock manure compost after sealing for 60 minutes (g).

[0086] Table 5 NH3 adsorption capacity of each batch of livestock manure compost

[0087] batch <![CDATA[q e (mg / g)]]> batch <![CDATA[q e (mg / g)]]> A1 18.14 A7 50.76 A2 25.33 A8 44.02 A3 30.07 A9 38.22 A4 36.83 A10 57.49 A5 49.1 A11 70.72 A6 42.22 A12 60.49

[0088] Table 6 Correlation between NH3 adsorption capacity and quality indexes of each batch of livestock manure compost

[0089]

[0090] In the table, * indicates significant correlation at the P < 0.05 level, and ** indicates extremely significant correlation at the P < 0.01 level.

[0091] The results showed that the adsorption capacity of NH3 by different batches of livestock manure compost varied greatly.

[0092] The results of correlation analysis showed that the q of each batch of livestock manure compost e The relative content of carboxyl carbonyl carbon was extremely significantly positively correlated with the relative content of carboxyl carbonyl carbon, and significantly negatively correlated with the relative content of alkoxy carbon. The relative content of carboxyl carbonyl carbon in the livestock manure composts of batches A11 and A12 was independently greater than 19%, and their NH3 adsorption capacity was independently greater than 60 mg / g, indicating that when the humic acid content of livestock manure compost is ≥100 g / kg and the relative content of carboxyl carbonyl carbon is greater than 19%, the livestock manure compost has the function of reducing soil ammonia volatilization.

[0093] Experimental Example 1: Verification of the Function of Compost in Promoting Crop Growth and Nutrient Absorption

[0094] 100 kg of chicken manure + 20 kg of rice straw and 100 kg of pig manure + 20 kg of rice husk were respectively placed in a closed reactor and aerobic fermentation was carried out using the method described in Example 1. Compost I and compost II were obtained after 56 days of fermentation, respectively. Each compost was air-dried, crushed, and passed through a 2 mm sieve. The humic acid content, relative content of humic acid functional groups, E4 value, and E6 value of each compost were determined according to the method described in Example 2, and the E4 / E6 ratio and A / OA ratio were calculated. The results are shown in Table 7.

[0095] Compost I and compost II were added to peat at a ratio of 2% each to cultivate watermelon seedlings of the Qilin variety. A control was used to add a compound fertilizer containing the same nitrogen, phosphorus, and potassium contents. The watermelon seedlings were harvested at the two-leaf, one-heart stage, and the plant height and stem diameter of the watermelon seedlings were measured. The aboveground fresh weight, TN, TP, and TK of the watermelon seedlings were also measured using the method described in Example 3. The effects of each compost on promoting the growth and nutrient absorption of the watermelon seedlings were evaluated. The results are shown in Table 8.

[0096] Table 7 Quality indicators of various composts

[0097]

[0098] Table 8 Physiological indicators of watermelon seedlings cultured in different composts

[0099]

[0100] The results showed that the humic acid content of compost I and compost II was independently greater than 100 g / kg, the E4 / E6 values were independently between 1.5 and 2.0, and the A / OA values were independently greater than 1.4, indicating that compost I and compost II in this experimental example both have the function of promoting crop growth and nutrient absorption.

[0101] A watermelon seedling cultivation experiment showed that compared with the control, watermelon seedlings grown with composts I and II had greater plant height, stem diameter, and aboveground fresh weight. They also had higher TN, TP, and TK values. This suggests that composts I and II in this experiment indeed promote crop growth and nutrient absorption.

[0102] Experimental Example 2: Verification of the Function of Compost in Reducing Soil Ammonia Volatilization

[0103] Paddy soil was collected near the Jiangsu Academy of Agricultural Sciences. Gravel, plant roots, etc. were cleaned, air-dried, and passed through a 2 mm sieve. 100 g of the soil was placed in culture bottles. Each compost prepared in Experimental Example 1 was added to the paddy soil at a ratio of 2% and thoroughly mixed to obtain mixed loam. Urea with the same nitrogen content was added to the paddy soil as a control. The soil moisture content of the mixed loam was controlled to be 60% of the field water holding capacity. The soil was incubated at 25°C for 14 days, and gas samples were collected on the 1st, 2nd, 3rd, 5th, and 7th day of incubation. The soil NH3 volatilization rate of each compost was measured by static absorption-boric acid titration. The results are shown in Figure 2. Figure 3 shown.

[0104] The results showed that the humic acid content of compost I and compost II was independently greater than 100 g / kg, and the relative content of carboxyl carbonyl carbon was independently greater than 19%, indicating that both compost I and compost II in this experimental case have the function of reducing soil ammonia volatilization.

[0105] Compared to the control, the soil NH3 volatilization rates of the mixed loam soils obtained by adding compost I and compost II were significantly reduced, with the maximum volatilization rates being only 22.4% and 30.5% of the control, respectively, and the average volatilization rates being only 26.1% and 27.7%, respectively. This indicates that composts I and II in this experimental example do have the function of reducing soil ammonia volatilization.

[0106] As can be seen from the above examples, the present invention provides a method for evaluating the active functions of livestock and poultry manure compost and its application. This evaluation method incorporates evaluation indicators related to active functions such as promoting crop growth, nutrient absorption, and reducing soil ammonia volatilization, such as humic acid content, relative carboxyl carbonyl carbon content, alkylation index, and E4 / E6 ratio. This effectively avoids the potential bias associated with using a single evaluation indicator and is highly comprehensive, systematic, accurate, and relatively comprehensive.

[0107] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for evaluating the activity function of livestock and poultry manure compost, characterized in that: The steps include: (1) Determination of humic acid content in livestock and poultry manure compost; (2) Determination of the relative content of humic acid functional groups in livestock and poultry manure compost; The relative content of the humic acid functional groups includes the relative content of alkyl carbon, the relative content of alkoxy carbon, and the relative content of carboxyl carbonyl carbon; (3) calculating the alkylation index according to the relative content of alkyl carbon and the relative content of alkoxy carbon described in step (2); (4) Determine the absorbance of soluble organic carbon in livestock and poultry manure compost at 465 nm and 665 nm, and calculate the E4 / E6 value; (5) Evaluate and / or characterize the functional activity of livestock and poultry manure compost based on the humic acid content, relative content of carboxyl carbonyl carbon, alkylation index, and E4 / E6 value of livestock and poultry manure compost; The calculation formula of the alkylation index in step (3) is: alkylation index = relative content of alkyl carbon / relative content of alkoxy carbon; When the humic acid content of the livestock and poultry manure compost is ≥100 g / kg, the E4 / E6 value is 1.5 < 2.0, and the alkylation index is >1.4, the livestock and poultry manure compost has the function of promoting crop growth and nutrient absorption; When the humic acid content of the livestock and poultry manure compost is ≥100 g / kg and the relative content of carboxyl carbonyl carbon is >19%, the livestock and poultry manure compost has the function of reducing soil ammonia volatilization.

2. The evaluation method according to claim 1, wherein: The method for determining the humic acid content in step (1) is sodium hydroxide extraction-loss on ignition method.

3. The evaluation method according to claim 2, wherein: The method for determining the relative content of humic acid functional groups in step (2) is: 13 C cross-polarization / magic angle spinning-NMR method.

4. The evaluation method according to claim 3, wherein: The absorbance value in step (4) is determined by ultraviolet-visible spectrophotometry.

5. The evaluation method according to claim 4, wherein: The livestock and poultry manure compost is obtained by aerobic fermentation; The aerobic fermentation method is windrow aerobic fermentation, tank aerobic fermentation or reactor composting aerobic fermentation.

6. Use of the evaluation method according to any one of claims 1 to 5 in evaluating and / or characterizing the functional activity of livestock and poultry manure compost.

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