Experimental Evaluation of Soil Organic Matter Decomposition
Experimental Evaluation of Soil Organic Matter Decomposition
Evaluation of soil organic matter decomposition should simultaneously consider the organic matter pool, microbial decomposition processes, and nutrient release outcomes. SOC/SOM is used to assess organic matter storage, soil enzyme activity is used to locate carbon, nitrogen, and phosphorus transformation steps, inorganic nutrients are used to verify mineralization outcomes, and soil microbial DNA analysis is used to explain the underlying community structure.
Keywords: soil organic matter decomposition; soil microbial activity; soil enzyme activity; soil organic carbon; cellulose degradation; nitrogen mineralization; phosphorus mineralization; soil microbial DNA
1 Basic Logic for Evaluating Soil Organic Matter Decomposition
1.1 Distinguishing the Organic Matter Pool, Decomposition Process, and Transformation Outcomes
Soil organic matter decomposition involves three levels: changes in the organic matter pool, microbial enzyme-mediated decomposition processes, and inorganic nutrient release outcomes. SOC and SOM reflect the size of the organic matter pool, enzyme activity reflects microbial decomposition function, and ammonium nitrogen, nitrate nitrogen, inorganic phosphorus, and available phosphorus reflect the nutrient status formed after decomposition.
(1) SOC/SOM
SOC is suitable for evaluating carbon cycling and organic carbon pools, while SOM is suitable for routine assessment of soil organic matter levels. An increase in SOC or SOM usually indicates enhanced organic matter input, accumulation, or stabilization, but it cannot directly infer reduced microbial decomposition activity.
(2) Soil enzyme activity
Soil enzyme activity can be used to locate specific steps in organic matter decomposition. Carbon cycle enzymes mainly explain polysaccharide and plant residue decomposition, nitrogen cycle enzymes explain organic nitrogen mineralization and microbial residue turnover, phosphorus cycle enzymes explain organic phosphorus release, and oxidative enzymes explain the transformation of lignin, phenolic compounds, and humified components.
(3) Inorganic nutrients
NH₄⁺-N, NO₃⁻-N, inorganic phosphorus, and available phosphorus can be used to determine whether enzymatic decomposition has been converted into detectable nutrient release. If enzyme activity increases but inorganic nutrients do not increase synchronously, microbial assimilation, further transformation, soil adsorption/fixation, or leaching should be considered.
(4) Soil microbial DNA
Soil DNA extraction is suitable for 16S, ITS, and metagenomic analysis and can be used to explain changes in microbial community structure under different treatments. Community analysis cannot replace enzyme activity detection, but it can provide a microbial source basis for functional changes.
1.2 Selecting Indicator Combinations According to Experimental Purpose
Soil organic matter decomposition studies do not need to cover all testing items. Routine soil quality evaluation can select SOC/SOM, dehydrogenase or FDA, β-glucosidase, urease, and phosphatase. Plant residue decomposition studies should include cellulase, xylosidase, and lignin oxidases. Nitrogen and phosphorus release studies should simultaneously detect inorganic nitrogen, available phosphorus, and phosphorus fractions.
Table 1 Indicator hierarchy for evaluating soil organic matter decomposition
Evaluation Level | Representative Indicators | Main Question Addressed | Applicable Scenarios |
Organic matter pool | SOC, SOM, total phenols | Whether total organic matter or phenolic fractions have changed | Long-term management, organic fertilizer, straw return |
Overall microbial activity | Dehydrogenase, FDA hydrolase, catalase | Whether microbial metabolism and hydrolytic capacity have changed | Soil quality, pollution stress, amendment evaluation |
Carbon decomposition process | β-Glucosidase, cellulase, xylosidase, amylase, sucrase | Whether labile carbon, cellulose, and hemicellulose are being utilized | Plant residue decomposition, carbon mineralization studies |
Nitrogen transformation process | Urease, protease, LAP, NAG, chitinase | Whether urea, proteins, chitin, and microbial residues release nitrogen | Nitrogen mineralization, microbial residue turnover |
Phosphorus transformation process | ACP, ALP, NP, phytase, PDE, pyrophosphatase | Whether organic phosphorus is mobilized and released | Phosphorus limitation, soil pH difference studies |
Recalcitrant component transformation | PPO, POD, LiP, MnP, laccase | Whether lignin, phenolics, and humified components are oxidized | Late-stage straw decomposition, forest soil, humification research |
Microbial community | Soil DNA, humic acid removal | Which microbial groups may participate in decomposition | 16S, ITS, metagenomic analysis |
2 Carbon Decomposition Indicators: From Labile Carbon to Structural Carbon
2.1 Labile Carbon Transformation
Sucrase, invertase, amylase, and α-glucosidase mainly reflect the hydrolysis and utilization capacity of labile carbon sources. After root exudates, organic fertilizer, and fresh plant residues enter the soil, these enzymes usually respond earlier.
If SOC does not change significantly in the short term but sucrase, amylase, or α-glucosidase activity increases, this indicates that microorganisms are utilizing labile carbon sources. In this case, it is not appropriate to directly conclude that the soil organic carbon pool has changed significantly. Incubation time, CO₂ release, or DOC results should be further integrated for confirmation.
2.2 Cellulose Decomposition
Cellulose decomposition requires the sequential action of endo-β-1,4-glucanase, exo-β-1,4-glucanase, and β-glucosidase. Endoglucanase generates cleavage sites within cellulose chains, exoglucanase releases oligosaccharides or cellobiose from chain ends, and β-glucosidase further produces glucose.
β-Glucosidase alone should not be used to represent the entire cellulose decomposition process. When studying straw return, plant residue degradation, or organic matter mineralization, endoglucanase, exoglucanase, and β-glucosidase should be analyzed together. A synchronous increase in all three usually suggests enhanced decomposition of structural carbon in plant residues.
2.3 Hemicellulose Decomposition
α-Xylosidase and β-xylosidase are mainly used to evaluate xylan and hemicellulose transformation. Hemicellulose is easier to decompose than lignin, but it usually enters the main decomposition stage later than soluble sugars and starch-like substances.
If xylosidase and cellulase increase synchronously, this indicates active decomposition of structural polysaccharides in plant residues. If xylosidase increases while lignin-related oxidases show little change, the decomposition process may still be dominated by hemicellulose and cellulose degradation.
2.4 Lignin and Phenolic Oxidation
Late-stage plant residue decomposition is closely related to lignin, phenolic compounds, and humified components. Polyphenol oxidase, peroxidase, lignin peroxidase, manganese peroxidase, and laccase can be used to evaluate oxidative transformation of recalcitrant aromatic structures.
Total phenol content should be interpreted together with oxidative enzyme results. If total phenols decrease while PPO, POD, or laccase increases, phenolic substrates may be oxidatively consumed. If total phenols increase while oxidative enzyme activity remains low, phenolic accumulation or restricted transformation of recalcitrant components may be present.
3 Nitrogen Cycle Indicators: Distinguishing Urea, Protein, and Microbial Residue Sources
3.1 Urease and Ammonium Nitrogen
Urease is used to evaluate urea hydrolysis capacity and is suitable for soil studies involving urea, organic fertilizers, or amide nitrogen-containing materials. Increased urease activity usually indicates enhanced urea hydrolysis potential, but whether available nitrogen is formed should be judged together with NH₄⁺-N results.
If urease and NH₄⁺-N both increase, this indicates enhanced ammonium nitrogen release. If urease increases but NH₄⁺-N does not, ammonium nitrogen may have been assimilated by microorganisms, adsorbed by soil, or further nitrified.
3.2 Protease and Aminopeptidase
Acidic, neutral, and alkaline proteases are suitable for evaluating protein decomposition under different pH conditions. Leucine aminopeptidase, glycine aminopeptidase, and arylamidase can be used to evaluate amino acid release after protein degradation.
When studying organic nitrogen mineralization, urease alone is not recommended. Urease mainly reflects urea hydrolysis, whereas protease and aminopeptidase better reflect the decomposition of proteinaceous nitrogen sources in plant residues, microbial residues, and organic fertilizers.
3.3 NAG and Chitinase
N-Acetyl-β-D-glucosaminidase and chitinase are related to the decomposition of chitin, fungal cell walls, and microbial residues. They are carbon-nitrogen coupling indicators and are also suitable for studying microbial residue turnover.
If NAG, chitinase, and NH₄⁺-N increase synchronously, this suggests enhanced decomposition of nitrogen-containing polysaccharides or microbial residues. If NAG increases but inorganic nitrogen does not, microbial reassimilation of released nitrogen should be considered.
4 Phosphorus Cycle Indicators: Interpretation Based on pH and Phosphorus Forms
4.1 Acid, Neutral, and Alkaline Phosphatases
Phosphatases are used to evaluate organic phosphorus mineralization potential. Acid soils should prioritize acid phosphatase, neutral soils can focus on neutral phosphatase, and neutral-to-alkaline soils are more suitable for alkaline phosphatase evaluation.
Increased phosphatase activity does not necessarily mean sufficient phosphorus supply. If available phosphorus is low while phosphatase activity increases, this often indicates phosphorus limitation, with microorganisms or plants enhancing organic phosphorus hydrolysis to acquire phosphorus.
4.2 Phytase, PDE, and Pyrophosphatase
Phytase mainly targets phytate phosphorus release, phosphodiesterase mainly targets hydrolysis of nucleic acids and phosphodiester compounds, and pyrophosphatase mainly targets pyrophosphate hydrolysis. If the mechanism of phosphorus release is being studied, these enzyme activity indicators should be added on the basis of total phosphorus, organic phosphorus, and inorganic phosphorus measurements.
4.3 Available Phosphorus and Phosphorus Fractions
Available phosphorus is used to evaluate plant-available phosphorus levels, inorganic phosphorus is used to assess mineralization release outcomes, and total phosphorus/organic phosphorus/inorganic phosphorus can distinguish phosphorus pool composition. Only by combining phosphatase activity, available phosphorus, and phosphorus fractions can organic phosphorus mobilization be linked to increased available phosphorus.
5 Sample Pretreatment for Soil Microbial Community Analysis
5.1 Soil DNA Extraction
Soil DNA extraction is used for microbial community analysis and is suitable for 16S, ITS, and metagenomic studies. Soil samples often contain PCR inhibitors such as humic acids, polyphenols, and metal ions. Qualified DNA concentration does not necessarily mean that the template is suitable for amplification.
5.2 Humic Acid Removal
In high-organic-matter soils, forest soils, humus-rich soils, and manure-treated soils, humic acids can easily inhibit PCR amplification and sequencing library construction. Humic acid removal solutions can reduce inhibitor effects and improve the stability of microbial community analysis.
5.3 Correspondence Between Community Data and Functional Indicators
Microbial community results should be interpreted together with enzyme activity and chemical indicators. If fungal groups increase and lignin oxidase activity also increases, this more strongly supports enhanced transformation of recalcitrant organic matter. If bacterial groups change significantly and labile carbon-related enzymes increase, this is more likely to correspond to rapid carbon source utilization.
6 Product and Material Selection
Table 2 Products related to soil microbial activity and organic matter decomposition
Cat. No. | Product Name | Grade/Use | Application Module | Application Positioning |
Soil Organic Carbon (SOC) Content Assay Kit (Micro Method) | BioReagent | Organic matter pool evaluation | Used to determine soil organic carbon content; suitable for evaluating changes in organic carbon pools, carbon input accumulation, and carbon loss trends after organic matter decomposition | |
Soil Organic Matter (SOM) Content Assay Kit (Micro Method) | BioReagent | Organic matter pool evaluation | Used to determine soil organic matter levels; suitable for routine soil fertility evaluation, organic fertilizer treatment, and analysis of organic matter changes after straw returning | |
Soil Total Phenolics (TP) Content Assay Kit (Micro Method) | BioReagent | Phenolic component evaluation | Used to detect soil phenolic compound content in a microplate system; suitable for phenolic accumulation analysis with limited sample amounts or multiple treatment groups | |
Soil Total Phenolics (TP) Content Assay Kit (Colorimetric Method) | BioReagent | Phenolic component evaluation | Used for routine spectrophotometric determination of soil total phenols; suitable for joint interpretation with polyphenol oxidase and peroxidase results to assess phenolic oxidation and consumption | |
Soil Dehydrogenase (S-DHA) Activity Assay Kit (TTC, Micro Method) | BioReagent | Overall microbial activity | Used to detect soil dehydrogenase activity in a microplate system; suitable for comparing soil microbial redox metabolic intensity across multiple samples | |
Soil Dehydrogenase (S-DHA) Activity Assay Kit (TTC, Colorimetric Method) | BioReagent | Overall microbial activity | Used to detect soil dehydrogenase activity by colorimetry; suitable for routine soil activity evaluation and comparison under pollution, drought, and fertilization treatments | |
Soil Fluorescein Diacetate Hydrolase (S-FDA) Activity Assay Kit (Micro Method) | BioReagent | Overall hydrolase activity | Used to evaluate overall soil hydrolytic metabolic capacity by microplate method; suitable for rapid screening of microbial hydrolytic activity changes under different treatments | |
Soil Fluorescein Diacetate Hydrolase (S-FDA) Activity Assay Kit (Colorimetric Method) | BioReagent | Overall hydrolase activity | Used to detect FDA hydrolase activity in a routine colorimetric system; suitable for overall enzyme activity evaluation in soil amendments, organic fertilizer, and incubation experiments | |
Soil Catalase (S-CAT) Activity Assay Kit (UV Micro Method) | BioReagent | Oxidative stress/microbial activity | Used to detect soil hydrogen peroxide scavenging capacity; suitable for evaluating microbial oxidative stress, wet-dry alternation, and oxidative status during rapid organic matter decomposition | |
Soil Invertase Activity Assay Kit (DNS, Micro Method) | BioReagent | Labile carbon transformation | Used to detect sucrose hydrolysis capacity by microplate method; suitable for evaluating rhizosphere carbon input and labile carbon source transformation after organic fertilizer addition | |
Soil Invertase Activity Assay Kit (DNS, Colorimetric Method) | BioReagent | Labile carbon transformation | Used to detect soil sucrase activity by colorimetry; suitable for routine soil fertility evaluation and assessment of labile carbon transformation capacity | |
Soil Amylase (S-AL) Activity Assay Kit (DNS, Micro Method) | BioReagent, sterile | Starch carbon source transformation | Used to detect starch hydrolysis capacity in a microplate system; suitable for analyzing the utilization of starch substrates during early decomposition of plant residues | |
Soil Amylase Activity Assay Kit (DNS, Colorimetric Method) | BioReagent | Starch carbon source transformation | Used to determine soil amylase activity by colorimetry; suitable for routine incubation experiments and comparison of starch degradation capacity under different soil treatments | |
Soil β-Glucosidase (S-β-GC) Activity Assay Kit (Micro Method) | BioReagent | Terminal step of cellulose degradation | Used to detect β-glucosidase activity by microplate method; suitable for multi-sample screening of glucose release capacity at the terminal step of cellulose degradation | |
Soil β-Glucosidase (S-β-GC) Activity Assay Kit (Colorimetric Method) | BioReagent | Terminal step of cellulose degradation | Used to determine β-glucosidase activity by colorimetry; suitable for joint evaluation with endo- and exo-glucanases to assess the complete cellulose degradation chain | |
Soil Endo-β-1,4-Glucanase Activity Assay Kit (Micro Method) | BioReagent | Internal cleavage of cellulose chains | Used to detect internal cleavage activity of cellulose chains in a microplate system; suitable for assessing initial cellulose fragmentation capacity in plant residues | |
Soil Endo-β-1,4-Glucanase Activity Assay Kit (Colorimetric Method) | BioReagent | Internal cleavage of cellulose chains | Used to detect endo-β-1,4-glucanase activity by colorimetry; suitable for routine straw decomposition and structural carbon degradation studies | |
Soil Exo-β-1,4-Glucanase Activity Assay Kit (Micro Method) | BioReagent | Cellulose chain-end hydrolysis | Used to detect chain-end degradation activity of cellulose by microplate method; suitable for analyzing oligosaccharide or cellobiose release after cellulose cleavage | |
Soil Exo-β-1,4-Glucanase Activity Assay Kit (Colorimetric Method) | BioReagent | Cellulose chain-end hydrolysis | Used to determine exo-β-1,4-glucanase activity by colorimetry; suitable for evaluating terminal cellulose degradation efficiency together with β-glucosidase | |
Soil β-Xylosidase Activity Assay Kit (Micro Method) | BioReagent | Hemicellulose degradation | Used to detect β-xylosidase activity in a microplate system; suitable for evaluating the terminal step of xylan degradation and hemicellulose decomposition potential | |
Soil β-Xylosidase Activity Assay Kit (Colorimetric Method) | BioReagent | Hemicellulose degradation | Used to determine β-xylosidase activity by colorimetry; suitable for analyzing hemicellulose transformation during plant residue decomposition | |
Soil α-Xylosidase Activity Assay Kit (Micro Method) | BioReagent | Hemicellulose side-chain hydrolysis | Used to detect α-xylosidase activity by microplate method; suitable for evaluating hydrolysis of glycosidic bonds in hemicellulose side chains | |
Soil α-Xylosidase Activity Assay Kit (Colorimetric Method) | BioReagent | Hemicellulose side-chain hydrolysis | Used to detect α-xylosidase activity by colorimetry; suitable for joint analysis with β-xylosidase to assess hemicellulose degradation stages | |
Soil Polyphenol Oxidase (S-PPO) Activity Assay Kit (Micro Method) | BioReagent | Phenolic oxidation | Used to detect polyphenol oxidase activity by microplate method; suitable for analyzing phenolic oxidation, late-stage residue decomposition, and humification processes | |
Soil Polyphenol Oxidase (S-PPO) Activity Assay Kit (Colorimetric Method) | BioReagent | Phenolic oxidation | Used to determine polyphenol oxidase activity by colorimetry; suitable for joint interpretation with total phenol content to assess phenolic accumulation or consumption | |
Soil Peroxidase (S-POD) Activity Assay Kit (Micro Method) | BioReagent | Aromatic organic matter oxidation | Used to detect peroxidase activity in a microplate system; suitable for evaluating oxidative transformation capacity of recalcitrant soil organic matter | |
Soil Peroxidase (S-POD) Activity Assay Kit (Colorimetric Method) | BioReagent | Aromatic organic matter oxidation | Used to determine peroxidase activity by colorimetry; suitable for late-stage straw decomposition, forest soil, and humification studies | |
Soil Lignin peroxidase (S-Lip) Activity Assay Kit (Resveratrol, Micro Method) | BioReagent | Lignin oxidative degradation | Used to detect lignin peroxidase activity by microplate method; suitable for evaluating lignin-related degradation processes under low sample volume conditions | |
Soil Lignin Peroxidase (S-Lip) Activity Assay Kit (Veratryl Alcohol, Colorimetric Method) | BioReagent | Lignin oxidative degradation | Used to detect LiP activity by colorimetry; suitable for analysis of woody residues, straw decomposition, and recalcitrant aromatic carbon transformation | |
Soil Manganese Peroxidase (S-Mnp) Activity Assay Kit (Guaiacol, Micro Method) | BioReagent | Manganese-dependent lignin oxidation | Used to detect MnP activity by microplate method; suitable for analyzing manganese-involved lignin and phenolic oxidation reactions | |
Soil Manganese Peroxidase (S-Mnp) Activity Assay Kit (Guaiacol, Colorimetric Method) | BioReagent | Manganese-dependent lignin oxidation | Used to determine MnP activity by colorimetry; suitable for joint evaluation of lignin degradation systems with LiP, PPO, and POD | |
Soil Laccase Activity Assay Kit (Micro Method) | BioReagent | Phenolic polymerization/oxidative transformation | Used to detect laccase activity in a microplate system; suitable for studying humification, phenolic oxidation, and fungi-associated decomposition processes | |
Soil Laccase Activity Assay Kit (Colorimetric Method) | BioReagent | Phenolic polymerization/oxidative transformation | Used to detect laccase activity by colorimetry; suitable for evaluating forest soil, compost, and recalcitrant organic matter transformation | |
Soil N-Acetyl-β-D-glucosaminidase (S-NAG) Activity Assay Kit (Micro Method) | BioReagent | Microbial residue turnover | Used to detect NAG activity by microplate method; suitable for analyzing chitin, fungal residues, and microbial cell wall decomposition | |
Soil N-Acetyl-β-D-glucosaminidase (S-NAG) Activity Assay Kit (Colorimetric Method) | BioReagent | Microbial residue turnover | Used to determine NAG activity by colorimetry; suitable for interpreting microbial residue nitrogen release together with chitinase and ammonium nitrogen results | |
Soil Chitinase Activity Assay Kit (Micro Method) | BioReagent | Chitin degradation | Used to detect chitinase activity in a microplate system; suitable for evaluating fungal residue and nitrogen-containing polysaccharide decomposition under low sample volume conditions | |
Soil Chitinase Activity Assay Kit (Colorimetric Method) | BioReagent | Chitin degradation | Used to determine chitinase activity by colorimetry; suitable for evaluating microbial residue and chitin substrate turnover together with NAG activity | |
Soil Urease (S-UE) Activity Assay Kit (Micro Method) | BioReagent | Urea hydrolysis | Used to detect urease activity by microplate method; suitable for comparing urea hydrolysis potential and nitrogen release trends across multiple treatments | |
Soil Urease (S-UE) Activity Assay Kit (Colorimetric Method) | BioReagent | Urea hydrolysis | Used to determine soil urease activity by colorimetry; suitable for fertilization, organic fertilizer, and soil nitrogen mineralization studies | |
Soil Ammonium Nitrogen Content Assay Kit (IPB, Micro Method) | BioReagent | Nitrogen mineralization product | Used to detect NH₄⁺-N content; suitable for verifying whether increased urease, protease, or NAG activity leads to ammonium nitrogen accumulation | |
Soil Nitrate Nitrogen Content Assay Kit (SA, Micro Method) | BioReagent | Nitrification product | Used to detect NO₃⁻-N content by microplate method; suitable for comparing soil nitrification products and available nitrogen levels across multiple samples | |
Soil Nitrate Nitrogen Content Assay Kit (SA, Colorimetric Method) | BioReagent | Nitrification product | Used to determine NO₃⁻-N content by colorimetry; suitable for joint interpretation with ammonium nitrogen results to assess nitrogen mineralization and nitrification direction | |
Soil Acid Protease Activity Assay Kit (PMA, Micro Method) | BioReagent | Protein decomposition under acidic conditions | Used to evaluate proteinaceous organic nitrogen decomposition capacity in acidic soils by microplate method | |
Soil Acid Protease Activity Assay Kit (PMA, Colorimetric Method) | BioReagent | Protein decomposition under acidic conditions | Used to determine acidic protease activity by colorimetry; suitable for organic nitrogen mineralization studies in acidic soils | |
Soil Neutral Protease Activity Assay Kit (PMA, Micro Method) | BioReagent | Protein decomposition under neutral conditions | Used to detect protease activity under neutral conditions by microplate method; suitable for neutral soils and routine incubation systems | |
Soil Neutral Protease Activity Assay Kit (PMA, Colorimetric Method) | BioReagent | Protein decomposition under neutral conditions | Used to evaluate proteinaceous organic nitrogen hydrolysis capacity by colorimetry; suitable for joint analysis with LAP and NH₄⁺-N results | |
Soil Alkaline Protease Activity Assay Kit (PMA, Micro Method) | BioReagent | Protein decomposition under alkaline conditions | Used to detect protease activity in alkaline soils by microplate method; suitable for evaluating organic nitrogen decomposition in alkaline soils | |
Soil Alkaline Protease Activity Assay Kit (PMA, Colorimetric Method) | BioReagent | Protein decomposition under alkaline conditions | Used to determine alkaline protease activity by colorimetry; suitable for studying protein nitrogen release in alkaline soils or lime-treated soils | |
Soil Leucine Aminopeptidase (S-LAP) Activity Assay Kit (LNA, Micro Method) | BioReagent | Amino acid release | Used to detect LAP activity by microplate method; suitable for evaluating downstream amino acid release after protein degradation and microbial nitrogen acquisition | |
Soil Leucine Aminopeptidase (S-LAP) Activity Assay Kit (LNA, Colorimetric Method) | BioReagent | Amino acid release | Used to determine LAP activity by colorimetry; suitable for interpreting organic nitrogen transformation together with protease and inorganic nitrogen results | |
Soil Acid Phosphatase(S-ACP) Activity Assay Kit (DPP, Micro Method) | BioReagent | Organic phosphorus mineralization in acidic soils | Used to detect acid phosphatase activity by microplate method; suitable for analyzing organic phosphorus mobilization capacity in acidic soils | |
Soil Acid Phosphatase (S-ACP) Activity Assay Kit (DPP, Colorimetric Method) | BioReagent | Organic phosphorus mineralization in acidic soils | Used to determine acid phosphatase activity by colorimetry; suitable for joint interpretation with available phosphorus results in acidic soils to assess phosphorus limitation | |
Soil Neutral Phosphatase(S-NP) Activity Assay Kit (DPP, Micro Method) | BioReagent | Organic phosphorus mineralization in neutral soils | Used to detect neutral phosphatase activity by microplate method; suitable for evaluating phosphate ester hydrolysis in neutral soils or neutral reaction systems | |
Soil Neutral Phosphatase (S-NP) Activity Assay Kit (DPP, Colorimetric Method) | BioReagent | Organic phosphorus mineralization in neutral soils | Used to determine neutral phosphatase activity by colorimetry; suitable for analyzing organic phosphorus release potential in neutral soils | |
Soil Alkaline Phosphatase(S-AKP/ALP) Activity Assay Kit (DPP, Micro Method) | BioReagent | Organic phosphorus mineralization in neutral to alkaline soils | Used to detect alkaline phosphatase activity by microplate method; suitable for evaluating phosphorus limitation in neutral to alkaline soils | |
Soil Alkaline Phosphatase (S-AKP/ALP) Activity Assay Kit (DPP, Colorimetric Method) | BioReagent | Organic phosphorus mineralization in neutral to alkaline soils | Used to determine alkaline phosphatase activity by colorimetry; suitable for assessing organic phosphorus mobilization together with available phosphorus in neutral/alkaline soils | |
Soil Phytase Activity Assay Kit (Micro Method) | BioReagent | Phytate phosphorus release | Used to detect phytase activity by microplate method; suitable for studying mineralization of phytate-bound organic phosphorus and phosphorus release potential | |
Soil Phytase Activity Assay Kit (Colorimetric Method) | BioReagent | Phytate phosphorus release | Used to determine phytase activity by colorimetry; suitable for analyzing phytate phosphorus transformation in organic fertilizer, plant residues, or soils rich in organic phosphorus | |
Soil Phosphodiesterase (S-PDE) Activity Assay Kit (Micro Method) | BioReagent | Phosphodiester organic phosphorus hydrolysis | Used to detect PDE activity by microplate method; suitable for analyzing transformation of nucleic acid-like and phosphodiester organic phosphorus compounds | |
Soil Phosphodiesterase (S-PDE) Activity Assay Kit (Colorimetric Method) | BioReagent | Phosphodiester organic phosphorus hydrolysis | Used to determine PDE activity by colorimetry; suitable for interpreting organic phosphorus mineralization together with phosphatase, inorganic phosphorus, and phosphorus fraction results | |
Soil Inorganic Phosphate (S-PHOS) Content Assay Kit (MB, Micro Method) | BioReagent | Inorganic phosphorus release result | Used to detect soil inorganic phosphorus content; suitable for verifying phosphorus release after changes in phosphatase, phytase, or PDE activity | |
Soil Total Phosphorus, Organic Phosphorus and Inorganic Phosphorus Content Assay Kit (Colorimetric Method) | BioReagent | Phosphorus fraction analysis | Used to distinguish total phosphorus, organic phosphorus, and inorganic phosphorus by colorimetry; suitable for routine phosphorus pool composition and organic phosphorus mineralization analysis | |
Soil Total Phosphorus, Organic Phosphorus and Inorganic Phosphorus Content Assay Kit (Micro Method) | BioReagent | Phosphorus fraction analysis | Used to analyze soil phosphorus fractions by microplate method; suitable for comparing phosphorus pool changes with limited sample amounts or multiple treatment groups | |
Acid Soil Available Phosphorous Assay Kit (Micro Method) | BioReagent | Available phosphorus in acidic soils | Used to detect available phosphorus in acidic soils by microplate method; suitable for assessing phosphorus limitation in acidic soils together with acid phosphatase | |
Acid Soil Available Phosphorus Assay Kit (Colorimetric Method) | BioReagent | Available phosphorus in acidic soils | Used to determine available phosphorus in acidic soils by colorimetry; suitable for routine evaluation of available phosphorus supply in acidic soils | |
Neutral/Alkaline Soil Available Phosphorous Assay Kit (Micro Method) | BioReagent | Available phosphorus in neutral/alkaline soils | Used to detect available phosphorus in neutral or alkaline soils by microplate method; suitable for joint analysis with neutral/alkaline phosphatases | |
Neutral/Alkaline Soil Available Phosphorus Assay Kit (Colorimetric Method) | BioReagent | Available phosphorus in neutral/alkaline soils | Used to determine available phosphorus in neutral or alkaline soils by colorimetry; suitable for routine soil nutrient evaluation and phosphorus limitation assessment | |
Magnetic Soil/Stool DNA Kit | BioReagent, for DNA and RNA applications | Magnetic bead-based soil DNA extraction | Used for magnetic bead-based extraction of DNA from soil and fecal samples; suitable for batch samples and automated workflows | |
Humic Acid Removal Solution for Soil | BioReagent, molecular biology grade, for DNA and RNA applications | PCR inhibitor removal | Used to remove humic acid interference from soil DNA; suitable for improving template quality for PCR amplification, 16S/ITS sequencing, and metagenomic library preparation |
7 Indicator Combinations Under Different Experimental Scenarios
7.1 Routine Soil Quality Evaluation
Routine soil quality evaluation does not need to cover all enzyme indicators. SOC or SOM can reflect the baseline level of organic matter, dehydrogenase or FDA can reflect overall microbial activity, and β-glucosidase, urease, and phosphatase can represent carbon, nitrogen, and phosphorus transformation processes, respectively.
7.2 Straw Return and Plant Residue Decomposition
Straw and plant residue decomposition experiments should prioritize endo-β-1,4-glucanase, exo-β-1,4-glucanase, β-glucosidase, and xylosidase to evaluate cellulose and hemicellulose decomposition. If late-stage decomposition is studied, PPO, POD, LiP, MnP, and laccase should be added to explain lignin and phenolic transformation.
7.3 Nitrogen Mineralization and Microbial Residue Turnover
Nitrogen mineralization studies can include urease, protease, LAP, NAG, chitinase, NH₄⁺-N, and NO₃⁻-N. Urease is suitable for urea hydrolysis, protease and LAP are suitable for protein degradation, and NAG and chitinase are more suitable for microbial residue and chitin turnover.
7.4 Organic Phosphorus Mineralization and Phosphorus Limitation
Phosphorus cycle studies should select acid, neutral, or alkaline phosphatase according to soil pH and combine available phosphorus, inorganic phosphorus, and total phosphorus/organic phosphorus/inorganic phosphorus detection. If organic phosphorus sources need to be further distinguished, phytase and phosphodiesterase can be added.
Table 3 Recommended indicator combinations for different research scenarios
Research Scenario | Recommended Indicator Combination | Interpretation Focus |
Routine soil quality evaluation | SOC/SOM, DHA or FDA, β-GC, UE, ACP/ALP | Determines whether the organic matter pool matches microbial function |
Straw/plant residue decomposition | Endoglucanase, exoglucanase, β-GC, xylosidase, PPO, POD, LiP, MnP | Distinguishes polysaccharide decomposition from lignin oxidation stages |
Nitrogen mineralization experiment | UE, protease, LAP, NAG, NH₄⁺-N, NO₃⁻-N | Evaluates organic nitrogen release, microbial assimilation, and nitrification outcomes |
Phosphorus limitation evaluation | Available phosphorus, inorganic phosphorus, ACP/ALP/NP, phytase, PDE | Interprets phosphorus release together with pH and phosphorus fractions |
Phenolic and humification research | Total phenols, PPO, POD, LiP, MnP, laccase | Evaluates phenolic accumulation or oxidative consumption |
Microbial community research | Soil DNA extraction, humic acid removal, enzyme activity | Links community structure with functional indicators |
8 Frequently Asked Questions
8.1 Is it necessary to detect SOC and SOM in soil organic matter decomposition studies?
At least one of SOC and SOM should be selected. SOC is more suitable for carbon cycle studies, whereas SOM is more suitable for routine organic matter level evaluation. If the mechanism of organic matter decomposition is being studied, SOC/SOM should be interpreted together with enzyme activity, inorganic nitrogen, and available phosphorus.
8.2 Why is it not appropriate to detect only β-glucosidase?
β-Glucosidase only reflects the terminal step of cellulose degradation and cannot fully represent cellulose decomposition. Plant residue studies should also consider endo-β-1,4-glucanase, exo-β-1,4-glucanase, and xylosidase.
8.3 Why are NAG and chitinase important?
NAG and chitinase are related to the decomposition of chitin and microbial residues and can reflect turnover of fungal residues, microbial cell walls, and nitrogen-containing polysaccharides. They are suitable for studying the contribution of microbial residues to stable organic matter formation.
8.4 Does increased phosphatase activity indicate increased soil phosphorus supply?
Not necessarily. Increased phosphatase activity often suggests insufficient available phosphorus, with microorganisms or plants enhancing organic phosphorus hydrolysis to acquire phosphorus. Available phosphorus, inorganic phosphorus, organic phosphorus, and soil pH should be interpreted together.
8.5 Why should total phenols and oxidative enzymes be detected?
Total phenols, PPO, POD, LiP, MnP, and laccase can explain oxidative transformation of lignin, phenolics, and humified components. If late-stage straw decomposition, forest soil, or humus formation is being studied, these indicators are more targeted than a single hydrolase.
8.6 Why is humic acid removal needed for soil DNA extraction?
Humic acids can inhibit PCR amplification and sequencing library construction, leading to failed community analysis or biased results. High-organic-matter soils, humus-rich soils, and manure-treated soil samples especially require attention to humic acid interference.
Evaluation of soil microbial activity and organic matter decomposition should select indicators based on the specific experimental question. SOC/SOM is used to assess the organic matter pool, carbon-nitrogen-phosphorus cycling enzymes are used to locate decomposition processes, inorganic nutrients are used to verify release outcomes, and soil DNA analysis is used to explain the microbial community basis.
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