Abstract
Abstract Background Soil carbon-rich organic amendments (biochar, humic substances) may improve the quality and fertility of arable soil. Their co-application can additively enhance the beneficial effect on soil. Hypothetically, the pre-treatment of biochar, by aging via soaking in a solution of commercially available humic substances, could result in synergism, which may exceed the benefit from simple co-application of both amendments to the soil. Therefore, the aim of this study was to investigate the impact of biochar, humic substances, the combination of both, and the impact of biochar aged by humic substances solution on soil microbial activities and plant growth in a short-term pot experiment with lettuce. Results The aging of biochar decreased the C:N ratio as compared to non-activated biochar. The co-application of biochar and humic substances into the soil resulted in the highest microbial biomass carbon and respiration activity. The majority of enzyme activities (β-glucosidase, arylsulfatase, N -acetyl-β- d -glucosaminidase, phosphatase) were the highest in humic substances-amended soil. The application of humic substances and biochar with humic substances seemed to stimulate microbial growth and activity followed by the competition of microflora for nutrients with plants, whereas the aged biochar behaved differently. The plants treated by aged biochar achieved the highest values of dry aboveground and root biomass of all variants. However, the assumed rapid uptake of nutrients by plants resulted in lower nutrient availability for microflora, and a decline in microbial viability. Conclusions Based on this study, the positive effect of co-applied humic substances and biochar on soil fertility, quality, and health can be concluded. The usability of biochar aging by humic solution requires further study. Graphic abstract
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Claims 8
Claim · model-written summary
Aging biochar decreased its C:N ratio compared with non-activated biochar.
Not reportedTaxon
Verbatim
e0“The aging of biochar decreased the C:N ratio as compared to non-activated biochar”
Claim · model-written summary
Co-application of biochar and humic substances into soil gave the highest microbial biomass carbon and respiration activity.
- Treatment
- co-application of biochar and humic substancese1
- Outcome
- microbial biomass carbon and respiration activitye1
- Direction
- higheste1
Not reportedTaxonComparator
Verbatim
e1“The co-application of biochar and humic substances into the soil resulted in the highest microbial biomass carbon and respiration activity”
Claim · model-written summary
Most soil enzyme activities (β-glucosidase, arylsulfatase and N-acetyl-β-D-glucosaminidase) were highest in humic substances-amended soil.
- Treatment
- humic substances-amended soile2
- Outcome
- β-glucosidase, arylsulfatase, N -acetyl-β- d -glucosaminidasee2
- Direction
- higheste2
- Qualifier
- majority of enzyme activitiese2
Not reportedTaxonComparator
Verbatim
e2“The majority of enzyme activities (β-glucosidase, arylsulfatase, N -acetyl-β- d -glucosaminidase, phosphatase) were the highest in humic substances-amended soil”
Claim · model-written summary
Phosphatase activity was highest in humic substances-amended soil.
Not reportedTaxonComparator
Verbatim
e2“The majority of enzyme activities (β-glucosidase, arylsulfatase, N -acetyl-β- d -glucosaminidase, phosphatase) were the highest in humic substances-amended soil”
Claim · model-written summary
Application of humic substances seemed to stimulate soil microbial growth and activity.
- Treatment
- application of humic substancese3
- Outcome
- microbial growth and activitye3
- Direction
- stimulatee3
Not reportedTaxonComparator
Verbatim
e3“The application of humic substances and biochar with humic substances seemed to stimulate microbial growth and activity”
Claim · model-written summary
Lettuce plants treated with aged biochar had the highest dry aboveground and root biomass of all variants.
- Taxon
- lettuce
Lactuca sativae6 - Organ / stage
- aboveground and roote4
- Treatment
- aged biochare4
- Outcome
- dry aboveground and root biomasse4
- Direction
- higheste4
- Comparator
- all variantse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“The plants treated by aged biochar achieved the highest values of dry aboveground and root biomass of all variants”
e6“short-term pot experiment with lettuce”
Claim · model-written summary
Rapid nutrient uptake by plants might lower nutrient availability for soil microflora.
- Taxon
- lettuceLactuca sativae6
- Outcome
- nutrient availability for microflorae5
- Direction
- lowere5
- Qualifier
- assumed rapid uptake of nutrients by plantse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“However, the assumed rapid uptake of nutrients by plants resulted in lower nutrient availability for microflora, and a decline in microbial viability”
e6“short-term pot experiment with lettuce”
Claim · model-written summary
Rapid nutrient uptake by plants might cause a decline in microbial viability.
- Taxon
- lettuceLactuca sativae6
- Outcome
- microbial viabilitye5
- Direction
- declinee5
- Qualifier
- assumed rapid uptake of nutrients by plantse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“However, the assumed rapid uptake of nutrients by plants resulted in lower nutrient availability for microflora, and a decline in microbial viability”
e6“short-term pot experiment with lettuce”
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