Abstract
Objective: Biochar and a commercial humic acid-rich product, Humac (modified leonardite), represent soil amendments with the broad and beneficial effects on various soil properties. Their combination has been scarcely tested so far, although the positive impact of their interaction might be desirable. Materials and Methods: The dehydrogenase activity (DHA), microbial biomass carbon (Cmic), soil respiration (basal and substrate-induced), enzyme activities, total carbon (Ctot), and both shoot and root biomass yield were measured and compared in the short-term pot experiment with the lettuce seedlings. The following treatments were tested: the unamended soil (control), the Humac-amended soil (0.8 g·kg−1), the biochar-amended soil (low biochar 32 g·kg−1, high biochar 80 g·kg−1), and the soil-amended with biochar + Humac. Results: The effect of both amendments on the soil pH was insignificant. The highest average values of Ctot and Cmic were detected in high biochar treatment and the highest average values of basal and substrate-induced respiration (glucose, glucosamine, alanine) were detected in the low biochar treatment. The phosphatase activity and fresh and dry lettuce aboveground biomass were the highest in the low biochar + Humac treatment. Conclusions: Even though the combination of both biochar + Humac decreased the microbial activities in the amended soil (Cmic, DHA, enzymes, substrate-induced respiration) at the low biochar dose, they mitigated the detrimental effect of the high biochar dose on respiration (all the types) and the enzyme (phosphatase, arylsulphatase) activities. In contrast to the previously published research in this issue, the effects could not be attributed to the change of the soil pH.
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Claims 10
Claim · model-written summary
Humac and biochar amendments did not change soil pH in lettuce pot experiment.
- Taxon
- lettuce
Lactuca sativae2 - Treatment
- both amendmentse1
- Outcome
- soil pHe1
- Direction
- no_changeinferrede1
- Comparator
- the unamended soil (control)e3
- Setting
- short-term pot experimente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The effect of both amendments on the soil pH was insignificant”
e2“short-term pot experiment with the lettuce seedlings”
e3“the unamended soil (control)”
Claim · model-written summary
High biochar treatment had the highest Ctot and Cmic values in lettuce pot experiment.
- Taxon
- lettuceLactuca sativae2
- Treatment
- high biochar treatmente4
- Outcome
- Ctot and Cmice4
- Direction
- higheste4
- Setting
- short-term pot experimente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e4“The highest average values of Ctot and Cmic were detected in high biochar treatment”
Claim · model-written summary
Basal and substrate-induced respiration was highest in the low biochar treatment in lettuce pot experiment.
- Taxon
- lettuceLactuca sativae2
- Treatment
- low biochar treatmente5
- Outcome
- basal and substrate-induced respiratione5
- Direction
- higheste5
- Qualifier
- (glucose, glucosamine, alanine)e5
- Setting
- short-term pot experimente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e5“the highest average values of basal and substrate-induced respiration (glucose, glucosamine, alanine) were detected in the low biochar treatment”
Claim · model-written summary
Low biochar combined with Humac gave the highest phosphatase activity in lettuce pot experiment.
- Taxon
- lettuceLactuca sativae6
- Treatment
- low biochar + Humac treatmente6
- Outcome
- phosphatase activitye6
- Direction
- higheste6
- Setting
- short-term pot experimente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e6“The phosphatase activity and fresh and dry lettuce aboveground biomass were the highest in the low biochar + Humac treatment”
Claim · model-written summary
Low biochar combined with Humac gave the highest fresh and dry aboveground lettuce biomass.
- Taxon
- lettuceLactuca sativae6
- Organ / stage
- abovegrounde6
- Treatment
- low biochar + Humac treatmente6
- Outcome
- fresh and dry lettuce aboveground biomasse6
- Direction
- higheste6
- Setting
- short-term pot experimente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e6“The phosphatase activity and fresh and dry lettuce aboveground biomass were the highest in the low biochar + Humac treatment”
Claim · model-written summary
The combination of biochar and Humac decreased Cmic, DHA and enzyme activities at the low biochar dose.
- Taxon
- lettuceLactuca sativae2
- Treatment
- combination of both biochar + Humace7
- Outcome
- Cmic, DHA, enzymese7
- Direction
- decreasede7
- Qualifier
- at the low biochar dosee7
- Setting
- short-term pot experimente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e7“the combination of both biochar + Humac decreased the microbial activities in the amended soil (Cmic, DHA, enzymes, substrate-induced respiration) at the low biochar dose”
Claim · model-written summary
The combination of biochar and Humac decreased substrate-induced respiration at the low biochar dose.
- Taxon
- lettuceLactuca sativae2
- Treatment
- combination of both biochar + Humace7
- Outcome
- substrate-induced respiratione7
- Direction
- decreasede7
- Qualifier
- at the low biochar dosee7
- Setting
- short-term pot experimente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e7“the combination of both biochar + Humac decreased the microbial activities in the amended soil (Cmic, DHA, enzymes, substrate-induced respiration) at the low biochar dose”
Claim · model-written summary
The combination of biochar and Humac mitigated the detrimental effect of the high biochar dose on respiration.
- Taxon
- lettuceLactuca sativae2
- Treatment
- combination of both biochar + Humace0
- Outcome
- respiration (all the types)e1
- Direction
- mitigatede1
- Comparator
- the high biochar dosee1
- Setting
- short-term pot experimente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e0“the combination of both biochar + Humac decreased the microbial activities in the amended soil (Cmic, DHA, enzymes, substrate-induced respiration) at the low biochar dose”
e1“they mitigated the detrimental effect of the high biochar dose on respiration (all the types) and the enzyme (phosphatase, arylsulphatase) activities”
Claim · model-written summary
The combination of biochar and Humac mitigated the detrimental effect of the high biochar dose on enzyme activities.
- Taxon
- lettuceLactuca sativae2
- Treatment
- combination of both biochar + Humace0
- Outcome
- enzyme (phosphatase, arylsulphatase) activitiese1
- Direction
- mitigatede1
- Comparator
- the high biochar dosee1
- Setting
- short-term pot experimente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e0“the combination of both biochar + Humac decreased the microbial activities in the amended soil (Cmic, DHA, enzymes, substrate-induced respiration) at the low biochar dose”
e1“they mitigated the detrimental effect of the high biochar dose on respiration (all the types) and the enzyme (phosphatase, arylsulphatase) activities”
Claim · model-written summary
The effects of the amendments could not be attributed to the change of soil pH.
- Taxon
- lettuceLactuca sativae2
- Outcome
- the effectse0
- Qualifier
- could not be attributed to the change of the soil pHe0
- Setting
- short-term pot experimente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“short-term pot experiment with the lettuce seedlings”
e0“the effects could not be attributed to the change of the soil pH”
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.