Abstract
Greenhouses, commonly used for vegetable production, are experiencing large nitrogen (N) inputs in North China, which leads to soil acidification, increases soil N availability, and affects microbial community structure and composition. However, it remains unclear how N enrichment influences soil microbial functional activities in this region. In this study, we conducted a two-year pot experiment in a greenhouse to evaluate the effects of four different rates of N addition (0, 334, 668, and 1002 kg N ha−1 year−1) on cucumber soil properties, extracellular enzyme activities, and community level physiological profiles (CLPP). We found that high-N addition (1002 kg N ha−1) caused a massive accumulation of inorganic nitrogen and soil acidification, which was not beneficial to soil microbial activities. The color development (AWCD) values for the metabolism of microbial carbon sources and the activities of soil extracellular enzymes also showed a significant decrease in high N(N3) treatment. Additionally, the activity of leucine aminopeptidase (LAP) and polyphenol oxidase (PPO) of N3 decreased by 36% and 50% compared to the N0 and could be a good predictor for microbial functional diversity and microbial biomass carbon (MBC). Structural equation modeling (SEM) confirmed that the reduction of microbial functional diversity is mainly coregulated by the decline of soil pH and the change of cucumber BGB (belowground biomass) resulting from soil C and N imbalance. Overall, excessive N-fertilizer amendment can be more dangerous to microbial community functional diversity, especially for carbohydrate utilization which adversely affects cucumber yield in current intensive management.
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Claims 10
Claim · model-written summary
High N caused inorganic nitrogen accumulation in cucumber soil.
- Taxon
- Cucumber
Cucumis sativust0 - Treatment
- high-N addition (1002 kg N ha−1)e0
- Outcome
- inorganic nitrogene0
- Direction
- massive accumulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high-N addition (1002 kg N ha−1) caused a massive accumulation of inorganic nitrogen and soil acidification”
t0“Cucumber Cultivation”
Claim · model-written summary
High N caused soil acidification in cucumber cultivation.
- Taxon
- CucumberCucumis sativust0
- Treatment
- high-N addition (1002 kg N ha−1)e0
- Outcome
- soil acidificatione0
- Direction
- acidificatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high-N addition (1002 kg N ha−1) caused a massive accumulation of inorganic nitrogen and soil acidification”
t0“Cucumber Cultivation”
Claim · model-written summary
High N significantly decreased microbial carbon-source metabolism AWCD.
- Taxon
- CucumberCucumis sativust0
- Treatment
- high N(N3) treatmente0
- Outcome
- color development (AWCD) values for the metabolism of microbial carbon sourcese0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The color development (AWCD) values for the metabolism of microbial carbon sources and the activities of soil extracellular enzymes also showed a significant decrease in high N(N3) treatment”
t0“Cucumber Cultivation”
Claim · model-written summary
High N significantly decreased soil extracellular enzyme activities.
- Taxon
- CucumberCucumis sativust0
- Treatment
- high N(N3) treatmente0
- Outcome
- activities of soil extracellular enzymese0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The color development (AWCD) values for the metabolism of microbial carbon sources and the activities of soil extracellular enzymes also showed a significant decrease in high N(N3) treatment”
t0“Cucumber Cultivation”
Claim · model-written summary
N3 reduced LAP activity by 36% versus N0.
- Taxon
- CucumberCucumis sativust0
- Treatment
- N3e0
- Outcome
- activity of leucine aminopeptidase (LAP)e0
- Direction
- decreasede0
- Value
- 36%e0
- Comparator
- N0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activity of leucine aminopeptidase (LAP) and polyphenol oxidase (PPO) of N3 decreased by 36% and 50% compared to the N0”
t0“Cucumber Cultivation”
Claim · model-written summary
N3 reduced PPO activity by 50% versus N0.
- Taxon
- CucumberCucumis sativust0
- Treatment
- N3e0
- Outcome
- polyphenol oxidase (PPO)e0
- Direction
- decreasede0
- Value
- 50%e0
- Comparator
- N0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activity of leucine aminopeptidase (LAP) and polyphenol oxidase (PPO) of N3 decreased by 36% and 50% compared to the N0”
t0“Cucumber Cultivation”
Claim · model-written summary
LAP and PPO activity could predict microbial functional diversity and MBC.
- Taxon
- CucumberCucumis sativust0
- Outcome
- microbial functional diversity and microbial biomass carbon (MBC)e0
- Qualifier
- good predictore0
- Setting
- Cucumber Cultivationt0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“could be a good predictor for microbial functional diversity and microbial biomass carbon (MBC)”
t0“Cucumber Cultivation”
Claim · model-written summary
SEM linked reduced microbial functional diversity to declining soil pH.
- Taxon
- cucumberCucumis sativuse0
- Outcome
- reduction of microbial functional diversitye0
- Qualifier
- decline of soil pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduction of microbial functional diversity is mainly coregulated by the decline of soil pH and the change of cucumber BGB (belowground biomass) resulting from soil C and N imbalance”
Claim · model-written summary
SEM linked reduced microbial functional diversity to changing cucumber BGB.
- Taxon
- cucumberCucumis sativuse0
- Outcome
- reduction of microbial functional diversitye0
- Qualifier
- change of cucumber BGB (belowground biomass)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reduction of microbial functional diversity is mainly coregulated by the decline of soil pH and the change of cucumber BGB (belowground biomass) resulting from soil C and N imbalance”
Claim · model-written summary
Excess N was judged to harm microbial carbohydrate use and cucumber yield.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- excessive N-fertilizer amendmente0
- Outcome
- cucumber yielde0
- Qualifier
- carbohydrate utilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“excessive N-fertilizer amendment can be more dangerous to microbial community functional diversity, especially for carbohydrate utilization which adversely affects cucumber yield”
The same questions in other papers
nitrogen · quality: postharvest · Cucumis sativus (cucumber)Positive and negative results
1 in the opposite direction
- positive
nitrogen · physiology: enzyme activity · Cucumis sativus (cucumber)Positive and negative results
2 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- positive
6 papers more in this group
See all 10 papers →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.