Abstract
Leaf nitrogen (N) concentration plays an important role in biochemical and physiological functions, and N availability directly influences rice yield. However, excessive N fertilization is considered to be a root cause of environmental issues and low nitrogen use efficiency. Therefore, the selection of appropriate nutrient management practices and organic amendments is key to maximizing nitrogen uptake and maintaining high and sustainable rice production. Here, we evaluated the effects of different 15N-labelled nitrogen sources (urea, ammonium nitrate, and ammonium sulfate at 315 kg ha−1) with or without biochar (30 t ha−1) on paddy soil properties, root growth, leaf gas exchange, N metabolism enzymes, and N uptake in the early and late seasons of 2019. We found significant differences among N fertilizer sources applied with or without biochar (P < 0.05). Across the seasons, the combination of biochar with N fertilizers significantly increased soil organic carbon by 51.21% and nitrogen availability by 27.51% compared with N fertilizers alone. Correlation analysis showed that rice root morphological traits were strongly related to soil chemical properties, and higher root growth was measured in the biochar treatments. Similarly, net leaf photosynthetic rate averaged 9.34% higher, chlorophyll (Chl) a concentration 12.91% higher, and Chl b concentration 10.05% higher in the biochar treatments than in the biochar-free treatments across the seasons. Notably, leaf 15N concentration was 23.19% higher in the biochar treatments in both seasons. These results illustrated higher activities of N metabolism enzymes such as NR, GS, and GOGAT by an average 23.44%, 11.26% and 18.16% in the biochar treatments across the seasons, respectively. The addition of biochar with synthetic N fertilizers is an ecological nutrient management strategy that can increase N uptake and assimilation by ameliorating soil properties and improving the morpho-physiological factors of rice.
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Claims 12
Claim · model-written summary
Biochar with N fertilizers increased soil organic carbon by 51.21% compared with fertilizers alone.
- Taxon
- rice
Oryza sativat0 - Treatment
- biochar with N fertilizerse0
- Outcome
- soil organic carbone0
- Direction
- increasede0
- Value
- 51.21%e0
- Comparator
- N fertilizers alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combination of biochar with N fertilizers significantly increased soil organic carbon by 51.21% and nitrogen availability by 27.51% compared with N fertilizers alone”
t0“rice”
Claim · model-written summary
Biochar with N fertilizers increased soil nitrogen availability by 27.51%.
- Taxon
- riceOryza sativat0
- Treatment
- biochar with N fertilizerse0
- Outcome
- nitrogen availabilitye0
- Direction
- increasede0
- Value
- 27.51%e0
- Comparator
- N fertilizers alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combination of biochar with N fertilizers significantly increased soil organic carbon by 51.21% and nitrogen availability by 27.51% compared with N fertilizers alone”
t0“rice”
Claim · model-written summary
Rice root morphology was strongly related to soil chemistry.
- Taxon
- riceOryza sativae0
- Outcome
- root morphological traitse0
- Setting
- soil chemical propertiese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rice root morphological traits were strongly related to soil chemical properties”
Claim · model-written summary
Rice root growth was higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Outcome
- root growthe0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher root growth was measured in the biochar treatments”
t0“rice”
Claim · model-written summary
Net leaf photosynthetic rate was 9.34% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Outcome
- net leaf photosynthetic ratee0
- Direction
- highere0
- Value
- 9.34%e0
- Comparator
- biochar-free treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“net leaf photosynthetic rate averaged 9.34% higher, chlorophyll (Chl) a concentration 12.91% higher, and Chl b concentration 10.05% higher in the biochar treatments than in the biochar-free treatments across the seasons”
t0“rice”
Claim · model-written summary
Chlorophyll a concentration was 12.91% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Outcome
- chlorophyll (Chl) a concentratione0
- Direction
- highere0
- Value
- 12.91%e0
- Comparator
- biochar-free treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“chlorophyll (Chl) a concentration 12.91% higher, and Chl b concentration 10.05% higher in the biochar treatments than in the biochar-free treatments”
t0“rice”
Claim · model-written summary
Chlorophyll b concentration was 10.05% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Outcome
- Chl b concentratione0
- Direction
- highere0
- Value
- 10.05%e0
- Comparator
- biochar-free treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chl b concentration 10.05% higher in the biochar treatments than in the biochar-free treatments”
t0“rice”
Claim · model-written summary
Leaf 15N concentration was 23.19% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Outcome
- leaf 15N concentratione0
- Direction
- highere0
- Value
- 23.19%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf 15N concentration was 23.19% higher in the biochar treatments in both seasons”
t0“rice”
Claim · model-written summary
NR activity was 23.44% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Gene
- NRe0
- Outcome
- activities of N metabolism enzymese0
- Direction
- highere0
- Value
- 23.44%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher activities of N metabolism enzymes such as NR, GS, and GOGAT by an average 23.44%, 11.26% and 18.16% in the biochar treatments”
t0“rice”
Claim · model-written summary
GS activity was 11.26% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Gene
- GSe0
- Outcome
- activities of N metabolism enzymese0
- Direction
- highere0
- Value
- 11.26%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher activities of N metabolism enzymes such as NR, GS, and GOGAT by an average 23.44%, 11.26% and 18.16% in the biochar treatments”
t0“rice”
Claim · model-written summary
GOGAT activity was 18.16% higher with biochar.
- Taxon
- riceOryza sativat0
- Treatment
- biochar treatmentse0
- Gene
- GOGATe0
- Outcome
- activities of N metabolism enzymese0
- Direction
- highere0
- Value
- 18.16%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher activities of N metabolism enzymes such as NR, GS, and GOGAT by an average 23.44%, 11.26% and 18.16% in the biochar treatments”
t0“rice”
Claim · model-written summary
The authors recommend adding biochar to synthetic nitrogen fertilizer to increase rice nitrogen uptake and assimilation.
- Taxon
- riceOryza sativae0
- Outcome
- increase N uptake and assimilatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The addition of biochar with synthetic N fertilizers is an ecological nutrient management strategy that can increase N uptake and assimilation by ameliorating soil properties and improving the morpho-physiological factors of rice”
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