Abstract
A two-year field experiment was conducted to evaluate residual and cumulative effects of rice husk charcoal (RC) application on physicochemical soil properties and rice productivity in an Andosol paddy field. Three RC application rates, 10, 20, and 40 Mg ha−1, one rice husk (RH) application rate of 20 Mg ha−1, and a control with no application of RC or RH were laid out in the first year of the experiment. In the second year, the experimental plot was divided into halves: one with the same application rates as in the first year (successive applications) and the other without additional RC or RH (single application). Significant impacts of RC application were observed from the first year on soil bulk density, porosity, carbon (C) content, and carbon-to-nitrogen (C/N) ratio. Soil C content was directly proportional to the amount of RC application over the 2 years showing that the C derived from RC was markedly recalcitrant in soil compared to that from RH. The increased C was present not only in the plow layer but also spread over the top 20 cm of paddy field. As compared to the control, successive RC applications at 20 Mg ha–1 increased soil C contents by 12.7 g kg–1 and 14.4 g kg–1 in the 0–10 cm and 10–20 cm layers after two rice seasons, respectively. Successive RC applications significantly increased straw weight and panicle number, partly due to the increased Si uptake by rice plants. However, grain yield did not significantly differ among the treatments because RC application decreased 1000-grain weight. We speculate that the reduction in 1000-grain weight may be due to immobilization of available N at the reproductive stage under high soil C/N ratio conditions. This suggests the need for N fertilizer top-dressing to obtain the potential yield in the RC-applied fields. Furthermore, the diminishing residual effects of RC application on the rice growth and yield parameters in the second season suggest that successive, or applications at an interval of 2–3 years, would be required to maintain the higher Si deposits in plants, thereby sustaining rice productivity.
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Claims 13
Claim · model-written summary
Rice husk charcoal application significantly affected soil bulk density and porosity from the first year.
- Taxon
- rice
Oryza sativat0 - Treatment
- rice husk charcoal (RC) applicatione3
- Outcome
- soil bulk density, porositye1
- Comparator
- control with no application of RC or RHe0
- Setting
- Andosol paddy fielde3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e0“and a control with no application of RC or RH were laid out in the first year of the experiment”
e1“Significant impacts of RC application were observed from the first year on soil bulk density, porosity”
e3“A two-year field experiment was conducted to evaluate residual and cumulative effects of rice husk charcoal (RC) application on physicochemical soil properties and rice productivity in an Andosol paddy field”
Claim · model-written summary
Rice husk charcoal application significantly affected soil carbon content and carbon-to-nitrogen ratio from the first year.
- Taxon
- riceOryza sativat0
- Treatment
- RC applicatione2
- Outcome
- carbon (C) content, and carbon-to-nitrogen (C/N) ratioe2
- Comparator
- control with no application of RC or RHe0
- Setting
- Andosol paddy fielde3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e0“and a control with no application of RC or RH were laid out in the first year of the experiment”
e2“Significant impacts of RC application were observed from the first year on soil bulk density, porosity, carbon (C) content, and carbon-to-nitrogen (C/N) ratio”
e3“A two-year field experiment was conducted to evaluate residual and cumulative effects of rice husk charcoal (RC) application on physicochemical soil properties and rice productivity in an Andosol paddy field”
Claim · model-written summary
Soil carbon content was directly proportional to the amount of rice husk charcoal applied over two years.
- Taxon
- riceOryza sativat0
- Treatment
- RC applicatione4
- Outcome
- Soil C contente4
- Direction
- directly proportionale4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e4“Soil C content was directly proportional to the amount of RC application over the 2 years”
Claim · model-written summary
Successive rice husk charcoal applications at 20 Mg ha–1 increased soil carbon content by 12.7 g kg–1 in the 0–10 cm layer compared with the control after two rice seasons.
- Taxon
- riceOryza sativat0
- Treatment
- successive RC applications at 20 Mg ha–1e5
- Outcome
- soil C contentse5
- Direction
- increasede5
- Value
- 12.7 g kg–1e5
- Qualifier
- 0–10 cme5
- Comparator
- controle5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e5“As compared to the control, successive RC applications at 20 Mg ha–1 increased soil C contents by 12.7 g kg–1 and 14.4 g kg–1 in the 0–10 cm and 10–20 cm layers after two rice seasons, respectively”
Claim · model-written summary
Successive rice husk charcoal applications at 20 Mg ha–1 increased soil carbon content by 14.4 g kg–1 in the 10–20 cm layer compared with the control after two rice seasons.
- Taxon
- riceOryza sativat0
- Treatment
- successive RC applications at 20 Mg ha–1e5
- Outcome
- soil C contentse5
- Direction
- increasede5
- Value
- 14.4 g kg–1e5
- Qualifier
- 10–20 cm layere5
- Comparator
- controle5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e5“As compared to the control, successive RC applications at 20 Mg ha–1 increased soil C contents by 12.7 g kg–1 and 14.4 g kg–1 in the 0–10 cm and 10–20 cm layers after two rice seasons, respectively”
Claim · model-written summary
Successive rice husk charcoal applications significantly increased straw weight and panicle number.
- Taxon
- riceOryza sativat0
- Treatment
- Successive RC applicationse6
- Outcome
- straw weight and panicle numbere6
- Direction
- increasede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e6“Successive RC applications significantly increased straw weight and panicle number”
Claim · model-written summary
Increased straw weight and panicle number are partly attributed to increased silicon uptake by rice plants.
- Taxon
- riceOryza sativat0
- Compound
- Sie7
- Outcome
- straw weight and panicle numbere6
- Qualifier
- increased Si uptake by rice plantse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e6“Successive RC applications significantly increased straw weight and panicle number”
e7“partly due to the increased Si uptake by rice plants”
Claim · model-written summary
Grain yield did not differ significantly among the treatments.
- Taxon
- riceOryza sativat0
- Treatment
- RC applicatione7
- Outcome
- grain yielde7
- Direction
- did not significantly differe7
- Comparator
- among the treatmentse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e7“grain yield did not significantly differ among the treatments because RC application decreased 1000-grain weight”
Claim · model-written summary
Rice husk charcoal application decreased 1000-grain weight.
- Taxon
- riceOryza sativat0
- Treatment
- RC applicatione7
- Outcome
- 1000-grain weighte7
- Direction
- decreasede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e7“grain yield did not significantly differ among the treatments because RC application decreased 1000-grain weight”
Claim · model-written summary
The reduction in 1000-grain weight may be due to immobilization of available nitrogen at the reproductive stage under high soil C/N ratio conditions.
- Taxon
- riceOryza sativat0
- Organ / stage
- reproductive stagee7
- Compound
- available Ne7
- Outcome
- reduction in 1000-grain weighte7
- Qualifier
- immobilization of available N at the reproductive stage under high soil C/N ratio conditionse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e7“We speculate that the reduction in 1000-grain weight may be due to immobilization of available N at the reproductive stage under high soil C/N ratio conditions”
Claim · model-written summary
Nitrogen fertilizer top-dressing is needed to obtain the potential yield in rice husk charcoal-applied fields.
- Taxon
- riceOryza sativat0
- Treatment
- N fertilizer top-dressinge7
- Outcome
- potential yielde7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e7“This suggests the need for N fertilizer top-dressing to obtain the potential yield in the RC-applied fields”
Claim · model-written summary
Successive or 2–3-year-interval rice husk charcoal applications are required to maintain higher Si deposits in plants and sustain rice productivity.
- Taxon
- riceOryza sativat0
- Treatment
- successive, or applications at an interval of 2–3 yearse7
- Outcome
- maintain the higher Si deposits in plantse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e7“successive, or applications at an interval of 2–3 years, would be required to maintain the higher Si deposits in plants, thereby sustaining rice productivity”
Claim · model-written summary
Residual effects of rice husk charcoal on rice growth and yield parameters diminish in the second season.
- Taxon
- riceOryza sativat0
- Treatment
- residual effects of RC applicatione7
- Outcome
- rice growth and yield parameterse7
- Direction
- diminishinge7
- Qualifier
- in the second seasone7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice productivity”
e7“the diminishing residual effects of RC application on the rice growth and yield parameters in the second season”
The same questions in other papers
charcoal · yield · Oryza sativa (rice)Results differ
10 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- no effect
- positive
9 papers more in this group
See all 13 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.