Abstract
Vegetable production with high N inputs is a potential source of greenhouse gas emission and N2O from soils. However, in Central Vietnam, high rates of N fertilization on sandy soils may not generate much N2O by denitrification due to limited anoxia. This study was carried out to evaluate the impact of four N fertilizer rates including: 0, 30, 60 and 90 kg N ha -1 and three N fertilizer forms supplied as urea, ammonium sulfate and calcium nitrate on the yield of lettuce and the N2O emission from loam and deep sandy soils in two crop seasons from January to April, 2015. The increase in the cumulative N2O emission and the yield based N2O intensity is proportional to the increase in N fertilizer application. Calcium nitrate fertilizer application at rate of 90 kg N ha -1 had the highest N2O emission as compared with ammonium sulfate and urea fertilizers application, which raised more than 1.20 to 1.82 times (ammonium sulfate) and 1.60 to 1.91 times (urea) in loam and deep sandy soils, respectively. Compared to the N90 treatment, N2O emission of N60 was reduced by 42% in loam soil and 30% in deep sandy soil without decreasing crop yield. The growing season emission factors (EFgs) were 0.40% to 0.61% of added N, emitted as N2O and increased with N fertilizer application rate. N2O fluxes reduced as the amount of applied N-fertilizer decreased significantly.
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Claims 10
Claim · model-written summary
Cumulative N2O emissions increased in proportion to nitrogen fertilizer application.
- Taxon
- Lettuce
Lactuca sativat0 - Treatment
- N fertilizer applicatione0
- Outcome
- cumulative N2O emissione0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in the cumulative N2O emission and the yield based N2O intensity is proportional to the increase in N fertilizer application.”
t0“Lettuce”
Claim · model-written summary
Yield-based N2O intensity increased in proportion to nitrogen fertilizer application.
- Taxon
- LettuceLactuca sativat0
- Treatment
- N fertilizer applicatione0
- Outcome
- yield based N2O intensitye0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in the cumulative N2O emission and the yield based N2O intensity is proportional to the increase in N fertilizer application.”
t0“Lettuce”
Claim · model-written summary
Calcium nitrate at 90 kg N ha -1 had the highest N2O emissions, 1.20 to 1.82 times ammonium sulfate.
- Taxon
- LettuceLactuca sativat0
- Treatment
- Calcium nitrate fertilizer application at rate of 90 kg N ha -1e0
- Outcome
- N2O emissione0
- Direction
- higheste0
- Value
- 1.20 to 1.82 timese0
- Comparator
- ammonium sulfatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Calcium nitrate fertilizer application at rate of 90 kg N ha -1 had the highest N2O emission as compared with ammonium sulfate and urea fertilizers application, which raised more than 1.20 to 1.82 times (ammonium sulfate) and 1.60 to 1.91 times (urea) in loam and deep sandy soils, respectively.”
t0“Lettuce”
Claim · model-written summary
Calcium nitrate at 90 kg N ha -1 had the highest N2O emissions, 1.60 to 1.91 times urea.
- Taxon
- LettuceLactuca sativat0
- Treatment
- Calcium nitrate fertilizer application at rate of 90 kg N ha -1e0
- Outcome
- N2O emissione0
- Direction
- higheste0
- Value
- 1.60 to 1.91 timese0
- Comparator
- ureae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Calcium nitrate fertilizer application at rate of 90 kg N ha -1 had the highest N2O emission as compared with ammonium sulfate and urea fertilizers application, which raised more than 1.20 to 1.82 times (ammonium sulfate) and 1.60 to 1.91 times (urea) in loam and deep sandy soils, respectively.”
t0“Lettuce”
Claim · model-written summary
Reducing nitrogen from N90 to N60 cut N2O emissions by 42% in loam soil.
- Taxon
- LettuceLactuca sativat0
- Treatment
- N60e0
- Outcome
- N2O emissione0
- Direction
- reducede0
- Value
- 42%e0
- Comparator
- N90 treatmente0
- Setting
- loam soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the N90 treatment, N2O emission of N60 was reduced by 42% in loam soil and 30% in deep sandy soil without decreasing crop yield.”
t0“Lettuce”
Claim · model-written summary
Reducing nitrogen from N90 to N60 cut N2O emissions by 30% in deep sandy soil.
- Taxon
- LettuceLactuca sativat0
- Treatment
- N60e0
- Outcome
- N2O emissione0
- Direction
- reducede0
- Value
- 30%e0
- Comparator
- N90 treatmente0
- Setting
- deep sandy soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the N90 treatment, N2O emission of N60 was reduced by 42% in loam soil and 30% in deep sandy soil without decreasing crop yield.”
t0“Lettuce”
Claim · model-written summary
Reducing nitrogen from N90 to N60 did not decrease lettuce yield.
- Taxon
- LettuceLactuca sativat0
- Treatment
- N60e0
- Outcome
- crop yielde0
- Direction
- without decreasinge0
- Comparator
- N90 treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the N90 treatment, N2O emission of N60 was reduced by 42% in loam soil and 30% in deep sandy soil without decreasing crop yield.”
t0“Lettuce”
Claim · model-written summary
Growing-season N2O emission factors ranged from 0.40% to 0.61% of added nitrogen.
- Taxon
- LettuceLactuca sativat0
- Outcome
- growing season emission factors (EFgs)e0
- Value
- 0.40% to 0.61% of added Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The growing season emission factors (EFgs) were 0.40% to 0.61% of added N, emitted as N2O and increased with N fertilizer application rate.”
t0“Lettuce”
Claim · model-written summary
Growing-season N2O emission factors increased with nitrogen fertilizer rate.
- Taxon
- LettuceLactuca sativat0
- Treatment
- N fertilizer application ratee0
- Outcome
- growing season emission factors (EFgs)e0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The growing season emission factors (EFgs) were 0.40% to 0.61% of added N, emitted as N2O and increased with N fertilizer application rate.”
t0“Lettuce”
Claim · model-written summary
N2O fluxes fell significantly as applied nitrogen fertilizer amounts decreased.
- Taxon
- LettuceLactuca sativat0
- Treatment
- applied N-fertilizere0
- Outcome
- N2O fluxese0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N2O fluxes reduced as the amount of applied N-fertilizer decreased significantly.”
t0“Lettuce”
The same questions in other papers
nitrogen · environment: emissions · Lactuca sativa (garden lettuce)Positive and negative results
1 in the opposite direction
- positive
fertilization · environment: emissions · Lactuca sativa (garden lettuce)Positive and negative results
2 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- negative
1 paper more in this group
See all 5 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.