Abstract
Abstract Agricultural intensification on existing arable lands has been proposed to reduce deforestation in the Congo Basin, although the effects of intensification on soil greenhouse gas (GHG) emissions have not yet been investigated. Here, we present the first field study to quantify the trade-offs between yield and GHG emissions across different intensification options in this region. We show that intercropping with nitrogen-fixing beans not only provided additional protein-rich food but also increased maize yields by 1.4-fold while leaving N 2 O emissions and the soil CH 4 sink unchanged compared to unfertilized maize. In contrast, a moderate mineral fertilizer application of 66 kg N ha −1 yr −1 doubled yields, but reduced the soil CH 4 sink strength, and increased N 2 O emissions fivefold to about 4 kg N 2 O-N ha −1 yr − 1 . These N 2 O emissions also exceeded those of natural forests by more than a factor of three, highlighting the GHG cost of mineral fertilizer use in addition to CO 2 emissions from soil organic carbon loss following land conversion. In sum, intercropping with nitrogen-fixing beans had the lowest yield-scaled GHG emissions and can help to address protein malnutrition in regions with limited access to mineral fertilizers or particularly high N 2 O emissions.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
Bean intercropping increased maize yield 1.4-fold relative to unfertilized maize.
- Treatment
- intercropping with nitrogen-fixing beanse0
- Outcome
- maize yieldse0
- Direction
- increasede0
- Value
- 1.4-folde0
- Comparator
- unfertilized maizee0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“intercropping with nitrogen-fixing beans not only provided additional protein-rich food but also increased maize yields by 1.4-fold while leaving N 2 O emissions and the soil CH 4 sink unchanged compared to unfertilized maize”
Claim · model-written summary
Bean intercropping left soil N2O emissions and CH4 sink unchanged relative to unfertilized maize.
- Treatment
- intercropping with nitrogen-fixing beanse0
- Outcome
- N 2 O emissions and the soil CH 4 sinke0
- Direction
- unchangede0
- Comparator
- unfertilized maizee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“intercropping with nitrogen-fixing beans not only provided additional protein-rich food but also increased maize yields by 1.4-fold while leaving N 2 O emissions and the soil CH 4 sink unchanged compared to unfertilized maize”
Claim · model-written summary
Moderate mineral fertilizer doubled maize yields.
Not reportedTaxonComparator
Verbatim
e0“a moderate mineral fertilizer application of 66 kg N ha −1 yr −1 doubled yields”
Claim · model-written summary
Moderate mineral fertilizer reduced soil methane sink strength.
- Treatment
- mineral fertilizer application of 66 kg N ha −1 yr −1e0
- Outcome
- soil CH 4 sink strengthe0
- Direction
- reducede0
Not reportedTaxonComparator
Verbatim
e0“a moderate mineral fertilizer application of 66 kg N ha −1 yr −1 doubled yields, but reduced the soil CH 4 sink strength”
Claim · model-written summary
Moderate mineral fertilizer increased soil N2O emissions fivefold to about 4 kg N2O-N per hectare per year.
- Outcome
- N 2 O emissionse0
- Direction
- increasede0
- Value
- fivefolde0
- Qualifier
- about 4 kg N 2 O-N ha −1 yr − 1e0
Not reportedTaxonTreatmentComparator
Verbatim
e0“increased N 2 O emissions fivefold to about 4 kg N 2 O-N ha −1 yr − 1”
Claim · model-written summary
Fertilized plot N2O emissions exceeded natural forest emissions by more than threefold.
- Outcome
- N 2 O emissionse0
- Direction
- exceedede0
- Value
- more than a factor of threee0
- Comparator
- natural forestse0
Not reportedTaxon
Verbatim
e0“These N 2 O emissions also exceeded those of natural forests by more than a factor of three”
Claim · model-written summary
Bean intercropping had the lowest yield-scaled greenhouse-gas emissions.
Not reportedTaxon
Verbatim
e0“intercropping with nitrogen-fixing beans had the lowest yield-scaled GHG emissions”
Claim · model-written summary
The authors recommend bean intercropping for regions with limited fertilizer access or high N2O emissions.
- Outcome
- intercropping with nitrogen-fixing beanse0
- Qualifier
- regions with limited access to mineral fertilizers or particularly high N 2 O emissionse0
Not reportedTaxon
Verbatim
e0“intercropping with nitrogen-fixing beans had the lowest yield-scaled GHG emissions and can help to address protein malnutrition in regions with limited access to mineral fertilizers or particularly high N 2 O emissions”
The same questions in other papers
intercropping · environment: emissions · Zea mays (maize)Positive and negative results
1 paper in the same direction as this paper · 11 in the opposite direction
- positive
- positive
- positive
9 papers more in this group
See all 13 papers →nitrogen · environment: emissions · Zea mays (maize)Positive and negative results
20 papers in the same direction as this paper · 45 in the opposite direction
- positive
- positive
- positive
62 papers more in this group
See all 66 papers →intercropping · yield · Zea mays (maize)Positive and negative results
612 papers in the same direction as this paper · 181 in the opposite direction · 40 reporting no difference from an alternative
- no effect
- positive
- positive
830 papers more in this group
See all 834 papers →nitrogen · yield · Zea mays (maize)Positive and negative results
1,905 papers in the same direction as this paper · 234 in the opposite direction · 45 reporting no difference from an alternative
- negative
- no effect
- negative
2,181 papers more in this group
See all 2,185 papers →fertilization · yield · Zea mays (maize)Positive and negative results
3,484 papers in the same direction as this paper · 338 in the opposite direction · 85 reporting no difference from an alternative
- positive
- negative
- no effect
3,904 papers more in this group
See all 3,908 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.