Trade-off between C and N recycling and N2O emissions of soils with summer cover crops in subtropical agrosystems

Weiler, Douglas Adams; Giacomini, Sandro José; Recous, Sylvie; Bastos, Leonardo M.; Pilecco, Getúlio Elias; Dietrich, Guilherme; Aita, Celso

doi:10.1007/s11104-018-3831-2

Cited by 16 publications

(15 citation statements)

References 39 publications

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“…Given our finding that N 2 O intensity responded positively to legume biomass and its N content in a drought year with poor maize growth, intercrop species as well as sowing and harvest dates (relative to the main crop) emerge as viable management factors for controlling the accumulation of legume biomass between the maize rows and hence the risk for increased N 2 O emission. Legume species and cultivar in intercropping systems are known to be critical for N loss both during the intercropping and the subsequent seasons (Pappa et al, 2011;Weiler et al, 2018). The stimulating effect of crop residues on N 2 O emissions has been reported to depend on residue quality and soil moisture, with denitrification being the likely process (Li et al, 2016).…”

Section: Total Non-co 2 Ghg Emissionsmentioning

confidence: 99%

“…Inorganic and organic N added to soil provide ammonium (NH + 4 ) and nitrate (NO − 3 ) for nitrification and denitrification, respectively, which are the two main processes of microbial N 2 O production in soil (Khalil et al, 2004). The rate of N 2 O formation depends greatly on the extent and distribution of anoxic microsites in soils, which is controlled by moisture, texture and the distribution of decomposable organic matter and NH + 4 fueling heterotrophic and autotrophic respiration, respectively (Schlüter et al, 2019;Wrage-Mönnig et al, 2018). The magnitude of soil N 2 O emissions depends on O 2 availability as controlled by soil moisture and respiration, the availability of mineral N and readily decomposable C (Harrison-Kirk et al, 2013), and soil pH (Russenes et al, 2016), all of which are affected by management practices.…”

Section: Introductionmentioning

confidence: 99%

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Effect of legume intercropping on N2O emissions and CH4 uptake during maize production in the Great Rift Valley, Ethiopia

Raji

Dörsch

2020

Biogeosciences

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Abstract. Intercropping with legumes is an important component of climate-smart agriculture (CSA) in sub-Saharan Africa, but little is known about its effect on soil greenhouse gas (GHG) exchange. A field experiment was established at Hawassa in the Ethiopian rift valley, comparing nitrous oxide (N2O) and methane (CH4) fluxes in minerally fertilized maize (64 kg N ha−1) with and without Crotalaria (C. juncea) or lablab (L. purpureus) as intercrops over two growing seasons. To study the effect of intercropping time, intercrops were sown either 3 or 6 weeks after maize. The legumes were harvested at flowering, and half of the aboveground biomass was mulched. In the first season, cumulative N2O emissions were largest in 3-week lablab, with all other treatments being equal to or lower than the fertilized maize mono-crop. After reducing mineral N input to intercropped systems by 50 % in the second season, N2O emissions were comparable with the fully fertilized control. Maize-yield-scaled N2O emissions in the first season increased linearly with aboveground legume N yield (p=0.01), but not in the second season when early rains resulted in less legume biomass because of shading by maize. Growing-season N2O-N emission factors varied from 0.02 % to 0.25 % in 2015 and 0.11 % to 0.20 % in 2016 of the estimated total N input. Growing-season CH4 uptake ranged from 1.0 to 1.5 kg CH4-C ha−1, with no significant differences between treatments or years but setting off the N2O-associated emissions by up to 69 %. Our results suggest that leguminous intercrops may increase N2O emissions when developing large biomass in dry years but, when mulched, can replace part of the fertilizer N in normal years, thus supporting CSA goals while intensifying crop production in the region.

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Section: Total Non-co 2 Ghg Emissionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of legume intercropping on N2O emissions and CH4 uptake during maize production in the Great Rift Valley, Ethiopia

Raji

Dörsch

2020

Biogeosciences

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“…There is a common agreement that peaks of N 2 O are observed during the 3–4 weeks following incorporation of legume residues. While some studies reported that there was no increase in N 2 O emissions compared to a fallow when considering the whole cycle (Sanz‐Cobena et al, ; Weiler et al, ), others reported that legumes enhance N 2 O emissions (Basche et al, ; Muhammad et al, ). In our study, N fertilization was reduced and replaced by the N supply by cover crops and, even though, N 2 O emissions were enhanced by legumes.…”

Section: Discussionmentioning

confidence: 99%

Integrated management for sustainable cropping systems: Looking beyond the greenhouse balance at the field scale

Quemada

Lassaletta

Leip

et al. 2020

Global Change Biology

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Cover crops (CC) promote the accumulation of soil organic carbon (SOC), which provides multiple benefits to agro‐ecosystems. However, additional nitrogen (N) inputs into the soil could offset the CO2 mitigation potential due to increasing N2O emissions. Integrated management approaches use organic and synthetic fertilizers to maximize yields while minimizing impacts by crop sequencing adapted to local conditions. The goal of this work was to test whether integrated management, centered on CC adoption, has the potential to maximize SOC stocks without increasing the soil greenhouse gas (GHG) net flux and other agro‐environmental impacts such as nitrate leaching. To this purpose, we ran the DayCent bio‐geochemistry model on 8,554 soil sampling locations across the European Union. We found that soil N2O emissions could be limited with simple crop sequencing rules, such as switching from leguminous to grass CC when the GHG flux was positive (source). Additional reductions of synthetic fertilizers applications are possible through better accounting for N available in green manures and from mineralization of soil reservoirs while maintaining cash crop yields. Therefore, our results suggest that a CC integrated management approach can maximize the agro‐environmental performance of cropping systems while reducing environmental trade‐offs.

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“…An alternative to reach these conditions is the inclusion of soil cover crops in cropping systems. Soil cover crops have numerous benefits mainly under no-till system, such as preventing soil erosion, increasing soil C stocks (Amado et al, 2006;Bayer et al, 2009), nutrient cycling (Tiecher et al, 2017), and adding nitrogen (N) to soil by biological N fixation combined with low nitrous oxide emissions (Bayer et al, 2015;Weiler et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Summer Cover Crops Shoot Decomposition and Nitrogen Release in a No-Tilled Sandy Soil

Weiler

Giacomini

Aita

et al. 2019

Rev. Bras. Ciênc. Solo

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Cover crops have numerous benefits when used in a no-till system. Understanding the processes of decomposition and N release of summer cover crops (SCC) may help select species and management to be used in cropping systems. This study aimed to evaluate C and N loss of SCC shoots. Six SCCs were evaluated: velvet bean (Mucuna aterrima), pearl millet (Pennisetum americanum), dwarf pigeon pea (Cajanus cajan), sunn hemp (Crotalaria juncea), showy rattlebox (Crotalaria spectabilis), and jack bean (Canavalia ensiformis). The experiment was conducted for two years under no-till in soil classified as Typic Hapludalf (Argissolo). The C and N remaining of crop shoots were evaluated for 140 days using litter bags and the results were fitted with a simple nonlinear regression model. Elevated air temperature and rainfall volume accelerated C and N loss in the first year. Carbon and N loss was characterized by a rapid initial phase followed by a slower one. Jack bean had the highest C loss rates, while the lowest rates were found in pearl millet. Velvet bean and pearl millet had the lowest N loss rates in the first year, together with showy rattlebox in the second year. The rates of C (kC) and N (kN) loss were positively correlated with total N and water-soluble C and N in crop shoots. During the 35 days after cover crop termination, SCCs released 35 to 137 kg ha-1 N in 2010 and 5 to 66 kg ha-1 N in 2011. Velvet bean and showy rattlebox showed more gradual N release, which may favor the synchronization between N release and N uptake by the succeeding crop. The sunn hemp was the legume species that combined higher remaining residues on the soil surface, releasing less N but preventing soil erosion.

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Trade-off between C and N recycling and N2O emissions of soils with summer cover crops in subtropical agrosystems

Cited by 16 publications

References 39 publications

Effect of legume intercropping on N<sub>2</sub>O emissions and CH<sub>4</sub> uptake during maize production in the Great Rift Valley, Ethiopia

Effect of legume intercropping on N<sub>2</sub>O emissions and CH<sub>4</sub> uptake during maize production in the Great Rift Valley, Ethiopia

Integrated management for sustainable cropping systems: Looking beyond the greenhouse balance at the field scale

Summer Cover Crops Shoot Decomposition and Nitrogen Release in a No-Tilled Sandy Soil

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Trade-off between C and N recycling and N2O emissions of soils with summer cover crops in subtropical agrosystems

Cited by 16 publications

References 39 publications

Effect of legume intercropping on N&lt;sub&gt;2&lt;/sub&gt;O emissions and CH&lt;sub&gt;4&lt;/sub&gt; uptake during maize production in the Great Rift Valley, Ethiopia

Effect of legume intercropping on N&lt;sub&gt;2&lt;/sub&gt;O emissions and CH&lt;sub&gt;4&lt;/sub&gt; uptake during maize production in the Great Rift Valley, Ethiopia

Integrated management for sustainable cropping systems: Looking beyond the greenhouse balance at the field scale

Summer Cover Crops Shoot Decomposition and Nitrogen Release in a No-Tilled Sandy Soil

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Effect of legume intercropping on N<sub>2</sub>O emissions and CH<sub>4</sub> uptake during maize production in the Great Rift Valley, Ethiopia

Effect of legume intercropping on N<sub>2</sub>O emissions and CH<sub>4</sub> uptake during maize production in the Great Rift Valley, Ethiopia