Cover crop and tillage systems effect on soil CO2 and N2O fluxes in contrasting topographic positions

Negassa, Wakene; Price, Richard F.; Basir, Abdul; Snapp, Sieglinde S.; Kravchenko, Alexandra

doi:10.1016/j.still.2015.06.015

Cited by 63 publications

(30 citation statements)

References 68 publications

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“…Although the late‐terminated CC produced greater biomass, this is only about half the residue produced by corn (9–11 Mg ha −1 ) (Ruis et al, 2017). The increased CO 2 flux under the late‐terminated CC is possibly due to both plant respiration and microbial activity on fresh organic matter (i.e., heterotrophic respiration) (Liebig et al, 2010; Negassa et al, 2015); however, separating soil and plant respiration is difficult. The literature review also suggests that CCs are more likely to change plant + soil respiration during the CC period than after CC termination or the main crop period.…”

Section: Discussionmentioning

confidence: 99%

“…Studies investigating gas fluxes under different CC termination dates are very few. In many studies, CCs are terminated early with low biomass production (<1 Mg ha −1 ), which may reduce gas fluxes (Negassa et al, 2015; Thomas et al, 2017). For example, Negassa et al (2015) showed that CO 2 and N 2 O fluxes were not affected when CC biomass yield was below 0.5 Mg ha −1 .…”

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confidence: 99%

“…In many studies, CCs are terminated early with low biomass production (<1 Mg ha −1 ), which may reduce gas fluxes (Negassa et al, 2015; Thomas et al, 2017). For example, Negassa et al (2015) showed that CO 2 and N 2 O fluxes were not affected when CC biomass yield was below 0.5 Mg ha −1 . Similarly, CO 2, N 2 O, and CH 4 fluxes were unaffected when CC biomass yield was 0.5 to 1.11 Mg ha −1 (Guardia et al, 2016; Thomas et al, 2017).…”

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confidence: 99%

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Impacts of Early‐ and Late‐Terminated Cover Crops on Gas Fluxes

et al. 2018

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Cover crops (CCs) could alter soil processes, but the effects of early versus late termination of CCs on gas fluxes are not well known. We evaluated temporal changes in fluxes of CO2, N2O, and CH4 and related soil properties in no‐till corn (Zea mays L.) with and without winter rye (Secale cereale L.) CCs that were terminated early (30 d before planting) or late (at planting) in a rainfed silty clay loam and an irrigated silt loam in Nebraska from April 2016 to June 2017. Gas fluxes, soil temperature, and soil water content were measured biweekly to monthly, and wet aggregate stability and particulate organic matter concentrations were measured seasonally. We also compared our results with a global literature review. Late‐terminated CCs did not affect CH4 fluxes but increased daily CO2 fluxes by 59% compared with no CC at both sites and N2O fluxes by 92% at the rainfed site only. Early termination did not affect gas fluxes. Termination date did not affect cumulative fluxes and had minimal effects on soil properties. The literature review supports our study results, which indicate that CC effects on (i) CO2 fluxes are driven by plant respiration during the CC growing period, and (ii) N2O and CH4 fluxes are minimal under grass CCs. Overall, under no‐till, CC termination date has small effects on N2O and CH4 fluxes, but late CC termination can increase CO2 fluxes in spring due to greater biomass yield compared with early termination. Core Ideas Early‐terminated cover crops had limited effects on CO2 fluxes in this study. Late‐terminated cover crops increased CO2 flux mainly in spring due to higher cover crop biomass yield. Cover crop termination effects on N2O and CH4 fluxes were generally nonsignificant. Our literature review showed cover crops affected CO2 mostly during their growing period. Our literature results also showed grass cover crops had limited effects on N2O.

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Section: Discussionmentioning

confidence: 99%

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Impacts of Early‐ and Late‐Terminated Cover Crops on Gas Fluxes

et al. 2018

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“…Nevertheless, many studies did not report basic soil information and very few considered interactions between the management practices and ecosystem state factors. For instance, while many studies recognized the importance of landscape characteristics on N 2 O emissions (Corre et al 1996;Castellano et al 2010;Vilain et al 2010;Gu et al 2011;Li et al 2012;Schelde et al 2011) only few examined the interaction between landscape characteristics and management strategies (Sehy et al 2003;Izaurralde et al 2004;Negassa et al 2015). Sehy et al (2003) found that adjusting fertilizer rates for different landscape positions was effective at reducing N 2 O.…”

Section: Ecologically-based Nutrient Management Practicesmentioning

confidence: 99%

N2O emissions from grain cropping systems: a meta-analysis of the impacts of fertilizer-based and ecologically-based nutrient management strategies

Han

Walter

Drinkwater

2017

Nutr Cycl Agroecosyst

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Understanding how agricultural management practices impact nitrous oxide (N 2 O) emissions is prerequisite for developing mitigation protocols. We conducted a meta-analysis on 597 pairwise comparisons (129 papers) to assess how management affects N 2 O emissions. Pairwise comparisons of practices aimed at improving fertilizer use efficiency (39%) and tillage (30%) dominated the dataset, while ecologically-based nutrient management (ENM) practices constituted 15% of the pairs. In general, across management practices, the quantity of N added was a more significant driver of N 2 O fluxes than was the form of N (fertilizer, legume biomass or animal manures). Manure interacted with soil texture so that in coarse soils, N 2 O emissions from manures tended to be higher compared to inorganic N fertilizers. The studies of ENM strategies frequently involved overapplication of N inputs in the ENM treatments. Cover crops reduced N 2 O emissions compared to bare fallows. However, during the cash crop growing season, when differences in N added and N source were confounded, the extra N inputs from cover crops were significantly correlated with the differences in N 2 O emissions between treatments with and without cover crops. Overall, in 38% of the data pairs, N 2 O emissions were reduced with limited impacts on yields; in half of these pairs, yields were maintained or increased while in the other half they were reduced by only B10%. Knowledge gaps on mitigation of agricultural N 2 O emissions could be addressed by applying an ecosystem-based, cross-scale perspective in conjunction with the N saturation conceptual framework to guide research priorities and experimental designs.

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“…Results of studies on the effect of tillage on N 2 O emissions are contradictory. When compared to conventional tillage, RT reduced N 2 O emissions ( i.e ., Koga , ; Wang and Dalal , ), resulted in similar N 2 O emissions ( i.e ., Abdalla et al., ; Negassa et al., ) or, which was the majority of experiments, increased emission ( i.e ., Baggs et al., ; Venterea et al., ). Lognoul et al.…”

Section: Introductionmentioning

confidence: 95%

Nitrous oxide emissions after incorporation of winter oilseed rape (Brassica napus L.) residues under two different tillage treatments

Kesenheimer

Pandeya

Müller

et al. 2018

J. Plant Nutr. Soil Sci.

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The aim of this study was to investigate the effect of crop residues from winter oilseed rape on N2O emissions from a loamy soil and to determine the effect of different tillage practices on N2O fluxes. We therefore conducted a field experiment in which crop residues of winter oilseed rape (Brassica napus L., OSR) were replaced with 15N labelled OSR residues. Nitrous oxide (N2O) emissions and 15N abundance in the N2O were determined for a period of 11 months after harvest of OSR and in the succeeding crop winter wheat (Triticum aestivum L.) cultivated on a Haplic Luvisol in South Germany. Measurements were carried out with the closed chamber method in a treatment with conventional tillage (CT) and in a treatment with reduced soil tillage (RT). In both tillage treatments we also determined N2O fluxes in control plots where we completely removed the crop residues. High N2O fluxes occurred in a short period just after OSR residue replacement in fall and after N‐fertilization to winter wheat in the following spring. Although N2O emissions differed for distinct treatments and sub‐periods, cumulative N2O emissions over the whole investigation period (299 days) ranged between 1.7 kg and 2.4 kg N2O‐N ha−1 with no significant treatment effects. More than half of the cumulative emissions occurred during the first eight weeks after OSR replacement, highlighting the importance of this post‐harvest period for annual N2O budgets of OSR. The contribution of residue N to the N2O emission was low and explained by the high C/N‐ratio fostering immobilization of mineral N. In total only 0.03% of the N2O‐N emitted in the conventional tillage treatment and 0.06% in the reduced tillage treatment stemmed directly from the crop residues. The 15N recovery in the treatments with crop residues was 62.8% (CT) and 75.1% (RT) with more than 97% of the recovered 15N in the top soil. Despite our measurements did not cover an entire year, the low contribution of the OSR residues to the direct N2O emissions shows, that the current IPCC tier 1 approach, which assumes an EF of 1%, strongly overestimated direct emissions from OSR crop residues. Furthermore, we could not observe any relationship between tillage and crop residues on N2O emission, only during the winter period were N2O emissions from reduced tillage significantly higher compared to conventional tillage. Annual N2O emission from RT and CT did not differ.

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Cover crop and tillage systems effect on soil CO2 and N2O fluxes in contrasting topographic positions

Abstract:  Sensitivity of CO 2 emissions to soil temperature was higher in cover crop than no cover 7 crop treatments. 8 CO 2 emissions from the ridge tillage were higher than from the chisel tillage.

Cited by 63 publications

References 68 publications

Impacts of Early‐ and Late‐Terminated Cover Crops on Gas Fluxes

Impacts of Early‐ and Late‐Terminated Cover Crops on Gas Fluxes

N2O emissions from grain cropping systems: a meta-analysis of the impacts of fertilizer-based and ecologically-based nutrient management strategies

Nitrous oxide emissions after incorporation of winter oilseed rape (Brassica napus L.) residues under two different tillage treatments

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