Greater humification of belowground than aboveground biomass carbon into particulate soil organic matter in no-till corn and soybean crops

Mazzilli, Sebastián R.; Kemanian, Armen R.; Ernst, Oswaldo; Jackson, Robert B.; Piñeiro, Gervasio

doi:10.1016/j.soilbio.2015.02.014

Cited by 107 publications

(41 citation statements)

References 53 publications

(61 reference statements)

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“…Killing the rye cover crop added additional decomposable residues, albeit in low quantities (<2 Mg ha À1 ). Second, chisel plowing prior to rhizome establishment caused a greater level of soil disturbance in Miscanthus compared to no-till switchgrass seeding, which may have accelerated soil organic matter decomposition (Grandy & Robertson, 2006;Mazzilli et al, 2015). Third, due to the different techniques used to establish the energy crops, the switchgrass stands were denser than that of Miscanthus early in the growing season, allowing switchgrass an earlier canopy closure and higher N uptake.…”

Section: Discussionmentioning

confidence: 99%

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

et al. 2016

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Future liquid fuel demand from renewable sources may, in part, be met by converting the seasonally wet portions of the landscape currently managed for soil and water conservation to perennial energy crops. However, this shift may increase nitrous oxide (N 2 O) emissions, thus limiting the carbon (C) benefits of energy crops. Particularly high emissions may occur during the transition period when the soil is disturbed, plants are establishing, and nitrate and water accumulation may favor emissions. We measured N 2 O emissions and associated environmental drivers during the transition of perennial grassland in a Conservation Reserve Program (CRP) to switchgrass (Panicum virgatum L.) and Miscanthus x giganteus in the bottom 3-ha of a watershed in the Ridge and Valley ecoregion of the northeastern United States. Replicated treatments of CRP (unconverted), unfertilized switchgrass (switchgrass), nitrogen (N) fertilized switchgrass (switchgrass-N), and Miscanthus were randomized in four blocks. Each plot was divided into shoulder, backslope, and footslope positions based on the slope and moisture gradient. Soil N 2 O flux, soil moisture, and soil mineral nitrogen availability were monitored during the growing season of 2013, the year after the land conversion. Growing season N 2 O flux showed a significant vegetation-bylandscape position interaction (P < 0.009). Switchgrass-N and Miscanthus treatments had 3 and 6-times higher cumulative flux respectively than the CRP in the footslope, but at other landscape positions fluxes were similar among land uses. A peak N 2 O emission event, contributing 26% of the cumulative flux, occurred after a 10.8-cm of rain during early June. Prolonged subsoil saturation coinciding with high mineral N concentration fueled N 2 O emission hot spots in the footslopes under energy crops. Our results suggest that mitigating N 2 O emissions during the transition of CRP to energy crops would mostly require a site-specific management of the footslopes.

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Section: Discussionmentioning

confidence: 99%

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

et al. 2016

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“…Several studies have shown that belowground root‐derived inputs contribute disproportionately to soil C compared to aboveground shoot inputs (Balesdent & Balabane, ; Clapp et al ., ; Rasse et al ., ; Kong & Six, ; Mendez‐Millan et al ., ; Clemmensen et al ., ; Mazzilli et al ., ). Studies using biomarkers specific to root and shoot tissue (Mendez‐Millan et al ., ; Ji et al ., ) and natural abundance isotopes (Balesdent & Balabane, ; Mazzilli et al ., ) show more root than shoot C in SOM, as do studies of cover crops using isotope labels (Puget & Drinkwater, ; Kong & Six, , ).…”

Section: Introductionmentioning

confidence: 97%

“…Rhizodeposits thus represent a significant input to soil C that may differ from biomass inputs because they are continuous, differ in chemical composition, and enter SOM in close physical proximity to soil minerals and microbial communities. Continuous rhizodeposition can stimulate microbial biomass production and activity, a key precursor for SOM formation (Grandy & Neff, ; Schmidt et al ., ; Wieder et al ., , ; Kallenbach et al ., ), and rhizodeposits may be preferentially protected in aggregates on mineral surfaces (Rasse et al ., ; Dungait et al ., ; Mazzilli et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Cover crop root contributions to soil carbon in a no‐till corn bioenergy cropping system

et al. 2017

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Crop residues are potential biofuel feedstocks, but residue removal may reduce soil carbon (C). The inclusion of a cover crop in a corn bioenergy system could provide additional biomass, mitigating the negative effects of residue removal by adding to stable soil C pools. In a no-till continuous corn bioenergy system in the northern US Corn Belt, we used 13 CO 2 pulse labeling to trace plant C from a winter rye (Secale cereale) cover crop into different soil C pools for 2 years following rye cover crop termination. Corn stover left as residue (30% of total stover) contributed 66, corn roots 57, rye shoots 61, rye roots 50, and rye rhizodeposits 25 g C m À2 to soil. Five months following cover crop termination, belowground cover crop inputs were three times more likely to remain in soil C pools than were aboveground inputs, and much of the root-derived C was in mineral-associated soil fractions. After 2 years, both above-and belowground inputs had declined substantially, indicating that the majority of both root and shoot inputs are eventually mineralized. Our results underscore the importance of cover crop roots vs. shoots and the importance of cover crop rhizodeposition (33% of total belowground cover crop C inputs) as a source of soil C. However, the eventual loss of most cover crop C from these soils indicates that cover crops will likely need to be included every year in rotations to accumulate soil C.

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“…In the soil-plant system, both aboveground biomass (AGB) and belowground biomass (BGB) act as primary input sources for the soil carbon pool (Mazzilli, Kemanian, Ernst, Jackson, & Piñeiro, 2015;Sun, Cheng, & Li, 2013). The allocation of AGB and BGB is frequently used to assess growth responses to ambient ecological conditions or to evaluate the responses of individual plants to experimental manipulation (Hunt & Burnett, 1973;Hunt & Lloyd, 1987).…”

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Grazing enhances soil nutrient effects: Trade‐offs between aboveground and belowground biomass in alpine grasslands of the Tibetan Plateau

2017

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Understanding the impact of grazing patterns on grassland production is of fundamental importance for grassland conservation and management. The objective of this study is to obtain an understanding of the trade‐offs between aboveground biomass and belowground biomass, which are influenced by environmental factors in free grazing (FG) and grazing exclusion (GE) alpine grasslands on the Tibetan Plateau. We explored the relationships between the trade‐off and environmental factors using correlation analysis, a generalized additive model and a structural equation model, and then found that the key factors that determine trade‐off showed differences in FG and GE grasslands and that the final structural equation modeling result explained that 96% (path coefficient = 0.96) and 65% (path coefficient = 0.65) of the variations in the trade‐off were due to FG or GE classifications, respectively. The results demonstrated that soil organic carbon, soil carbon/soil nitrogen, and soil available nitrogen affect the trade‐off between aboveground and belowground biomass in FG grasslands more obviously than in GE grasslands. However, the effects of growing season temperature on the trade‐off were insignificant, −0.218 and −0.181 in FG and GE grasslands, respectively. FG increased the soil bulk density, which resulted in an alteration in the soil pore size distribution and a greater resistance to root penetration. In addition, FG affected the level of soil nutrition, which will affect the nitrogen mineralization of decomposition and absorption, as well as the root biomass. Consequently, this study can provide guidance to improve the quality of grassland.

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Greater humification of belowground than aboveground biomass carbon into particulate soil organic matter in no-till corn and soybean crops

Cited by 107 publications

References 53 publications

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Cover crop root contributions to soil carbon in a no‐till corn bioenergy cropping system

Grazing enhances soil nutrient effects: Trade‐offs between aboveground and belowground biomass in alpine grasslands of the Tibetan Plateau

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