• Authors:
    • Lubbers,Ingrid M.
    • van Groenigen,Kees Jan
    • Brussaard,Lijbert
    • van Groenigen,Jan Willem
  • Source: Scientific Reports
  • Volume: 5
  • Year: 2015
  • Summary: Concerns about rising greenhouse gas (GHG) concentrations have spurred the promotion of no-tillage practices as a means to stimulate carbon storage and reduce CO2 emissions in agro-ecosystems. Recent research has ignited debate about the effect of earthworms on the GHG balance of soil. It is unclear how earthworms interact with soil management practices, making long-term predictions on their effect in agro-ecosystems problematic. Here we show, in a unique two-year experiment, that earthworm presence increases the combined cumulative emissions of CO2 and N2O from a simulated no-tillage (NT) system to the same level as a simulated conventional tillage (CT) system. We found no evidence for increased soil C storage in the presence of earthworms. Because NT agriculture stimulates earthworm presence, our results identify a possible biological pathway for the limited potential of no-tillage soils with respect to GHG mitigation.
  • Authors:
    • Ho,A.
    • Reim,A.
    • Kim SangYoon
    • Meima-Franke,M.
    • Termorshuizen,A.
    • Boer,W. de
    • Putten,W. H. van der
    • Bodelier,P. L. E.
  • Source: Global Change Biology
  • Volume: 21
  • Issue: 10
  • Year: 2015
  • Summary: Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO 2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may compensate for the loss of the methane sink function following land-use change.
  • Authors:
    • Crittenden,S. J.
    • Poot,N.
    • Heinen,M.
    • van Balen,D. J. M.
    • Pulleman,M. M.
  • Source: Soil and Tillage Research
  • Volume: 154
  • Year: 2015
  • Summary: Reduced tillage can improve soil physical quality relative to mouldboard ploughing by lessening soil disturbance, leaving organic matter at the soil surface, and stimulating soil biological activity. In organic farming, continuous ploughing may negate benefits to soil structure and function from increased use of manures and more diverse crop rotations, which are particularly important components of organic farming. The current study examined soil physical quality (i.e., properties and functioning) of a 4-year old reduced tillage system under organic and conventional farming with crop rotations that included root crops. Reduced tillage was compared to conventional mouldboard ploughing (MP) in 2 organic fields at different points of the same crop rotation (Org A and Org B) and 1 conventional field (Conv A). Reduced tillage consisted of non-inversion tillage (NIT) to 18-23. cm depth whereas MP was characterised by annual mouldboard ploughing to 23-25. cm depth. NIT improved soil water retention in Org B but had no effect in Org A. NIT increased soil aggregate stability at 10-20. cm depth compared to MP in all fields, and additionally at 0-10. cm in Conv A. Penetration resistance was higher in NIT in all fields. Furthermore, soil organic matter content was higher in NIT than MP at 0-10. cm depth in all fields and at 10-20. cm in Org B and Conv A. NIT increased carbon stocks in Org B but not in Org A. NIT statistically increased crop yields in spring wheat/faba bean mixture in Org A, and there was no yield penalty from NIT in Org B spring wheat nor Conv A sugar beet. In contrast, field-saturated hydraulic conductivity in all fields in autumn was lower in NIT. Differences in crop (i.e., phase of rotation) and associated organic inputs between Org A and B likely accounted for the differences in effects of tillage system. Overall, the NIT system improved or imposed no penalty on soil physical quality (except field-saturated hydraulic conductivity) and improved or imposed no penalty on crop yields and could therefore be considered as a viable alternative for farmers. © 2015 Elsevier B.V..
  • Authors:
    • Don, A.
    • Poeplau, C.
  • Source: GCB Bioenergy
  • Volume: 6
  • Issue: 4
  • Year: 2014
  • Summary: Bioenergy has to meet increasing sustainability criteria in the EU putting conventional bioenergy crops under pressure. Alternatively, perennial bioenergy crops, such as Miscanthus, show higher greenhouse gas savings with similarly high energy yields. In addition, Miscanthus plantations may sequester additional soil organic carbon (SOC) to mitigate climate change. As the land-use change in cropland to Miscanthus involves a C-3-C-4 vegetation change (VC), it is possible to determine the dynamic of Miscanthus-derived SOC (C-4 carbon) and of the old SOC (C-3 carbon) by the isotopic ratio of C-13 to C-12. We sampled six croplands and adjacent Miscanthus plantations exceeding the age of 10 years across Europe. We found a mean C-4 carbon sequestration rate of 0.78 +/- 0.19 Mg ha(-1) yr(-1), which increased with mean annual temperature. At three of six sites, we found a significant increase in C-3 carbon due to the application of organic fertilizers or difference in baseline SOC, which we define as non-VC-induced SOC changes. The Rothamsted Carbon Model was used to disentangle the decomposition of old C-3 carbon and the non-VC-induced C3 carbon changes. Subsequently, this method was applied to eight more sites from the literature, resulting in a climate-dependent VC-induced SOC sequestration rate (0.40 +/- 0.20 Mg ha(-1) yr(-1)), as a step toward a default SOC change function for Miscanthus plantations on former croplands in Europe. Furthermore, we conducted a SOC fractionation to assess qualitative SOC changes and the incorporation of C-4 carbon into the soil. Sixteen years after Miscanthus establishment, 68% of the particulate organic matter (POM) was Miscanthus-derived in 0-10 cm depth. POM was thus the fastest cycling SOC fraction with a C-4 carbon accumulation rate of 0.33 +/- 0.05 Mg ha(-1) yr(-1). Miscanthus-derived SOC also entered the NaOCl-resistant fraction, comprising 12% in 0-10 cm, which indicates that this fraction was not an inert SOC pool.
  • Authors:
    • Fleming, R.
    • McKenney, D. J.
    • Guo, X.
    • Tan, C. S.
    • Yang, X. M.
    • Reynolds, W. D.
    • Drury, C. F.
    • Denholme, K.
  • Source: Canadian Journal of Soil Science
  • Volume: 94
  • Issue: 3
  • Year: 2014
  • Summary: The impacts of compost type on corn grain yields over 10 yr and N 2O and CO 2 emissions in the first 3 yr after compost application were evaluated on a Brookston clay loam soil in Woodslee, ON. The treatments included yard waste compost (YWC), kitchen food waste compost (FWC), and pig manure compost (PMC), which were applied once in the fall of 1998 to field plots at a rate of 75 Mg ha -1 (dry weight basis) and no further applications occurred thereafter as well as a fertilized control treatment. Large application rates were examined to see if the various compost sources could have a lasting effect on soil C storage, N 2O and CO 2 emissions and corn yields. Compost application significantly increased corn grain yields by 12.9 to 19.4% over 3 yr. However, after 10 yr, FWC was the only compost source which significantly increased yields by 11.3% compared with the fertilized control. Emissions of N 2O and CO 2 varied with compost type, soil water content and time. Greater N 2O emissions occurred in 1999 from PMC (5.4 kg N ha -1) than YWC (2.7 kg N ha -1) and FWC (1.3 kg N ha -1); however, the N 2O emissions from the PMC were less than from YWC and FWC in 2001. The 3-yr average N 2O emissions were significantly greater with PMC (2.7 kg N ha -1) and YWC (2.5 kg N ha -1) compared with the control (1.5 kg N ha -1). Hence, the timing of N 2O emissions varied by compost type, but the overall losses were similar as the higher N 2O losses in the first year with PMC were offset by the reduced losses with PMC in the third year. Significantly more CO 2 was produced from the FWC in 2000 and from PMC in 2001 than the control.
  • Authors:
    • Shangguan, Z. P.
    • Liu, G. B.
    • Deng, L.
  • Source: GLOBAL CHANGE BIOLOGY
  • Volume: 20
  • Issue: 11
  • Year: 2014
  • Summary: The establishment of either forest or grassland on degraded cropland has been proposed as an effective method for climate change mitigation because these land use types can increase soil carbon (C) stocks. This paper synthesized 135 recent publications (844 observations at 181 sites) focused on the conversion from cropland to grassland, shrubland or forest in China, better known as the 'Grain-for-Green' Program to determine which factors were driving changes to soil organic carbon (SOC). The results strongly indicate a positive impact of cropland conversion on soil C stocks. The temporal pattern for soil C stock changes in the 0-100 cm soil layer showed an initial decrease in soil C during the early stage (5 years) coincident with vegetation restoration. The rates of soil C change were higher in the surface profile (0-20 cm) than in deeper soil (20-100 cm). Cropland converted to forest (arbor) had the additional benefit of a slower but more persistent C sequestration capacity than shrubland or grassland. Tree species played a significant role in determining the rate of change in soil C stocks (conifer < broadleaf, evergreen < deciduous forests). Restoration age was the main factor, not temperature and precipitation, affecting soil C stock change after cropland conversion with higher initial soil C stock sites having a negative effect on soil C accumulation. Soil C sequestration significantly increased with restoration age over the long-term, and therefore, the large scale of land-use change under the 'Grain-for-Green' Program will significantly increase China's C stocks.
  • Authors:
    • Zhong, Q. C.
    • Zhang, C.
    • Hyvonen, N.
    • Wang, K. Y.
    • Shurpali, N. J.
    • Kellomaki, S.
    • Gong, J. N.
    • Martikainen, P. J.
  • Source: AGRICULTURAL AND FOREST METEOROLOGY
  • Volume: 198
  • Year: 2014
  • Summary: In this study, a process-based model (RCG-C) was developed, parameterized and calibrated for studying the annual and seasonal dynamics of the ecosystem CO2 exchange (NEE) in a cutaway peatland (Linnansuo, eastern Finland) cultivated with a perennial bioenergy crop (Phalaris arundinaceae, L., RCG). Based on a number of prior studies and an environmentally controlled experiment, RCG-C emphasized several key processes beyond the generality of previous diplotelmic models for pristine peatlands. These processes included the effects of management (e.g., drainage, peat extraction, tilling, harvesting and fertilization) on the soil hydrology and the cycling of carbon and nitrogen, the influence of climatic factors on photosynthesis and the phenological cycle and phenological and soil-moisture controls on biomass production and canopy development. The model was validated based on continuous measurements of meteorological parameters, energy and CO2 fluxes (eddy covariance system) performed at the site from 2005 to 2010, including variation associated with both wet and dry years. The results showed that the model captured the seasonal and annual trends of the latent heat flux and NEE during the six-year period. Moreover, the simulated values for the total C sink capacity, accumulation of rhizome biomass and peat formation from RCG obtained during the six-year period also agreed well with the field measurements. Based on the FINADAPT climate scenarios, a sensitivity analysis of the model showed that the potential increases in the atmospheric CO2 concentration (Ca) and air temperature (Ta) could be the main forces driving the changes in NEE. The model simulation suggested that the effects of Ta tend to offset those of Ca and lead to a decrease in the total C sink capacity of the site during the main rotation period (4-15th year of cultivation). This decrease tends to become more intensive toward the end of the 21st century. During the period from 2060 to 2099, the total CO2 sink capacity could decrease by 79% during the main rotation period at the Linnansuo site.
  • Authors:
    • Siegfried, W.
    • Rohr, C.
    • Riemann, D.
    • Retso, D.
    • Pribyl, K.
    • Nordl, O.
    • Litzenburger, L.
    • Limanowka, D.
    • Labbe, T.
    • Kotyza, O.
    • Kiss, A.
    • Himmelsbach, I.
    • Glaser, R.
    • Dobrovolny, P.
    • Contino, A.
    • Camenisch, C.
    • Burmeister, K.
    • Brazdil, R.
    • Bieber, U.
    • Barriendos, M.
    • Alcoforado, M.
    • Luterbacher, J.
    • Gruenewald, U.
    • Herget, J.
    • Seneviratne, S.
    • Wagner, S.
    • Zorita, E.
    • Werner, J.
    • Pfister, C.
    • Wetter, O.
    • Soderberg, J.
    • Spring, J.
  • Source: Climatic Change
  • Volume: 125
  • Issue: 3-4
  • Year: 2014
  • Summary: The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring-summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km(2), we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.
  • Authors:
    • Priesack, E.
    • Palosuo, T.
    • Osborne, T. M.
    • Olesen, J. E.
    • O'Leary, G.
    • Nendel, C.
    • Kumar, S. Naresh
    • Mueller, C.
    • Kersebaum, K. C.
    • Izaurralde, R. C.
    • Ingwersen, J.
    • Hunt, L. A.
    • Hooker, J.
    • Heng, L.
    • Grant, R.
    • Goldberg, R.
    • Gayler, S.
    • Doltra, J.
    • Challinor, A. J.
    • Biernath, C.
    • Bertuzzi, P.
    • Angulo, C.
    • Aggarwal, P. K.
    • Martre, P.
    • Basso, B.
    • Brisson, N.
    • Cammarano, D.
    • Rotter, R. P.
    • Thorburn, P. J.
    • Boote, K. J.
    • Ruane, A. C.
    • Hatfield, J. L.
    • Jones, J. W.
    • Rosenzweig, C.
    • Ewert, F.
    • Asseng, S.
    • Ripoche, D.
    • Semenov, M. A.
    • Shcherbak, I.
    • Steduto, P.
    • Stoeckle, C.
    • Stratonovitch, P.
    • Streck, T.
    • Supit, I.
    • Tao, F.
    • Travasso, M.
    • Waha, K.
    • Wallach, D.
    • White, J. W.
    • Williams, J. R.
    • Wolf, J.
  • Source: Nature Climate Change
  • Volume: 3
  • Issue: 9
  • Year: 2013
  • Summary: Projections of climate change impacts on crop yields are inherently uncertain(1). Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate(2). However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop simulation models(1,3) are difficult(4). Here we present the largest standardized model intercomparison for climate change impacts so far. We found that individual crop models are able to simulate measured wheat grain yields accurately under a range of environments, particularly if the input information is sufficient. However, simulated climate change impacts vary across models owing to differences in model structures and parameter values. A greater proportion of the uncertainty in climate change impact projections was due to variations among crop models than to variations among downscaled general circulation models. Uncertainties in simulated impacts increased with CO2 concentrations and associated warming. These impact uncertainties can be reduced by improving temperature and CO2 relationships in models and better quantified through use of multi-model ensembles. Less uncertainty in describing how climate change may affect agricultural productivity will aid adaptation strategy development and policy making.
  • Authors:
    • Ju, X. T.
    • Su, F.
    • Huang, T.
    • Gao, B.
    • Jia, X. Y.
    • Wang, H. F.
  • Source: Acta Pedologica Sinica
  • Volume: 50
  • Issue: 6
  • Year: 2013
  • Summary: Illustrating mechanisms of N 2O generation in and emissions of CO 2 and CH 4 from the soil could help us design greenhouse gas mitigation strategies. An experiment was carried out in fields of acid red soil different in land use, i. e. vegetable garden, paddy field, tea garden and forest in Jinjing river region, Changsha, to study effects of application of carbon, nitrogen and nitrification inhibitor on N 2O, CO 2 and CH 4 emissions under constant temperature and soil moisture, using the static incubation-gas chromatograph method. Results show that less N 2O emission was observed from the acid red soil, low in pH, after application of N fertilizer; the addition of glucose stimulated N 2O emission from the soil applied with urea and from soil denitrification. Heterotrophic nitrification might be the main pathway of N 2O generation in acid red soil and nitrification inhibitor Dicyandiamide (DCD) had no significant effect on N 2O reduction in the acid red soil. In terms of total N 2O emission from the soil applied with N and C, the fields different in land use followed the order of tea garden > vegetable garden > paddy field > forest land. Extraneous organic carbon could significantly stimulate soil C0 2 emission from the four fields, showing an order of tea garden and paddy field > vegetable garden and forest land, but did not have much effect on CH 4 emission in all the four fields except paddy field.