• Authors:
    • Mangalassery,S.
    • Sjoegersten,S.
    • Sparkes,D. L.
    • Mooney,S. J.
  • Source: The Journal of Agricultural Science
  • Volume: 153
  • Issue: 7
  • Year: 2015
  • Summary: The benefits of reduced and zero-tillage systems have been presented as reducing runoff, enhancing water retention and preventing soil erosion. There is also general agreement that the practice can conserve and enhance soil organic carbon (C) levels to some extent. However, their applicability in mitigating climate change has been debated extensively, especially when the whole profile of C in the soil is considered, along with a reported risk of enhanced nitrous oxide (N2O) emissions. The current paper presents a meta-analysis of existing literature to ascertain the climate change mitigation opportunities offered by minimizing tillage operations. Research suggests zero tillage is effective in sequestering C in both soil surface and sub-soil layers in tropical and temperate conditions. The C sequestration rate in tropical soils can be about five times higher than in temperate soils. In tropical soils, C accumulation is generally correlated with the duration of tillage. Reduced N2O emissions under long-term zero tillage have been reported in the literature but significant variability exists in the N2O flux information. Long-term, location-specific studies are needed urgently to determine the precise role of zero tillage in driving N2O fluxes. Considering the wide variety of crops utilized in zero-tillage studies, for example maize, barley, soybean and winter wheat, only soybean has been reported to show an increase in yield with zero tillage (77% over 10 years). In several cases yield reductions have been recorded e.g. c. 1-8% over 10 years under winter wheat and barley, respectively, suggesting zero tillage does not bring appreciable changes in yield but that the difference between the two approaches may be small. A key question that remains to be answered is: are any potential reductions in yield acceptable in the quest to mitigate climate change, given the importance of global food security?
  • Authors:
    • Thomazini,A.
    • Spokas,K.
    • Hall,K.
    • Ippolito,J.
    • Lentz,R.
    • Novak,J.
  • Source: Agriculture, Ecosystems and Environment
  • Volume: 207
  • Year: 2015
  • Summary: One potential strategy to abate increasing atmospheric carbon dioxide (CO 2) levels is to sequester CO 2 as biochar, a structural form of carbon created through the pyrolysis of various biomass materials. Biochar may be applied to soils, but has resulted in variable impacts on net soil greenhouse gas (GHG) emissions, with results spanning from suppression to stimulation. This laboratory incubation study examined the impacts of the same hardwood biochar (fast pyrolysis at 550°C) to elucidate driving variables affecting previously observed carbon dioxide (CO 2) fluctuations as well as nitrous oxide (N 2O), and methane (CH 4) production impacts across ten different US soils with and without biochar (10% w/w). Biochar application significantly impacted CO 2 ( P=0.04) and N 2O ( P=0.03) production following amendment across all soils, but there were no differences observed in CH 4 production/oxidation rates ( P=0.90). Interestingly, the induced biochar GHG alterations were significantly correlated to the original GHG production activity in the control soil, suggesting a more universal response across various soils to the same biochar than has been previously hypothesized. After correcting for the amount of CO 2 released from the biochar itself [24 g C g BC-1 d -1], there was no statistically significant alteration in the actual soil CO 2 mineralization rate for any soil. This suggests that the observed increase in CO 2 production was solely attributed to the abiotic CO 2 releases from the biochar. On the other hand, there was an average suppression of 63% in the N 2O production across all soils following biochar addition, which was again correlated to initial N 2O production activity. For this particular biochar, there are predictable impacts on the GHG production potential across various soils despite differences in soil chemistry, texture, and microbial communities.
  • Authors:
    • He, X.
    • Guan, Q.
    • Lu, X.
    • Lu, M.
    • Wu, H.
  • Source: Biology Article
  • Volume: 88
  • Year: 2015
  • Summary: Soil fauna can significantly affect soil CO2 and N2O emissions, but little is known about interactions between faunal groups and their relative contribution to such emissions. Over a 64-day microcosm incubation, we studied the effects of an epigeic earthworm (Eisenia fetida), mesofauna (Collembola plus oribatid mites) and their combinations on soil CO2 and N2O emissions under two faunal densities. Earthworms significantly enhanced soil CO2 and N2O emissions, while mesofauna only increased N2O emissions. Soil CO2 and N2O emissions were significantly affected by earthworm density, but not by mesofauna density. No significant interactive effects between earthworms and mesofauna were found on soil CO2 and N2O emissions. Our results indicate that earthworms probably play the dominant roles in determining soil CO2 and N2O emissions where they coexist with soil mesofauna. (C) 2015 Elsevier Ltd. All rights reserved.
  • Authors:
    • Mu, J.
    • Guo, J.
    • Zhao, J.
  • Source: Science Article
  • Volume: 207
  • Year: 2015
  • Summary: Understanding regional relationships between climate change and crop yield will help with making the strategic decisions for food security in China under climate change. In this study, the contributions of climate change to spring maize yield over the past three decades in Northeast China were decoupled based on the daily climate variables gathered from 68 meteorological stations and detailed observed data of spring maize from 55 agricultural meteorological experimental stations for the period 1978-2010 in Northeast China, analyzed with a linear statistical model. Then, the key climatic factors limiting the climate-induced yield of spring maize were identified. The agro-climatic similarity theory was applied. Finally, the relationships between the climatic variables and the climate-induced yield of spring maize were further explored by provinces. The results show that: from 1978 to 2010, the observed yields of spring maize in Northeast China increased markedly, with inter-annual fluctuations. Compared with the methods of moving average and harmonic average, Logistic regression optimally decoupled the climate-induced yield of spring maize. The key meteorological factors limiting the climate-induced yield were temperature, precipitation and sunshine, varying in the different regions. In Heilongjiang Province, the climate-induced yields of spring maize were mainly affected by maximum temperatures in August and precipitation in June. In Jilin Province, climate-induced yield was closely related to precipitation during daily the average temperature stably passing 10°C (≥10°C). In Liaoning Province, when the maximum temperature was high and the sunshine was abundant in June, the climate-induced yield of spring maize significantly increased. Finally, the regression models between climatic variables and climate-induced yield of spring maize in 11 representative zones in Northeast China also established geographical differences.
  • Authors:
    • Fontana,M.
    • Berner,A.
    • Mäder,P.
    • Lamy,F.
    • Boivin,P.
  • Source: Soil Science Society of America Journal
  • Volume: 79
  • Issue: 5
  • Year: 2015
  • Summary: soil conservation practices are growingly used with different aims such as reducing fuel consumption and preserving soil organic carbon (soc). among others, reduced tillage (rt) often replaces conventional tillage (ct). However, the compared impact of these practices on soil quality remains a matter of controversy. Moreover, the various changes expected are rarely considered all together though they are known to interact. this study aimed at characterizing together the changes in soc, microbial activity, and a large set of physical properties when comparing rt and ct performed on a clayey soil. shrinkage analysis allowed to characterize simultaneously the soil pore systems, their volume, air and water content, the hydro-structural stability, and the swelling properties of the soil. analysis of covariance (ancoVa) was used to compare the soil properties taking in account clay content variability. we showed that clay and soc changes induced most of the variance of the other parameters. at standardized clay content soc was increased with rt in the topsoil and homogenized with smaller values in the ct layer. Many soil physical and biochemical properties were enhanced accordingly with rt which induced a more stable soil with increased porosity and improved microbial activity. sharp changes in soil quality seem to occur at the ct plow limit, while smooth changes with depth are observed with rt. independently from the soc increase with rt, changes in physical properties and microbial activity could be due to mechanical stress in ct or changes in organic matter quality in rt. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
  • Authors:
    • Hierold, W.
    • Miller, B. A.
    • Koszinski, S.
    • Haelbich, H.
    • Sommer, M.
  • Source: Soil Science Society of America Journal
  • Volume: 79
  • Issue: 5
  • Year: 2015
  • Summary: Spatial variation of c stocks within peatlands is an overall challenge for monitoring global c cycle processes, which is critical for responding to climate change induced by greenhouse gases (GHGs). the objective of this study was to evaluate the ability of high-resolution, minimally invasive sensor data to predict spatial variation of soil organic c (soc) stocks within highly degraded peatland soils in northeast Germany. within the rhin-Havelluch, a paludification mire that has been cultivated and drained for about 300 yr, seven fields were sampled by soil cores up to 2 m in depth, nine points for each field. soil horizons were examined for dry bulk density, soil organic c content (socc), and thickness to calculate soc stocks and to test for relationships with overall peat thickness, elevation, and electrical conductivity (eca). elevation was determined by light detection and ranging (LIDAR) and eca by an eM38dd, both producing maps of high resolution (1 m). soil organic c density (socd) was related to elevation, eca, and peat thickness. Based on these relationships, maps of socd were produced. within field variation of socd was high, which could be modeled by use of the covariate maps. if available, eca maps can improve the prediction of socd based on elevation. Modeling peat thickness based on sensor data needs additional research, but seems to be a valuable covariate in digital soil mapping. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All Rights reserved.
  • Authors:
    • Kurganova,I.
    • Gerenyu,V. L. de
    • Kuzyakov,Y.
  • Source: Research Articles
  • Volume: 133
  • Year: 2015
  • Summary: Most land use changes (LUC) significantly affect the amount of carbon (C) sequestered in vegetation and soil, thereby, shifting the C balance in ecosystems. Disintegration of the USSR and the followed collapse of collective farming system have led to abandonment of more than 58 million ha (Mha) of former croplands in Russia and Kazakhstan that comprise together about 90% of land area in the former USSR. This was the most widespread and abrupt LUC in the 20th century in the northern hemisphere. The spontaneous withdrawal of croplands in 1990s caused several benefits for environment including substantial C sequestration in post-agrogenic ecosystems. The new estimations of net ecosystem production (NEP) and changes in soil organic carbon stocks (Delta SOC) in post-agrogenic ecosystems presented here are based on the uniform bio-climatic approach, and hereby, allow to update C balance of the former USSR. The total extra C sink in abandoned croplands in Russia (45.5 Mha) and Kazakhstan (12.9 Mha) is estimated to be 15527 Mt C yr -1 and 312 Mt C yr -1, respectively. This additional C sink could cover about 18% of the global CO 2 release due to deforestation and other land use changes or compensate annually about 36% and 49% of the current fossil fuel emissions in Russia and Kazakhstan, respectively. The extra C sink to the post-agrogenic ecosystems in Russia and Kazakhstan contributes possibly about 1/3 part to the total current C balance of the former USSR. Hence, the disintegration of the former USSR significantly affected national and global C budget over few decades after LUC.
  • Authors:
    • Meshalkina,J.
    • Yaroslavtsev,A.
    • Mazirov,I.
    • Samardzic,M.
    • Valentini,R.
    • Vasenev,I.
  • Source: Eurasian Journal of Soil Science
  • Volume: 4
  • Issue: 3
  • Year: 2015
  • Summary: The eddy covariance (EC) technique as a powerful statistics-based method of measurement and calculation the vertical turbulent fluxes of greenhouses gases within atmospheric boundary layers provides the continuous, long-term flux information integrated at the ecosystem scale. An attractive way to compare the agricultural practices influences on GHG fluxes is to divide a crop area into subplots managed in different ways. The research has been carried out in the Precision Farming Experimental Field of the Russian Timiryazev State Agricultural University (RTSAU, Moscow) in 2013 under the support of RF Government grant # 11.G34.31.0079, EU grant # 603542 LUC4C (7FP) and RF Ministry of education and science grant # 14-120-14-4266-ScSh. Arable Umbric Albeluvisols have around 1% of SOC, 5.4 pH (KCl) and NPK medium-enhanced contents in sandy loam topsoil. The CO 2 flux seasonal monitoring has been done by two eddy covariance stations located at the distance of 108 m. The LI-COR instrumental equipment was the same for the both stations. The stations differ only by current crop version: barley or vetch and oats. At both sites, diurnal patterns of NEE among different months were very similar in shape but varied slightly in amplitude. NEE values were about zero during spring time. CO 2 fluxes have been intensified after crop emerging from values of 3 to 7 mol/s.m 2 for emission, and from 5 to 20 mol/s.m 2 for sink. Stabilization of the fluxes has come at achieving plants height of 10-12 cm. Average NEE was negative only in June and July. Maximum uptake was observed in June with average values about 8 mol CO 2 m -2 s -1. Although different kind of crops were planted on the fields A and B, GPP dynamics was quite similar for both sites: after reaching the peak values at the mid of June, GPP decreased from 4 to 0.5 g C CO 2 m -2 d -1 at the end of July. The difference in crops harvesting time that was equal two weeks did not significantly influence the daily GPP patterns. Cumulative assimilation of CO 2 at the end of the growing season was about 150 g C m -2 for both sites. So the difference in NEE was the consequence of essentially higher respiration rates in case of vetch and oats (about 350 g C m -2) comparing to barley (250 g C m -2) that needs additional research. The results have shown high daily and seasonal dynamic of CO 2 emission too as a result of different and contrasted conditions: crop type, crop development stage, soil moisture and air temperature. Obtained unique for Russian agriculture data are useful for land-use practices environmental assessment, for soil organic carbon dynamics analysis and agroecological evaluation.
  • Authors:
    • Nugroho,P. A.
    • Shimizu,M.
    • Nakamato,H.
    • Nagatake,A.
    • Suwardi,S.
    • Sudadi,U.
    • Hatano,R.
  • Source: Plant, Soil and Environment
  • Volume: 61
  • Issue: 9
  • Year: 2015
  • Summary: The effect of mineral fertilizer (F) and mineral combined with organic fertilizer (MF) on N 2O flux in grassland and cornfield was investigated for one year in Southern Hokkaido, Japan. Annual N 2O flux was higher in grassland than in cornfield, and it was higher in MF plot (14.9 kg N/ha/period) than in F plot (11.1 kg N/ha/period) in grassland. However, in cornfield, the annual N 2O flux was equal between both plots (5.6 kg N/ha/period). These results clarified that high nitrogen application was not always responsible for the high soil N 2O flux. N 2O flux was significantly correlated with air, soil temperature and water-filled pore space. More than 80% of the annual N 2O flux occurred before freezing and less than 4% during melting period. Denitrification was the main process of N 2O flux during study, it was evidenced by the distribution of N 2O and NO ratio which is from 1 to 1000. The denitrification activity (DEA) potentially increased in grassland soil in the beginning and the end of winter season when NO 3-N was abundant; on the other hand the abundance of carbon potentially increased DEA in cornfield soil.
  • Authors:
    • Ramirez,T.
    • Meas,Y.
    • Dannehl,D.
    • Schuch,I.
    • Miranda,L.
    • Rocksch,T.
    • Schmidt,U.
  • Source: Journal of Cleaner Production
  • Volume: 104
  • Year: 2015
  • Summary: The water and carbon footprint of the presented dried tomato value chain is compared to the conventional process. The coupling of pre- and post-harvest processes, namely growing and drying respectively, is analyzed for resource consumption optimization. The growing system of tomatoes ( Solanum lycopersicon L. cv, Pannovy) in an energy efficient greenhouse (operating as a solar thermal collector) is databased; while the post-harvest process consists of a model-based solar drying system. The thermodynamic operation zones (temperature, humidity and enthalpy) are detailed to apply energy interaction between both processes. The results of the monthly record of a season show that the water footprint was reduced from 91 to 51.1 L kg -1 with a standard deviation from 53.2 to 12.4 L kg -1. The carbon footprint was reduced from 40.2 to 11 kg kg -1 with a standard deviation from 23.9 to 11.4 kg carbon dioxide kg -1. From the observed variation from monthly values, the relevance of the seasonal effect on resources needed for implementing process improvements is highlighted. The use of renewable energy and energy efficiency concepts is shown to have a positive impact when applied at industrial level in 'compound industries' that share sub-processes in the value chains.