• 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:
    • van Groenigen, J. W.
    • Garcia-Torres, L.
    • Sanz-Cobena, A.
    • Abalos, D.
    • Vallejo, A.
  • Source: Plant and Soil
  • Volume: 364
  • Issue: 1-2
  • Year: 2013
  • Summary: Agricultural soils in semiarid Mediterranean areas are characterized by low organic matter contents and low fertility levels. Application of crop residues and/or manures as amendments is a cost-effective and sustainable alternative to overcome this problem. However, these management practices may induce important changes in the nitrogen oxide emissions from these agroecosystems, with additional impacts on carbon dioxide emissions. In this context, a field experiment was carried out with a barley (Hordeum vulgare L.) crop under Mediterranean conditions to evaluate the effect of combining maize (Zea mays L.) residues and N fertilizer inputs (organic and/or mineral) on these emissions. Crop yield and N uptake, soil mineral N concentrations, dissolved organic carbon (DOC), denitrification capacity, N2O, NO and CO2 fluxes were measured during the growing season. The incorporation of maize stover increased N2O emissions during the experimental period by c. 105 %. Conversely, NO emissions were significantly reduced in the plots amended with crop residues. The partial substitution of urea by pig slurry reduced net N2O emissions by 46 and 39 %, with and without the incorporation of crop residues respectively. Net emissions of NO were reduced 38 and 17 % for the same treatments. Molar DOC:NO (3) (-) ratio was found to be a robust predictor of N2O and NO fluxes. The main effect of the interaction between crop residue and N fertilizer application occurred in the medium term (4-6 month after application), enhancing N2O emissions and decreasing NO emissions as consequence of residue incorporation. The substitution of urea by pig slurry can be considered a good management strategy since N2O and NO emissions were reduced by the use of the organic residue.
  • Authors:
    • De Nocker, L.
    • Aertsens, J.
    • Gobin, A.
  • Source: Land Use Policy
  • Volume: 31
  • Year: 2013
  • Summary: Purpose: This paper aims at indicating the potential of agricultural measures in sequestering carbon as an option for climate change mitigation. The related value for society is estimated. Principle results: Agricultural practices like agroforestry, introducing hedges, low and no tillage and cover crops have an important potential to increase carbon sequestration. The total technical potential in the EU-27 is estimated to be 1566 million tonnes CO2-equivalent per year. This corresponds to 37% of all CO2-equivalent emissions in the EU in 2007. The introduction of agroforestry is the measure with the highest potential, i.e. 90% of the total potential of the measures studied. Taking account only of the value for climate change mitigation, the introduction of agroforestry is estimated to have a value of 282 euro/ha in 2012 that will gradually increase to 1007 euro/ha in 2030. Major conclusions: This implies that there is a huge potential which represents an important value for society in general and for the agricultural sector in specific. At the European level, only in the last few years policy makers have recognized the important benefits of agroforestry. In their rural development programmes some European countries now support farmers to introduce agroforestry. But still the current level of support is only a small fraction of the societal value of agroforestry. If this value would be fully recognized by internalizing the positive externality, we expect that agroforestry will be introduced to a very large extent in the next decades, in Europe and the rest of the world, and this will importantly change the rural landscapes. (C) 2012 Elsevier Ltd. All rights reserved.
  • Authors:
    • Sanchez-Diaz, M.
    • Araus, J. L.
    • Irigoyen, J. J.
    • Jauregui, I.
    • Sanz-Saez, A.
    • Aranjuelo, I.
    • Erice, G.
  • Source: Journal of Experimental Botany
  • Volume: 64
  • Issue: 7
  • Year: 2013
  • Summary: The expansion of the worlds population requires the development of high production agriculture. For this purpose, it is essential to identify target points conditioning crop responsiveness to predicted [CO2]. The aim of this study was to determine the relevance of ear sink strength in leaf protein and metabolomic profiles and its implications in photosynthetic activity and yield of durum wheat plants exposed to elevated [CO2]. For this purpose, a genotype with high harvest index (HI) (Triticum durum var. Sula) and another with low HI (Triticum durum var. Blanqueta) were exposed to elevated [CO2] (700 mol mol(1) versus 400 mol mol(1) CO2) in CO2 greenhouses. The obtained data highlighted that elevated [CO2] only increased plant growth in the genotype with the largest HI; Sula. Gas exchange analyses revealed that although exposure to 700 mol mol(1) depleted Rubisco content, Sula was capable of increasing the light-saturated rate of CO2 assimilation (A(sat)) whereas, in Blanqueta, the carbohydrate imbalance induced the down-regulation of A(sat). The specific depletion of Rubisco in both genotypes under elevated [CO2], together with the enhancement of other proteins in the Calvin cycle, revealed that there was a redistribution of N from Rubisco towards RuBP regeneration. Moreover, the down-regulation of N, NO3, amino acid, and organic acid content, together with the depletion of proteins involved in amino acid synthesis that was detected in Blanqueta grown at 700 mol mol(1) CO2, revealed that inhibition of N assimilation was involved in the carbohydrate imbalance and consequently with the down-regulation of photosynthesis and growth in these plants.
  • Authors:
    • Lloveras, J.
    • Santiveri, F.
    • Biau, A.
  • Source: Agronomy Journal
  • Volume: 105
  • Issue: 5
  • Year: 2013
  • Summary: The incorporation of crop stover into the soil improves soil fertility and crop productivity by increasing C sequestration and reducing the emission of greenhouse gases among other parameters. Interactions between crop stover management and N fertilization could help to improve C sequestration while increasing productivity. The objective of this study was to evaluate the impact of incorporating or removing corn (Zea mays L.) stover, in combination with different N fertilization rates (0, 100, 200, and 300 kg N ha(-1)), on corn production, soil organic carbon (SOC), and soil mineral nitrogen (SMN) in high production areas. We performed two field experiments (Exp. 1 and 2) for 3 yr under sprinkler irrigation. Over the duration of the experiment (short-term period), stover management did not affect corn production or SMN levels, while high average grain yields were achieved (16-20 Mg ha(-1)) when N was applied. After 3 yr, removing the stover reduced SOC levels by approximately 0.82 and 1.06 g C m(-2) (0-30-cm depth) in 2012 in Exp. 1 and 2, respectively. The amounts of corn stover incorporated were higher than 16 Mg ha(-1) yr(-1) of dry matter. Our data suggest that returning stover to the soil has a positive short-term impact on soil quality without grain yield penalties. Although selling the stover provides a short-term economic advantage, continuous stover removal may cause significant soil degradation in the future.
  • Authors:
    • Parras-Alcantara, L.
    • Lozano-Garcia, B.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 165
  • Year: 2013
  • Summary: Olive grove soils in semi-arid Mediterranean areas are very poor in organic matter and are exposed to progressive degradation processes. Therefore, additions of the olive mill by-products as organic amendments can improve soil quality and hence mitigate the negative environmental and agronomic limitations of these soils. A field study was conducted to assess the short-term effects of two oil mill by-products [olive leaves and alperujo (a two-phase olive mill waste)] and determine soil organic carbon (SOC), total nitrogen (TN), the C:N ratio, and their stratification across the soil profile, in an area under Mediterranean conditions. The experimental design consisted on three large plots each spanning a 100 m * 100 m area covered with unirrigated olive trees of the Picual variety less than 30 years old under conventional tillage (CT) in the province of Jaen (southern Spain). One of the plots (CT) was used as control plot and the other two were treated with alperujo (CTa) and olive leaves (CTol), respectively. Soil properties were assessed three years after the by-products were applied. Supplying the soil with the by-products increased C and N stocks. Thus, the SOC stock was 75.4 Mg ha -1 in CT, 91.5 Mg ha -1 in CTa and 136.3 Mg ha -1 in CTol; and the TN stock 12.1, 13.9 and 16.1 Mg ha -1 in CT, CTa and CTol, respectively. SOC, TN and the C:N ratio in the surface horizon were higher in the treated plots (viz. 18.5 g C kg -1, 1.4 g N kg -1 and 13.2:1 in CTa, and 84.1 g C kg -1, 5.7 g N kg -1 and 14.7:1 in CTol) than in the control plot (8.9 g C kg -1, 0.9 g N kg -1 and 9.8:1, respectively). In addition, application of the by-products improved soil quality (the stratification ratio, SR, for SOC was greater than 2). Oil mill by-products such as olive leaves and alperujo are thus potentially useful as soil amendments since they are effective sources of organic matter and nitrogen, improve soil quality and alleviate the environmental and agronomic limitations of Mediterranean agricultural soils, even those under using CT. In addition, the by-products can be recycled on site.
  • Authors:
    • Berns, A. E.
    • Knicker, H.
    • Panettieri, M.
    • Murillo, J. M.
    • Madejon, E.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 177
  • Year: 2013
  • Summary: The impact on soil aggregates status of two tillage practices (moldboard plowing, TT, and chisel plowing, RT) applied to a farm previously cultivated under no-tillage (NT) was studied. The experiment was carried out on a Leptic Typic Xerorthent soil at the "Las Navas" dryland experimental farm located in Jerez de la Frontera (Cadiz, SW Spain). Several organic C pools such as total organic carbon (TOC), water soluble carbon (WSC), permanganate oxidizable carbon (POxC), and microbial biomass carbon (MBC) were analyzed, together with two enzymatic activities related to soil organic matter (SOM) oxidization metabolism: dehydrogenase activity (DH) and beta-glucosidase activity (beta-Glu). 13C cross polarization magic angle spinning nuclear magnetic resonance ( 13C CPMAS NMR) spectroscopy was used to characterize the composition of the SOM and its degradation status. Two years after the implementation of the new management practices, analysis of the aggregate distribution of the topsoil (0-10 cm) showed that, even after a short term, TT enhanced aggregate disruption. The apparent reduction in soil quality of TT plots was evident from the lower contents of total organic carbon (TOC), permanganate oxidizable carbon (POxC) and microbial biomass carbon (MBC) if compared with RT and NT. Moreover, TT soil showed also a lower beta-glucosidase activity. As confirmed by 13C CPMAS NMR, the SOM of the TT fractions revealed higher alkyl C to O-alkyl ratios than their RT and NT counterparts. Also signals commonly referred to lignin structures were absent in the spectra of the TT fractions, but were still present in those of the larger fractions of the NT treatment. After a short term evaluation, RT samples did not show the same declining trend as observed for the TT treatment. For this reason, chisel plowing seems to offer a viable occasional management option when required during long-term NT.
  • Authors:
    • Macias, F.
    • Martin, F.
    • Verde, R.
    • Martinez, F.
    • Sierra, M.
  • Source: Soil & Tillage Research
  • Volume: 130
  • Year: 2013
  • Summary: The potential of soils as a sink of atmospheric carbon and the implications related to mitigate greenhouse-gas emissions are well recognized. The raising of tree crops on agricultural soils can augment soil-carbon sequestration more than do other agricultural uses such as corn crops. Thus, 6 plots with different durations of use as poplar plantation (5, 10, 20, 30, 50, and 100 years) were studied in comparison with 6 adjacent plots with corn crop. The carbon pool in poplar-plantation soils was positively correlated to the time of use at the three soil depths studied (0-20, 20-50, and 50-100 cm), the mean annual increase being 1.16 Mg C ha(-1) year(-1). Poplar-plantation soils also increased the total carbon content in a more effective way because the duration of use was also correlated with the most recalcitrant carbon forms. Therefore, land-use change from corn crops to poplar-plantation soils is economically profitable as well as positive both for the total organic-carbon pool as well as for the efficiency of carbon sequestration by the increase of non-oxidizable forms in the soil. (c) 2013 Elsevier B.V. All rights reserved.
  • Authors:
    • Moriondo,M.
    • Jones,G. V.
    • Bois,B.
    • Dibari,C.
    • Ferrise,R.
    • Trombi,G.
    • Bindi,M.
  • Source: Climatic Change
  • Volume: 119
  • Issue: 3-4
  • Year: 2013
  • Summary: This research simulates the impact of climate change on the distribution of the most important European wine regions using a comprehensive suite of spatially informative layers, including bioclimatic indices and water deficit, as predictor variables. More specifically, a machine learning approach (Random Forest, RF) was first calibrated for the present period and applied to future climate conditions as simulated by HadCM3 General Circulation Model (GCM) to predict the possible spatial expansion and/or shift in potential grapevine cultivated area in 2020 and 2050 under A2 and B2 SRES scenarios. Projected changes in climate depicted by the GCM and SRES scenarios results in a progressive warming in all bioclimatic indices as well as increasing water deficit over the European domain, altering the climatic profile of each of the grapevine cultivated areas. The two main responses to these warmer and drier conditions are 1) progressive shifts of existing grapevine cultivated area to the north-northwest of their original ranges, and 2) expansion or contraction of the wine regions due to changes in within region suitability for grapevine cultivation. Wine regions with climatic conditions from the Mediterranean basin today (e.g., the Languedoc, Provence, Ctes Rhne M,ridionales, etc.) were shown to potentially shift the most over time. Overall the results show the potential for a dramatic change in the landscape for winegrape production in Europe due to changes in climate.
  • Authors:
    • Roger-Estrade, J.
    • Basch, G.
    • Moreno, F.
    • Soane, B. D.
    • Ball, B. C.
    • Arvidsson, J.
  • Source: Soil & Tillage Research
  • Volume: 118
  • Year: 2012
  • Summary: Recent literature on no-till is reviewed with particular emphasis on research on commercial uptake and environmental concerns in northern, western and south-western Europe. Increased interest in no-till, and minimum or reduced tillage, results from changes in the economic circumstances of crop production, the opportunity to increase the area of more profitable autumn-sown crops and increased concern about environmental damage associated with soil inversion by ploughing. Highly contrasting soil and climate types within and between these regions exert a strong influence on the success of no-till. While no-till may often result in crop yields which equal or exceed those obtained after ploughing, modest reductions in yield may be tolerated if production costs are lower than with ploughing. The relative costs of fuel and herbicides have changed appreciably in recent years making no-till more attractive commercially. While effective weed control is an essential aspect of no-till, current herbicide technology may not yet fully achieve this. In northern regions no-till usually allows earlier drilling of winter-sown crops but will give lower soil temperature and higher moisture content in spring, causing delayed drilling of spring-sown crops. No-till soils have greater bulk density and bearing capacity than ploughed soils with a pronounced vertical orientation of macroporosity allowing penetration of roots and water, especially in view of the increased population of deep-burrowing earthworms. Particular care must be taken with no-till to minimise soil damage at harvest and to ensure the even distribution of crop residues prior to drilling. Reduced erosion and runoff after adoption of no-till are widely observed and are of particular importance in southwestern Europe. No-till reduces losses of phosphorus in runoff and, in some cases, reduces the loss of nitrate through leaching. Emissions of greenhouse gases CO 2 and N 2O from no-till soils are highly variable and depend on complex interactions of soil properties. Emission of CO 2 from fuel during machinery usage is always appreciably reduced with no-till. Increased soil organic carbon in surface layers of no-till soils is widely found but may not be associated with increased carbon sequestration throughout the profile. The evaluation of the relative carbon balance for no-till and ploughing depends upon complex inter-relationships between soil and climate factors which are as yet poorly understood. Adoption of no-till could be encouraged by government financial assistance in recognition of environmental benefits, although future restrictions on the use of herbicides may be a deterrent. Opportunities for further research on no-till are outlined.