• Authors:
    • Luis Arrue, J.
    • Alvaro-Fuentes, J.
    • Plaza-Bonilla, D.
    • Cantero-Martinez, C.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 189
  • Issue: May
  • Year: 2014
  • Summary: There is a strong need to identify the combination of tillage and N fertilization practices that reduce the amount of nitrous oxide (N2O) emissions while maintaining crop productivity in dryland Mediterranean areas. We measured the fluxes of N2O in two field experiments with 3 and 15 years since their establishment. In the long-term experiment, two types of tillage (NT, no-tillage, and CT, conventional intensive tillage) and three mineral N fertilization rates (0, 60 and 120 kg N ha(-1)) were compared. In the short-term experiment, the same tillage systems (CT and NT) and three N fertilization doses (0,75 and 150 kg N ha(-1)) and two types of fertilizers (mineral N and organic N with pig slurry) were compared. N2O emissions, water-filled pore space, soil mineral N content, grain yields, N-biomass inputs and soil total nitrogen (STN) stocks were quantified and the N2O yield-scaled ratio as kg of CO2 equivalents per kg of grain produced was calculated. In both experiments tillage treatments significantly affected the dynamics of N2O fluxes. Cumulative losses of N as N2O were similar between tillage treatments in the long-term field experiment. Contrarily, although not significant, cumulative N losses were about 35% greater under NT than CT in the short-term experiment. NT significantly increased the production of grain and the inputs of N to the soil as above-ground biomass in both experiments. Averaged across fertilizer treatments, CT emitted 0.362 and 0.104 kg CO2 equiv. kg grain(-1) in the long-term and the short-term experiment, respectively, significantly more than NT that emitted 0.033 and 0.056 kg CO2 equiv. kg grain(-1), respectively. Nitrogen fertilization rates did not affect the average N2O fluxes or the total N losses during the period of gas measurement in the long-term experiment. Contrarily, in the short-term experiment, N2O emissions increased with application rate for both mineral and organic fertilizers. The use of pig slurry increased grain production when compared with the mineral N treatment, thus reducing the yield-scaled emissions of N2O by 44%. Our results showed that in rainfed Mediterranean agroecosystems, the use of NT and pig slurry are effective means of yield-scaled N2O emissions reduction. (C) 2014 Elsevier B.V. All rights reserved.
  • Authors:
    • Mihalache, M.
    • Fintineru, G.
    • Stan, V.
  • Source: Notulae Botanicae Horti Agrobotanici Cluj-Napoca
  • Volume: 42
  • Issue: 1
  • Year: 2014
  • Summary: Burning crop residues is frequently used by Romanian land users to clean agricultural fields after crop harvest for ease in postharvest soil tillage. Huge amounts of crop residues biomass, on very large areas, were burned in Romania in the last twenty years, as compared to other countries. There are several reasons (e.g. the lack of equipment to gather the crop residues and to transport and store them, the diminishing of the livestock after 1990, the absence of other alternatives, especially in the 1990s, but also the lack of information regarding the good practices) that are evocated to support the use of this method. However, this method is not a sustainable one since it can cause many environmental damages, especially related to soil properties (physical, chemical and biological), greenhouse gas emission and crop yields. Contrary to the above stated, crop residues' addition to the soil may restore damaged soil structure, improve aggregate stability, soil water retention, soil fertility, increase total organic carbon (TOC) and total nitrogen (TN) etc. The purpose of this paper is to make a multicriteria analyze of the effects of crop residue management on the soil, agricultural productivity and environment. At the same time, the use of crop residues biomass as a source of energy is presented as an alternative, given its potential ability to offset fossil fuels and reduce CO 2 emissions.
  • Authors:
    • Antolin, M. C.
    • Goicoechea, N.
    • Irigoyen, J. J.
    • Aguirreolea, J.
    • Sanchez-Diaz, M.
    • Pascual, I.
    • Morales, F.
    • Oyarzun, M.
    • Urdiain, A.
  • Source: Plant Science
  • Volume: 226
  • Year: 2014
  • Summary: Human activities are increasing atmospheric CO 2 concentration and temperature. Related to this global warming, periods of low water availability are also expected to increase. Thus, CO 2 concentration, temperature and water availability are three of the main factors related to climate change that potentially may influence crops and ecosystems. In this report, we describe the use of growth chamber - greenhouses (GCG) and temperature gradient greenhouses (TGG) to simulate climate change scenarios and to investigate possible plant responses. In the GCG, CO 2 concentration, temperature and water availability are set to act simultaneously, enabling comparison of a current situation with a future one. Other characteristics of the GCG are a relative large space of work, fine control of the relative humidity, plant fertirrigation and the possibility of light supplementation, within the photosynthetic active radiation (PAR) region and/or with ultraviolet-B (UV-B) light. In the TGG, the three above-mentioned factors can act independently or in interaction, enabling more mechanistic studies aimed to elucidate the limiting factor(s) responsible for a given plant response. Examples of experiments, including some aimed to study photosynthetic acclimation, a phenomenon that leads to decreased photosynthetic capacity under long-term exposures to elevated CO 2, using GCG and TGG are reported.
  • Authors:
    • Porter, J. R.
    • Rasmussen, A.
    • Sanchez, B.
  • Source: Global Change Biology
  • Volume: 20
  • Issue: 2
  • Year: 2014
  • Summary: Because of global land surface warming, extreme temperature events are expected to occur more often and more intensely, affecting the growth and development of the major cereal crops in several ways, thus affecting the production component of food security. In this study, we have identified rice and maize crop responses to temperature in different, but consistent, phenological phases and development stages. A literature review and data compilation of around 140 scientific articles have determined the key temperature thresholds and response to extreme temperature effects for rice and maize, complementing an earlier study on wheat. Lethal temperatures and cardinal temperatures, together with error estimates, have been identified for phenological phases and development stages. Following the methodology of previous work, we have collected and statistically analysed temperature thresholds of the three crops for the key physiological processes such as leaf initiation, shoot growth and root growth and for the most susceptible phenological phases such as sowing to emergence, anthesis and grain filling. Our summary shows that cardinal temperatures are conservative between studies and are seemingly well defined in all three crops. Anthesis and ripening are the most sensitive temperature stages in rice as well as in wheat and maize. We call for further experimental studies of the effects of transgressing threshold temperatures so such responses can be included into crop impact and adaptation models.
  • Authors:
    • López-Solanilla, E.
    • Navas, M.
    • García-Marco, S.
    • Tellez-Rio, A.
    • Rees, R. M.
    • Tenorio, J. L.
    • Vallejo, A.
  • Source: Biology and Fertility of Soils
  • Volume: 51
  • Year: 2014
  • Summary: Lower greenhouse gas (GHG) emissions from legume-based cropping systems have encouraged their use to deliver mitigation in agricultural systems. Considerable uncertainties remain about the interaction of legumes with long-term tillage systems on GHG emissions under rainfed agroecosystems. In this context, a field experiment was undertaken under a rainfed vetch crop to evaluate the effect of three long-term tillage systems (i.e. no tillage (NT), minimum tillage (MT) and conventional tillage (CT)) on nitrous oxide (N2O) and methane (CH4) emissions for 1 year. Different N2O flux patterns were observed among tillage systems during the growth period of vetch, which depended on the soil conditions favouring nitrification and denitrification. The NT system maintained a higher sink for N2O than MT and CT from January to mid-April, which significantly reduced N2O emissions at this stage. In this period, denitrification capacity and nirK gene numbers were higher for MT than NT and CT. Additionally, an increase in soil NO 3 - content and more favourable denitrification conditions in MT and NT than in CT for the last crop period increased N2O emissions in conservation tillage systems. Total annual N2O losses were significantly higher in MT (124.2 g N2O-N ha-1) than NT (51.1 g N2O-N ha-1) and CT (54 g N2O-N ha-1) in a vetch crop. Low net uptake of CH4 was observed for all tillage systems. These results suggested that long-term NT may be a better option than MT to mitigate GHG emissions in rainfed legume-cereal rotation. © 2014 Springer-Verlag Berlin Heidelberg.
  • Authors:
    • Soto-García, M.
    • Martin-Gorriz, B.
    • Martínez-Alvarez, V.
  • Source: ENERGY
  • Volume: 77
  • Year: 2014
  • Summary: Global warming is leading to a water resources decrease in the Mediterranean basin, where future farming resilience depends on incorporating alternative water sources and improving water-energy use efficiency. This paper assesses water and energy consumption when natural water sources are partially replaced by desalinated sea water. Initially, energy consumption, water supply and GHG (greenhouse gas) emissions were recorded for the current farming practices in SE (southeast) Spain. The results of our study indicate that citrus orchards have the lowest energy consumption and GHG emissions. Annual vegetables were the least energy efficient crops. Subsequently, two alternative water supply scenarios were analysed, in which the reduction of natural water resources associated to climate change was compensated with desalinated sea water. The use of 16.8% of desalinated seawater would increase energy consumption by 32.4% and GHG emissions by 19.6%, whereas for the use of 26.5% of desalinated seawater such increases would amount to 50.0% and 30.3%, respectively. Therefore maintaining irrigated agriculture in water-stressed regions by incorporating high energy demanding non-traditional water sources could negatively contribute to combat global warming.
  • Authors:
    • Escobar,N.
    • Ribal,F. J.
    • Clemente,G.
    • Sanjuan,N.
  • Source: Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector
  • Year: 2014
  • Summary: Imported biodiesel has accounted for a large share of the total amount consumed in Spain, the main supplier of which was Argentina at least until anti-dumping duties on biodiesel imports from this origin were approved by the European Commission in November 2013. A consequential LCA is carried out in the present study to compare this pathway, which was the prevailing one until almost 2014, with the alternative of using domestic biodiesel from Used Cooking Oil (UCO). System expansion is performed in order to take the indirect functions of both systems into account, functions arising from interactions between co-products (protein meals) in the animal feed market. The marginal suppliers of these co-products in the international market are identified and emissions from direct and indirect Land Use Change (LUC) are calculated. When they are not considered, imported soybean biodiesel leads to lower GHG emissions, due to the carbon uptake by biomass. However, when global LUC is taken into account, UCO biodiesel generates a much lower impact, because it causes a contraction in the area diverted to biofuel feedstock production in other parts of the world. The results underline the importance of considering emissions from LUC when comparing biodiesel alternatives and, thus, interactions in the global market must be addressed.
  • Authors:
    • Vazquez-Rowe,I.
    • Villanueva-Rey,P.
    • Otero,M.
    • Moreira,M. T.
    • Feijoo,G.
  • Source: Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector (LCA Food 2014)
  • Year: 2014
  • Summary: Land use changes (LUCs) are an important source of environmental changes in production systems, especially in the agricultural sector, where LUCs have been found to be a relevant factor to take into consideration when analyzing greenhouse gas (GHG) emissions. The viticulture subsector, as part of a broader agricultural sector, is not alien to the problematic of GHG emissions and climate change. Spain, as one of the main producers of wine worldwide, but also due to the important legislative and productive changes that have occurred ever since it joined the European Union, plays an important role in the analysis of how LUCs linked to the viticulture sector have effects on the environment. Therefore, in the current study we examined the LUCs that have occurred in the Ribeiro appellation in NW Spain between 1989 and 2009. For this, GIS was used to map the gradual dynamic changes on an annual basis of the areas used for wine production. Thereafter, the different land uses that substituted or were substituted by vineyards were identified in order to calculate the carbon storage and carbon emission dynamics based on the IPCC guidelines. Finally, operational activities linked to viticulture, including changes in technology over time, were added to the model in order to obtain a broad picture of entire impact of viticulture in terms of GHG emissions. The results present an interesting pattern, with GHG emissions linked to LUCs steadily decreasing in the timeframe analyzed. Similarly, the improvement of machinery, the reduction on fossil dependency in the Spanish electricity mix and the stricter use of specific standards for the use of plant protection agents also contributed to a gradual decrease in GHG emissions per functional unit (i.e. 1 ha of cultivated vineyards). These results are aimed at providing the appellation and other appellations throughout with environmentally relevant information regarding how different factors influencing their change through time can be analyzed to give support in policy making and decision making at a business level.
  • Authors:
    • Alvaro-Fuentes,J.
    • Plaza-Bonilla,D.
    • Arrue,J. L.
    • Lampurlanes,J.
    • Cantero-Martinez,C.
  • Source: Plant and Soil
  • Volume: 376
  • Issue: 1-2
  • Year: 2014
  • Summary: The duration of soil organic carbon (SOC) sequestration in agricultural soils varies according to soil management, land-use history and soil and climate conditions. Despite several experiments have reported SOC sequestration with the adoption of no-tillage (NT) in Mediterranean dryland agroecosystems scarce information exists about the duration and magnitude of the sequestration process. For this reason, 20 years ago we established in northeast Spain a NT chronosequence experiment to evaluate SOC sequestration duration under Mediterranean dryland conditions. In July 2010 we sampled five chronosequence phases with different years under NT (i.e., 1, 4, 11, and 20 years) and a continuous conventional tillage (CT) field, in which management prevailed unchanged during decades. Soil samples were taken at four depths: 0-5, 5-10, 10-20 and 20-30 cm. The SOC stocks were calculated from the SOC concentration and soil bulk density. Furthermore, we applied the Century ecosystem model to the different stages of the chronosequence to better understand the factors controlling SOC sequestration with NT adoption. Differences in SOC stocks were only found in the upper 5 cm soil layer in which 4, 11 and 20 years under NT showed greater SOC stocks compared with 1 year under NT and the CT phase. Despite no significant differences were found in the total SOC stock (0-30 cm soil layer) there was a noteworthy difference of 5.7 Mg ha(-1) between the phase with the longest NT duration and the phase under conventional tillage. The maximum annual SOC sequestration occurred after 5 years of NT adoption with almost 50% change in the annual rate of SOC sequestration. NT sequestered SOC over the 20 years following the change in management. However, more than 75% of the total SOC sequestered was gained during the first 11 years after NT adoption. The Century model predicted reasonably well SOC stocks over the NT chronosequence. In Mediterranean agroecosystems, despite the continuous use of NT has limited capacity for SOC sequestration, other environmental and agronomic benefits associated to this technique may justify the maintenance of NT over the long-term.
  • Authors:
    • Domene, X.
    • Alcaniz, J. M.
    • Marks, E. A. N.
  • Source: Regular Article
  • Volume: 385
  • Issue: 1-2
  • Year: 2014
  • Summary: Background and aims Biochar has demonstrably improved crop yields in weathered and acidic soils, but studies in calcareous soils are particularly lacking, so biochar effects on plant growth was investigated under these conditions. Methods Six biochars were obtained from different feedstocks and production technologies. Chemical characterization of fresh biochars included total and extractable nutrients, labile carbon, and Fourier transform infrared spectroscopy. Extractable nutrients were also evaluated in biochar-soil mixtures with a basic (pH >8.2) test soil. Bioassays with lettuce and ryegrass were carried out to relate biochar chemical properties to effects on plant biomass. Results A sewage sludge slow pyrolysis char was stimulatory to plant growth, as was a slow pyrolysis pine wood char at an intermediate concentration, while gasification and fast-pyrolysis pine and poplar wood chars were strongly inhibitory, with reductions in biomass at realistic application rates of 519 t ha(-1). Conclusions Statistical comparison of plant responses with biochar composition led to the assessment that plant responses were most correlated with volatile matter content and total P content, whose availability was likely regulated by pH and Ca content. Potential effects of phytotoxins were considered, but these were seen to be much less probable than effects due to nutrient availability.