19902015
  • Authors:
    • Ghorbani, R.
    • Khorasani, R.
    • Mahallati, M. N.
    • Koocheki, A.
    • Khorramdel, S.
  • Source: Soil and Tillage Research
  • Volume: 133
  • Issue: October
  • Year: 2013
  • Summary: Carbon sequestration could be an effective way to reduce atmospheric carbon dioxide which is the most important greenhouse gas. Two field experiments were conducted at Agricultural Research Station of Ferdowsi University of Mashhad, Iran, during growing seasons of 2008-2009 and 2009-2010. Four treatments including two low input management systems based on application of cow manure or compost municipal made from house-hold waste, a medium input system and a high input system were applied. In low input system 30 t ha(-1) cow manure or 30 t ha(-1) compost municipal made from house-hold-waste was applied and twice hand weeding were carried out. In medium input system, 15 t ha(-1) compost, 150 kg ha(-1) urea, disking and ploughing, 1.5 l ha(-1) 2,4-D applied at five leaf stage with only one hand weeding. In high input system, management practices included twice disking, twice ploughing, 21 ha(-1) Paraquat applied after planting and 1.5 1 ha(-1) 2,4-D applied at five leaf stage. Results showed that the maximum carbon and nitrogen yields in corn residues observed in high input system (0.8 and 0.02 kg m(-2)) and its minimum were in low input system with using compost (0.5 and 0.01 kg m-2). The highest and lowest labile and recalcitrant carbon rates were observed in low input system with manure (0.92 and 1.05%) and high input system (0.06 and 0.004%), respectively. The maximum sequestered carbon obtained in low input management system with using cow manure (4.1 t ha(-1)) and the minimum sequestered carbon were in high input management system (0.01 t ha(-1)). In low input system due to slow releasing nutrients, long term crop growth and hence higher recalcitrant carbon content of the soil were enhanced which could be an indication of its potential for carbon sequestration in low input management system. (C) 2013 Published by Elsevier B.V.
  • Authors:
    • Mousazadeh, H.
    • Omid, M.
    • Rafiee, S.
    • Khoshnevisan, B.
  • Source: Energy
  • Volume: 58
  • Issue: September
  • Year: 2013
  • Summary: In this study, DEA (data envelopment analysis) was applied to analyze the energy efficiency of wheat farms in order to separate efficient and inefficient growers and to calculate the wasteful uses of energy. Additionally, the degrees of TE (technical efficiency), PTE (pure technical efficiency) and SE (scale efficiency) were determined. Furthermore, the effect of energy optimization on GHG (greenhouse gas) emission was investigated and the total amount of GHG emission of efficient farms was compared with inefficient ones. Based on the results it was revealed that 18% of producers were technically efficient and the average of TE was calculated as 0.82. Based on the BCC (Banker-Charnes-Cooper) model 154 growers (59%) were identified efficient and the mean PTE of these farmers was found to be 0.99. Also, it was concluded that 2075.8 MJ ha(-1) of energy inputs can be saved if the performance of inefficient farms rises to a high level. Additionally, it was observed that the total GHG emission from efficient and inefficient producers was 27133 and 2740.8 kg CO2eq. ha(-1), respectively. By energy optimization the total GHG emission can be reduced to the value of 2684.29 kg CO2eq. ha(-1). (C) 2013 Elsevier Ltd. All rights reserved.
  • Authors:
    • Mosier, A. R.
    • Chen, D.
    • Lam, S. K.
    • Roush, R.
  • Source: Scientific Reports
  • Volume: 3
  • Issue: July
  • Year: 2013
  • Summary: Concerns about increasing concentrations of greenhouse gases in the atmosphere, primarily carbon dioxide (CO2), have raised worldwide interest in the potential of agricultural soils to be carbon (C) sinks. In Australia, studies that have quantified the effects of improved management practices in croplands on soil C have generally been inconclusive and contradictory for different soil depths and durations of the management changes. We therefore quantitatively synthesised the results of Australian studies using meta-analytic techniques to assess the technical and economic feasibility of increasing the soil C stock by improved management practices. Our results indicate that the potential of these improved practices to store C is limited to the surface 0-10 cm of soil and diminishes with time. None of these widely adopted practices is currently financially attractive under Australia's new legislation known as the Carbon Farming Initiative.
  • Authors:
    • Shang, Z. H.
    • Chen, X. P.
    • Pan, J. L.
    • Dai, W. A.
    • Wang, X. M.
    • Ma, L. N.
    • Guo, R. Y.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 21
  • Issue: 11
  • Year: 2013
  • Summary: Soil carbon and nitrogen in vegetable fields are the core elements of soil quality and environmental pollution. The decrease of soil C/N ratio of vegetable fields under greenhouse conditions causes an imbalance in soil carbon and nitrogen content. An effective way of adjusting soil carbon and nitrogen conditions in vegetable fields has been by improving soil quality and decreasing environmental pollution. Furthermore, there has been little research on soil carbon and nitrogen mineralization under greenhouse conditions in the Tibetan region. After transformations of alpine meadows and farmlands into solar greenhouse vegetable fields, there was the need to study the characteristics and processes of soil mineralization. In this study therefore, carbon and nitrogen mineralization in soils of alpine grassland, farmland and greenhouse (1-year, 5-year) were analyzed in an indoor incubation experiment. The results showed that soil carbon mineralization in different soil types mainly occurred during the first seven days (0-7 d) after treatment. Soil carbon mineralization was higher under alpine grassland than in farmland and 5-year greenhouse conditions ( P0.05). This was attributed to soil nutrient and soil microbial environment sensitivity to temperature. Soil CO 2-C accumulation in farmland soil was higher than in alpine grassland soil. It was also higher in alpine grassland soil than in the 1-year greenhouse and 5-year greenhouse soils. However, the differences in soil organic carbon mineralization and accumulation among alpine grassland, farmland, 1-year greenhouse and 5-year greenhouse soil conditions were not significant ( P>0.05) at 28 days after treatment. Soil nitrogen mineralization mainly happened in different soil types during the first three days (3 d) after treatment. With delayed incubation, the main process of soil nitrogen mineralization was nitrogen fixation. Soil inorganic nitrogen content in alpine grassland, farmland, 1-year greenhouse and 5-year greenhouse soils at 28 days after incubation were 29.04%, 75.94%, 66.86% and 65.70% of that at 0 day, respectively. The results showed that soil nitrogen mineralization capacity of alpine grassland soil was stronger than farmland, 1-year greenhouse and 5-year greenhouse soils. Soil nitrogen mineralization capacity of farmland was weaker than alpine grassland, 1-year greenhouse and 5-year greenhouse. Also soil nitrogen mineralization capacities of 1-year greenhouse and 5-year greenhouse were similar. Moreover, soil mineralization processes were similar among different soil conditions.
  • Authors:
    • Silva, P.
    • Pino, V.
    • Fuentes, J.-P.
    • Martinez, E.
    • Acevedo, E.
  • Source: Soil and Tillage Research
  • Volume: 126
  • Year: 2013
  • Summary: Soil management practices may change the soil properties. The magnitude of the change varies according to the soil property, the climate, and the type and time of implementation of a particular management system. The aim of this study was to evaluate the effects of no-tillage (NT) on the chemical and biological properties of an Entic Haploxeroll in Central Chile. Soil organic carbon (SOC), microbial biomass and associated indicators q(CO2), q(Mic), q(Min), available N, P and K, pH, electrical conductivity (EC), and crop yield were determined in a field experiment having a wheat (Triticum turgidum L)-maize (Zea mays L.) crop rotation. The change in soil chemical properties was further evaluated using a greenhouse bioassay in which ryegrass (Lolium perenne L) was grown in soil samples extracted at 0-2,2-5, and 5-15 cm depth. After nine years SOC in the NT treatment was 29.7 Mg ha(-1) compared to 24.8 Mg ha(-1) of CT, resulting in 4.98 Mg ha(-1) C gain. The NT therefore resulted in an average annual sequestration of 0.55 Mg C ha(-1) yr(-1) in the upper 15 cm soil. The soil organic C stored under NT was mainly accumulated in the top 2-cm of soil. The biological indicators showed a greater biological soil quality under NT than under CT. Soil organic C was positively associated with available N, P. and K, but negatively with soil pH. The iyegrass bioassay yielded higher biomass in NT than CT. An improvement in the soil chemical quality of the NT soil was considered to be the main reason for this result. The maize yield under NT had the tendency to improve in time as compared to CT. Wheat, however, had lower yield under NT. It was concluded that NT increased C sequestration and SOC improving the chemical and biological properties of this soil. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Mousavi-Avval, S. H.
    • Keyhani, A.
    • Knudsen, M. T.
    • Dalgaard, T.
    • Jafari, A.
    • Rafiee, S.
    • Mohammadi, A.
    • Hermansen, J. E.
  • Source: Journal of Cleaner Production
  • Volume: 54
  • Year: 2013
  • Summary: Joint implementation of Life Cyc00le Assessment (LCA) and Data Envelopment Analysis (DEA) has recently showed to be a suitable tool for measuring efficiency in agri-food systems. In the present study, LCA + DEA methodologies were applied for a total of 94 soybean farms in Iran to benchmark the level of operational input efficiency of each farmer. Likewise, potential reductions in the consumption levels of the physical inputs were determined, while estimating the environmental improvements linked to these reduction targets. Our results indicate that 46% of the farms studied operated efficient. The estimated Global Warming Potential (GWP) reduction for the whole sample was obtained similar to 11% according to DEA model results. Among the field operations, the contribution of irrigation to the total GWP reduction was the highest (63%) followed by fertilization (34%). The results also revealed that farms which burnt crop residue in the field generate significantly more greenhouse gas emissions than other farms. The raising of operational input efficiency and limiting of crop residue burning in the field are recommended options to ensure more environmental friendly soybean farming systems in the region. (C) 2013 Elsevier Ltd. All rights reserved.
  • Authors:
    • La Scala, N.,Jr.
    • Panosso, A. R.
    • Padovan, M. P.
    • Moitinho, M. R.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 37
  • Issue: 6
  • Year: 2013
  • Summary: The soil is one of the main C pools in terrestrial ecosystem, capable of storing significant C amounts. Therefore, understanding the factors that contribute to the loss of CO2 from agricultural soils is critical to determine strategies reducing emissions of this gas and help mitigate the greenhouse effect. The purpose of this study was to investigate the effect of soil tillage and sugarcane trash on CO2 emissions, temperature and soil moisture during sugarcane (re) planting, over a study period of 15 days. The following managements were evaluated: no-tillage with crop residues left on the soil surface (NTR); without tillage and without residue (NTNR) and tillage with no residue (TNR). The average soil CO2 emission (FCO2) was lowest in NTR (2.16 mu mol m(-2) s(-1)), compared to the managements NTNR (2.90 mu mol m(-2) s(-1)) and TNR (3.22 mu mol m(-2) s(-1)), indicating that the higher moisture and lower soil temperature variations observed in NTR were responsible for this decrease. During the study period, the lowest daily average FCO2 was recorded in NTR (1.28 mu mol m(-2) s(-1)), and the highest in TNR (6.08 mu mol m(-2) s(-1)), after rainfall. A loss of soil CO2 was lowest from the management NTR (367 kg ha(-1) of CO2-C) and differing significantly (p<0.05) from the managements NTNR (502 kg ha(-1) of CO2-C) and TNR (535 kg ha(-1) of CO2-C). Soil moisture was the variable that differed most managements and was positively correlated (r = 0.55, p<0.05) with the temporal variations of CO2 emission from NTR and TNR. In addition, the soil temperature differed (p<0.05) only in management NTR (24 degrees C) compared to NTNR (26 degrees C) and TNR (26.5 degrees C), suggesting that under the conditions of this study, sugarcane trash left on the surface induced an average rise in the of soil temperature of 2 degrees C.
  • Authors:
    • Reardon-Smith, K.
    • Maraseni, T. N.
    • Mushtaq, S.
  • Source: Agricultural Systems
  • Volume: 117
  • Year: 2013
  • Summary: There are significant concerns about the longer term impact of climate change and climate variability on water availability in Australia. Modern irrigation technologies are seen as a way to manage climate change impacts and improve water security. However, while modern irrigation technologies may save volumes of water, it is likely that they will result in increased on-farm energy consumption and greenhouse gas (GHG) emissions, suggesting potential conflicts in terms of mitigation and adaptation policies. Five irrigation technology transformation scenarios-three historical and two adoption-were developed to evaluate industry-wide tradeoffs between water savings, energy consumption (and GHG emissions), and economic returns associated with irrigation technology transformations under current Australian Government water resource policies. Three of the five scenarios tested showed tradeoffs between water savings and GHG emissions, with water savings through conversion of irrigation systems increasing both energy consumption and GHG emissions. For example, 120 GL/year of water savings achieved through drip irrigation adoption for cotton cropping would increase energy consumption by 889 TJ/year and GHG emissions by 250,000 t CO(2)e/year. A carbon price of $20/t CO(2)e would result in additional costs nationally of about $5 m/year. However, this study also indicated that significant benefit in terms of water savings and GHG reduction can be achieved when replacing older inefficient and energy-intensive systems, such as hand shift and roll-line sprinkler systems, especially when these are replaced with drip irrigation systems. We suggest priority should be given to replacing such systems while implementing the on-farm infrastructure investment policy. The findings of the study support the use of an integrated approach to avoid possible conflicts in designing national climate change mitigation and adaptation policies, both of which are being developed in Australia.
  • Authors:
    • Nosrati,K.
    • Ahmadi,F.
  • Source: Journal of Applied Sciences and Environmental Management
  • Volume: 17
  • Issue: 2
  • Year: 2013
  • Summary: Soil organic carbon (SOC) and soil nitrogen (SN) are the principal components in soil quality assessment, and in mitigation the global greenhouse effect. In Iran, little information exists on the stocks of SOC and SN. SOC and SN stocks are a function of the SOC and SN concentrations and the bulk density of the soil that are prone to changes under land use types and soil erosion. The objective of this study was to evaluate SOC and SN stock in different land use types under surface erosion at catchment scale. In view of this, bulk density, SOC and SN concentration were measured in 39 different sampling sites of three main groups of land use affected by surface erosion namely, rangeland, crop field, and forest land at Taleghani catchment, Khoramabad, Iran. The results showed that SOC and SN stock under all land use types was significantly different (P rangeland (63.3 Mg ha -1) > crop field (47.2 Mg ha -1; P<0.01). Also the SN stock had the same trend in all studied land uses. These results can be useful as a scientific basis for selecting the proper soil management as a simple and low-cost approach to mitigate the SOC and SN loss.
  • Authors:
    • Ashraf, M.
    • Shahbaz, M.
    • Perveen, S.
  • Source: Photosynthetica
  • Volume: 51
  • Issue: 4
  • Year: 2013
  • Summary: A greenhouse experiment was conducted to examine the effect of foliar application of triacontanol (TRIA) on two cultivars (cv. S-24 and MH-97) of wheat ( Triticum aestivum L.) at different growth stages. Plants were grown in full strength Hoagland's nutrient solution under salt stress (150 mM NaCl) or control (0 mM NaCl) conditions. Three TRIA concentrations (0, 10, and 20 M) were sprayed over leaves at three different growth stages, i.e. vegetative (V), boot (B), and vegetative + boot (VB) stages (two sprays on same plants, i.e., the first at 30-d-old plants and the second 78-d-old plants). Salt stress decreased significantly growth, net photosynthetic rate ( PN), transpiration rate ( E), chlorophyll contents (Chl a and b), and electron transport rate (ETR), while membrane permeability increased in both wheat cultivars. Stomatal conductance ( gs ) decreased only in salt-sensitive cv. MH-97 under saline conditions. Foliar application of TRIA at different growth stages enhanced significantly the growth, PN, gs , Chl a and b contents, and ETR, while membrane permeability was reduced in both cultivars under salt stress. Of various growth stages, foliar-applied TRIA was comparatively more effective when it was applied at V and VB stages. Overall, 10 M TRIA concentration was the most efficient in reducing negative effects of salinity stress in both wheat cultivars. The cv. S-24 showed the better growth and ETR, while cv. MH-97 exhibited higher nonphotochemical quenching.