• Authors:
    • Tode, J.
    • Herrmann, A.
    • Taube, F.
  • Source: Grassland - a European resource? Proceedings of the 24th General Meeting of the European Grassland Federation, Lublin, Poland, 3-7 June 2012
  • Volume: 17
  • Year: 2012
  • Summary: Land use change represents a major source of anthropogenic induced greenhouse gas emissions. A monitoring study was conducted to quantify the impact of land use systems on soil organic carbon stocks on various sites throughout Schleswig-Holstein, Northern Germany. Results revealed higher SOC stocks under grassland compared to arable cropping. Long-term maize monoculture, however, did not show lower C sequestration than arable rotations with or without maize.
  • Authors:
    • Cervantes-Santiago, F.
    • Reyes-Varela, V.
    • Conde, E.
    • Fernandez-Luqueno, F.
    • Juarez-Rodriguez, J.
    • Botello-Alvarez, E.
    • Cardenas-Manriquez, M.
    • Dendooven, L.
  • Source: Journal of Plant Nutrition
  • Volume: 35
  • Issue: 4
  • Year: 2012
  • Summary: Sludge derived from cow manure anaerobically digested to produce biogas (methane; CH4) was applied to maize (Zea mays L.) cultivated in a nutrient-low, alkaline, saline soil with electrolytic conductivity 9.4 dS m(-1) and pH 9.3. Carbon dioxide (CO2) emission increased 3.1 times when sludge was applied to soil, 1.6 times when cultivated with maize and 3.5 times in sludge-amended maize cultivated soil compared to the unamended uncultivated soil (1.51 mg C kg(-1) soil day(-1)). Nitrous oxide (N2O) emission from unamended soil was -0.0004 mu g nitrogen (N) kg(-1) soil day(-1) and similar from soil cultivated with maize (0.27 mu g N kg(-1) soil day(-1)). Application of sludge increased the N2O emission to 4.59 mu g N kg(-1) soil day(-1), but cultivating this soil reduced it to 2.42 mu g N kg(-1) soil day(-1). It was found that application of anaerobic digested cow manure stimulated maize development in an alkaline saline soil and increased emissions of CO2 and N2O.
  • Authors:
    • Mueller, C.
    • Eckhard, C.
    • Ratering, S.
    • Kammann, C.
  • Source: Journal of Environmental Quality
  • Volume: 41
  • Issue: 4
  • Year: 2012
  • Summary: With a growing world population and global warming, we are challenged to increase food production while reducing greenhouse gas (GHG) emissions. We studied the effects of biochar (BC) and hydrochar (HC) produced via pyrolysis or hydrothermal carbonization, respectively, on GHG fluxes in three laboratory incubation studies. In the first experiment, ryegrass was grown in sandy loam mixed with equal amounts of a nitrogen-rich peanut hull BC, compost, BC+compost, double compost, or no addition (control); wetting-drying cycles and N fertilization were applied. Biochar with or without compost significantly reduced N2O emissions and did not change the CH4 uptake, whereas ryegrass yield was significantly increased. In the second experiment, 0% (control) or 8% (w/w) of BC (peanut hull, maize, wood chip, or charcoal) or 8% HC (beet chips or bark) was mixed into a soil and incubated at 65% water-holding capacity (WHC) for 140 d. Treatments included simulated plowing and N fertilization. All BCs reduced N2O emissions by similar to 60%. Hydrochars reduced N2O emissions only initially but significantly increased them after N fertilization to 302% (HC-beet) and 155% (HC-bark) of the control emissions, respectively. Large HC-associated CO2 emissions suggested that microbial activity was stimulated and that HC was less stable than BC. In the third experiment, nutrient-rich peanut hull BC addition and incubation over 1.5 yr at high WHCs did not promote N2O emissions. However, N2O emissions were significantly increased with BC after NH4 NO3 addition. In conclusion, BC reduced N2O emissions and improved the GHG-to-yield ratio under field-relevant conditions. However, the risk of increased N2O emissions with HC addition must be carefully evaluated.
  • Authors:
    • Menendez, S.
    • Castellon, A.
    • Artetxe, A.
    • Merino, P.
    • Aizpurua, A.
    • Estavillo, J. M.
  • Source: Soil & Tillage Research
  • Volume: 123
  • Year: 2012
  • Summary: Nitrous oxide is a greenhouse gas contributing to global warming. Biocrops have been proposed as an alternative for energy production. Nevertheless, the use of biofuels could be a counterproductive approach to mitigate global warming, as the fuel energy gained from biofuel crops might be offset against the nitrogen inputs and associated N2O emissions. The objective of this work was to determine the warming potential of a rapeseed crop in northern Spain caused by direct N2O emissions and CO2 emitted during farm machinery operations. Mineral fertilizer was applied at a rate of 180 kg N ha(-1) Fluxes of N2O were measured year round. The emission factor of direct N2O losses was determined, together with the relative warming with regard to plant N content and the CO2 emissions from farm equipment operation. The emission factor from direct N2O losses from rapeseed crop was 2.54%. Emissions of CO2 produced by farm machinery in rapeseed crop represented 8.5% of the CO2 equivalents in terms of N2O emitted by the crop. Thus, rapeseed grown in our conditions leads to N2O emissions whose warming effect is compensated by the "saved fossil CO2" of biofuel production. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Beyene, S.
    • Kebede, M.
  • Source: Journal of Environment and Earth Science
  • Volume: 2
  • Issue: 4
  • Year: 2012
  • Summary: Greenhouse experiments were conducted at DZARC on soil sampled from farmers' field to examine the influence of floriculture effluent on soil quality and crop performance, and to see the most likely trends. The sample was splitted into two; the first remained to be as it is while the second was subjected to sterilization and call it non-sterilized (NS) and sterilized (S) soil, respectively. Seven rates of effluent was used as a treatment and laid out in CRD with four replications. The effluent was found to have high pH, EC, N, P, S, exchangeable bases, low in micronutrients and very low in heavy metals. The shoot dry weight was reduced by 36.9 and 58.8% for NS and S soils respectively in the first harvest. The second round experiment further confirmed that it keeps decreasing due to effluent additions. However, at lower volumes, the non-sterilized soil showed benefit from the effluent and hence the value started to increase but later it followed the same trends with application of higher volumes. Chemical properties were highly influenced by effluent additions. The pH and EC continuously increased whereas OC and TN increased to some extent but decreased as the volume of effluent increased. Exchangeable bases and micro-nutrients were continuously increased. The trends indicated that dry weight on Fluvisols will decline corresponding to the decrease in soil organic matter while pH, CEC and ESP continuously increases ending in the shift of slight alkaline soil to sodic soil. Generally, the effluent was found to disturb the performance of the crop and soil quality parameters. Disturbance in terms of shoot dry weight and soil quality parameters revealed that it was much less for the NS owing to the presence of organism.
  • Authors:
    • Abera, Y.
    • Beyene, S.
    • Kebede, M.
  • Source: Journal of Environment and Earth Science
  • Volume: 2
  • Issue: 2
  • Year: 2012
  • Summary: Floriculture is one of the booming sectors in Ethiopia. With its expansion, there is a growing concern as to its adverse effect on the environment. The objectives of this study were therefore, to provide concrete information on the influence of floriculture effluents on soil quality and crop productivity. Two permanent greenhouse experiments were conducted at Debre Zeit Agricultural Research Center on soils samples collected from farmer's field using wheat as a test crop. The soil samples were divided into two equal parts as sterilized and non-sterilized. Seven rates of floriculture effluents (0, 15.0, 30.0, 45.0, 60.0, 75.0 and 90.0 ml pot -1) were used as treatment in CRD with four replications. The effluent was characterized by high pH, EC, N, P, S and basic cations (K, Ca, Mg and Na), low in micronutrients (Cu, Fe, Mn and Zn) and very low in heavy metals (Mo, Ni, Cd and Cr). Accordingly, its application did not significantly influence the texture and water holding capacity (WHC) of the soil, though decreasing values of FC, PWP and WHC were obtained both from sterilized and non-sterilized soils. Chemical properties were highly influenced by effluent additions. The pH, EC, exchangeable bases and micronutrients of the soil were significantly raised after first and second harvest. Organic carbon and Total Nitrogen increased with increasing volume of effluent, but decreased at high levels. Shoot dry weight of the wheat was also significantly affected by increasing volume of effluent. In non-sterilized soils, addition of low volume effluent increased shoot dry weight which later followed the same trends as sterilized soils. The decreasing trend in shoot dry weight was in line with that of soil organic matter, whereas continuous increments in pH, CEC and ESP resulted in changing the neutral soil to saline. Hence, floriculture effluent was found to affect the performance of wheat and soil quality parameters, where the effect was pronounced for sterilized soil. Future research should focus on long-term effects of floriculture effluents on physical, chemical and biological properties of soil and crop productivity.
  • Authors:
    • Tolentino, J. B.
    • Coelho, R. D.
    • Vellame, L. M.
  • Source: Revista Brasileira de Fruticultura
  • Volume: 34
  • Issue: 1
  • Year: 2012
  • Summary: The total citrus area irrigated in Brazil has increased over the decades. The main cause of this increasing is due to the use of rootstocks tolerant to Citrus Sudden Death however they are less tolerant to drought than Rangpur lime. This research aims to study the influence of rootstock and soil type on transpiration of young plants of Valencia orange. The experiment was conducted in a greenhouse at the Department of Biosystems Engineering, ESALQ/USR Orange seedlings were planted in boxes of 500 L. It was determined simultaneously sweating of 20 plants through thermal dissipation probes (sap flow). It was monitored solar radiation, relative humidity and air temperature sensors were installed to 2 m tall at the center of the greenhouse. The reference evapotranspiration (ETo PM) was calculated by the standard method suggested by FAO. According to these results it is concluded that plant transpiration of Valencia oranges are influenced not only by the type of rootstock but also by leaf area growth and phenological stage, and its relationship with ETo pM is not linear in the whole range of evaporative demand of the atmosphere.
  • Authors:
    • Coquet, Y.
    • Justes, E.
    • Benoit, P.
    • Alletto, L.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 153
  • Year: 2012
  • Summary: Water drainage and herbicide degradation and leaching were studied during four years in a continuous maize field managed with two tillage systems and two types of fallow periods. The tillage systems consisted of either a conventional practice with mouldboard ploughing (28 cm-depth) or a conservation practice with superficial tillage (
  • Authors:
    • Walling, D. E.
    • Russell, M. A.
    • Taylor, P.
    • Ficken, K. J.
    • Blake, W. H.
  • Source: Geomorphology
  • Volume: 139
  • Year: 2012
  • Summary: A Compound Specific Stable Isotope (CSSI) sediment tracing approach is evaluated for the first time in an agricultural catchment setting against established geochemical fingerprinting techniques. The work demonstrates that novel CSSI techniques have the potential to provide important support for soil resource management policies and inform sediment risk assessment for the protection of aquatic habitats and water resources. Analysis of soil material from a range of crop covers in a mixed land-use agricultural catchment shows that the carbon CSSI signatures of particle-reactive fatty acids label surface agricultural soil with distinct crop-specific signatures, thus permitting sediment eroded from each land-cover to be tracked downstream. High resolution sediment sampling during a storm event and analysis for CSSI and conventional geochemical fingerprints elucidated temporal patterns of sediment mobilisation under different crop regimes and the specific contribution that each crop type makes to downstream sediment load. Pasture sources (65% of the catchment area) dominated the sediment load but areal yield (0.13 +/- 0.02 t ha(-1)) was considerably less than that for winter wheat (0.44 +/- 0.15 t ha(-1)). While temporal patterns in crop response matched runoff and erosion response predictions based on plot-scale rainfall simulation experiments, comparison of biomarker and geochemical fingerprinting data indicated that the latter overestimated cultivated land inputs to catchment sediment yield due to inability to discriminate temporary pasture (in rotation) from cultivated land. This discrepancy, however, presents an opportunity since combination of the two datasets revealed the extremely localised nature of erosion from permanent pasture fields in this system (estimated at up to 0.5 t ha(-1)). The novel use of CSSI and geochemical tracers in tandem provided unique insights into sediment source dynamics that could not have been derived from each method alone. Research into CSSI signature development (plant and soil processes) and the influence of cultivation regimes are required to support future development of this new tool. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Saran, S.
  • Source: Science
  • Volume: 338
  • Issue: 6110
  • Year: 2012
  • Summary: Biochar is the solid, carbon-rich product of heating biomass with the exclusion of air (pyrolysis or “charring”). If added to soil on a large scale, biochar has the potential to both benefit global agriculture and mitigate climate change. It could also provide an income stream from carbon abatement for farmers worldwide. However, biochar properties are far from uniform, and biochar production technologies are still maturing. Research is beginning to point the way toward a targeted application of biochar to soils that maximizes its benefits.