• Authors:
    • Mauser, W.
    • Weidinger, R.
    • Reiter, A.
  • Source: CLIMATIC CHANGE
  • Volume: 111
  • Issue: 3-4
  • Year: 2012
  • Summary: The following study investigates temperature and precipitation trends in instrumental time series between 1960 and 2006 at 88 meteorological stations located in the Upper Danube Basin. Time series were tested for inhomogeneities with several common homogeneity tests, trend magnitudes of annual and seasonal time series were calculated by least square fitting and the significance of trend values was checked and quantified by the Mann-Kendall test. The results confirm a particularly strong recent Climate Change in the investigation area. Increasing temperature trends show remarkably high trend values up to 0.8 degrees C/decade in the summer season. The trends are highly significant for all investigated summer, spring and annual time series. Winter and spring temperature trends show consistently positive trend values as well even though some time series show no significance at all and the calculated trend values are smaller. Autumn temperature trends are mostly non-significant with low values (up to 0.3 degrees C/decade) and several negative trends. Most of the highest trend values can be found in lower altitudes whereas stations situated in alpine regions tend to show low trend magnitudes and often exhibit nonsignificant results. Precipitation time series show positive as well as negative trends in the annual and seasonal analysis. At most stations a precipitation decrease in summer and autumn and an increase in winter was observed during the last 47 years whereas the spring and mean annual precipitation exhibits no change at all. But most time series are not conclusive since they show predominantly no significance and they often exhibit only low trend values.
  • Authors:
    • Hellweg, S.
    • Pfister, S.
    • Juraske, R.
    • Stoessel, F.
  • Source: Environmental Science & Technology
  • Volume: 46
  • Issue: 6
  • Year: 2012
  • Summary: Food production and consumption is known to have significant environmental impacts. In the present work, the life cycle assessment methodology is used for the environmental assessment of an assortment of 34 fruits and vegetables of a large Swiss retailer, with the aim of providing environmental decision-support to the retailer and establishing life cycle inventories (LCI) also applicable to other case studies. The LCI includes, among others, seedling production, farm machinery use, fuels for the heating of greenhouses, irrigation, fertilizers, pesticides, storage and transport to and within Switzerland. The results show that the largest reduction of environmental impacts can be achieved by consuming seasonal fruits and vegetables, followed by reduction of transport by airplane. Sourcing fruits and vegetables locally is only a good strategy to reduce the carbon footprint if no greenhouse heating with fossil fuels is involved. The impact of water consumption depends on the location of agricultural production. For some crops a trade-off between the carbon footprint and the induced water stress is observed. The results were used by the retailer to support the purchasing decisions and improve the supply chain management.
  • Authors:
    • Haeberli, M.
    • Keiser, A.
    • Stamp, P.
  • Source: Field Crops Research
  • Volume: 128
  • Year: 2012
  • Summary: Today over 90% of the potatoes for the fresh market are washed; therefore consumers already object to minor external quality deficiencies. The quality assessment performed by potato traders does not distinguish in detail between quality deficiencies and potential links to the farming systems and site parameters are unknown. Thus, the cause for the observed increase of external quality problems is unknown. From 2001 to 2003 the extent and the potential causes of quality deficiencies were studied on totally 278 fields on conventional, integrated and organic farms in the wet and cool climate of Switzerland. Just before harvest samples consisting of 810 tubers were collected on each field in a standardised sampling pattern. Wireworms, slugs and drycore were responsible for important economic losses in all farming systems. In the organic farming system the quality damage was higher for all three deficiencies. While wireworm and slug damage were of general importance, drycore was significantly most severe in the organic farming system in all three years. Crass clover ley in the years preceding potatoes increased the risk for all three quality deficiencies. Slug damage increased with soil cover (catch crops) and with the percentage of crops favourable to slugs in the crop rotation (e.g. vegetables). Seed tubers without black scurf infestation reduced the occurrence of black scurf and drycore on harvested tubers. Fungicide seed treatment reduced black scurf significantly if seed tubers were infested. Insecticide seed treatment for cereals preceding potatoes as well as molluscicide treatments in the potato crop had a beneficial but not always sufficient effect. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Prasuhn, V.
  • Source: Soil & Tillage Research
  • Volume: 120
  • Year: 2012
  • Summary: The positive effects of soil conserving farming methods have mostly been demonstrated using small test plots. The present study is aimed at confirming that they also occur on the catchment scale. The impact of crops and soil tillage practises on the extent of soil erosion was determined in 203 crop fields over 10 years in the Swiss Midlands. Soil erosion totalled 1969 t or 0.75 t ha(-1) yr(-1). Most erosion took place in winter wheat fields (33%), which accounted for 22% of the crop area. Second and third most erosion was observed in potato (26%) and fallow (14%) fields. By far the highest mean soil loss was found for potatoes, at 2.87 t ha(-1) yr(-1). Fallow (1.06 t ha(-1) yr(-1)) and winter wheat (1.05 t ha(-1) yr(-1)) fields were also relatively susceptible to soil erosion. In contrast, values for soil loss below mean were observed for maize (0.44 t ha(-1) yr(-1)), sugar beet (0.27 t ha(-1) yr(-1)), and rape seed (0.39 t ha(-1) yr(-1)). 88% of soil erosion took place on plough tilled land (PT), 9% on non-ploughed land with less than 30% surface residue cover (RT), 1% on mulch-tilled land with more than 30% surface residue cover (MT), and 2% in non-tilled or strip-tilled land with >30% soil cover (NT). At 0.07 and 0.12 t ha(-1) yr(-1), respectively, the mean soil loss in MT and NT fields was more than an order of magnitude lower than that under PT (1.24 t ha(-1) yr(-1)). Field mappings confirmed the positive effects of the soil conserving soil tillage practises. The risk of soil erosion was significantly influenced by crop rotation. The carry-over effects should be taken into account when studying the effects of cropping methods on soil erosion. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Zegada-Lizarazu, W.
    • Walter, K.
    • Valentine, J.
    • Djomo, S. Njakou
    • Monti, A.
    • Mander, U.
    • Lanigan, G. J.
    • Jones, M. B.
    • Hyvonen, N.
    • Freibauer, A.
    • Flessa, H.
    • Drewer, J.
    • Carter, M. S.
    • Skiba, U.
    • Hastings, A.
    • Osborne, B.
    • Don, A.
    • Zenone, T.
  • Source: GCB Bioenergy
  • Volume: 4
  • Issue: 4
  • Year: 2012
  • Summary: Bioenergy from crops is expected to make a considerable contribution to climate change mitigation. However, bioenergy is not necessarily carbon neutral because emissions of CO2, N2O and CH4 during crop production may reduce or completely counterbalance CO2 savings of the substituted fossil fuels. These greenhouse gases (GHGs) need to be included into the carbon footprint calculation of different bioenergy crops under a range of soil conditions and management practices. This review compiles existing knowledge on agronomic and environmental constraints and GHG balances of the major European bioenergy crops, although it focuses on dedicated perennial crops such as Miscanthus and short rotation coppice species. Such second-generation crops account for only 3% of the current European bioenergy production, but field data suggest they emit 40% to >99% less N2O than conventional annual crops. This is a result of lower fertilizer requirements as well as a higher N-use efficiency, due to effective N-recycling. Perennial energy crops have the potential to sequester additional carbon in soil biomass if established on former cropland (0.44 Mg soil C ha(-1) yr(-1) for poplar and willow and 0.66 Mg soil C ha(-1) yr(-1) for Miscanthus). However, there was no positive or even negative effects on the C balance if energy crops are established on former grassland. Increased bioenergy production may also result in direct and indirect land-use changes with potential high C losses when native vegetation is converted to annual crops. Although dedicated perennial energy crops have a high potential to improve the GHG balance of bioenergy production, several agronomic and economic constraints still have to be overcome.
  • Authors:
    • Dubois, D.
    • Gaillard, G.
    • Schaller, B.
    • Chervet, A.
    • Nemecek, T.
    • Huguenin-Elie, O.
  • Source: Agricultural Systems
  • Volume: 104
  • Issue: 3
  • Year: 2011
  • Summary: Extensive or low-input farming is considered a way of remedying many problems associated with intensive farming practices. But do extensive farming systems really result in a clear reduction in environmental impacts, especially if their lower productivity is taken into account? This question is studied for Swiss arable cropping and forage production systems in a comprehensive life cycle assessment (LCA) study. Three long-term experiments (DOC) experiment comparing bio-dynamic, bio-organic and conventional farming, the "Burgrain" experiment including integrated intensive, integrated extensive and organic systems and the "Oberacker" experiment with conventional ploughing and no-till soil cultivation, are considered in the LCA study. Furthermore, model systems for arable crops and forage production for feeding livestock are investigated by using the Swiss Agricultural Life Cycle Assessment method (SALCA). The analysis covers an overall extensification of cropping systems and forage production on the one hand and a partial extensification of fertiliser use, plant protection and soil cultivation on the other. The overall extensification of an intensively managed system reduced environmental impacts in general, both per area unit and per product unit. In arable cropping systems medium production intensity gave the best results for the environment, and the intensity should not fall below the environmental optimum in order to avoid a deterioration of eco-efficiency. In grassland systems, on the contrary, a combination of both intensively and extensively managed plots was preferable to medium intensity practices on the whole area. The differences in yield, production intensity and environmental impact were much more pronounced in grassland than in arable cropping systems. Partial extensification of a farming system should be conceived in the context of the whole system in order to be successful. For example, the extensification solely of fertiliser use and soil cultivation resulted in a general improvement in the environmental performance of the farming system, whereas a reduction in plant protection intensity by banning certain pesticide categories reduced negative impacts on ecotoxicity and biodiversity only, while increasing other burdens such as global warming, ozone formation, eutrophication and acidification per product unit. The replacement of mineral fertilisers by farmyard manure as a special form of extensification reduced resource use and improved soil quality, while slightly increasing nutrient losses. These results show that a considerable environmental improvement potential exists in Swiss farming systems and that a detailed eco-efficiency analysis could help to target a further reduction in their environmental impacts.
  • Authors:
    • Armengot, L.
    • Berner, A.
    • Sans, F. X.
    • Maeder, P.
  • Source: Weed Research
  • Volume: 51
  • Issue: 4
  • Year: 2011
  • Summary: Conservation tillage could provide environmental benefits to organic farming. However, potential weed problems often tend to discourage farmers from adopting it. The effects of tillage (reduced vs. conventional), fertilisation (slurry vs. manure compost) and the application of biodynamic preparations (with and without) on crop yield and on weed cover, diversity and biological attributes were investigated in a cropping sequence of wheat, sunflower and spelt. Total weed cover and perennial cover in reduced tillage treatments were two to three times greater than in conventional treatments. Monocotyledon cover in reduced tillage was three times that in conventional tillage in spelt, whereas the dicotyledon Stellaria media dominated in sunflower. Weed diversity was similar across treatments, regardless of cereal crop, whereas lower diversity values were observed with reduced tillage in sunflower, because of the dominance of S. media. There was virtually no effect of fertilisation and biodynamic preparations on weed parameters. Although wheat and spelt yield decreased in reduced tillage plots (14% and 8% respectively), the sunflower grain yield was unaffected. Reduced tillage could thus be useful in organic cropping systems but would require proper management of perennial and monocotyledonous weeds, which are often problematic for annual crops.
  • Authors:
    • Sun, O. J.
    • Wang, E.
    • Luo, Z.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 139
  • Issue: 1-2
  • Year: 2010
  • Summary: Adopting no-tillage in agro-ecosystems has been widely recommended as a means of enhancing carbon (C) sequestration in soils. However, study results are inconsistent and varying from significant increase to significant decrease. It is unclear whether this variability is caused by environmental, or management factors or by sampling errors and analysis methodology. Using meta-analysis, we assessed the response of soil organic carbon (SOC) to conversion of management practice from conventional tillage (CT) to no-tillage (NT) based on global data from 69 paired-experiments, where soil sampling extended deeper than 40 cm. We found that cultivation of natural soils for more than 5 years, on average, resulted in soil C loss of more than 20 t ha-1, with no significant difference between CT and NT. Conversion from CT to NT changed distribution of C in the soil profile significantly, but did not increase the total SOC except in double cropping systems. After adopting NT, soil C increased by 3.15 +- 2.42 t ha-1 (mean ± 95% confidence interval) in the surface 10 cm of soil, but declined by 3.30 ± 1.61 t ha-1 in the 20-40 cm soil layer. Overall, adopting NT did not enhance soil total C stock down to 40 cm. Increased number of crop species in rotation resulted in less C accumulation in the surface soil and greater C loss in deeper layer. Increased crop frequency seemed to have the opposite effect and significantly increased soil C by 11% in the 0-60 cm soil. Neither mean annual temperature and mean annual rainfall nor nitrogen fertilization and duration of adopting NT affected the response of soil C stock to the adoption of NT. Our results highlight that the role of adopting NT in sequestrating C is greatly regulated by cropping systems. Increasing cropping frequency might be a more efficient strategy to sequester C in agro-ecosystems. More information on the effects of increasing crop species and frequency on soil C input and decomposition processes is needed to further our understanding on the potential ability of C sequestration in agricultural soils.
  • Authors:
    • Andrasko, K.
    • Bosquet, B.
  • Year: 2010
  • Authors:
    • Maeder, P.
    • Niggli, U.
    • Wiemken, A.
    • Burger, D.
    • Berner, A.
    • Krauss, M.
  • Source: Soil Use and Management
  • Volume: 26
  • Issue: 1
  • Year: 2010
  • Summary: To promote conservation tillage in organic farming systems, weed control and ley removal within arable-ley rotations need to be optimized. A long-term field trial was thus established in Frick, Switzerland in 2002 on a clayey soil and with a mean precipitation of 1000 mm/year. The tillage experiment distinguished between conventional tillage with mouldboard ploughing (CT, 15 cm depth) and reduced tillage (RT), including a chisel plough (15 cm) and a stubble cleaner (5 cm). Results of a 2-year grass-clover ley (2006/2007) and silage maize (2008) are presented. Due to dry conditions, mean grass-clover yields were 25% higher in RT than in CT, indicating better water retention of RT soils. Clover cover and mineral contents of the fodder mixture were also higher in RT. The ley was successfully removed in autumn 2007 in RT plots, and a winter pea catch crop was sown before maize. In CT, ploughing took place in spring 2008. Maize yields were 34% higher in RT than in CT, despite a two- to three-fold higher but still tolerable weed infestation. Maize in RT plots benefited from an additional 61.5 kg of easily decomposable organic N/ha incorporated into the soil via the pea mulch. Measurement of arbuscular mycorrhizal colonization of maize roots indicated a similar mechanical disturbance of the topsoil through the reduced ley removal system compared with ploughing. It is suggested that RT is applicable in organic farming, even in arable-ley rotations, but long-term effects need further assessment.