• Authors:
    • Barbera, V.
    • Poma, I.
    • Gristina, L.
    • Novara, A.
    • Egli, M.
  • Source: Land Degradation & Development
  • Volume: 23
  • Issue: 1
  • Year: 2012
  • Summary: A calcareous and clayey xeric Chromic Haploxerept of a long-term experimental site in Sicily (Italy) was sampled (0-15 cm depth) under different land use management and cropping systems (CSs) to study their effect on soil aggregate stability and organic carbon (SOC). The experimental site had three tillage managements (no till [NT], dual-layer [DL] and conventional tillage [CT]) and two CSs (durum wheat monocropping [W] and durum wheat/faba bean rotation [WB]). The annually sequestered SOC with W was 2.75-times higher than with WB. SOC concentrations were also higher. Both NT and CT management systems were the most effective in SOC sequestration whereas with DL system no C was sequestered. The differences in SOC concentrations between NT and CT were surprisingly small. Cumulative C input of all cropping and tillage systems and the annually sequestered SOC indicated that a steady state occurred at a sequestration rate of 7.4 Mg C ha -1 y -1. Independent of the CSs, most of the SOC was stored in the silt and clay fraction. This fraction had a high N content which is typical for organic matter interacting with minerals. Macroaggregates (>250 m) and large microaggregates (75-250 m) were influenced by the treatments whereas the finest fractions were not. DL reduced the SOC in macroaggregates while NT and CT gave rise to higher SOC contents. In Mediterranean areas with Vertisols, agricultural strategies aimed at increasing the SOC contents should probably consider enhancing the proportion of coarser soil fractions so that, in the short-term, organic C can be accumulated.
  • Authors:
    • Oztekin, M. E.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2 part 3
  • Year: 2012
  • Summary: Land use is an important global issue in terms of preserving the soils, agricultural crop production and farmers' economy as well as the other usage purposes. There are many useful approaches and tools for efficient determination of the land use types. In this study, distribution of different field crops and citrus orchards were monitored and determined for land use types (LUTs) using the low cost ASTER satellite images and GIS in Akarsu Irrigation District of Lower Seyhan Plain (9495 ha) in southern Turkey. Prior to parceling in the field, study area maps of 1:5000 scale were digitized by using ArcGIS software. The enhanced satellite images were overlaid onto the digitized parcel map for ground observations. The images were printed and checked for all crops of the fields. Commonly grown different field crops and orchards were mapped during the field work. A database for this research was established after an intensive field work. The crop types and their coordinates were determined and recorded during the field works. Five LUTs were identified in the study area, and corn and citrus were the most planted LUTs. Furthermore, suitability of soil series for LUTs was investigated; Canakci and Mursel soil series in the study area were found to be highly suitable for all LUTs. It was concluded that cost effective ASTER images could be potentially used for the determination of different crops and orchards which have different reflection values. However, the images must be obtained during the appropriate time period.
  • Authors:
    • Espadaler, X.
    • Ribes, J.
    • Ribes, E.
    • Piñol, J.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 158
  • Year: 2012
  • Summary: The Heteroptera assemblage of a citrus grove and how it was affected by ant-exclusion was examined during transformation from conventional to organic agriculture. The results showed that the Heteroptera assemblage changed dramatically over the eight years of the study: at first, it mainly consisted of herbivorous lygaeids and predatory anthocorids but became dominated by predatory mirids in 2008-2009. The predator/herbivore ratio increased steadily over the eight years of the study. Ants can form mutualistic relationships with heteropteran pests. However, exclusion of ants from canopies did not affect the Heteroptera assemblage at the beginning of the study, but had a profound effect later on. In particular, ant-exclusion increased the abundance of most predatory Heteroptera, except for the myrmecomorphic mirid Pilophorus perplexus, which was approximately five times more abundant in control than in ant-excluded trees; the analyses showed that the only mimicked ant species was Lasius grandis.
  • Authors:
    • Lithourgidis, A.
    • Vlachostergios, D.
    • Dordas, C.
  • Source: Crop & Pasture Science
  • Volume: 63
  • Issue: 1
  • Year: 2012
  • Summary: Pea ( Pisum arvense L.) is an important legume in many areas of the world, which is used for forage and grain production and could be used in intercropping systems. Intercropping of pea with oat ( Avena sativa L.) and barley ( Hordeum vulgare L.), in two seeding ratios 60:40 and 80:20, was compared with pea and two cereal monocrops for two growing seasons (2008-10), at the Aristotle University of Thessaloniki, Greece. The effect of the intercropping systems was determined on growth rate, plant height, chlorophyll content, DM, and N yield. Also, several competition and economic indices were used to evaluate the intercropping systems, such as land equivalent ratio (LER), relative crowding coefficient (K), aggressivity (A), competitive ratio (CR), actual yield loss (AYL), system productivity index (SPI), monetary advantage index (MAI), and intercropping advantage (IA). Growth rate of pea and cereals was lower by an average of 39 and 64%, respectively, in the intercrops than in the monocrops. DM yield was the highest in barley monocrop (13.00 Mg ha -1) followed by P 80O 20 intercrop (11.73 Mg ha -1). Pea monocrop, and P 80O 20 and P 80B 20 intercrops showed the highest crude protein (CP) concentration (137, 132 and 130 g kg -1 DM, respectively), whereas P 80O 20 intercrop also produced the highest CP yield (1552 kg ha -1). The LER, K, and AYL values (average 1.09, 1.75 and 0.29, respectively), were greater for both pea-oat intercrops compared with the pea-barley intercrops (average 0.98, 0.92 and 0.06, respectively), indicating that in these systems there was an advantage of intercropping for exploiting the resources of the environment. The A, CR, and partial AYL values in all intercrops were greater for oat and barley than pea, which indicated that cereals were more competitive partners than pea. The highest MAI, IA, and SPI values were recorded for P 80O 20 followed by P 60O 40 intercrops indicating that these intercropping systems were the most profitable. The results from this study showed that both pea-oat intercrops were more productive with high CP yield, and also they showed the best land-use efficiency.
  • Authors:
    • Christiansen, S.
    • Murari, S.
    • Ryan, J.
  • Source: Archives of Agronomy and Soil Science
  • Volume: 58
  • Issue: 3
  • Year: 2012
  • Summary: Traditional Mediterranean rainfed cereal/fallow systems are being replaced by cereal monoculture due to land-use pressure. Food or forage legumes in rotation with cereals are an alternative sustainable cropping system. Complex cropping systems can only be assessed by long-term trials. This 11-year rainfed barley-based rotation trial in northern Syria assessed rotation effects on yields of barley and legumes, with particular emphasis on the management of vetch. The mean order of barley grain yields from the rotations was: vetch for hay, vetch for grazing > fallow=medic=vetch for seed > lentil, and continuous barley. Straw yields followed a similar pattern. Nitrogen (60 kg ha -1) increased grain (39%) and straw (65%) yields. The N fertilization of barley had no carryover effect on the alternative legume crops. Although there were no significant differences in seed or straw yield between lentil and vetch, seasonal rainfall influenced overall yields. Total biomass yields were in the order of vetch, medic and lentil. There is a compelling case for annual vetch paired with barley in rotations for the Mediterranean region. Thus, barley/vetch rotations can potentially enhance barley yields and improve soil quality, and provide valuable fodder for small ruminants as well in the region's agricultural systems.
  • Authors:
    • Jones, J.
    • Porter, C.
    • Orsini, R.
    • Seddaiu, G.
    • Roggero, P.
    • Sanctis, G.
  • Source: European Journal of Agronomy
  • Volume: 40
  • Year: 2012
  • Summary: The differential impact on soil organic carbon (SOC) of applying no tillage (NT) compared to conventional tillage (CT, i.e. mouldboard ploughing), along with three rates of nitrogen (N) fertilizer application (0, 90 and 180 kg ha -1 y -1), was studied under rain-fed Mediterranean conditions in a long-term experiment based on a durum wheat-maize rotation, in which crop residues were left on the soil (NT) or incorporated (CT). Observed SOC content following 8 and 12 years of continuous treatment application was significantly higher in the top 10 cm of the soil under NT than CT, but it was similar in the 10-40 cm layer. NT grain yields for both maize and durum wheat were below those attained under CT (on average 32% and 14% lower respectively) at a given rate of N fertilizer application. Soil, climate and crop data over 5 years were used to calibrate DSSAT model in order to simulate the impact of the different management practices over a 50-year period. Good agreement was obtained between observed and simulated values for crops grain yield, above-ground biomass and observed SOC values. Results from the simulations showed that under NT the weeds growing during the intercrop fallow period made a significant contribution to the observed SOC increase. When the contribution of the weed fallow was considered, NT significantly increased SOC in the top 40 cm of the soil at an average rate of 0.43, 0.31 and 0.03 t ha -1 per year, respectively for 180, 90 and 0 kg N ha -1 year -1, within the simulated 50 years. Under CT, a significant SOC increase was simulated under N180 and a significant decrease when no fertilizer was supplied.
  • Authors:
    • van Ranst, E.
    • Fadlaoui, A.
    • Moussadek, R.
    • Mrabet, R.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Moroccan agriculture is characterized by the co-existence of both modern and smallholder traditional agriculture. Both types of agriculture are under degradative processes due to mis-use of tillage implements, mis-management of crop residues and inappropriate links between grain and livestock productions. From the research conducted over the last three decades, the vast majority of beneficial tillage effects are transient. Conversely, the harmful effects of conventional tillage (CT) systems are long-lasting, if not permanent. The present paper aims at evaluating major achievements in conservation or no-tillage agriculture (CA or NT) research conducted in dry areas of Morocco and presenting important ways to implement these achievements within the Moroccan rural society. CA has been introduced in response to issues of soil conservation, drought mitigation and soil quality management. NT systems have resulted in reduced soil erosion, greater soil water conservation, improved soil quality and stable and higher crop yields. Changes in crop production practices due to shifting to NT or CA systems and retention of crop residues at or near the surface produced progressive qualitative and quantitative variations in soil organic matter. This can allow agriculture to contribute to country's efforts to reduce and control greenhouse gas emissions. These effects benefited both farmers and society in terms of higher returns and efficiencies. Under NT, benefits from improved agriculture's environmental performance must be added to remunerations of reducing costs of production and improving well-being of farmers. The other strong benefits that CA brings come from the opportunity for early sowing and savings in time, machinery and fuel. Even though, many agronomic, socio-economic and environmental benefits accrue from NT and increasing crop diversity; lack of incentives from the government and social factors encourage the continued use of CT systems. CA systems were sufficiently tested in research stations but found limited adoption in farm communities. The shift in the late nineties to more on-farm research did not result in the envisaged breakthroughs, mainly due to poor research-extension linkages and several social and technical barriers. Consequently, in order to realize durable agricultural growth, there is a huge challenge to out- and up-scale CA in Morocco through linkage of all stakeholders (farmers, developers, researchers, industrials and policy makers). This paper fulfills information gaps and presents a thorough discussion on constraints to CA adoption as well. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Cichelli, A.
    • Raggi, A.
    • Pattara, C.
  • Source: Environmental Management
  • Volume: 49
  • Issue: 6
  • Year: 2012
  • Summary: Global warming represents one of the most critical internationally perceived environmental issues. The growing, and increasingly global, wine sector is one of the industries which is under increasing pressure to adopt approaches for environmental assessment and reporting of product-related greenhouse gas emissions. The International Organization for Vine and Wine has recently recognized the need to develop a standard and objective methodology and a related tool for calculating carbon footprint (CF). This study applied this tool to a wine previously analyzed using the life cycle assessment (LCA) methodology. The objective was to test the tool as regards both its potential and possible limitations, and thus to assess its suitability as a standard tool. Despite the tool's user-friendliness, a number of limitations were noted including the lack of accurate baseline data, a partial system boundary and the impossibility of dealing with the multi-functionality issue. When the CF and LCA results are compared in absolute terms, large discrepancies become obvious due to a number of different assumptions, as well as the modeling framework adopted. Nonetheless, in relative terms the results seem to be quite consistent. However, a critical limitation of the CF methodology was its focus on a single issue, which can lead to burden shifting. In conclusion, the study confirmed the need for both further improvement and adaptation to additional contexts and further studies to validate the use of this tool in different companies.
  • Authors:
    • Sauer, T.
    • Soolaneyakanahally, R.
    • de Gooijer, H.
    • Bentrup, G.
    • Schoeneberger, M.
    • Brendle, J.
    • Zhou, X.
    • Current, D.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 5
  • Year: 2012
  • Authors:
    • Venkat, K.
  • Source: Journal of Sustainable Agriculture
  • Volume: 36
  • Issue: 6
  • Year: 2012
  • Summary: Given the growing importance of organic food production, there is a pressing need to understand the relative environmental impacts of organic and conventional farming methods. This study applies standards-based life cycle assessment to compare the cradle-to-farm gate greenhouse gas emissions of 12 crop products grown in California using both organic and conventional methods. In addition to analyzing steady-state scenarios in which the soil organic carbon stocks are at equilibrium, this study models a hypothetical scenario of converting each conventional farming system to a corresponding organic system and examines the impact of soil carbon sequestration during the transition. The results show that steady-state organic production has higher emissions per kilogram than conventional production in seven out of the 12 cases (10.6% higher overall, excluding one outlier). Transitional organic production performs better, generating lower emissions than conventional production in seven cases (17.7% lower overall) and 22.3% lower emissions than steady-state organic. The results demonstrate that converting additional cropland to organic production may offer significant GHG reduction opportunities over the next few decades by way of increasing the soil organic carbon stocks during the transition. Nonorganic systems could also improve their environmental performance by adopting management practices to increase soil organic carbon stocks.