Shrinkage and fragmentation of grasslands in the West Songnen Plain,China

In the past century, especially the past five decades, the grasslands of the West Songnen Plain, Northeast China, were rapidly converted into croplands and salinized wasteland, and experienced a fragmentation process that is still ongoing. Almost no information is available on the spatial-temporal changes of grasslands in this area. In this study, grassland cover change, agricultural reclamation and salinized wasteland expansion were investigated during the past five decades. Grassland fragmentation was studied based on four landscape metrics. The grassland cover change was detected from a time series of topographic maps from 1954, satellite images of Landsat TM in 1986, 1995, and 2000 using remote sensing and geographic information systems (GIS). In addition, the land use changes were analyzed using a transition matrix of land use types, while the driving forces were explored according to climatic changes and socioeconomic developments. The results indicated a significant decrease in grassland area. Of the 1 418 945 ha of native grassland in 1954, approximately 64% was removed by 2000, while the number of patches (NP) increased from 865 to 2035 and the mean patch size (MPS) decreased from 1640 ha to 252 ha. During the whole study period, the average annual decrease rate of grassland was 34 894 ha/year. Cropland and salinized wasteland were the two main land use types into which grassland converted. During the past decades, obvious climatic changes occurred, which supplied a favorable potential environment for agricultural development but damaged grassland productivity. On the other hand, population, GDP and livestock number increased significantly as grassland quality decreased. According to the results, the shrinkage and fragmentation of grasslands may well be explained by socioeconomic development and aided by changing climatic conditions.     

The Satoyama Index: A biodiversity indicator for agricultural landscapes

Agricultural development to meet rapidly growing demands for food and biofuel and the abandonment of traditional land use have had major impacts on biodiversity. Habitat diversity is one of the most important factors influencing biodiversity in agricultural landscapes. In this study we propose an ecological index of ecosystem or habitat diversity in agricultural landscapes – the Satoyama Index (SI) – that is discernible under appropriate spatial units (e.g., 6 km × 6 km) from 1 km × 1 km gridded land-cover data available from an open-access web site. A high SI value is an indicator of high habitat diversity, which is characteristic of traditional agricultural systems, including Japanese satoyama landscapes, while a low value indicates a monotonic habitat condition typical of extensive monoculture landscapes. The index correlated well with the spatial patterns of occurrence of a bird of prey (Butastur indicus) and species richness of amphibians and damselflies in Japan. The values of the SI also corresponded well to the spatial patterns of typical traditional agricultural landscapes with high conservation value in other countries, for example, the dehesas of the Iberian Peninsula and shade coffee landscapes in Central America. Globally, the pattern of East/South-East Asian paddy belts with their high index values contrasts markedly with the low values of the Eurasian, American, and Australian wheat or corn belts. The SI, which correlates landscapes with biodiversity through potential habitat availability, is highly promising for assessing and monitoring the status of biodiversity irrespective of scale.     

Links and broken chains: evidence of human-caused changes in land cover in remotely sensed images

Land use intensification on shrinking forage resources characterizes many livestock producing communities. Remotely sensed images can show land cover change, but how household decision making is reflected in images had not been synthesized. For eight areas in the US, Africa, and Mongolia (>340,000 km²), we ranked constraints in decision making, and quantified vegetation greenness trends from 1981 to 2004 and land cover change using 1990 and 2000 Landsat images. Constraints in decision making varied across the sites, but ecological settings ranked highest. Five sites showed increasing greenness (2.4–8.0% increase per decade; P ≤ 0.01); the African sites showed no change or declining greenness (−2.5%; P = 0.048). Land cover change in the US sites was modest, with most sites suitable for cultivation already converted by 1990. Cover change was minor in Mongolia, despite profound changes in government and economy. The Kenyan site showed the largest change in land cover. We hypothesize a humped relationship, where households in undeveloped regions lack the resources to convert land cover. Developed regions have reached some stasis in land use. Developing regions with high human population growth and residents with access to machinery show the greatest land cover change.     

‘Formiguers’, a historical system of soil fertilization (and biochar production?)

‘Formiguers’ are structures similar to charcoal-kilns that were used to burn piles of biomass with a soil cover in order to produce fertilizers for agricultural plots. Their use was widespread in Spain up to the 1960s and similar structures are still in use in India and Bhutan. Our objective was to study the effects of the ‘formiguer’ on its soil cover in terms of changes in nutrient availability. We built an experimental 0.5-m³ ‘formiguer’ with 68 kg of plant material with a 12% moisture content and 550 kg of soil with a 16% moisture content. The content of organic carbon and mineral nitrogen decreased in the soil cover as a result of burning. After aerobic incubation all samples had a similar content of mineral nitrogen. Exchangeable potassium and total and labile phosphorus increased after burning as a result of the soil cover mixing with the ashes of the biomass as the ‘formiguer’ collapsed during burning in the first two cases, while mineralization of organic compounds produced the increase in labile phosphorus. This input of nutrients for the agricultural plots occurs at a net loss of 0.4–2.5 Mg organic C ha^?1. Very small amounts of charcoal were produced and this may be the reason for their low occurrence in soils today. Burning of ‘formiguers’ required the harvest of vegetation from a considerable forest area (10–25 ha per hectare of agricultural land) and represented a significant disturbance of these systems.     

Carbon stocks in Swiss agricultural soils predicted by land-use,soil characteristics,and altitude

Effects of agricultural land-use and land-use change on soil organic carbon (SOC) pools play an important role in the mitigation of the global greenhouse effect. To estimate these effects, baseline SOC data for individual regions or countries are needed. The aim of this study was to quantify current SOC stocks in Swiss agricultural soils, to identify meaningful predictors for SOC, and to estimate historical SOC losses. SOC stocks in mineral soils were estimated from combined georeferenced data for land-use, topography, and profile data (n=544) from soil surveys. Mean SOC density in the layer 0–20 cm ranged between 40.6±8.9 t ha⁻¹ (±95% confidence interval (CI)) for arable land and 50.7±12.2 t ha⁻¹ for favourable permanent grassland, and in the layer 0–100 cm from 62.9±15.2 t ha⁻¹ for unfavourable grassland to 117.4±29.8 t ha⁻¹ for temporary grasslands (leys). SOC stocks in organic soils were quantified separately for intact and cultivated peatlands using data from peatland inventories and current SOC densities calculated from average peat decay rates. Organic soils account for less than 3% of the total area but store about 28% (47.2±7.3 Mt) of the total SOC stock of 170±17 Mt. Land-use type, clay content, and altitude (serving as a climate proxy for grassland soils at higher altitudes) were identified as main SOC predictors in mineral soils. Clay content explained up to 44% of the variability in SOC concentrations in the fine earth of arable soils, but was not significantly related to SOC in grassland soils at higher altitudes. SOC concentration under permanent grassland increases linearly with altitude, but because soil depth and stone content limit carbon storage in alpine grassland soils, no relationship was found between altitude and SOC stock. A preliminary estimate suggested that about 16% of the national SOC stock has been lost historically due to peatland cultivation, urbanisation, and deforestation. It seems unlikely that future changes in agricultural practices could compensate for this historical SOC loss in Swiss agricultural soils.     

Global implications of biomass and biofuel use in Germany – Recent trends and future scenarios for domestic and foreign agricultural land use and resulting GHG emissions

The global land area required to meet the German consumption of agricultural products for food and non-food use was quantified, and the related greenhouse gas (GHG) emissions, particularly those induced by land-use changes in tropical countries, were estimated. Two comprehensive business-as-usual scenarios describe the development corridor of biomass for non-food use in terms of energetic and non-energetic purposes. In terms of land use, Germany was already a net importer of agricultural land in 2004, and the net additional land required by 2030 is estimated to comprise 2.5–3.4 Mha. This is mainly due to biofuel demand driven by current policy targets. Meeting the required biodiesel import demand would result in an additional GWP of 23–37 Tg of CO₂ equivalents through direct and indirect land-use changes. Alternative scenario elements outline the potential options for reducing Germany's land requirement, which reflect future global per capita availability.     

Streamwater phosphorus and nitrogen across a gradient in rural–agricultural land use intensity

This paper provides an overview of the impacts of rural land use on lowland streamwater phosphorus (P) and nitrogen (N) concentrations and P loads and sources in lowland streams. Based on weekly water quality monitoring, the impacts of agriculture on streamwater P and N hydrochemistry were examined along a gradient of rural–agricultural land use, by monitoring three sets of ‘paired’ (near-adjacent) rural headwater streams, draining catchments which are representative of the major geology, soil types and rural/agricultural land use types of large areas of lowland Britain. The magnitude and timing of P and N inputs were assessed and the load apportionment model (LAM) was applied to quantify ‘continuous’ (point) source and ‘flow-dependent’ (diffuse) source contributions of P to these headwater streams. The results show that intensive arable farming had only a comparatively small impact on streamwater total phosphorus (TP loads), with highly consistent stream diffuse-source TP yields of ca. 0.5 kg-P ha^?1 year^?1 for the predominantly arable catchments with both clay and loam soils, compared with 0.4 kg-P ha^?1 year^?1 for low agricultural intensity grassland/woodland on similar soil types. In contrast, intensive livestock farming on heavy clay soils resulted in dramatically higher stream diffuse-source TP yields of 2 kg-P ha^?1 year^?1. The streamwater hydrochemistry of the livestock-dominated catchment was characterised by high concentrations of organic P, C and N fractions, associated with manure and slurry sources. Across the study sites, the impacts of human settlement were clearly identifiable with effluent inputs from septic tanks and sewage treatment works resulting in large-scale increases in soluble reactive phosphorus (SRP) loads and concentrations. At sites heavily impacted by rural settlements, SRP concentrations under baseflow conditions reached several hundred μg-P L^?1. Load apportionment modelling demonstrated significant ‘point-source’ P inputs to the streams even where there were no sewage treatment works within the upstream catchment. This indicates that, even in sparsely populated rural headwater catchments, small settlements and even isolated groups of houses are sufficient to cause significant nutrient pollution and that septic tank systems serving these rural communities are actually operating as multiple point sources, rather than a diffuse input.     

Are soils of Iowa USA currently a carbon sink or source? Simulated changes in SOC stock from 1972 to 2007

Upscaling the spatial and temporal changes in carbon (C) stocks and fluxes from sites to regions is a critical and challenging step toward improving our understanding of the dynamics of C sources and sinks over large areas. This study simulated soil organic C (SOC) dynamics within 0–100 cm depth of soils across the state of Iowa in the USA from 1972 to 2007 using the General Ensemble biogeochemical Modeling System (GEMS). The model outputs with variation coefficient were analyzed and assembled from simulation unit to the state scale based upon major land use types at annual step. Results from this study indicate that soils (within a depth of 0–100 cm) in Iowa had been a SOC source at a rate of 190 ± 380 kg C ha^?1 yr^?1. This was likely caused by the installation of a massive drainage system which led to the release of SOC from deep soil layers previously protected under poor drainage conditions. The annual crop rotation was another major force driving SOC variation and resulted in spatial variability of annual budgets in all croplands. Annual rate of change of SOC stocks in all land types depended significantly on the baseline SOC levels; soils with higher SOC levels tended to be C sources, and those with lower levels tended to be C sinks. Management practices (e.g., conservation tillage and residue management practices) slowed down the C emissions from Iowa soils, but could not reverse the general trend of net SOC loss in view of the entire state due mainly to a high level of baseline SOC stocks.     

Influence of land use on organic carbon pool and chemical properties of Vertic Cambisols in central and southern Italy

Land use strongly influences soil properties and unsuitable practices lead to degradation of soil and environmental quality. The aim of this study was to assess the impact of different land uses on some chemical properties of soils developed from Pliocene clays, within hilly environments of central and southern Italy. The areas investigated are located in Vicarello di Volterra (Pisa, Tuscany), S. Quirico d’Orcia (Siena, Tuscany) and Soveria Simeri (Catanzaro, Calabria). Within each area different land uses were compared, including a natural ecosystem (Mediterranean bush), a perennial grass or pasture and an intensive crop (wheat, as monoculture or in rotation). The soils were sampled at 0.0–0.1, 0.1–0.2 and 0.2–0.4 m depth and analysed for particle size, pH, bulk density, cation exchange capacity and exchangeable cations, total organic carbon (TOC) and humified carbon (HC) concentrations, organic carbon stock and total N. The stratification ratio of soil organic carbon was calculated to characterize soil organic carbon distribution with depth. At all sites, soil under Mediterranean bush contained the largest amounts of TOC (as both concentration and stock), HC, total N and exchangeable K, together with the highest cation exchange capacity and the lowest pH values. The decrease in soil OC stock with land use change from natural to agricultural ecosystem was 65–85% to 0.1 m depth, 55–82% to 0.2 m depth and 44–76% to 0.4 m depth, with the lowest decrements for perennial grass from S. Quirico and the highest decrement for continuous wheat from Soveria Simeri. Continuous wheat cropping, based on conventional tillage, proved to be the least sustainable land use. At Soveria Simeri, the organic carbon content under pasture was not significantly larger than under wheat cultivation, probably because of grazing mismanagement; however, organic carbon under pasture was more humified. At S. Quirico, the perennial grass resulted in a significant increase in soil organic carbon at the soil surface relative to the wheat cultivation, while at Vicarello no differences were observed between alfalfa/wheat rotation and perennial grass. Our results lead to the questioning of sustainability of intensive cereal farming and uncontrolled grazing in the considered environments, emphasizing the need for greater attention to conservative land managements.     

Spatial characterisation of multi-level in-use copper and zinc stocks in Australia

A methodology has been developed to characterise the in-use stocks of copper and zinc at a variety of spatial levels. The approach employs representative concentrations of copper and zinc in their main in-use reservoirs (which account for virtually all the metal put into service) together with geographic information system (GIS) data sets of the spatial locations and densities of these reservoirs. The authors have applied this methodology to Australia at four spatial levels: central city, urban region, states/territories, and country, to produce what is believed to be the first multi-level spatial characterisations of the in-use stocks of technological materials. The results are presented quantitatively and as a series of stock density maps for Inner Sydney, Sydney Metro, all Australian states/territories, and Australia itself. The total stocks in Australia are estimated at about 4.3 Tg Cu (4.3 thousand million kg) and 3.8 Tg Zn (3.8 thousand million kg), or about 240 kg Cu/capita and 205 kg Zn/capita. A statistical analysis of the data shows that the metal stock density at a given spatial level is largely determined by a small number of high-density components at the next lower level. The spatial analysis of the in-use stocks indicates that 50% of all copper and zinc stock resides in just 10% of Australia's local government areas. The largest stocks occur in large urban regions, which can contain copper and zinc densities more than a hundred times higher than rural areas. These regions are expected to be major Australian “metal mines” in the future.     

Environmental consequences of different beef production systems in the EU

The aim of this paper is to examine the environmental consequences of beef meat production in the EU, using a life cycle approach. Four beef production systems were studied – three from intensively reared dairy calves and one from suckler herds. According to the results of the analysis, the contributions from the production of 1 kg beef meat (slaughter weight) to global warming, acidification, eutrophication, land use and non-renewable energy use were lower for beef from dairy calves than from suckler herds (16.0–19.9 versus 27.3 kg CO₂e, 101–173 versus 210 g SO₂e, 622–1140 versus 1651 g NO₃e, 16.5–22.7 versus 42.9 m²year, and 41.3–48.2 versus 59.2 MJ, respectively). The breakdown analysis helped identify the key areas in the “cradle to farm gate” beef production system where sustainable management strategies are needed to improve environmental performance. The study also included a sensitivity analysis to preliminarily estimate GHG emissions from beef production systems if land opportunity cost and land use change related to grazing and feed crop production for beef were taken into account. If so, the contribution from the production of 1 kg beef to global warming would increase by a factor of 3.1–3.9, based on a depreciation period of 20 years. This highlights the importance of taking into account the impacts of land use in assessing the environmental impacts of livestock production.     

Erosion risk associated with rapid and extensive agricultural clearances on dispersive materials in southeast Spain

This research explores the socio-economic, climatic and lithological components of the contemporary erosion problems in the Sorbas area of Almeria, Spain, and devises a mapping schedule to describe the particular risks associated with the large-scale clearance of dispersive soils for arboriculture. The paper firstly tracks the pace of the agricultural change across this sensitive landscape using provincial agricultural statistics. Secondly, the elements of geomorphological sensitivity in a 70 km² study area southwest of Sorbas are considered. Previous work has suggested that dispersive properties of local lithologies are important risk-associated variables alongside vegetation cover and topography. A method whereby all these factors can be included in the assessment of the degree of erosion risk is developed. Using repeat NERC air photography for 1996 and 2001 as a basis, aerial photomosaics of the study area are compared, producing a map of land-use change between 1996 and 2001. With this map as a basis, the risk-mapping schedule is piloted for a sub-study area on newly cleared land. The sustainable management of these extensive changes is discussed in a final section. It is argued that the proposed algorithm for erosion risk mapping could facilitate the management of existing agricultural clearances, and the siting of new developments to minimise soil loss.     

Post-dispersal predation of weed seeds by small vertebrates: Interactive influences of neighbor land use and local environment

The influences of spatial scale, local conditions, and small vertebrate preferences on post-dispersal predation of weed seeds were tested in agricultural ecosystems of the Southern Pampas Region of Argentina. Seeds from different weed species were offered through exclusion experiments at different distances from the weedy field borders, inside maize (2005) and wheat (2006) stubbles with contrasting land use in the neighbor fields (annual crop fields vs. seminatural grasslands), and inside seminatural grasslands adjacent to stubbles. Canopy structure was characterized inside the wheat stubbles, and small mammals were sampled in both stubble crops and grasslands. All weed species were predated in both 2005 and 2006 trials, but predation ratios varied among weed species, partly due to their seed size, with larger ones being more preferred. While in the maize stubbles no distance or neighbor field land use effects, or interactions between the different factors were detected, in the wheat stubbles, influence of neighbor field land use on weed species predation varied according to distance from field border and the height of the stubble canopy. In wheat stubbles adjacent to annual crop fields, predation increased with canopy height at every different distance from the field borders (5 m, 30 m and 60 m). The opposite was found in wheat stubbles adjacent to seminatural grasslands, where seed predation sharply decreased with canopy height, except for the farthest distance to the border. Capture results suggest a predominance of Calomys spp. populations in crop areas (stubbles adjacent to annual crops) which contrasted with the more diverse small mammal’s community of the grasslands. Based on these data, we provide an insight into the hierarchical nature of factors affecting the predation of weed seeds and discuss some implications of land use patterns on the regulation of weed populations by small vertebrates.     

Linking spatio-temporal variation of crop response with sediment deposition along paddy rice terraces

In tropical mountainous regions of South East Asia, intensive cultivation of annual crops on steep slopes makes the area prone to erosion resulting in decreasing soil fertility. Sediment deposition in the valleys, however, can enhance soil fertility, depending on the quality of the sediments, and influence crop productivity. The aim of the study was to assess (i) the spatio-temporal variation in grain yield along two rice terrace cascades in the uplands of northern Viet Nam, (ii) possible linkage of sediment deposition with the observed variation in grain yield, and (iii) whether spatial variation in soil water or nitrogen availability influenced the obtained yields masking the effect of inherent soil fertility using carbon isotope (¹³C) discrimination and ¹⁵N natural abundance techniques. In order to evaluate the impact of seasonal conditions, fertilizer use and sediment quality on rice performance, ¹⁵N and ¹³C stable isotope compositions of rice leaves and grains taken after harvest were examined and combined with soil fertility information and rice performance using multivariate statistics. The observed grain yields for the non-fertilized fields, averaged over both cascades, accounted for 4.0 ± 1.4 Mg ha^?1 and 6.6 ± 2.5 Mg ha^?1 in the spring and summer crop, respectively, while for the fertilized fields, grain yields of 6.5 ± 2.1 Mg ha^?1 and 6.9 ± 2.1 Mg ha^?1 were obtained. In general, the spatial variation of rice grain yield was strongly and significantly linked to sediment induced soil fertility and textural changes, such as soil organic carbon (r 0.34/0.77 for Cascades 1 and 2, respectively) and sand fraction (r ?0.88/?0.34). However, the observed seasonal alteration in topsoil quality, due to sediment deposition over two cropping cycles, was not sufficient to fully account for spatial variability in rice productivity. Spatial variability in soil water availability, assessed through ¹³C discrimination, was mainly present in the spring crop and was linearly related to the distance from the irrigation channel, and overshadowed in Cascade 2 the expected yield trends based on sediment deposition. Although δ¹⁵N signatures in plants indicated sufficient N uptake, grain yields were not found to be always significantly influenced by fertilizer application. These results showed the importance of integrating sediment enrichment in paddy fields within soil fertility analysis. Furthermore, where the effect of inherent soil fertility on rice productivity is masked by soil water or nitrogen availability, the use of ¹³C and ¹⁵N stable isotopes and its integration with conventional techniques showed potential to enhance the understanding of the influence of erosion – sedimentation and nutrient fluxes on crop productivity, at toposequence level.     

Assessing soil chemical and physical property responses to deforestation and subsequent cultivation in smallholders farming system in Ethiopia

In Ethiopia land degradation in the forms of soil erosion and declining soil fertility are serious challenges to agricultural productivity and economic growth. Despite the general recognition of the threat from land degradation on agricultural productivity, few studies have been made to quantify the extent, rate and process of soil fertility depletion under various land use systems and management practices in the country. In this study we assessed soil chemical and physical property responses to deforestation and subsequent cultivation along a chronosequence of closely located farmlands of different ages (7, 10, 26, 34 and 53 years) since conversion from a tropical dry Afromontane natural forest in Ethiopia. These properties were compared with soil properties under an adjacent natural forest. The changes were used as indicators to evaluate the sustainability of the farm management. All the soils in the study were Mollic Andosols/Humic Haplustands. Soil bulk density (g cm⁻³) in the 0–10 and 10–20 cm soil layers increased significantly while percent pore space decreased significantly in a continuum with increasing cultivation period. Soil C and total N contents (g kg⁻¹) in the 0–10 cm soil layer declined significantly and exponentially with increasing years under cultivation. However, in the 10–20 cm soil layer both soil C and total N on the farmlands were significantly higher until after 34 years of continuous cultivation compared to the same soil layer under the natural forest. Consequently, the soil C stock (g m⁻²) of the upper 0.20 m mineral soil was not significantly lower on the farmlands until after 26 years of continuous cultivation compared to the natural forest soil. Available P and K (mg kg⁻¹) in the 0–10 cm layer were higher in the soils of the farmlands throughout the 53 years of continuous cultivation compared to the soil under the natural forest. Exchangeable Ca, CEC and base saturation in the 0–10 cm soil layer declined more or less throughout the cultivation period while in the 10–20 cm soil layer they followed the patterns of soil C of that depth. Generally, the magnitudes and rates of degradation of the soil properties following conversion and subsequent cultivation were lower than expected for a low input tropical farming system as the one investigated. Nevertheless, almost all soil quality attributes showed overall declining trends in the long perspective. This continuous decline, albeit slowly, in soil quality with increasing cultivation period indicated that the present land management is not sustainable. Therefore, improved management is imperative to sustain the soil quality and maintain long-term productivity of the farmlands.     

Correlating negotiation hotspot issues,Paris climate agreement and the international climate policy regime

The concerns over climate change negotiation, decision texts and links to domestic policy interests of countries to keep warming within an acceptable limit have become the ‘hotspot issues’ of the United Nations Framework Convention on Climate Change (UNFCCC). Hotspot issues are the human – political economy factors which have evolved over time from negotiation texts or phrases, principles or behaviors with tendencies to influence climate negotiations yet cannot be identified with the scientific literature. Whilst big emitters have been accused as having hegemony over the negotiations, the effects of disunity amongst the parties over domestic policy interests have been overlooked. Hence the article examines the emergence of hotspot issues and how they manifest within the international climate policy regime. The Intended Nationally Determined Contributions (INDCs) of 130 countries submitted before the Paris agreement, were analyzed using the following texts: Adaptation, Mitigation, Co-benefits, Finance, Land use, Food security, Poverty, Resilience, Green growth, Green economy, Sustainable development, Biodiversity, Ecosystem services and Conservation. Of these, ‘adaptation’ was cited 2780 times, 1956 for ‘mitigation’ and 32 for ‘ecosystem services’ in the nature conservation category. Ten phases of the climate policy regime and historical hotspot issues were identified for the period 1980–2030. ‘Adaptation’ and mitigation appeared more frequently in the INDCs and correlated with each other (r = 0.56), as the two correlated further with ‘land use’ (0.50 < r < 0.60), and similarly with sustainable development (0.40 < r < 0.70) where ‘r’ is the Pearson Rank Correlation. Therefore the success of the ‘ambitious targets’ for mitigation will depend on similar ambitious goals for adaptation, land use and sustainable development. Several differences existed in the correlation of the hotspot issues within the regional geographical blocs (Africa, Asia, Europe, North America, Oceania, South America) and split along the hotspot issues yet Europe mostly oriented towards mitigation and land use, and Oceania on resilience building. These differences provide favorable conditions for increased cooperation and true multilateralism if they are properly diagnosed.     

Climate-driven changes in air quality over Europe by the end of the 21st century,with special reference to Portugal

Climate change alone may deeply impact air quality levels in the atmosphere because the changes in the meteorological conditions will induce changes on the transport, dispersion and transformation of air pollutants. The aim of this work was to evaluate the impact of climate change on the air quality over Europe and Portugal, using a reference year (year 1990) and a IPCC SRES A2 year (year 2100). The Hadley Centre global atmospheric circulation model (HadAM3P) was used to provide results for these two climatic scenarios, which were then used as synoptic forcing for the MM5-CHIMERE air quality modelling system. In order to assess the contribution of future climate change on O₃ and PM concentrations, no changes in regional emissions were assumed and only climate change forcing was considered. The modelling results suggest that the O₃ monthly mean levels in the atmosphere may increase almost 50 μg m^?3 across Europe in July under the IPCC SRES A2 scenario. In Portugal, this increase may reach 20 μg m^?3. The changes of PM10 monthly average values over Europe will depend on the region. The increase in PM10 concentrations during specific months could be explained by the average reduction of the boundary layer height and wind speed.     

Grass–legume mixtures can yield more nitrogen than legume pure stands due to mutual stimulation of nitrogen uptake from symbiotic and non-symbiotic sources

Concerted use of legumes and of functional diversity in grassland forage systems can provide major contributions to the challenges of agricultural systems being productive yet environmental friendly. Acquisition and transformation of nitrogen (N) resources by legumes and grasses were studied in a temperate grassland experiment near Zurich (Switzerland) to investigate mechanisms driving effects of functional diversity in mixed swards and to optimise mixtures for efficient resource use.Grass–legume interactions and N availability were varied by manipulating legume percentage of the sward (0–100%) and N fertiliser application (50, 150 or 450 kg of N ha^?1 year^?1). ¹⁵N technology quantified N derived from symbiotic (Nsym) and non-symbiotic (Nnonsym) sources.Generally, acquisition of Nsym by the entire mixture was stimulated by grasses. As a result, strong overyielding of Nsym occurred (e.g. 75 and 114% for year 1 and 2 at N150) and mixtures with only 60% and 37% legumes (year 1 and 2) already attained the same Nsym yield as pure legume stands. Legumes stimulated Nnonsym acquisition by the entire mixture, largely via increased uptake by the grass component. Thus, overyielding of Nnonsym of 31% occurred in year 1 (N150).Mutual grass–legume interactions stimulated acquisition of Nsym, acquisition of Nnonsym and efficient transformation of N into biomass compared to either monocultures. These effects of functional diversity can substantially contribute to productive and resource efficient agricultural grassland systems and were maximised in mixtures with 40–60% legumes.     

Evaluation of two soil carbon models using two Kenyan long term experimental datasets

RothC and Century are two of the most widely used soil organic matter (SOM) models. However there are few examples of specific parameterisation of these models for environmental conditions in East Africa. The aim of this study was therefore, to evaluate the ability of RothC and the Century to estimate changes in soil organic carbon (SOC) resulting from varying land use/management practices for the climate and soil conditions found in Kenya. The study used climate, soils and crop data from a long term experiment (1976–2001) carried out at The Kabete site at The Kenya National Agricultural Research Laboratories (NARL, located in a semi-humid region) and data from a 13 year experiment carried out in Machang’a (Embu District, located in a semi-arid region). The NARL experiment included various fertiliser (0, 60 and 120 kg of N and P₂O₅ ha⁻¹), farmyard manure (FYM—5 and 10 t ha⁻¹) and plant residue treatments, in a variety of combinations. The Machang’a experiment involved a fertiliser (51 kg N ha⁻¹) and a FYM (0, 5 and 10 t ha⁻¹) treatment with both monocropping and intercropping. At Kabete both models showed a fair to good fit to measured data, although Century simulations for treatments with high levels of FYM were better than those without. At the Machang’a site with monocrops, both models showed a fair to good fit to measured data for all treatments. However, the fit of both models (especially RothC) to measured data for intercropping treatments at Machang’a was much poorer. Further model development for intercrop systems is recommended. Both models can be useful tools in soil C predictions, provided time series of measured soil C and crop production data are available for validating model performance against local or regional agricultural crops.     

Reconnecting crop and cattle farming to reduce nitrogen losses to river water of an intensive agricultural catchment (Seine basin,France): past,present and future

Nitrate and pesticide contamination of surface and groundwater has become a major problem in intensive farming regions in Europe, with nitrate concentrations reaching values above the standard defined in 2000 by the European Water Framework Directive. In the Seine basin, a major issue is the closure and abandonment of drinking-water wells, which force water managers and drinking-water producers to explore solutions for water resource protection. Organic farming has appeared as a credible alternative to conventional farming, and this study explores the potential of organic farming to reconcile agricultural production and water quality. On the basis of agricultural statistics, survey questionnaires and experimental data, the nitrogen soil surface balance (N-SSB) has been established at the scale of a small 104-km² catchment (The Orgeval sub-basin), representative of the intensive cash crop farming in the Seine basin. The N-surplus for arable land in specialized organic cash crop systems has been found to be half that of current conventional systems (15 kg N ha⁻¹ yr⁻¹ versus 30 kg N ha⁻¹ yr⁻¹, respectively). The N-yield in organic systems is 21% lower than in conventional systems, but total fertilization (mostly symbiotic N fixation) is also 26% lower. Whereas 2–3 years of forage legume (e.g., alfalfa) as a starter crop of the typical 7- to 10-year diversified rotation builds up N soil fertility and helps prevent weeds without pesticides, the existence of an outlet for this fodder production is a limiting factor for the economic sustainability and the environmental benefits of these farming systems. Therefore, we explored the possibility of a reconnection of livestock and crop farming systems in the Orgeval catchment, a traditional dairy farming and Brie cheese production region. We calculated the N-SSB for this type of a reconnected livestock and cropping system and found a value very close to the specialized organic cash crop system with full utilization of fodder production, leading to profitable animal production, essentially as milk in this farm design. This reconnected system is compared with the estimated situation in 1955 before separation of plant and livestock production. Furthermore, the N-SSB values were converted into infiltrating sub-root concentrations and used as a boundary condition to a biogeochemical model. Organic cropping and organic reconnected livestock cropping systems result in a 50% reduction of surface water nitrate concentrations, a surface water quality 20% better than that reconstructed for 1955, with an overall higher protein production.