Sources of nitrous and nitric oxides in paddy soils：Nitrification and denitrification

Rice-paddies are regarded as one of the main agricultural sources of N 2O and NO emissions. To date, however, specific N2O and NO production pathways are poorly understood in paddy soils. ^15N-tracing experiments were carded out to investigate the processes responsible for N2O and NO production in two paddy soils with substantially different soil properties. Laboratory incubation experiments were carried out under aerobic conditions at moisture contents corresponding to 60% of water holding capacity. The relative importance of nitrification and denitrification to the flux of NaO was quantified by periodically measuring and comparing the enrichments of the N2O, NH~-N and NO3-N pools. The results showed that both N2O and NO emission rates in an alkaline paddy soil with clayey texture were substantially higher than those in a neutral paddy soil with silty loamy texture. In accordance with most published results, the ammonium N pool was the main source of N2O emission across the soil profiles of the two paddy soils, being responsible for 59.7% to 97.7% of total N2O emissions. The NO3-N pool of N2O emission was relatively less important under the given aerobic conditions. The rates of N2O emission from nitrification （N2On） among different soil layers were significantly different, which could be attributed to both the differences in gross N nitrification rates and to the ratios of nitrified N emitted as NzO among soil layers. Furthermore, NO fluxes were positively correlated with the changes in gross nitrification rates and the ratios of NO/N2O in the two paddy soils were always greater than one （from 1.26 to 6.47）. We therefore deduce that, similar to N2O, nitrification was also the dominant source of NO in the tested paddy soils at water contents below 60% water holding capacity.     

Mitigation of agricultural nonpoint-source pesticide pollution in artificial wetland ecosystems

Contamination caused by pesticides in agriculture is a source of environmental poor water quality in some of the European Union countries. Without treatment or targeted mitigation, this pollution is diffused in the environment. Pesticides and some metabolites are of increasing concern because of their potential impacts on the environment, wildlife and human health. Within the context of the European Union (EU) water framework directive context to promote low pesticide-input farming and best management practices, the EU LIFE project ArtWET assessed the efficiency of ecological bioengineering methods using different artificial wetland (AW) prototypes throughout Europe. We optimized physical and biological processes to mitigate agricultural nonpoint-source pesticide pollution in artificial wetland ecosystems. Mitigation solutions were implemented at full-scale demonstration and experimental sites. We tested various bioremediation methods at seven experimental sites. These sites involved (1) experimental prototypes, such as vegetated ditches, a forest microcosm and 12 wetland mesocosms, and (2) demonstration prototypes: vegetated ditches, three detention ponds enhanced with technology of constructed wetlands, an outdoor bioreactor and a biomassbed. This set up provides a variety of hydrologic conditions, with some systems permanently flooded and others temporarily flooded. It also allowed to study the processes both in field and controlled conditions. In order to compare the efficiency of the wetlands, mass balances at the inlet and outlet of the artificial wetland will be used, taking into account the partition of the studied compound in water, sediments, plants, and suspended solids. The literature background necessary to harmonize the interdisciplinary work is reviewed here and the theoretical framework regarding pesticide removal mechanisms in artificial wetland is discussed. The development and the implementation of innovative approaches concerning various water quality sampling strategies for pesticide load estimates during flood, specific biological endpoints, innovative bioprocess applied to herbicide and copper mitigation to enhance the pesticide retention time within the artificial wetland, fate and transport using a 2D mixed hybrid finite element model are introduced. These future results will be useful to optimize hydraulic functioning, e.g., pesticide resident time, and biogeochemical conditions, e.g., dissipation, inside the artificial wetlands. Hydraulic retention times are generally too low to allow an optimized adsorption on sediment and organic materials accumulated in artificial wetlands. Absorption by plants is not either effective. The control of the hydraulic design and the use of adsorbing materials can be useful to increase the pesticides residence time and the contact between pesticides and biocatalyzers. Pesticide fluxes can be reduced by 50–80% when hydraulic pathways in artificial wetlands are optimized by increasing ten times the retention time, by recirculation of water, and by deceleration of the flow. Thus, using a bioremediation method should lead to an almost complete disappearance of pesticides pollution. To retain and treat the agricultural nonpoint-source po a major stake for a sustainable development.     

The Evolution of the Environmental Quality Concept: From the US EPA Red Book to the European Water Framework Directive

- DOI: http://dx.doi.org/10.1065/espr2006.01.003 Background Water Quality Criteria were firstly defined in the 1970s by the EPA in the USA and the EIFAC in Europe, recognizing the need for protecting water quality in order to allow the use of water resources by man. In the 1990s, the European Commission emphasized the importance of safeguarding structure and function of biologic communities. These approaches were chemically-based. The European Water Framework Directive (WFD) substantially changes the concept of Water Quality, by assuming that a water body needs to be protected as an environmental good and not as a resource to be exploited. In this frame, the biological-ecological quality assumes a prevailing role. Main Features The Water Quality concept introduced by the WFD is a challenge for environmental sciences. Reference conditions should be defined for different typologies of water bodies and for different European ecoregions. Suitable indicators should be developed in order to quantify ecological status and to define what a 'good' ecological status is. Procedures should be developed for correlating the deviation from a good ecological to the effects of multiple stressors on function and structure of the ecosystem. The protection of biodiversity becomes a key objective. In this frame, the traditional procedures for ecotoxicological risk assessment, mainly based on laboratory testing, should be overcome by more site-specific approaches, taking into account the characteristics and the homeostatic capabilities of natural communities. In the paper an overview of the present knowledge and of the new trends in ecotoxicology to get these objectives will be given. A procedure is suggested based on the concept of Species Sensitivity Distribution (SSD). Recommendations and Perspective . The need for more site-specific and ecologically-oriented approaches in ecotoxicology is strongly recommended. The development of new tools for implementing the concept of 'Stress Ecology' has been recently proposed by van Straalen (2003). In the same time, more 'cological realism'is needed in practically applicable procedures for regulatory purposes.     

Smart nanopackaging for the enhancement of food shelf life

Environmental Chemistry Letters - Food spoilage is a major global concern due to the lack of proper packaging technology. Nanotechnology is expected to improve food packaging. Indeed, novel...     

Effect of buffer strips and soil texture on runoff losses of flufenacet and isoxaflutole from maize fields

The influence of buffer strips and soil texture on runoff of flufenacet and isoxaflutole was studied for two years in Northern Italy. The efficacy of buffer strips was evaluated on six plots characterized by different soil textures; two plots had Riva soil (18.6% sand, 63.1% silt, 18.3% clay) while the remaining four plots had Tetto Frati (TF) soil (37.1% sand, 57% silt, 5.9% clay). Additionally, the width of the buffer strips, constituted of spontaneous vegetation grown after crop sowing, was also compared for their ability to abate runoff waters. Chemical residues in water following runoff events were investigated, as well as their dissipation in the soil. After the first runoff events, concentrations of herbicides in water samples collected from Riva plots were as much as four times lower in waters from TF plots. On average of two growing seasons, the field half-life of flufenacet in the upper soil layer (5 cm) ranged between 8.1 and 12.8 days in Riva soil, 8.5 and 9.3 days in TF soil. Isoxaflutole field half-life was less than 1 day. The buffer strip was very affective by the uniformity of the vegetative cover, particularly, at the beginning of the season. In TF plots, concentration differences were generally due to the presence or absence of the buffer strip, regardless of its width.     

Sixty years of habitat decline: impact of land-cover changes in northern Italy on the decreasing ortolan bunting <Emphasis Type=Italic>Emberiza hortulana</Emphasis>

Habitat loss and degradation are main global threats to biodiversity, and land-use changes in agriculture-dominated landscapes are crucial for an important portion of biodiversity, especially in Europe. We evaluated the effects of land-use changes (1954–2012) on a threatened species, the ortolan bunting, in an agricultural area crucial for its conservation in Italy. We built a distribution model for ortolan bunting in current landscapes and then re-projected it to past scenarios (1954 and 1999–2000). We evaluated the most important land-use changes occurred and estimated their effects on habitat suitability. Bunting occurrence was mostly affected by the extent of grassland (positively; used as foraging/breeding ground), shrubland (quadratic effect; perches/shelter), forest and urbanized land (negatively), and by solar radiation (positively) and slope (quadratic), consistent with other studies carried out especially in southern Europe. The potential distribution of the species was much larger in the past: the estimated decline in suitable habitat is 44–72 % (since 1999–2000/1954), coherent with historical data suggesting strong decline and contraction. Changes in suitability (1954–2012) were mostly associated with changes in the cover of forest, vineyards and abandoned areas (negatively), and shrubland (positively). Land-use/land-cover changes are the main drivers of species occurrence and of habitat decline. The heterogeneous landscape of hilly/low-mountain sites in this area, characterized by a mix of habitats offering complementary resources to ortolan buntings and other species of conservation concern, is currently threatened by abandonment and intensification, but its maintenance may be promoted by a correct definition of Rural Development Programme measures.     

Agronomic adaptation strategies under climate change for winter durum wheat and tomato in southern Italy: irrigation and nitrogen fertilization

Agricultural crops are affected by climate change due to the relationship between crop development, growth, yield, CO₂ atmospheric concentration and climate conditions. In particular, the further reduction in existing limited water resources combined with an increase in temperature may result in higher impacts on agricultural crops in the Mediterranean area than in other regions. In this study, the cropping system models CERES-Wheat and CROPGRO-Tomato of the Decision Support System for Agrotechnology Transfer (DSSAT) were used to analyse the response of winter durum wheat (Triticum aestivum L.) and tomato (Lycopersicon esculentum Mill.) crops to climate change, irrigation and nitrogen fertilizer managements in one of most productive areas of Italy (i.e. Capitanata, Puglia). For this analysis, three climatic datasets were used: (1) a single dataset (50?km?×?50?km) provided by the JRC European centre for the period 1975–2005; two datasets from HadCM3 for the IPCC A2 GHG scenario for time slices with +2°C (centred over 2030–2060) and +5°C (centred over 2070–2099), respectively. All three datasets were used to generate synthetic climate series using a weather simulator (model LARS-WG). Adaptation strategies, such as irrigation and N fertilizer managements, have been investigated to either avoid or at least reduce the negative impacts induced by climate change impacts for both crops. Warmer temperatures were primarily shown to accelerate wheat and tomato phenology, thereby resulting in decreased total dry matter accumulation for both tomato and wheat under the +5°C future climate scenario. Under the +2°C scenario, dry matter accumulation and resulting yield were also reduced for tomato, whereas no negative yield effects were observed for winter durum wheat. In general, limiting the global mean temperature change of 2°C, the application of adaptation strategies (irrigation and nitrogen fertilization) showed a positive effect in minimizing the negative impacts of climate change on productivity of tomato cultivated in southern Italy.     

Image processing tools in the study of environmental contamination by microplastics: reliability and perspectives

Environmental Science and Pollution Research - Microplastic pollution is one of the greatest environmental concerns for contemporary times and the future. In the last years, the number of...     

Effects of spatial autocorrelation and sampling design on estimates of protected area effectiveness

Estimating the effectiveness of protected areas (PAs) in reducing deforestation is useful to support decisions on whether to invest in better management of areas already protected or to create new ones. Statistical matching is commonly used to assess this effectiveness, but spatial autocorrelation and regional differences in protection effectiveness are frequently overlooked. Using Colombia as a case study, we employed statistical matching to account for confounding factors in park location and accounted for for spatial autocorrelation to determine statistical significance. We compared the performance of different matching procedures—ways of generating matching pairs at different scales—in estimating PA effectiveness. Differences in matching procedures affected covariate similarity between matched pairs (balance) and estimates of PA effectiveness in reducing deforestation. Independent matching yielded the greatest balance. On average 95% of variables in each region were balanced with independent matching, whereas 33% of variables were balanced when using the method that performed worst. The best estimates suggested that average deforestation inside protected areas in Colombia was 40% lower than in matched sites. Protection significantly reduced deforestation, but PA effectiveness differed among regions. Protected areas in Caribe were the most effective, whereas those in Orinoco and Pacific were least effective. Our results demonstrate that accounting for spatial autocorrelation and using independent matching for each subset of data is needed to infer the effectiveness of protection in reducing deforestation. Not accounting for spatial autocorrelation can distort the assessment of protection effectiveness, increasing type I and II errors and inflating effect size. Our method allowed improved estimates of protection effectiveness across scales and under different conditions and can be applied to other regions to effectively assess PA performance.