David Fangueiro
Instituto Superior de Agronomia
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Featured researches published by David Fangueiro.
Talanta | 2005
David Fangueiro; Alain Bermond; Eduarda B.H. Santos; Helena M. Carapuça; Armando C. Duarte
Studies of trace metal mobilization in sediments are generally performed using sequential extraction schemes at equilibrium. In the present work, a kinetic fractionation of trace metals in sediments has been developed to assess that information. The extraction rate data have been obtained using a single extraction scheme with EDTA and following a protocol previously optimized. Two kinetic equations and two kinetic models were used to fit the experimental data. The two constants equation fits well the extraction rate data used in this work but does not present any physico-chemical meaning. The diffusion model and the two first-order reactions model allow determining which parameter (the reaction between the metal M and the EDTA or the diffusion of the complex M/EDTA) is rate limiting in the trace metal extraction by EDTA. It appears that the two first-order reactions model is more efficient than the diffusion model to fit the present extraction rate data so it can be deduced that the diffusion of the complex M/EDTA is not the limiting step of the trace metal extraction by EDTA in estuarine sediments. In a second part, relationships between the fraction of metals determined with the two first-order reactions model and the sediments composition were established.
Bioresource Technology | 2008
David Fangueiro; Mehmet Senbayran; Henrique Trindade; David Chadwick
Five cattle slurry fractions with distinct characteristics were obtained using a combined separation process (screw press+chemically enhanced settling using polyacrylamide (PAM)). The purpose of the present study was to assess the effect of each fraction relatively to the untreated slurry (US) on the emissions of greenhouse gases (CH4, N2O) after grassland application and on the grass yield. Methane emissions occurred mainly in the first two days after application and were observed only in treatments with the US and liquid fractions. Significant N2O emissions were observed only in the US and liquid fractions treatments. A significant increase of the grass yield relatively to the US was observed in plots amended with the composted solid fraction and with the PAM-sup fraction resulting from the PAM sediment settling of the liquid fraction previously obtained by screw press separation, whereas in all other treatments, no significant differences were observed. Considering the overall separation process, the proposed scheme did not lead to an increase, relative to the US, of gas emissions after soil application of the fractions obtained except in the case of CH4 where a small increase was observed.
Journal of Environmental Management | 2015
David Fangueiro; Maibritt Hjorth; F. Gioelli
Ammonia emissions are a major problem associated with animal slurry management, and solutions to overcome this problem are required worldwide by farmers and stakeholders. An obvious way to minimize ammonia emissions from slurry is to decrease slurry pH by addition of acids or other substances. This solution has been used commonly since 2010 in countries such as Denmark, and its efficiency with regard to the minimization of NH3 emissions has been documented in many studies. Nevertheless, the impact of such treatment on other gaseous emissions during storage is not clear, since the studies performed so far have provided different scenarios. Similarly, the impact of the soil application of acidified slurry on plant production and diffuse pollution has been considered in several studies. Also, the impact of acidification upon combination with other slurry treatment technologies (e.g. mechanical separation, anaerobic digestion …) is important to consider. Here, a compilation and critical review of all these studies has been performed in order to fully understand the global impact of slurry acidification and assess the applicability of this treatment for slurry management.
Chemosphere | 2010
J.A. Pereira; David Fangueiro; David Chadwick; T.H. Misselbrook; João Coutinho; Henrique Trindade
The application of untreated or treated animal manure to soils can result in increased N and C gaseous emissions contributing to ecosystem change and global warming. In the present study, dairy cattle slurry (liquid manure) was subjected first to pre-treatment by separation using a screw press to obtain a liquid (LF) and a solid fraction (SF). Then, the different fractions and the whole slurry (WS) were combined with two nitrification inhibitors (NI), dicyandiamide (DCD) or 3,4-dimethylpyrazole phosphate (DMPP), were applied to soil to assess the effect of slurry treatment by separation and NI addition on soil N dynamics and CH4, CO2, NH3, NO and N2O emissions. The WS and the two slurry fractions, combined or not with DCD or DMPP, were applied to soil at an equivalent field dosage of 120 kg total N ha(-1). Controls including a soil only, soil-DCD and soil-DMPP treatments were also included. The mixtures were incubated for 93-d at 20 degrees C. Results obtained show that NI inhibited nitrification between 16 and 30-d in WS and LF, with DMPP having a longer effect over time compared to DCD. There was no significant effect of NI on nitrification for the SF treatment. Nitrification inhibitors did not significantly affect (P>0.05) the CH4, CO2 and N2O emissions, but significantly decreased (P<0.05) NO emissions. Furthermore, the two NIs had a similar effect on gaseous emissions. Throughout the entire experiment, the greatest amount of NO was released from the LF treatment (without NI), while the greatest amount of N2O was released from the SF treatment. Slurry separation had no impact on N emissions, while the combination of this process with one of the two NI led to a small reduction in total N emissions.
Journal of Environmental Quality | 2008
David Fangueiro; João Coutinho; David Chadwick; Nuno Moreira; Henrique Trindade
Storage of cattle slurry leads to emissions of methane (CH(4)), nitrous oxide (N(2)O), ammonia (NH(3)), and carbon dioxide (CO(2)). On dairy farms, winter is the most critical period in terms of slurry storage due to cattle housing and slurry field application prohibition. Slurry treatment by separation results in reduced slurry dry matter content and has considerable potential to reduce gaseous emissions. Therefore, the efficiency of slurry separation in reducing gaseous emissions during winter storage was investigated in a laboratory study. Four slurry fractions were obtained: a solid and a liquid fraction by screw press separation (SPS) and a supernatant and a sediment fraction by chemically enhanced settling of the liquid fraction. Untreated slurry and the separated fractions were stored in plastic barrels for 48 d under winter conditions, and gaseous emissions were measured. Screw press separation resulted in an increase of CO(2) (650%) and N(2)O (1240%) emissions due to high releases observed from the solid fraction, but this increase was tempered by using the combined separation process (CSP). The CSP resulted in a reduction of CH(4) emissions ( approximately 50%), even though high emissions of CH(4) (46% of soluble C) were observed from the solid fraction during the first 6 d of storage. Screw press separation increased NH(3) emissions by 35%, but this was reduced to 15% using the CSP. During winter storage greenhouse gas emissions from all treatments were mainly in the form of CH(4) and were reduced by 30 and 40% using SPS and CSP, respectively.
Bioresource Technology | 2009
David Fangueiro; Henrique M. Ribeiro; Ernesto Vasconcelos; João Coutinho; F. Cabral
The aim of the present work was to assess the effect of treatments by acidification, solid-liquid separation or acidification followed by solid-liquid separation on the physical and chemical composition of pig slurry (S) and pig slurry fractions (non acidified and acidified solid (SF and ASF) and liquid (LF and ALF) fractions), as well as on the potential of N mineralization of these pig slurry derived materials. Acidification strongly decrease the inorganic carbon content of S, SF and LF and it also affects the distribution of P, Ca and Mg between the solid and liquid fraction leading to an ALF more equilibrated than LF in terms of nutrients. Acidification increases the potential of organic N mineralization in SF and decreases the potential of N immobilization in S and LF. It can be concluded that the proposed treatment generates valuable slurry fractions with distinct characteristics and potential of N mineralization that may be incorporated to soil at different periods after sowing to comply with plant nutrient requirements.
Communications in Soil Science and Plant Analysis | 2009
David Fangueiro; A. Fernandes; João Coutinho; Nuno Moreira; Henrique Trindade
Nitrogen (N) losses through nitrate leaching, occurring after slurry spreading, can be reduced by the use of nitrification inhibitors (NIs) such as dicyandiamide (DCD) and 3,4‐dimethyl pyrazole phosphate (DMPP). In the present work, the effects of DCD and DMPP, applied at two rates with cattle slurry, on soil mineral N profiles, annual ryegrass yield, and N uptake were compared under similar pedoclimatic conditions. Both NIs delayed the nitrate formation in soil; however, DMPP ensured that the soil mineral N was predominantly in the ammonium form rather than in the nitrate form for about 100 days, whereas with DCD such effect was observed only during the first 40 days after sowing. Furthermore, the use of NIs led to an increase of the dry‐matter (DM) yields in a range of 32–54% and of the forage N removal in a range of 34–68% relative to the slurry‐only (SO) treatment (without NIs). A DM yield of 8698 kg ha−1 was obtained with the DMPP applied at the greater rate against only 7444 kg ha−1 obtained with the greater rate of DCD (4767 kg ha−1 in the SO treatment). Therefore, it can be concluded that DMPP is more efficient as an NI than DCD when combined with cattle slurry.
Chemosphere | 2010
David Fangueiro; David Chadwick; Liz Dixon; João Grilo; Nicolas Walter; Roland Bol
Little is known about the interaction of the soils physicochemical environment and livestock slurry throughout the soil profile. In this study, five soil layers (2-6, 6-10, 10-14, 14-18, 18-22 cm) amended with a<45 microm slurry fraction (FS) or water (control) were incubated for 58 d at 20 degrees C to determine the effect of the slurry position in the soil profile on the production of CO(2), N(2)O, CH(4) and total greenhouse gas (GHG) expressed as CO(2) equivalent. FS application increased the CO(2) production in all soil layers by 3-8 times compared to the controls. The total CO(2) produced during the incubation in the 2-6 cm amended soil layer (>1,600 mg CO(2)-C kg(-1) dry soil) was significantly greater (P<0.05) than in other amended layers (<800 mg CO(2)-C kg(-1) dry soil). No detectable N(2)O production was observed from control treatments, and application of FS induced a slow increase in N(2)O production. N(2)O production occurred earlier and at a higher rate in deeper soil layers. Furthermore, a good correlation (r=0.899, P<0.05) was observed between N(2)O production and soil depth. The higher N(2)O production in the deeper soil layers could have been due to enhanced denitrification promoted by a lower aeration and low soil respiration in the deep soil. At the end of the incubation, >11% of the total applied N was lost as N(2)O from the two deeper soil layers against 2.5-5% in all other soil layers. Methane production was only observed from FS amended treatments within the first 7d (range 0.02-0.41 mg C kg(-1) soil d(-1)). The greatest net production of GHGs, expressed as CO(2) equivalents, was observed from the two deeper soil layers ( approximately 4.5 CO(2) eq kg(-1) soil). N(2)O and CO(2) contributed equally (50%) to the total GHG production in 2-14 cm soil layers, whereas N(2)O contributed reached 80% to the total GHG production in the deeper soil layers. The CH(4) contribution was not significant in any treatment.
Biology and Fertility of Soils | 2014
David Fangueiro; João Coutinho; L. Borges; F. Cabral; Ernesto Vasconcelos
Solid–liquid separation is now a common slurry management on European farms and many separation techniques are now available. The choice of technique used is based mostly on financial reasons even if the dry matter separation efficiency is also considered. Nevertheless, previous studies showed that the separation technique used influenced the composition of the resulting liquid (LF) and solid (SF) fractions. Hence, our hypothesis is that separation technique influences the C and N dynamics in soils amended with the resulting SF and LF. A laboratory incubation was performed with a sandy soil to assess the influence of five different separation techniques on the N and C dynamics in soil amended with the resulting LF and SF, namely the potential of each fraction for N and organic matter supply to plant and soil systems. Our results showed that the separation technique affects significantly the soil C pools in soils amended with the resulting LF and SF. Nevertheless, the differences between SFs were very low, whereas higher C losses were observed from LFs obtained with active separation techniques such as sieving relative to passive techniques such as sediment settling. The N dynamics in soils amended with the different SF obtained were similar but the extent of NH4+ immobilization differs with the LF considered. Furthermore, higher and faster nitrification was observed with LFs obtained by sediment settling and centrifugation relative to sieving. A higher N mineralization relative to untreated slurry was observed in most fractions and the N mineralization rates were significantly influenced by the separation technique.
Journal of Environmental Management | 2015
David Fangueiro; J.A. Pereira; André Bichana; S. Surgy; F. Cabral; João Coutinho
Cattle-slurry (liquid manure) application to soil is a common practice to provide nutrients and organic matter for crop growth but it also strongly impacts the environment. The objective of the present study was to assess the efficiency of cattle-slurry treatment by solid-liquid separation and/or acidification on nitrogen dynamics and global warming potential (GWP) following application to an acidic soil. An aerobic laboratory incubation was performed over 92 days with a Dystric Cambisol amended with raw cattle-slurry or separated liquid fraction (LF) treated or not by acidification to pH 5.5 by addition of sulphuric acid. Soil mineral N contents and NH3, N2O, CH4 and CO2 emissions were measured. Results obtained suggest that the acidification of raw cattle-slurry reduced significantly NH3 emissions (-88%) but also the GWP (-28%) while increased the N availability relative to raw cattle-slurry (15% of organic N applied mineralised against negative mineralisation in raw slurry). However, similar NH3 emissions and GWP were observed in acidified LF and non-acidified LF treatments. On the other hand, soil application of acidified cattle-slurry rather than non-acidified LF should be preferred attending the lower costs associated to acidification compared to solid-liquid separation. It can then be concluded that cattle-slurry acidification is a solution to minimise NH3 emissions from amended soil and an efficient strategy to decrease the GWP associated with slurry application to soil. Furthermore, the more intense N mineralisation observed with acidified slurry should lead to a higher amount of plant available N and consequently to higher crop yields.