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Nitric oxide and nitrous oxide emissions from cattle-slurry and mineral fertiliser treated with nitrification inhibitor to an agricultural soil: a laboratory approach
Publication . Pereira, José; Coutinho, João; Fangueiro, David; Trindade, Henrique
The application of organic and mineral fertilisers to soil can result in increased gaseous emissions to the atmosphere such as
nitric oxide (NO) and nitrous oxide (N2O) gases. The aim of this study was to evaluate under laboratory conditions the effects on
mineral N dynamics and NO and N2O emissions of application to soil of cattle slurry derived liquid fraction (LF) obtained by screw
press and mineral fertiliser (MF), both treated with or without the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP).
An aerobic laboratory incubation was performed over 93 days with a Dystric Cambisol amended with mechanically separated LF
or mineral fertiliser ammonium sulphate only or combined with DMPP. Two additional treatments were included: soil only and soil
amended with DMPP. Nitrogen immobilisation was the dominant process with MF amendment, whereas N mineralisation has been
observed with LF. The application of LF reduced significantly NO emissions by 80% relative to mineral but no differences were
observed with N2O emissions. The addition of DMPP to MF induced a decrease of 18 and 29% in NO and N2O emissions whereas
DMPP combined with LF reduced (numerically but not statistically) these emissions in 20 and 10%, respectively. Results obtained
in our study suggest that N (NO + N2O) losses can be mitigated by adding DMPP to mineral fertilisers or replacing mineral fertiliser
by LF
Integrated modelling to assess N pollution swapping in slurry amended soils
Publication . Cameira, Maria; Li, Rick; Fangueiro, David
In the present work, it was hypothesized that through modelling it is possible to overcome the constraints that
arise in the quantification of N pollution swapping associated to slurry application practiceswhen using individual
experimental data. For this, environmental N losses were assessed under two methods of dairy slurry application
to a double cropping system (rainfed oats (Avena strigosa)/irrigated maize (Zea mays)) in two different
soils. An integrated experimentation and modelling approach was applied using the RZWQM2 model. The
modelwas first tested using four years of experimental data concerningN fluxes to/fromdifferent environmental
compartments (soilmineralization, N gas emissions, and N leaching). Themodel estimated emissionswith overall
efficiencies of ~70% and r2 ~ 0.75. Total N losses were higher for surface band application (95.4 and
40.2 kg ha−1 for the sandy and sandy loam soils, respectively). However, when slurry was injected, nitrate
leaching considerably increased (by 107 and 64% for the sandy and sandy loam soils, respectively), even though
gas emissions were minimized. This N swapping among path losses requires targeting of the N mitigation measures
to the environmental compartment showing the highest vulnerability. Generally, the estimated emission
factors (EFs) were lower than or equal to (slurry injection in the sandy loam soil) the IPCC default. The values
showed high variability, reinforcing the need to use agricultural system specific EFs. The methodologies used
in this study, focused on scenario analysis, can support policy as they can be used to set up integral strategies
to decrease N emissions fromlivestock farming systems, taking into account possible synergies and antagonisms
produced by the measures among NH3 and N2O emissions and NO3
− leaching
Dinâmica do azoto em solos fertilizados com chorume de bovino tratado
Publication . Martins, Maria de Fátima Vasques; Fangueiro, David; Cabral, Fernanda Maria Miranda
The incorrect use of effluents from cattle farming can lead to potential pollution of the environment. The aim of this work was to study the effects of pre-treatment of slurry by acidification and/or the method of slurry application on soil on the nitrogen dynamics, namely gaseous emissions of ammonia (NH3) and nitrous oxide (N2O) as well as nitrate leaching. A field trial with oat (Avena strigosa) has been carried out in two types of soil, with a sandy structure and the other one with a sandy-loam structure. The treatments applied were control (without slurry application), raw slurry applied by injection, raw slurry applied to soil surface followed by incorporation and acidified slurry applied to soil surface followed or not by incorporation. For each treatment, three replicates have been carried. Gaseous emissions of NH3 and N2O have been measured, as well as leachate sampling whenever precipitation occurred. Leachate samples were analyzed for nitrate concentration, pH and EC. From the results obtained and according to the treatments, it was found that to reduce nitrogen losses by ammonia volatilization and nitrate leaching, the use of acidified slurry followed by soil incorporation is the best option for both soils without causing any decrease in oat production.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
PTDC/AGR-PRO/119428/2010