Browsing by Author "Moreira, N."
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- Comparison of field methods to assess net N mineralization in soils under different rates of cattle-slurry application and a maize / annual ryegrass cropping systemPublication . Pereira, J.; Coutinho, J.; Moreira, N.; Trindade, H.Knowledge of the amount of N mineralized from manure applied to soil and its availability to crops is extremely important for precise fertilization practices and environment protection. The objectives of our study were to evaluate the effect of cattle-slurry application rate on net N mineralization (NNM) and compare the field methods of soil core incubation with acetylene (SIA) and the sequential in situ incubation of undisturbed soil cores (SIU) to assess N mineralization in an intensive double-cropping forage system producing maize and Italian ryegrass (winter crop) for silage.
- Effect of dairy effluents pre-treatment on N2O emissions and N-organic degradation after soil applicationPublication . Fangueiro, D.; Pereira, J.; Coutinho, J.; Moreira, N.; Trindade, H.Nitrous oxide (N2O) is a potent greenhouse gas that plays a key role in climatic forcing contributing to the greenhouse effect by about 4 %, and also contributes to stratospheric ozone depletion. Cattle slurries are commonly applied to agricultural soils, inducing an increase of soil nitrous oxide emissions. Therefore, many procedures were developed for slurry pre-treatment in order to improve soil slurry application and reduce nitrogen losses, namely N2O emissions. The aim of this work was to compare N2O emissions and the kinetic of N organic degradation from treated and untreated cattle-slurry after its incorporation in agricultural soils.
- Effects of a urease inhibitor and aluminium chloride alone or combined with a nitrification inhibitor on gaseous N emissions following soil application of cattle urinePublication . Pereira, J.; Barneze, A.S.; Misselbrook, T.H.; Coutinho, J.; Moreira, N.; Trindade, H.Addition to soil of separated cattle-urine obtained from housing with urine-faeces segregation systems is an important source of gaseous nitrogen (N) emissions. This study aimed to evaluate the effect of adding different concentrations of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and aluminium chloride (AlCl3), alone or combined with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), on gaseous N losses and N transformations in soil amended with cattle-urine. Using laboratory incubations soil was amended with cattle-urine (200 kg total N ha!1 ) containing NBPT (0.1 or 1.0%) or AlCl3 (0.5 or 1.0%) either as a single additive or combined with 0.5% DMPP. Three additional treatments were included: soil only (Control), soil amended only with cattle-urine and soil amended with cattle-urine and DMPP. The addition of NBPT at 1% significantly delayed urea hydrolysis during the first 4- d after urine application comparatively to treatments receiving AlCl3. Nitrification was inhibited by addition of DMPP, with no further effect (P > 0.05) when DMPP was combined with NBPT or AlCl3. The AlCl3 treatment had no effect on urea hydrolysis or nitrification. The combination of DMPP with NBPT or AlCl3 increased (P < 0.05) NH3 emissions and reduced (P < 0.05) NO and N2O emissions compared with urine alone. It was concluded that NBPT was more effective at reducing gaseous N emissions from cattle-urine applications than AlCl3, and that NBPT alone was more effective than NBPT combined with DMPP. No advantages were gained from the combination of one of these additives with DMPP on total gaseous N emissions
- Influência da data de sementeira de culturas de Inverno na lixiviação de ião nitrato no sistema forrageiro intensivo do Entre Douro e MinhoPublication . Trindade, H.; Pereira, J.; Coutinho, J.; Moreira, N.
- Laboratory assessment of the effect of cattle slurry pre-treatment on organic N degradation after soil application and N2O and N2 emissionsPublication . Fangueiro, D.; Pereira, J.; Chadwick, D.; Coutinho, J.; Moreira, N.; Trindade, H.Slurry separation using mechanical and chemical methods is one of the options considered to solve problems of slurry management at the farm scale. The fractions obtained with such treatments have distinct compositions, which allow different options for their utilization (composting, direct application, and fertigation). In this study, four fractions of slurry were obtained using a combined treatment system including slurry treatment with a screw press separator (solid and liquid fractions) followed by sedimentation with the addition of Polyacrylamide (PAM) (PAM-Supernatant and PAM-Sediment) to the LF. These fractions were then incorporated into arable soil under controlled laboratory conditions and the organic N degradation from each treatment was followed for 94 days. Total N emissions (N2O + N2 ) as well as the sources of the N emissions (nitrification or denitrification) were also studied during this period. Results showed that the slurry fractions (SFs) had distinct behavior relative to the whole slurry (WS), namely in terms of N degradation in soil, where N mineralization was observed only in the WS treatment whereas N immobilization occurred in the other treatments. In terms of N2O emissions, higher losses, expressed as a percentage of the total N added, occurred from the LF treatments (liquid, PAM-Supernatant and PAM-Sediment). This work indicates that the slurry treatment by mechanical and chemical separation may be a good option for slurry management at the farm scale since it allows greater utilization of the different fractions with a small effect on N2O emissions after SFs’ application to soil
- Nitrogen mineralization in soils receiving different rates of cattle-slurry and cropped with forage maizePublication . Pereira, J.; Trindade, H.; Coutinho, J.; Moreira, N.The quantification and the time-course of organic nitrogen release from slurry applied at sowing of maize grown for silage is of major importance to increase the efficient use of slurry-N and to reduce environmental impacts. The objective of this work was to quantify the net N mineralization measured in the 0-30 cm soil layer during the forage maize growth period, when cattle slurry was applied at sowing to supply 340 (T1), 190 (T2) and 0 (T3) kg total N ha -1 . The experiment was carried out during 1999 in the NW region of Portugal. Net mineralization rates were significantly different and reached high values, being a relevant source of N for the plants. During the forage maize crop net mineralization represented 401, 281 and 174 Kg N ha -1 respectively on treatments T1, T2 and T3, values that correspond to average net N mineralization rates of 1.3, 0.9 and 0.6 mg N kg -1 soil day -1 . The forage maize dry matter yields on these treatments reached 22, 19 and 13 t ha -1 , respectively for T1, T2 and T3.
- NPK farm-gate nutrient balances in dairy farms from Northwest PortugalPublication . Fangueiro, D.; Pereira, J.; Coutinho, J.; Moreira, N.; Trindade, H.Farm-gate nutrient balances (N, P and K) were analysed in three groups of dairy farms from NW Portugal – medium, intensive and very intensive farms – during 3 consecutive years, 2003, 2004 and 2005. Results showed that the N surplus per hectare with values between 200 and 850 kg N ha−1 was positively correlated with the milk production per ha and the stocking rate of the farm, whereas the P and K surpluses showed fewer variations between groups. In all farms the main inputs were the mineral fertilizers and the feed concentrates whereas milk was the main output. Farmers involved in the study were advised in terms of nutrient management and significant decreases in the nutrient surpluses were observed during the 3 years study, mainly due to a decrease of the inputs, namely fertilizers. We conclude that advisory campaigns among farmers are efficient to reduce the nutrient surpluses. The N losses via NH3 emissions at farm scale were also estimated accordingly to IPCC emission factors and it appeared that such losses were significant and had to be considered together with the nutrient surpluses when strategies to enhance nutrient management are defined. On average, higher N surplus per hectare were observed in the studied dairy farms from NW Portugal relatively to other European regions, but NW Portugal present lower N surplus per production unit (kg milk) as well as higher N efficiency. Nevertheless, a target limit of 450 kg N ha−1 for N surplus should be easily reached as a first step by most of the farms of NW Portugal by improving nutrient management at farm scale. However, more efforts will be necessary to reduce NPK surplus and NH3 emissions to the mean values in a per hectare basis found in other European dairy regions with less intensive systems.
- Relatório Final do Projeto PTDC/AGR-AAM/102529/2008 “Emissões gasosas medidas em campos regados de arroz produzido em dois solos diferentes, em Portugal, por efeito das práticas culturais, do clima e do aumento da concentração de CO2 na atmosfera”Publication . Carranca, C.; Figueiredo, N.; Fareleira, P.; Vargues, A.; Prazeres, A.; Marques, P.; Trindade, H.; Coutinho, J.; Pereira, J.; Moreira, N.; Goufo, P.; Carneiro, J.; Ribeiro, A.; Mateus, E.; Gomes da Silva, M.; da Nazaré Alves, M.; Oliveira, C.; Justino, J.Os objetivos do estudo foram os seguintes: i) avaliação da dinâmica do azoto (N) em cada talhão, e na lâmina de água à superfície dos solos, durante os ciclos culturais do arroz, ii) avaliação da mineralização potencial do N nos solos, em condições aeróbias e anaeróbias, simulando o período cultural (25 ºC) e pós-colheita (10 ºC), iii) avaliação das actividades enzimáticas, biomassa microbiana e presença de cianobactérias em cada talhão, iv) avaliação da resposta do arroz (Oryza sativa L. cv. Ariete) às práticas culturais, tipo de solo e condições climáticas, v) avaliação da eficiência da utilização do N pela cultivar de arroz Ariete, num ensaio em vasos, vi) avaliação da cor das folhas (SPAD), capacidade fotossintética da cultura e qualidade do grão, em resposta aos tratamentos, vii) avaliação das emissões de gases com efeito de estufa (CH4, N2O, COV) e NH3 em cada talhão, viii) estabelecimento das relações entre as emissões de COVs e as práticas de cultivo, o tipo de solo e as características climáticas.
- Separação de sólidos e nutrientes com PAM e bentonite em chorumes bovinosPublication . Pereira, J.; Trindade, H.; Fangueiro, D.; Coutinho, J.; Moreira, N.A separação de sólidos do chorume e a aplicação de agentes floculantes à fracção líquida obtida constituem processos de tratamento deste efluente pecuário que permitem a obtenção de materiais com características distintas que ampliam as opções de utilização e de gestão do chorume. A redução do teor de sólidos e nutrientes na fracção sobrenadante apresenta vantagens em termos de odores, armazenamento, tratamento, aplicação aos solos e irrigação. Este trabalho teve como objectivo avaliar a utilização dos agentes floculantes poliacrilamida (PAM) e bentonite na remoção de sólidos e nutrientes da fracção líquida do chorume de explorações de bovinicultura leiteira. O trabalho experimental decorreu em Vila do Conde durante 2004, numa exploração de bovinicultura leiteira intensiva. O chorume bruto foi sujeito a separação mecânica de sólidos. Posteriormente a fracção líquida obtida foi bombeada para recipientes, e definiram-se 3 tratamentos com 2 repetições: controlo, adição de 200 mg L -1 de PAM e adição de 2 g L -1 de bentonite. Após a aplicação dos floculantes foram recolhidas amostras às fracções sobrenadante e sedimentada nos tempos 0, 2, 4, 20 e 30 horas. Essas amostras foram analisadas relativamente à concentração de N Kjeldahl, P e K totais, N-NH4 + , P solúvel em água, C orgânico solúvel em água, valor de pH e %MS. A separação mecânica do chorume bruto conduziu a uma eficiência de remoção pela fracção sólida obtida de 22, 25, 44 e 21%, respectivamente, dos teores de N Kjeldahl, P total, P solúvel em água e MS. Quanto à capacidade de remoção dos floculantes, a aplicação de PAM conduziu à eficiência de remoção da fracção sobrenadante de 46, 40, 65, 57 e 40%, respectivamente para o N Kjeldahl, P e K totais, P solúvel em água e MS; e a aplicação de bentonite a remoções de 19, 21, 11, 16 e 12%.