João Coutinho - Academia.edu (original) (raw)

Papers by João Coutinho

Research paper thumbnail of Efficiency of Organic Nitrogen Fertilization of Potato in Northeast Portugal

Acta Horticulturae, 2001

The study was conducted over a 4 year period with the purpose of measuring N mineralization using... more The study was conducted over a 4 year period with the purpose of measuring N mineralization using an in situ incubation technique, following the application of farmyard manure, poultry manure or municipal solid waste. The results varied from-10 % (net immobilization) to +28 % (net mineralization) in relation to the total organic N applied. N fluxes were assessed through plant N analysis during the growing season and through determination of potato tuber dry weight (TDW), N uptake by tubers and the apparent N recovery (ANR) of added N at harvest. Organic m aterial applications slightly increased TDW above the control treatment (9 to 25%), although the results indicate a shortage of N, where no N was added to the crop. The effect of organic fertilization on N uptake by tubers was also limited. Petiole nitrate concentration and estimated net N mineralization were in agreement with trends in TDW and N uptake by tubers, with no differences in soil N availability between the control and organic treatments. Values of ANR were particularly low, ranging from 4 to 23 %. The results suggest that caution is needed when judging the contribution of organic fertilization to N nutrition of crops, which have a short growing season. Synchronization between N release and plant uptake is discussed.

Research paper thumbnail of Foliar application of Sili-K® increases chestnut (Castanea spp.) growth and photosynthesis, simultaneously increasing susceptibility to water deficit

Plant and Soil, 2012

Background and aims The beneficial effects of Si have mainly been observed in herbaceous plants, ... more Background and aims The beneficial effects of Si have mainly been observed in herbaceous plants, while little is known about its role in deciduous trees. The aim of this work was to evaluate the effect of foliar application of Si on chestnut leaf growth, photosynthesis and water relations in the presence of short, but intense water deficit. Methods Sili-K® solution (containing 0.12 % Si and 0.15 % K) was repeatedly (× 3) sprayed onto leaves of potted chestnut plantlets and irrigation was suspended 7 weeks later, for 8 days. Leaf growth, anatomy, as well as physiological and biochemical traits of the plantlets were studied. Results Si application enhanced chestnut growth, due to increased photosynthetic traits, including higher chlorophyll content and chlorophyll a to b ratio, photochemical efficiency of PSII, gas exchange (stomatal conductance, transpiration rate, net CO 2 assimilation) and oxygen evolution rate. Meanwhile, Si yielded larger and thinner leaves, higher xylem, specific leaf area and transpiration rate, thus being beneficial to the tree in absorbing sunlight energy for photosynthesis and in alleviating heat stress. However, Si also lowered leaf sap osmotic pressure, causing the plant to lose water more quickly, thus being more susceptible to water stress. Conclusions Si improved chestnut photosynthesis, growth, and heat stress tolerance, but it also increased the susceptibility to drought.

Research paper thumbnail of Soil management system effects on N availability and tree productivity in chestnut plantations under Mediterranean conditions

Revista de Ciências Agrárias, 2015

Soil tillage with chisel ploughing is the conventional soil management system in chestnut stands ... more Soil tillage with chisel ploughing is the conventional soil management system in chestnut stands for fruit production in Northern Portugal. A study was developed to assess the effects of three soil management systems on in situ soil N mineralization dynamics, tree nutrition status and fruit productivity, in a 50-yr old chestnut stand. The treatments were: conventional tillage with a chisel ploughing twice a year (CT), no-tillage with rainfed improved pasture with leguminous and grasses plants (NIP), and no-tillage with spontaneous herbaceous vegetation-natural pasture (NP). The CT treatment showed a strong increase of the soil N mineral concentration following soil disturbance by tillage, but the cumulative net N mineralized along the year was significantly lower (51.8 kg ha-1) than in the NIP (85.1 kg ha-1) treatment. The NP treatment (65.9 kg ha-1) did not cause a reduction in the soil N mineralization when compared to the CT treatment. The mineralization rate (g mineralized N kg-1 total N) in 2004 was about 26, 30 and 38 in the treatments CT, NP and NIP, respectively. Treatments showed different soil N dynamics, the proportion of mineralized NO 3-N being lower in the NP (10-48%) than in CT and NIP treatments (53-74%). Our study indicates that no-tillage systems improve the tree nutrition status and enhance productivity.

Research paper thumbnail of Influence of the growing degree-days on chemical and technological properties of chestnut fruits (var. “Judia”)

CyTA - Journal of Food, 2012

Influence of the growing degree-days on chemical and technological properties of chestnut fruits ... more Influence of the growing degree-days on chemical and technological properties of chestnut fruits (var. ''Judia'') Influencia de dı´as-grado en la composicio´n quı´mica y propiedades tecnolo´gicas del fruto de castan˜a (var. ''Judia'')

Research paper thumbnail of Dataset on ammonia, nitrous oxide, methane, and carbon dioxide fluxes from two soils fertilized amended with treated and non-treated cattle slurry

Data in Brief, 2018

The current data article presents a set of fluxes of ammonia (NH 3), nitrous oxide (N 2 O), metha... more The current data article presents a set of fluxes of ammonia (NH 3), nitrous oxide (N 2 O), methane (CH 4), and carbon dioxide (CO 2) measured from two different soils under a Mediterranean doublecropping system (oat in autumn/winter followed by maize in spring/summer). The two soils were fertilized using four different treatments: (i) Injection of raw cattle slurry (100 mm depth), (ii) application of raw cattle slurry followed by soil incorporation (20 mm depth), (iii) band application of acidified (pH ¼5.5) cattle slurry followed by soil incorporation (20 mm depth), and (iv) band application of acidified (pH ¼ 5.5) cattle slurry without soil incorporation. A non-amended soil was also considered as control treatment. The data presented here were obtained over a three years experiment between 2012 and 2015. Fluxes were measured in a period between slurry applications to soil (before plant seeding) till crop harvest. The data presented here are supporting the research article "Band application of acidified slurry as an Contents lists available at ScienceDirect

Research paper thumbnail of Ultraviolet-B Radiation and Nitrogen Affect Nutrient Concentrations and the Amount of Nutrients Acquired by Above-Ground Organs of Maize

The Scientific World Journal, 2012

UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigat... more UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigated at silking and maturity at different levels of applied nitrogen under field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. At silking, UV-B increased N, K, Ca, and Zn concentrations, whereas at maturity Ca, Mg, Zn, and Cu increased and N, P and Mn decreased in some plant organs. Generally, at maturity, N, Ca, Cu, and Mn were lower, while P, K, and Zn concentrations in stems and nitrogen-use efficiency (NUE) were higher in N-starved plants. UV-B and N effects on shoot dry biomass were more pronounced than on nutrient concentrations. Nutrient uptake decreased under high UV-B and increased with increasing N application, mainly at maturity harvest. Significant interactions UV-B x N were observed for NUE and for concentration and mass of some elements. For instance, under enhanced UV-B, N, Cu, Zn, and Mn concentrations decreased in leaves, except on...

Research paper thumbnail of 47 - Eficiência de utilização do azoto pelas plantas

Eficiência de utilização do azoto pelas plantas

Research paper thumbnail of Can Dairy Slurry Application to Stubble, without Incorporation into the Soil, Be Sustainable?

Plants

In many countries, livestock slurry must be injected or incorporated into the soil to reduce nitr... more In many countries, livestock slurry must be injected or incorporated into the soil to reduce nitrogen losses. However, when the injection is not feasible, farmers adopting conservation practices discard the use of slurry as fertilizer. New approaches related to slurry treatment or application management can stimulate the use of slurry in conservation agriculture (CA). This study aimed to evaluate the agronomic effects of some new management strategies to use dairy slurry for fertilization of ryegrass grown on stubble-covered soil, using as reference standard practices (slurry injection and mineral fertilizer application). The following treatments were considered: (i) bare soil: control (CB), mineral fertilizer (MB), injection (IN); (ii) stubble: control (CS), acidified dairy slurry (ADS), raw dairy slurry (RDS), irrigation following RDS (IR), mineral fertilizer (MS), RDS placed under the stubble (US), raw slurry applied 16 days after sowing (RDS T16). Effects on ryegrass yield, appa...

Research paper thumbnail of Production of Table Potatoes in Europe - A Multinational Gross Margin Analysis

This paper examines different cropping practices, cost structures and gross margins for conventio... more This paper examines different cropping practices, cost structures and gross margins for conventional table potato cropping in 6 different regions within the European Union: Czech Republic, Denmark, Italy, Poland, Portugal and Slovakia. Findings from this study show that potato cropping practices varies significantly between the various countries with major differences in yield and costs. Italy and Denmark are the two regions with highest gross margins due to high yields and revenues. Poland is by far the largest potato producing country among the 6 countries. However, the production is primarily based on small scale farming with low yields and economic revenues.

Research paper thumbnail of Influência da dose e época de aplicação de um compostado na cultura de cebola biológica

No presente estudo avaliou-se o crescimento e a produtividade da cultura da cebola no modo de pro... more No presente estudo avaliou-se o crescimento e a produtividade da cultura da cebola no modo de produção biológico (MPB), na região NW de Portugal, com a aplicação ao solo de um compostado em diferentes épocas (à plantação e um mês antes da plantação), nas doses de 0, 20 e 40 t/ha, com e sem aplicação do fertilizante orgânico Monterra na dose de 2 t/ha à plantação. Avaliou-se a mesma cultura no modo de produção convencional (MPC, 150 kg N/ha). Realizaram-se 5 colheitas para quantificação do peso fresco e seco, diâmetro, firmeza, acidez total, pH e concentração de nutrientes do bolbo. A produtividade da cebola no MPB não aumentou significativamente com a antecipação na aplicação do compostado, nem com a aplicação do fertilizante Monterra, mas aumentou com a dose de aplicação de compostado ao solo, resultando numa produtividade média de 19,6 t/ha, 28,9 t/ha e 34,9 t/ha, respectivamente, para as doses de 0, 20 e 40 t/ha de compostado. As taxas aparentes de utilização do N orgânico do com...

Research paper thumbnail of Efeito da cinza de biomassa na dinâmica do C e N do solo de uma plantação de pinus pinaster

Estudou-se, através de incubação aeróbia, o efeito da aplicação de cinza de biomassa florestal na... more Estudou-se, através de incubação aeróbia, o efeito da aplicação de cinza de biomassa florestal nas características químicas e na actividade microbiana de um Arenossolo de um povoamento de Pinus pinaster Ait. As doses de cinza aplicadas foram de 0, 4, e 8 g kg-1solo, sob forma pulverulenta ou peletizada, e na presença ou ausência de fertilizante azotado. A aplicação de cinza sob forma pulverulenta aumentou rápida e significativamente os valores de pH e os teores de bases de troca e de P extraível do solo. A nitrificação líquida foi igualmente estimulada. A quantidade de C microbiano nos solos com cinza pulverulenta foi inferior ao controlo, não sendo observados efeitos significativos para a respiração basal do solo. O quociente metabólico foi superior na fase inicial da incubação. Os efeitos observados foram, em geral, tanto mais intensos quanto maior a dose de cinza aplicada e mais acentuados na presença de N. A cinza aplicada sob forma peletizada não produziu um efeito tão acentuad...

Research paper thumbnail of Mineralização de azoto de diferentes resíduos orgânicos em incubação laboratorial de longa duração

O objectivo do presente trabalho foi determinar, em condições laboratoriais e através de um ensai... more O objectivo do presente trabalho foi determinar, em condições laboratoriais e através de um ensaio de incubação de longa duração (443 dias), a mineralização do N orgânico resultante da incorporação de lamas de depuração, compostado de resíduos sólidos urbanos (RSU), chorume de bovinos e lamas celulósicas, num Solo Litólico de granito. À excepção das lamas celulósicas (80 kg N ha-1), os resíduos orgânicos foram incorporados em duas doses (80 e 160 kg N ha-1). A avaliação da mineralização do N orgânico dos resíduos foi efectuada através da medição do teor de N mineral acumulado ( N-NH4+ e N-NO3 ) no solo com resíduo, tendo as amostragens sido efectuadas aos 1, 2, 3, 4, 8, 11, 15, 22, 29, 36, 46, 59, 74, 88, 120, 144, 186, 249, 338 e 443 dias após o início da incubação. O chorume e as lamas de depuração foram os correctivos orgânicos que promoveram teores iniciais de N mineral no solo mais elevados, tendo o chorume disponibilizado no final do ensaio, na média das duas doses, 50% do N t...

Research paper thumbnail of O comportamento de pés-mãe de Eucalyptus globulus Labill. sujeitos a diferentes níveis de azoto e potássio

Nos sistemas de propagação vegetativa de plantas o estado nutricional dos pés-mãe é determinante ... more Nos sistemas de propagação vegetativa de plantas o estado nutricional dos pés-mãe é determinante para o sucesso do enraizamento das estacas que estes originam. Como tal, a recente implementação, em Portugal, da técnica de propagação vegetativa de Eucalyptus globulus Labill. ssp. globulus por enraizamento de estacas caulinares, justifica plenamente o estudo da fertilização de pés-mãe desta espécie e o seu efeito no enraizamento das estacas. Assim, e com o objectivo de avaliar o efeito do azoto e do potássio no crescimento de pés-mãe de E. globulus e no enraizamento das estacas obtidas, foi instalado um ensaio de fertilização que decorreu durante um período de 2 anos. No ensaio utilizaram-se 2 clones desta espécie (HD161 e CN5) e testaram-se 6 modalidades de fertilização, correspondentes à combinação de 3 níveis de azoto (50, 100, 200 mg N L-1) e 2 de potássio (50 e 100 mg K L-1) na solução nutritiva utilizada. No primeiro ano de crescimento (1998) os pés-mãe foram sujeitos a uma poda...

Research paper thumbnail of Compostagem de biomassa de acácia com casca de pinheiro

As acácias são espécies invasoras da família Fabaceae que poderão ser valorizadas através da comp... more As acácias são espécies invasoras da família Fabaceae que poderão ser valorizadas através da compostagem para produção de corretivos orgânicos e substratos hortícolas. Com esse objetivo construíram-se pilhas de grandes dimensões com detritos de acácia misturados com casca de pinheiro e diferente número de revolvimentos, para analisar as características físico-químicas durante a compostagem e modelar a decomposição da matéria orgânica (MO). As temperaturas foram superiores a 60oC durante um período de tempo suficientemente longo para a inativação de microrganismos patogénicos e a destruição de sementes de infestantes, devido à elevada quantidade de MO biodegradável deste material (600-620 g kg-1 de MO inicial) e à grande dimensão das pilhas. A elevada temperatura terá contribuído para as fortes perdas de N (450-470 g kg-1 de N inicial) por volatilização. No entanto, estas foram inferiores às perdas de C, e assim a razão C/N diminuiu de 56 no início, para 40-41 no final de compostagem...

Research paper thumbnail of A climate change scenario and soil ammonium fixation during the seasonal rice (Oryza sativa) growth in Portugal under intermittent flooding

Revista de Ciências Agrárias, 2013

The “newly fixed” NH4+ in clay minerals should be considered for an efficient management of plant... more The “newly fixed” NH4+ in clay minerals should be considered for an efficient management of plant nutrition. In a clay-loam soil cultivated in 2012 with rice under intermittent flooding and conventional agronomic practices, the dynamics of pH, N-inorganic and non-exchangeable NH4+ was evaluated i) under field conditions, air temperature and atmospheric [CO2] (375 µmol mol-1 air) in Salvaterra de Magos (Portugal), and ii) under elevated temperature and temperature+[CO2] in controlled microclimate. For that, open-top chambers were used to simulate the conditions of an increased mean air temperature (2-3 °C), alone or combined with increased [CO2] (550 µmol mol-1 air). Non-exchangeable NH4+ was significantly higher under open-field conditions compared with the temperature elevation, with or without elevated atmospheric [CO2]. Temperature elevation reduced the “fixation” rate of the cation, while the CO2 concentration rise did not affect particularly the non-exchangeable form. Further s...

Research paper thumbnail of Gestão do azoto no solo numa rotação hortícola no modo de produção biológico

Revista de Ciências Agrárias, 2013

Realizou-se uma rotacao anual com uma cultura de cobertura de ervilhaca (Vicia sativa L.) e cente... more Realizou-se uma rotacao anual com uma cultura de cobertura de ervilhaca (Vicia sativa L.) e centeio (Secale cereale L.) como adubo verde, seguida por batata (Solanum tuberosum L.) e alface (Lactuca sativa L.) com o objetivo de contribuir para melhorar a gestao do azoto (N) no solo em agricultura biologica. A mineralizacao de N foi determinada atraves de uma incubacao de campo em resposta a aplicacao de adubo verde, compostado (20 e 40 t ha-1) e adubo orgânico (1 e 2 t ha-1) a cultura da batata. A mineralizacao de N no compostado ocorreu durante todo o periodo de desenvolvimento das culturas, enquanto no adubo orgânico uma percentagem elevada de N mineralizou-se logo nos primeiros dias apos incorporacao ao solo, do que resultou uma maior disponibilidade de N e uma producao superior na cultura da batata com 2 t ha-1 de adubo em comparacao com a aplicacao de 20 t ha-1 de compostado e superior na alface com a aplicacao do compostado em comparacao com o adubo orgânico.

Research paper thumbnail of Potencialidade das leguminosas forrageiras anuais como fonte de azoto em agricultura biológica

Revista de Ciências Agrárias, 2011

A reduzida investigacao, a escala mundial, sobre a utilizacao de novas especies de leguminosas fo... more A reduzida investigacao, a escala mundial, sobre a utilizacao de novas especies de leguminosas forrageiras em condicoes mediterrânicas como fonte de N, conduziu-nos ao presente estudo, que teve como objectivos avaliar a producao de materia seca (MS), quantificar o N acumulado e determinar o potencial de fornecimento de N por diferentes plantas como culturas intercalares em duas datas de sementeira diferentes. Foram utilizadas 6 leguminosas forrageiras: trevo balansa, trevo glandulifero, trevo vesiculoso, trevo encarnado, serradela vulgar e tremocilha; uma graminea: azevem; uma consociacao de azevem com trevo balansa e a vegetacao espontânea. As sementeiras realizaram-se em Setembro e Outubro de 2007. Os melhores resultados foram obtidos para a 2a data de sementeira, para todas as variaveis. A serradela foi responsavel pela maior producao de MS (7179 kg ha-1). O trevo balansa obteve o maior teor de N (26,85 g kg-1) e o maior potencial de fornecimento de N atraves da biomassa aerea (1...

Research paper thumbnail of Cereais em rotações de sequeiro: Evolução dos teores de azoto inorgânico do solo

Revista de Ciências Agrárias, 2009

Analisamos, no ano final de um ensaio de rotacoes que decorreu durante dez anos em Vila Real (Tra... more Analisamos, no ano final de um ensaio de rotacoes que decorreu durante dez anos em Vila Real (Tras-os-Montes), a evolucao dos teores de azoto inorgânico do solo das varias rotacoes na profundidade ate 40 cm. O ensaio incluiu a rotacao tradicional das condicoes de sequeiro da regiao, cereal-alqueive (TA), e rotacoes alternativas susceptiveis de serem adoptadas nestas condicoes, as bienais cereal-leguminosa (TL) e cerealconsociacao forrageira (TC) e a plurianual cereal-prado de sequeiro (TP). Determinaram-se, e apresentaram-se noutros trabalhos, as producoes de grao, palha e biomassa aerea das diversas culturas, parâmetros de qualidade do grao de cereais e os parâmetros do solo, pH, materia orgânica e os teores de P2O5, K2O e bases de troca. Como principais resultados e conclusoes da analise realizada podem-se referir: uma reduzida influencia das rotacoes curtas na producao e qualidade das diversas culturas; o ano de alqueive e a consociacao deixam no solo um teor de azoto mineral ele...

Research paper thumbnail of Assessing the Impact of Rice Cultivation and Off-Season Period on Dynamics of Soil Enzyme Activities and Bacterial Communities in Two Agro-Ecological Regions of Mozambique

Agronomy, 2021

Soil ecosystem perturbation due to agronomic practices can negatively impact soil productivity by... more Soil ecosystem perturbation due to agronomic practices can negatively impact soil productivity by altering the diversity and function of soil health determinants. Currently, the influence of rice cultivation and off-season periods on the dynamics of soil health determinants is unclear. Therefore, soil enzyme activities (EAs) and bacterial community compositions in rice-cultivated fields at postharvest (PH) and after a 5-month off-season period (5mR), and fallow-fields (5-years-fallow, 5YF; 10-years-fallow, 10YF and/or one-year-fallow, 1YF) were assessed in two agroecological regions of Mozambique. EAs were mostly higher in fallow fields than in PH, with significant (p < 0.05) differences detected for β-glucosidase and acid phosphatase activities. Only β-glucosidase activity was significantly (p < 0.05) different between PH and 5mR, suggesting that β-glucosidase is responsive in the short-term. Bacterial diversity was highest in rice-cultivated soil and correlated with NO3−, NH...

Research paper thumbnail of Assessment of N Mineralization and N Leaching in Soil Using a New in situ Incubation Method

Communications in Soil Science and Plant Analysis, 2016

Field incubations have been pointed out as the more realistic method to provide estimates of nitr... more Field incubations have been pointed out as the more realistic method to provide estimates of nitrogen (N) mineralization. The aim of this study is to evaluate the quality of the results obtained in a field incubation using an open reactor to estimate net N mineralization and N leaching. The incubation experiment was initiated with 24 reactors. At each date, the reactors were destructed and mineral N in the soil and adsorbed on the exchange resins was determined. Net N mineralization and N leaching were estimated as 23.3 and 18.0 mg/kg, respectively. The results revealed an acceptable repeatability, with coefficient of variation (CV) of 9.0%, a significant adjustment (r 2 = 0.991), and a low root mean square error (S yx = 4.2) for the regression model used. The use of this type of reactor may be considered as a reliable alternative to assess N mineralization kinetics from native organic matter and probably for organic residues applied to soils in field studies.

Research paper thumbnail of Efficiency of Organic Nitrogen Fertilization of Potato in Northeast Portugal

Acta Horticulturae, 2001

The study was conducted over a 4 year period with the purpose of measuring N mineralization using... more The study was conducted over a 4 year period with the purpose of measuring N mineralization using an in situ incubation technique, following the application of farmyard manure, poultry manure or municipal solid waste. The results varied from-10 % (net immobilization) to +28 % (net mineralization) in relation to the total organic N applied. N fluxes were assessed through plant N analysis during the growing season and through determination of potato tuber dry weight (TDW), N uptake by tubers and the apparent N recovery (ANR) of added N at harvest. Organic m aterial applications slightly increased TDW above the control treatment (9 to 25%), although the results indicate a shortage of N, where no N was added to the crop. The effect of organic fertilization on N uptake by tubers was also limited. Petiole nitrate concentration and estimated net N mineralization were in agreement with trends in TDW and N uptake by tubers, with no differences in soil N availability between the control and organic treatments. Values of ANR were particularly low, ranging from 4 to 23 %. The results suggest that caution is needed when judging the contribution of organic fertilization to N nutrition of crops, which have a short growing season. Synchronization between N release and plant uptake is discussed.

Research paper thumbnail of Foliar application of Sili-K® increases chestnut (Castanea spp.) growth and photosynthesis, simultaneously increasing susceptibility to water deficit

Plant and Soil, 2012

Background and aims The beneficial effects of Si have mainly been observed in herbaceous plants, ... more Background and aims The beneficial effects of Si have mainly been observed in herbaceous plants, while little is known about its role in deciduous trees. The aim of this work was to evaluate the effect of foliar application of Si on chestnut leaf growth, photosynthesis and water relations in the presence of short, but intense water deficit. Methods Sili-K® solution (containing 0.12 % Si and 0.15 % K) was repeatedly (× 3) sprayed onto leaves of potted chestnut plantlets and irrigation was suspended 7 weeks later, for 8 days. Leaf growth, anatomy, as well as physiological and biochemical traits of the plantlets were studied. Results Si application enhanced chestnut growth, due to increased photosynthetic traits, including higher chlorophyll content and chlorophyll a to b ratio, photochemical efficiency of PSII, gas exchange (stomatal conductance, transpiration rate, net CO 2 assimilation) and oxygen evolution rate. Meanwhile, Si yielded larger and thinner leaves, higher xylem, specific leaf area and transpiration rate, thus being beneficial to the tree in absorbing sunlight energy for photosynthesis and in alleviating heat stress. However, Si also lowered leaf sap osmotic pressure, causing the plant to lose water more quickly, thus being more susceptible to water stress. Conclusions Si improved chestnut photosynthesis, growth, and heat stress tolerance, but it also increased the susceptibility to drought.

Research paper thumbnail of Soil management system effects on N availability and tree productivity in chestnut plantations under Mediterranean conditions

Revista de Ciências Agrárias, 2015

Soil tillage with chisel ploughing is the conventional soil management system in chestnut stands ... more Soil tillage with chisel ploughing is the conventional soil management system in chestnut stands for fruit production in Northern Portugal. A study was developed to assess the effects of three soil management systems on in situ soil N mineralization dynamics, tree nutrition status and fruit productivity, in a 50-yr old chestnut stand. The treatments were: conventional tillage with a chisel ploughing twice a year (CT), no-tillage with rainfed improved pasture with leguminous and grasses plants (NIP), and no-tillage with spontaneous herbaceous vegetation-natural pasture (NP). The CT treatment showed a strong increase of the soil N mineral concentration following soil disturbance by tillage, but the cumulative net N mineralized along the year was significantly lower (51.8 kg ha-1) than in the NIP (85.1 kg ha-1) treatment. The NP treatment (65.9 kg ha-1) did not cause a reduction in the soil N mineralization when compared to the CT treatment. The mineralization rate (g mineralized N kg-1 total N) in 2004 was about 26, 30 and 38 in the treatments CT, NP and NIP, respectively. Treatments showed different soil N dynamics, the proportion of mineralized NO 3-N being lower in the NP (10-48%) than in CT and NIP treatments (53-74%). Our study indicates that no-tillage systems improve the tree nutrition status and enhance productivity.

Research paper thumbnail of Influence of the growing degree-days on chemical and technological properties of chestnut fruits (var. “Judia”)

CyTA - Journal of Food, 2012

Influence of the growing degree-days on chemical and technological properties of chestnut fruits ... more Influence of the growing degree-days on chemical and technological properties of chestnut fruits (var. ''Judia'') Influencia de dı´as-grado en la composicio´n quı´mica y propiedades tecnolo´gicas del fruto de castan˜a (var. ''Judia'')

Research paper thumbnail of Dataset on ammonia, nitrous oxide, methane, and carbon dioxide fluxes from two soils fertilized amended with treated and non-treated cattle slurry

Data in Brief, 2018

The current data article presents a set of fluxes of ammonia (NH 3), nitrous oxide (N 2 O), metha... more The current data article presents a set of fluxes of ammonia (NH 3), nitrous oxide (N 2 O), methane (CH 4), and carbon dioxide (CO 2) measured from two different soils under a Mediterranean doublecropping system (oat in autumn/winter followed by maize in spring/summer). The two soils were fertilized using four different treatments: (i) Injection of raw cattle slurry (100 mm depth), (ii) application of raw cattle slurry followed by soil incorporation (20 mm depth), (iii) band application of acidified (pH ¼5.5) cattle slurry followed by soil incorporation (20 mm depth), and (iv) band application of acidified (pH ¼ 5.5) cattle slurry without soil incorporation. A non-amended soil was also considered as control treatment. The data presented here were obtained over a three years experiment between 2012 and 2015. Fluxes were measured in a period between slurry applications to soil (before plant seeding) till crop harvest. The data presented here are supporting the research article "Band application of acidified slurry as an Contents lists available at ScienceDirect

Research paper thumbnail of Ultraviolet-B Radiation and Nitrogen Affect Nutrient Concentrations and the Amount of Nutrients Acquired by Above-Ground Organs of Maize

The Scientific World Journal, 2012

UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigat... more UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigated at silking and maturity at different levels of applied nitrogen under field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. At silking, UV-B increased N, K, Ca, and Zn concentrations, whereas at maturity Ca, Mg, Zn, and Cu increased and N, P and Mn decreased in some plant organs. Generally, at maturity, N, Ca, Cu, and Mn were lower, while P, K, and Zn concentrations in stems and nitrogen-use efficiency (NUE) were higher in N-starved plants. UV-B and N effects on shoot dry biomass were more pronounced than on nutrient concentrations. Nutrient uptake decreased under high UV-B and increased with increasing N application, mainly at maturity harvest. Significant interactions UV-B x N were observed for NUE and for concentration and mass of some elements. For instance, under enhanced UV-B, N, Cu, Zn, and Mn concentrations decreased in leaves, except on...

Research paper thumbnail of 47 - Eficiência de utilização do azoto pelas plantas

Eficiência de utilização do azoto pelas plantas

Research paper thumbnail of Can Dairy Slurry Application to Stubble, without Incorporation into the Soil, Be Sustainable?

Plants

In many countries, livestock slurry must be injected or incorporated into the soil to reduce nitr... more In many countries, livestock slurry must be injected or incorporated into the soil to reduce nitrogen losses. However, when the injection is not feasible, farmers adopting conservation practices discard the use of slurry as fertilizer. New approaches related to slurry treatment or application management can stimulate the use of slurry in conservation agriculture (CA). This study aimed to evaluate the agronomic effects of some new management strategies to use dairy slurry for fertilization of ryegrass grown on stubble-covered soil, using as reference standard practices (slurry injection and mineral fertilizer application). The following treatments were considered: (i) bare soil: control (CB), mineral fertilizer (MB), injection (IN); (ii) stubble: control (CS), acidified dairy slurry (ADS), raw dairy slurry (RDS), irrigation following RDS (IR), mineral fertilizer (MS), RDS placed under the stubble (US), raw slurry applied 16 days after sowing (RDS T16). Effects on ryegrass yield, appa...

Research paper thumbnail of Production of Table Potatoes in Europe - A Multinational Gross Margin Analysis

This paper examines different cropping practices, cost structures and gross margins for conventio... more This paper examines different cropping practices, cost structures and gross margins for conventional table potato cropping in 6 different regions within the European Union: Czech Republic, Denmark, Italy, Poland, Portugal and Slovakia. Findings from this study show that potato cropping practices varies significantly between the various countries with major differences in yield and costs. Italy and Denmark are the two regions with highest gross margins due to high yields and revenues. Poland is by far the largest potato producing country among the 6 countries. However, the production is primarily based on small scale farming with low yields and economic revenues.

Research paper thumbnail of Influência da dose e época de aplicação de um compostado na cultura de cebola biológica

No presente estudo avaliou-se o crescimento e a produtividade da cultura da cebola no modo de pro... more No presente estudo avaliou-se o crescimento e a produtividade da cultura da cebola no modo de produção biológico (MPB), na região NW de Portugal, com a aplicação ao solo de um compostado em diferentes épocas (à plantação e um mês antes da plantação), nas doses de 0, 20 e 40 t/ha, com e sem aplicação do fertilizante orgânico Monterra na dose de 2 t/ha à plantação. Avaliou-se a mesma cultura no modo de produção convencional (MPC, 150 kg N/ha). Realizaram-se 5 colheitas para quantificação do peso fresco e seco, diâmetro, firmeza, acidez total, pH e concentração de nutrientes do bolbo. A produtividade da cebola no MPB não aumentou significativamente com a antecipação na aplicação do compostado, nem com a aplicação do fertilizante Monterra, mas aumentou com a dose de aplicação de compostado ao solo, resultando numa produtividade média de 19,6 t/ha, 28,9 t/ha e 34,9 t/ha, respectivamente, para as doses de 0, 20 e 40 t/ha de compostado. As taxas aparentes de utilização do N orgânico do com...

Research paper thumbnail of Efeito da cinza de biomassa na dinâmica do C e N do solo de uma plantação de pinus pinaster

Estudou-se, através de incubação aeróbia, o efeito da aplicação de cinza de biomassa florestal na... more Estudou-se, através de incubação aeróbia, o efeito da aplicação de cinza de biomassa florestal nas características químicas e na actividade microbiana de um Arenossolo de um povoamento de Pinus pinaster Ait. As doses de cinza aplicadas foram de 0, 4, e 8 g kg-1solo, sob forma pulverulenta ou peletizada, e na presença ou ausência de fertilizante azotado. A aplicação de cinza sob forma pulverulenta aumentou rápida e significativamente os valores de pH e os teores de bases de troca e de P extraível do solo. A nitrificação líquida foi igualmente estimulada. A quantidade de C microbiano nos solos com cinza pulverulenta foi inferior ao controlo, não sendo observados efeitos significativos para a respiração basal do solo. O quociente metabólico foi superior na fase inicial da incubação. Os efeitos observados foram, em geral, tanto mais intensos quanto maior a dose de cinza aplicada e mais acentuados na presença de N. A cinza aplicada sob forma peletizada não produziu um efeito tão acentuad...

Research paper thumbnail of Mineralização de azoto de diferentes resíduos orgânicos em incubação laboratorial de longa duração

O objectivo do presente trabalho foi determinar, em condições laboratoriais e através de um ensai... more O objectivo do presente trabalho foi determinar, em condições laboratoriais e através de um ensaio de incubação de longa duração (443 dias), a mineralização do N orgânico resultante da incorporação de lamas de depuração, compostado de resíduos sólidos urbanos (RSU), chorume de bovinos e lamas celulósicas, num Solo Litólico de granito. À excepção das lamas celulósicas (80 kg N ha-1), os resíduos orgânicos foram incorporados em duas doses (80 e 160 kg N ha-1). A avaliação da mineralização do N orgânico dos resíduos foi efectuada através da medição do teor de N mineral acumulado ( N-NH4+ e N-NO3 ) no solo com resíduo, tendo as amostragens sido efectuadas aos 1, 2, 3, 4, 8, 11, 15, 22, 29, 36, 46, 59, 74, 88, 120, 144, 186, 249, 338 e 443 dias após o início da incubação. O chorume e as lamas de depuração foram os correctivos orgânicos que promoveram teores iniciais de N mineral no solo mais elevados, tendo o chorume disponibilizado no final do ensaio, na média das duas doses, 50% do N t...

Research paper thumbnail of O comportamento de pés-mãe de Eucalyptus globulus Labill. sujeitos a diferentes níveis de azoto e potássio

Nos sistemas de propagação vegetativa de plantas o estado nutricional dos pés-mãe é determinante ... more Nos sistemas de propagação vegetativa de plantas o estado nutricional dos pés-mãe é determinante para o sucesso do enraizamento das estacas que estes originam. Como tal, a recente implementação, em Portugal, da técnica de propagação vegetativa de Eucalyptus globulus Labill. ssp. globulus por enraizamento de estacas caulinares, justifica plenamente o estudo da fertilização de pés-mãe desta espécie e o seu efeito no enraizamento das estacas. Assim, e com o objectivo de avaliar o efeito do azoto e do potássio no crescimento de pés-mãe de E. globulus e no enraizamento das estacas obtidas, foi instalado um ensaio de fertilização que decorreu durante um período de 2 anos. No ensaio utilizaram-se 2 clones desta espécie (HD161 e CN5) e testaram-se 6 modalidades de fertilização, correspondentes à combinação de 3 níveis de azoto (50, 100, 200 mg N L-1) e 2 de potássio (50 e 100 mg K L-1) na solução nutritiva utilizada. No primeiro ano de crescimento (1998) os pés-mãe foram sujeitos a uma poda...

Research paper thumbnail of Compostagem de biomassa de acácia com casca de pinheiro

As acácias são espécies invasoras da família Fabaceae que poderão ser valorizadas através da comp... more As acácias são espécies invasoras da família Fabaceae que poderão ser valorizadas através da compostagem para produção de corretivos orgânicos e substratos hortícolas. Com esse objetivo construíram-se pilhas de grandes dimensões com detritos de acácia misturados com casca de pinheiro e diferente número de revolvimentos, para analisar as características físico-químicas durante a compostagem e modelar a decomposição da matéria orgânica (MO). As temperaturas foram superiores a 60oC durante um período de tempo suficientemente longo para a inativação de microrganismos patogénicos e a destruição de sementes de infestantes, devido à elevada quantidade de MO biodegradável deste material (600-620 g kg-1 de MO inicial) e à grande dimensão das pilhas. A elevada temperatura terá contribuído para as fortes perdas de N (450-470 g kg-1 de N inicial) por volatilização. No entanto, estas foram inferiores às perdas de C, e assim a razão C/N diminuiu de 56 no início, para 40-41 no final de compostagem...

Research paper thumbnail of A climate change scenario and soil ammonium fixation during the seasonal rice (Oryza sativa) growth in Portugal under intermittent flooding

Revista de Ciências Agrárias, 2013

The “newly fixed” NH4+ in clay minerals should be considered for an efficient management of plant... more The “newly fixed” NH4+ in clay minerals should be considered for an efficient management of plant nutrition. In a clay-loam soil cultivated in 2012 with rice under intermittent flooding and conventional agronomic practices, the dynamics of pH, N-inorganic and non-exchangeable NH4+ was evaluated i) under field conditions, air temperature and atmospheric [CO2] (375 µmol mol-1 air) in Salvaterra de Magos (Portugal), and ii) under elevated temperature and temperature+[CO2] in controlled microclimate. For that, open-top chambers were used to simulate the conditions of an increased mean air temperature (2-3 °C), alone or combined with increased [CO2] (550 µmol mol-1 air). Non-exchangeable NH4+ was significantly higher under open-field conditions compared with the temperature elevation, with or without elevated atmospheric [CO2]. Temperature elevation reduced the “fixation” rate of the cation, while the CO2 concentration rise did not affect particularly the non-exchangeable form. Further s...

Research paper thumbnail of Gestão do azoto no solo numa rotação hortícola no modo de produção biológico

Revista de Ciências Agrárias, 2013

Realizou-se uma rotacao anual com uma cultura de cobertura de ervilhaca (Vicia sativa L.) e cente... more Realizou-se uma rotacao anual com uma cultura de cobertura de ervilhaca (Vicia sativa L.) e centeio (Secale cereale L.) como adubo verde, seguida por batata (Solanum tuberosum L.) e alface (Lactuca sativa L.) com o objetivo de contribuir para melhorar a gestao do azoto (N) no solo em agricultura biologica. A mineralizacao de N foi determinada atraves de uma incubacao de campo em resposta a aplicacao de adubo verde, compostado (20 e 40 t ha-1) e adubo orgânico (1 e 2 t ha-1) a cultura da batata. A mineralizacao de N no compostado ocorreu durante todo o periodo de desenvolvimento das culturas, enquanto no adubo orgânico uma percentagem elevada de N mineralizou-se logo nos primeiros dias apos incorporacao ao solo, do que resultou uma maior disponibilidade de N e uma producao superior na cultura da batata com 2 t ha-1 de adubo em comparacao com a aplicacao de 20 t ha-1 de compostado e superior na alface com a aplicacao do compostado em comparacao com o adubo orgânico.

Research paper thumbnail of Potencialidade das leguminosas forrageiras anuais como fonte de azoto em agricultura biológica

Revista de Ciências Agrárias, 2011

A reduzida investigacao, a escala mundial, sobre a utilizacao de novas especies de leguminosas fo... more A reduzida investigacao, a escala mundial, sobre a utilizacao de novas especies de leguminosas forrageiras em condicoes mediterrânicas como fonte de N, conduziu-nos ao presente estudo, que teve como objectivos avaliar a producao de materia seca (MS), quantificar o N acumulado e determinar o potencial de fornecimento de N por diferentes plantas como culturas intercalares em duas datas de sementeira diferentes. Foram utilizadas 6 leguminosas forrageiras: trevo balansa, trevo glandulifero, trevo vesiculoso, trevo encarnado, serradela vulgar e tremocilha; uma graminea: azevem; uma consociacao de azevem com trevo balansa e a vegetacao espontânea. As sementeiras realizaram-se em Setembro e Outubro de 2007. Os melhores resultados foram obtidos para a 2a data de sementeira, para todas as variaveis. A serradela foi responsavel pela maior producao de MS (7179 kg ha-1). O trevo balansa obteve o maior teor de N (26,85 g kg-1) e o maior potencial de fornecimento de N atraves da biomassa aerea (1...

Research paper thumbnail of Cereais em rotações de sequeiro: Evolução dos teores de azoto inorgânico do solo

Revista de Ciências Agrárias, 2009

Analisamos, no ano final de um ensaio de rotacoes que decorreu durante dez anos em Vila Real (Tra... more Analisamos, no ano final de um ensaio de rotacoes que decorreu durante dez anos em Vila Real (Tras-os-Montes), a evolucao dos teores de azoto inorgânico do solo das varias rotacoes na profundidade ate 40 cm. O ensaio incluiu a rotacao tradicional das condicoes de sequeiro da regiao, cereal-alqueive (TA), e rotacoes alternativas susceptiveis de serem adoptadas nestas condicoes, as bienais cereal-leguminosa (TL) e cerealconsociacao forrageira (TC) e a plurianual cereal-prado de sequeiro (TP). Determinaram-se, e apresentaram-se noutros trabalhos, as producoes de grao, palha e biomassa aerea das diversas culturas, parâmetros de qualidade do grao de cereais e os parâmetros do solo, pH, materia orgânica e os teores de P2O5, K2O e bases de troca. Como principais resultados e conclusoes da analise realizada podem-se referir: uma reduzida influencia das rotacoes curtas na producao e qualidade das diversas culturas; o ano de alqueive e a consociacao deixam no solo um teor de azoto mineral ele...

Research paper thumbnail of Assessing the Impact of Rice Cultivation and Off-Season Period on Dynamics of Soil Enzyme Activities and Bacterial Communities in Two Agro-Ecological Regions of Mozambique

Agronomy, 2021

Soil ecosystem perturbation due to agronomic practices can negatively impact soil productivity by... more Soil ecosystem perturbation due to agronomic practices can negatively impact soil productivity by altering the diversity and function of soil health determinants. Currently, the influence of rice cultivation and off-season periods on the dynamics of soil health determinants is unclear. Therefore, soil enzyme activities (EAs) and bacterial community compositions in rice-cultivated fields at postharvest (PH) and after a 5-month off-season period (5mR), and fallow-fields (5-years-fallow, 5YF; 10-years-fallow, 10YF and/or one-year-fallow, 1YF) were assessed in two agroecological regions of Mozambique. EAs were mostly higher in fallow fields than in PH, with significant (p < 0.05) differences detected for β-glucosidase and acid phosphatase activities. Only β-glucosidase activity was significantly (p < 0.05) different between PH and 5mR, suggesting that β-glucosidase is responsive in the short-term. Bacterial diversity was highest in rice-cultivated soil and correlated with NO3−, NH...

Research paper thumbnail of Assessment of N Mineralization and N Leaching in Soil Using a New in situ Incubation Method

Communications in Soil Science and Plant Analysis, 2016

Field incubations have been pointed out as the more realistic method to provide estimates of nitr... more Field incubations have been pointed out as the more realistic method to provide estimates of nitrogen (N) mineralization. The aim of this study is to evaluate the quality of the results obtained in a field incubation using an open reactor to estimate net N mineralization and N leaching. The incubation experiment was initiated with 24 reactors. At each date, the reactors were destructed and mineral N in the soil and adsorbed on the exchange resins was determined. Net N mineralization and N leaching were estimated as 23.3 and 18.0 mg/kg, respectively. The results revealed an acceptable repeatability, with coefficient of variation (CV) of 9.0%, a significant adjustment (r 2 = 0.991), and a low root mean square error (S yx = 4.2) for the regression model used. The use of this type of reactor may be considered as a reliable alternative to assess N mineralization kinetics from native organic matter and probably for organic residues applied to soils in field studies.