Browsing by Author "Trindade, Henrique"
Now showing 1 - 10 of 23
Results Per Page
Sort Options
- A 3-year field study to assess winter cover crops as nitrogen sources for an organic maize crop in Mediterranean PortugalPublication . Perdigão, Adelaide; Pereira, José L.S.; Moreira, Nuno; Trindade, Henrique; Coutinho, JoãoCurrent environmental concerns, the rising economic and environmental costs of mineral fertilizers and the need to respond to the limitations of N fertilization in organic farming motivate the search for alternative sources of N in maize cropping. Forage legumes used as winter cover crops may improve soil N fertility and offer benefits to the environment. The aim of this study was to examine the effects, in a factorial field experiment, of two sowing dates (SD) and nine different cover crop treatments (balansa clover, crimson clover, gland clover, arrowleaf clover, French serradella, yellow lupin, Italian ryegrass, a cover mixture and a weedy fallow) as a potential alternative N source in an organically managed maize crop. The experiment was conducted at Viseu (Portugal) for three years (2007/2008, 2008/2009 and 2011/12), in the same field. Results showed that maize grain yield was not influenced by cover crop species but was affected by SD and the higher dry matter (DM) aboveground biomass production was observed in early SD (6.1 t ha 1). The cover crops revealed their importance in maize N uptake: yellow lupin of earlier SD had the highest N uptake (83.6 kg N ha 1), but this was not significantly different from balansa clover (83.2 kg N ha 1). Ryegrass was the most efficient in depleting soil mineral N but values were just significantly lower than yellow lupin. Lupin was the least efficient, leaving more mineral N in the soil than the others cover crops, immediately before the period when the risk of leaching is high. It was concluded that, under the edaphoclimatic conditions tested, most of the tested cover crops were efficient in supplying N to maize, and balansa clover had the best performance.
- Ammonia and carbon dioxide concentrations in dairy-cattle houses of northwest PortugalPublication . Rodrigues, Ana Raquel; Gomes, Ana; Ferreira, Luís; Cabrita, Ana; Trindade, Henrique; Fonseca, António; Pereira, José Luís
- Ammonia and greenhouse gas emissions from a breeding hen building in PortugalPublication . Pereira, José Luís; Ferreira, Sílvia; Conde, André; Ferreira, Pedro; Pinheiro, Victor; Trindade, Henrique
- Assessement of ammonia concentrations from naturallly ventilated dairy cattle buildings of northwest PortugalPublication . Rodrigues, Ana Raquel; Gomes, Ana; Ferreira, Luís; Cabrita, Ana; Trindade, Henrique; Fonseca, António; Pereira, José Luís
- Assessment of ammonia and carbon dioxide concentrations in a breeding hen building under Portuguese winterPublication . Pereira, José; Garcia, Carla; Ferreira, Sílvia; Pinheiro, Victor; Trindade, Henrique; Conde, André; Ferreira, Pedro
- Assessment of ammonia and carbon dioxide concentrations in a breeding hen building under Portuguese winterPublication . Pereira, José Luís; Ferreira, Sílvia; Garcia, Carla; Conde, André; Ferreira, Pedro; Pinheiro, Victor; Trindade, HenriqueExcessive ammonia (NH3) and carbon dioxide (CO2) in the housing of breeding hens can cause various negative effects on the health of hens and the welfare of the workers who care for them. The aim of this study was to evaluate the NH3 and CO2 concentrations in the first month of housing the breeding hens during Portuguese winter. The study was conducted on a commercial hen breeding farm located in central Portugal. One modern building equipped with climate control system, automatic feeding and drinking systems and minimum transitional tunnel ridge system was selected. New litter material made with rice hulls was used in the building, and the breeding sample comprised five months old 6864 female and 720 male birds housed in the building on 7 November 2016. The outdoor and indoor environmental conditions and indoor gas concentrations were measured continuously from 10 November to 30 November 2016. (NH3)and CO2 concentrations were measured with a photoacoustic field gas monitor and air samples collected through 4 sampling points located indoor, by a multipoint sampler. Results showed that the CO2 concentrations did not exceed 3000 ppm during the first month of housing the breeding hens and under winter environment. However, the NH3 concentrations exceed 20 ppm on most measurement days. For a good indoor air quality, the study suggests the use of mitigating measures for maintaining NH3 concentration below 10 ppm.
- Assessment of Mineralized Nitrogen During Maize Growth Succeeding Different Winter Cover Crops in the Mediterranean EnvironmentPublication . Perdigão, Adelaide; Pereira, José L.S.; Moreira, Nuno; Trindade, Henrique; Coutinho, JoãoBackground: Understanding soil nitrogen (N) dynamics is essential to find alternative N sources and improve N use efficiency in agriculture. Objective: The aim of this study was to assess N mineralization rates from residues of winter cover crops, during maize crop season, under Mediterranean conditions. Methods: A field experiment was carried out from May to September in central Portugal, with four replications, two sowing dates of cover crops (15/10/2011 and 29/11/2011) and three cover crops residues (balansa clover, ryegrass and yellow lupine) that were incorporated in the soil. Plots were cropped with local maize and net N mineralization was measured during the crop cycle, using soil cylinders placed inside micro-perforated polyethylene bags. Results and Discussion: Early sowing of the cover crops residues increased the NH4+ and NO3- contents in the soil. Yellow lupine residue had the highest rate of daily N mineralization (0.71 mg N kg-1 day-1). For all treatments, the highest mineralization rate was found in the last incubation period, ranging between 0.78 mg N kg-1 day-1 and 1.84 mg N kg-1 day-1, both for balansa clover, from the second and the first sowing date, respectively. Conclusion: The present study suggests that, under Mediterranean field conditions, cover crops residue of Italian ryegrass, balansa clover and yellow lupin can be used as a nitrogen source namely for sustainable maize crops.
- Biochar as an Alternative Litter Additive to Mitigate Gaseous Emissions from Broiler Housing and Subsequent StoragePublication . Pereira, José L.S.; Martins, Filipa; Bonifácio, Gabriel; Garcia, Carla; Teixeira, José; Trindade, HenriqueBroiler farming is a significant source of gaseous emissions. The aim of this study was to assess the effects of different litter additives on the emission of NH3, N2O, CO2, and CH4 during broiler housing and subsequent manure storage. The gaseous emissions from the housing facilities were evaluated during one fattening cycle in environmentally controlled rooms with three different additives applied to the litter material (10% w/w aluminum sulphate or biochar and 2.50 mg m−2 urease inhibitor), as well as a control. A storage experiment was conducted under laboratory conditions for 90 days to evaluate the influence of these three additives on gaseous losses. During broiler housing, the results indicated that NH3 emissions were reduced significantly (40–60%) by litter additives, while global warming potential (GWP) emissions were reduced significantly (31%) by Alum. The addition of Biochar (a 58% reduction) had the same significant effect as Alum (a 60% reduction) to mitigate these losses. The re-application of Urease (a 41% reduction) may be required to reach an equal or higher reduction. During storage, NH3 and GWP emissions were not significantly affected by the litter additives. During broiler housing and subsequent manure storage, NH3 emissions were reduced significantly (22–41%) by litter additives, whereas GWP emissions did not decrease significantly. Globally, it can be concluded that Biochar appears to be a good alternative to Alum due to its equal effectiveness in mitigating NH3 losses, without increasing the GWP potential in the housing and avoiding pollution swapping.
- Carbon and nitrogen mineralisation from green manures as alternative nitrogen sources in Mediterranean farmingPublication . Perdigão, Adelaide; Pereira, José; Moreira, Nuno; Trindade, Henrique; Coutinho, JoãoThe soil incorporation of green manures is a practice that can be used in sustainable agriculture and in organic farming, where nitrogen (N) sources are limited. The aim of this study was to evaluate balansa clover (Trifolium michelianum Savi), yellow lupine (Lupinus luteus L.) and ryegrass (Lolium multiflorum Lam.) as potential alternative N sources. A total of nine treatments were considered in this study: control, aerial of balansa clover, roots of balansa clover, aerial of yellow lupine, roots of yellow lupine, aerial of ryegrass, roots of ryegrass, mixture aerial + roots of yellow lupine and mixture aerial + roots of ryegrass. A laboratory incubation experiment was conducted under controlled conditions during 196 days and carbon and N mineralisation were followed. Results showed that green manures are appropriate N sources for Mediterranean farming. No significant differences in terms of N mineralisation were observed between aerial or roots biomass of the green manures. Besides, 37–55% of total N applied was mineralised in treatments amended with balansa clover or yellow lupine, whereas 13–21% of total N applied was mineralised in ryegrass. It can be concluded that the most efficient green manure for supplying mineral N to the succeeding crop was yellow lupine.
- Changes in the nutritional value of rice grown under two projected climate change scenarios: elevated CO2 and elevated CO2 + elevated temperature.Publication . Goufo, Piebiep; Carranca, Carina; Rosa, Eduardo; Trindade, Henrique; Pereira, José Luís
- «
- 1 (current)
- 2
- 3
- »