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Projeto de investigação
Transition towards a more carbon and nutrient efficient agriculture in Europe
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Estudo da variabilidade temporal das emissões de CO2, CH4 e N2O num pomar fertilizado com efluentes pecuários
Publication . Mata, Miguel Reis da; Fangueiro, David Paulo; Ribeiro, Henrique Manuel Filipe
A agricultura é uma fonte de gases com efeito de estufa (GEE), provenientes de várias atividades, incluindo a fertilização dos solos. As emissões de GEE resultantes da fertilização, não só contribuem para as alterações climáticas, como diminuem a quantidade de nutrientes disponíveis para as plantas. A utilização de efluentes pecuários é uma alternativa ao uso de fertilizantes minerais, mas a sua utilização poderá levar ao aumento das emissões de GEE. Neste estudo, foram medidas as emissões de CO2, CH4 e N2O, resultantes da aplicação de efluentes pecuários em substituição parcial da fertilização mineral. Os 5 tratamentos estudados foram: controlo, estrume de bovino, estrume de aves, chorume de bovino, chorume de bovino acidificado. O controlo recebeu 100% do azoto disponível através da fertirrega (fertilizante mineral) e as restantes modalidades receberam 57% do azoto disponível através dos efluentes pecuários e os restantes 43% através da fertirrega. As emissões foram medidas recorrendo ao método da câmara estática e iniciaram-se após a aplicação dos efluentes pecuários, terminando antes da colheita das maçãs (4 de maio - 17 de agosto 2022). Os efluentes pecuários e os solos fertilizados foram analisados e a produção de maçãs foi quantificada. O controlo produziu a mesma quantidade de maçã que os restantes tratamentos, com exceção do estrume de bovino, que produziu menos. Não foram observadas diferenças significativas (p<0,05) entre as emissões de CO2 do controlo (160,7 g m-2) e as emissões de CO2 dos restantes tratamentos. O chorume de bovino acidificado (283,3 mg m-2) emitiu mais N2O do que o chorume de bovino bruto (155,9 mg m-2) e ambos emitiram mais N2O do que os restantes tratamentos. O chorume de bovino bruto (638 mg m-2) e o chorume de bovino acidificado (210,3 mg m-2) emitiram mais CH4 do que os restantes tratamentos. A acidificação do chorume de bovino não teve um efeito nas emissões de GEE.
Valorisation and increased use efficiency of animal manures for the fertilisation of orchards and vineyards
Publication . Esteves, Catarina Filipa Martins; Ribeiro, Henrique Manuel Filipe; Fangueiro, David Paulo; Braga, Ricardo Nuno da Fonseca Garcia Pereira
Current agricultural systems face challenges to increase agricultural production while
minimising environmental impacts. In this thesis, two approaches were suggested to
address these challenges: the replacement of mineral fertilisers (MF) with manures and
the adoption of variable-rate (VR) application of manures. In an apple orchard field
experiment, mineral nitrogen (N) fertilisation was partially replaced with two different solid
manures, a non-treated slurry and an acidified slurry, over a three-year period. The
control (CTRL) was the conventional scenario of exclusively applying MF. Fruit quality
and overall crop performance were not affected by replacing almost 60% of MF with
manures, except replacement with cattle manure which decreased crop productivity
compared with CTRL. Replacement with manures/slurries increased soil organic carbon
(24-61% relative to CTRL), soil nutrient content, and ꞵ-glucosaminidase activity (22-64%
relative to CTRL). Cattle slurry was the most suitable substitute for MF, as it resulted in
the same global warming potential (GWP) and crop yield as the CTRL. In the vineyard,
spatial variability was surveyed using remotely obtained data, allowing the delineation of
management zones and the implementation of VR within the study area (6.77 ha).
Subsequently, pig slurry (PgS) was applied using VR technique in soils with varying soil
phosphorus (P) content, at lab-scale. PgS was found to be as effective as a mineral P
fertiliser (superphosphate, SPP) at increasing soil P levels, without increasing the GWP.
An exception was PgS application on medium-P soils, which resulted in higher emissions
compared with SPP application in the same soil (922 and 698 mg CO2-eq kg-1 soil,
respectively). In P-deficient soils, the use of PgS is recommended over SPP, since the
slurry was able to sustain soil P levels at an optimal level, as opposed to SPP. The
implementation of these practices reduces MF use, increases fertiliser use efficiency and
potentially increases crop yield with no added environmental impacts.
Blending of raw and treated animal manures to produce organic fertilisers
Publication . Prado, Joana Rita Viana; Fangueiro, David Paulo; Ribeiro, Henrique Manuel Filipe; Alvarenga, Paula
Manures have an imbalance N:P ratio relative to crop needs, which prompt farmers to discard their application as fertilizer. In fact, this rendered agriculture to became dependent on the use of mineral fertilizers (MF). This thesis aims to produce a manure-based fertilizer (MBF) with a specific N:P ratio (1:1, 2:1 and 0.5:1) for basal fertilization, commonly found in MFs, under two scenarios: i) on-farm, where farmers will produce on their own the MBF, by mixing one manure with small amount of MFs and ii) central-solution, where the MBF is produced by mixing manures with other manures. First, for each scenario, an aerobic incubation was performed to estimate the N mineralization and nitrification rates, and the emission of greenhouse gases (GHG), moreover, the leaching experiment evaluated the nitrate and phosphorus potential leaching. Secondly, the agronomic efficiency of the preselected MBFs was ascertained in a pot experiment, comparing their performance with MFs. The results demonstrated that producing MBFs from raw materials can be challenging. From the MBF tested poultry manure (PoM) with pig slurry (PiS) (1:1), PiS mixed with its liquid fraction (LIQ) (2:1) and PoM with superphosphate (SP) (0.5:1) stimulated N mineralization and mitigated nitrate leaching. Even though PoM+SP is a P-enriched MBF, this enrichment did not increase the P leaching, instead enhanced P availability to values like MF. Still, the results demonstrated that it is necessary to rethink the MBFs because i) only PoM+PiS and PoM+SP obtained equal yields to MF and ii) the emissions of GHG from MBFs were considerable higher than MF but in the majority lower than the manure of origin. The production of MBF needs to be readjusted, however, the results showed promising outcomes, which suggest that with the proper alterations the adoption of MBF will potentially substitute MF in basal fertilization.
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Entidade financiadora
European Commission
Programa de financiamento
H2020
Número da atribuição
773682