Browsing by Author "Roboredo, Marta"
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- Animal manures applied to soil: phosphorus bioavailability, losses to water and erosionPublication . Monteiro, M.C.H.; Ribeiro, Paulo; Batista, Marta; Carneiro, J.P.; Duarte, A.C.; Roboredo, Marta; Torrent, J.; Sharpley, AndrewPhosphorus (P) is a non renewable resource which highlights the significance of developing and using alternative sources of P for a sustainable agriculture. Animal manure is an option but its application to soils to meet crop nitrogen needs requires careful management practices to minimize freshwater eutrophication. The aim of this work was to evaluate the partitioning of applied P between plant uptake, losses to water, and erosion losses when using different animal manures and a mineral P fertilizer. A field trial was conducted at an erosion experimental station. The treatments were: Control (0 kg P/ha); cattle manure; solid fraction of pig and duck slurry and superphosphate, each applied at a rate of 50 kg P/ha after Lolium sp was sown. Soil samples from each trial were collected over the 9-month study and the water extractable soil P determined. It was found that desorption of P from all additions rapidly increased soon after P application (2 weeks). After that water extractable soil P remained fairly constant. While duck slurry desorbed the largest concentration of P, all sources have the potential to desorb P that could accelerate eutrophication. Plant uptake of P was greater with cattle manure added and released the least amount of P to water compared with the other sources of P. The partitioning of applied P between plant uptake and losses to runoff and sediments ranged between 5-12 % with the higher values in Duck treatment. Animal manures significantly increased soil Olsen-P, plant production and P uptake relative to mineral fertilizer. Animal manures can be considered as a source of available P nevertheless to avoid eutrophication risks increase plant P use efficiency is also important.
- Aplicação de resíduos orgânicos de pecuária ao solo: dessorção potencial do fosfato para as águasPublication . Monteiro, M.C.H.; Roboredo, Marta; Torrent, J.A aplicação de resíduos orgânicos de pecuária no solo pode constituir uma alternativa à fertilização mineral fosfatada contribuindo para a reutilização do fósforo e diminuição no uso de fertilizantes minerais fosfatados. Contudo, esta prática pode aumentar o risco de eutrofização por poluição difusa de origem agrícola. Neste trabalho avaliou-se a capacidade potencial de dessorção de fosfato para as águas em solos fertilizados com resíduos orgânicos de pecuária por comparação com um adubo mineral fosfatado. As modalidades efetuadas foram: controlo (C; 0kg P/ha); estrume de vaca compostado (M); fração seca do chorume de suíno (S) e de pato (D) e superfosfato concentrado (F), cada um aplicado num quantitativo de 50Kg P/ha. Utilizaram-se relações solo:solução de 1:100, 1:1000 e 1:10000 para simular as condições típicas de dessorção para águas de drenagem interna, escoamento superficial e curos de águas e albufeiras, respetivamente. Tomaram-se porções de cada suspensão aos dias 14, 29, 59, 89, 119, 149, 179, 219 e 258 e quantificou-se o P no sobrenadante (Pd). Aos 14 dias, em todas as modalidades fertilizadas Pd atingiu valores que se mantiveram praticamente constantes ao longo do ensaio. Nas suspensões 1:100 e 1:1000 Pd excedeu o valor limite para prevenir a eutrofização nas modalidades fertilizadas, enquanto na suspensão 1:10000 as modalidades F e D excederam esse limite. O estrume de vaca compostado foi o fertilizante que mostrou maior capacidade de dessorção de P para as águas.
- Assessment of phosphorus bioavailability from animal manures applied to portuguese soils and site vulnerability to phosphorus lossesPublication . Roboredo, Marta; Monteiro, M.C.H.To assess phosphorus (P) dynamics and provide scientific knowledge to create an evaluation tool to identify the risk of P loss to surface water bodies in soil amended with animal manures.
- Ciclo do fósforo em agroecossistemas: Efeito da fertilização fosfatada com adubos minerais ou com resíduos orgânicos de pecuáriaPublication . Monteiro, M.C.H.; Ribeiro, Paulo; Carneiro, J.P.; Duarte, A.C.; Batista, Marta; Roboredo, MartaCiclo do fósforo em agroecossistemas: Efeito da fertilização fosfatada com adubos minerais ou com resíduos orgânicos de pecuária.
- Fertilizantes orgânicos : efeito na fertilidade do solo e na produção de azevémPublication . Monteiro, M.C.H.; Ribeiro, Paulo; Batista, Marta; Carneiro, J.P.; Duarte, A.C.; Roboredo, MartaFertilizantes orgânicos : efeito na fertilidade do solo e na produção de azevém.
- Organic amendments as a source of phosphorus: agronomic and environmental impact of different animal manures applied to an acid soil.Publication . Monteiro, M.C.H.; Roboredo, Marta; Carneiro, J.P.; Duarte, A.C.; Torrent, J.; Sharpley, AndrewPhosphorus (P) is a non-renewable resource highlighting the significance of developing and using alternative P sources for a sustainable agriculture. The work aims to compare the effects of different organic amendments (OA) and a mineral P fertiliser as reference on P use efficiency by the crop, and on P losses to runoff waters and eroded sediments. A two-year field trial was conducted in a Dystric Regosol with Lolium sp. Treatments were: cattle manure compost (CM), solid fraction of swine (SS) and duck (DS) slurries and triple superphosphate (TSP), each applied at 50 kg P ha−1 year−1. Olsen P (mg P kg−1) increased from ≈ 19 at the beginning to ≈ 30 (TSP, CM), 45 (SS) and 62 (DS) after the experiment. Most of applied P remained in soil, between 92% (SS) and 96% (TSP), plant uptake ranged from 5% (CM) to 3.5% (TSP) and total P loss in runoff and sediments ranged between 0.2% (CM) and 4% (SS). OA increased P-use efficiency by the ryegrass crop compared with mineral P fertilizer. Composted cattle manure showed the best agronomic and environmental behaviour, simultaneously increasing P-use efficiency and decreasing P losses by runoff and erosion.
- Relationship between Olsen P and ammonium lactate–extractable P in portuguese acid soilsPublication . Monteiro, M.C.H.; Roboredo, Marta; Coutinho, João; Torrent, J.The soil phosphorus (P) test in Portugal is based on extraction with ammonium lactate (AL) at acidic pH. Because this test is rarely used in other countries, it is desirable to see whether the AL-P values correlate with the more commonly used P tests. In this work, we compared AL-P with bicarbonate-extractable P (Olsen’s method) for a group of 48 samples from Portuguese acidic soils differing widely in P status. Despite their contrasting composition, both reagents extracted phosphate from the same sources, albeit in different proportions. Both Olsen P and AL-P were strongly correlated with resin-extractable and dilute electrolyte-desorbable P, which are respectively related to the soil contents in phytoavailable P and P that can be released to runoff or drainage water. Olsen P and AL-P were strongly correlated (R2 = 0.870), the correlation became stronger when three overfertilized soils were excluded (Olsen P = 2.35 + 0.45 AL-P; R2 = 0.908; P ≤ 0.001, n = 45). No correlation was observed for a group of soils recently fertilized with Gafsa phosphate probably because the acidic AL reagent dissolved residual calcium phosphate, thus overestimating the soil content in desorbable P. On the basis of the present results and the AL-P-based fertility classes used for fertilizer recommendation purposes, Olsen P–based fertility classes were tentatively proposed for Portuguese acidic soils.
- Valorização agrícola de resíduos orgânicos de pecuária: avaliação da fitodisponibilidade em fósforoPublication . Monteiro, M.C.H.; Ribeiro, Paulo; Batista, Marta; Carneiro, J.P.; Roboredo, Marta; Torrent, J.Este trabalho teve como objetivo avaliar a adequação de dois métodos analíticos, o método de Olsen (Olsen-P) e o método de Egnér-Riehm (AL-P), na quantificação do fósforo(P) fitodisponível, após aplicação ao solo, num ensaio de campo, de resíduos orgânicos de pecuária como fertilizantes.