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- Remote Sensing (NDVI) and Apparent Soil Electrical Conductivity (ECap) to Delineate Different Zones in a VineyardPublication . Esteves, Catarina; Ribeiro, Henrique; Braga, Ricardo; Fangueiro, DavidThe intensification of agriculture has greatly enhanced crop productivity, but also its potential environmental impact. Nutrient recycling and an increase in resource use efficiency are the key points to keep production at high levels with minimum impact. The present work’s goal was to provide new insight on the spatial variability of soil chemical properties in a vineyard. For this, three different zones were identified in a 6.77 ha parcel, according to the remote sensing of apparent soil electrical conductivity (ECap) and the normalized difference vegetation index (NDVI). Soil samples from specific locations were then collected and chemically described, and the resulting data were statistically analyzed. ECap and NDVI appeared to be efficient tools to define different zones within the vineyard, with most of the soil chemical properties varying at the highest significance level (p < 0.001) according to the F test, except for extractable phosphorus (Égner-Rhiem) and organic carbon (TOC method). Overall, our results revealed potential for the implementation of site-specific soil fertilization and soil quality management
- Mitigating ammonia and greenhouse gas emissions from stored pig slurry using chemical additives and biocharsPublication . Pereira, José L. S.; Perdigão, Adelaide; Marques, Francisco; Wessel, Dulcineia F.; Trindade, Henrique; Fangueiro, David: Slurry storage is a significant source of NH3 and greenhouse gas (GHG) emissions. The aim of this laboratory study was to assess the effects of different chemical additives and biochars on the emissions of NH3 , N2O, CO2 , and CH4 during the short-term storage of pig slurry. The experiment was performed using Kilner jars filled with raw slurry as control and six treatment additives (5% w/w): acidified slurry, alkalinized slurry, neutralized slurry, agroforestry biochar, cardoon biochar, and elderberry biochar. The gas emissions were measured for 30 days, and the composition of the slurries was determined. During short-term storage, the results of this laboratory study indicated that the NH3 emissions were reduced by 58% by acidification and by 20% by the biochars (Agroforestry, Cardoon, and Elderberry treatments), while neutralization reduced this loss by only 12%. Nitrous oxide emissions were not reduced by the chemical additives (Acidified, Alkalinized, and Neutralized treatments), while this loss was increased by 12% by the biochars. Carbon dioxide, CH4 , and global warming potential emissions were not affected by the chemical additives and biochars. Furthermore, the absence of differences between the biochars may be related to their similar composition. Regarding the influence of the studied additives on NH3 losses, it can be concluded that acidification was the best mitigation measure and the biochars were quite similar due to their composition. Furthermore, neutralization had the advantage of sanitizing the slurry, but only had a mild impact on NH3 preservation
- When the solution becomes the problem: a review on antimicrobial resistance in dairy cattlePublication . Pires, Ana José; Pereira, Gonçalo; Fangueiro, David; Bexiga, Ricardo; Oliveira, ManuelaAntibiotics' action, once a ‘magic bullet’, is now hindered by widespread microbial resistance, creating a global antimicrobial resistance (AMR) crisis. A primary driver of AMR is the selective pressure from antimicrobial use. Between 2000 and 2015, antibiotic consumption increased by 65%, reaching 34.8 billion tons, 73% of which was used in animals. In the dairy cattle sector, antibiotics are crucial for treating diseases like mastitis, posing risks to humans, animals and potentially leading to environmental contamination. To address AMR, strategies like selective dry cow therapy, alternative treatments (nanoparticles, phages) and waste management innovations are emerging. However, most solutions are in development, emphasizing the urgent need for further research to tackle AMR in dairy farms.
- Agro-industrial by-products as alternative additives for the agronomic valorization of pig slurry through pH modificationPublication . Chrysanthopoulos, Stamatis; Coutinho, João; Silva, Ana Carla; Brito, Luisa; Fangueiro, DavidThe use of animal slurry in modern agricultural systems is receiving considerable attention, mainly due to the latest increase in chemical fertilizer prices. However, the use of raw animal slurry to fertilize horticultural crops can, on the one hand, lead to significant ammonia emissions and, on the other hand, be an important source of zoonotic pathogens. Therefore, proper treatment is required. The present study explored the modification of the pH value of pig slurry using by-products from different agro-industrial activities as a strategy to control these two problems. Three approaches were used, namely acidification and biological acidification (bio-acidification) to pH 5 and alkalization to pH 9.5. The most promising of the 14 different additives and additive combinations initially considered should be able to reach the target pH at a dose of less than 20% (m/m). The presence of Salmonella and the number of Escherichia coli colony forming units (CFU) were evaluated in the slurry for each selected treatment. To ensure that treated slurry remains of interest as an organic fertilizer, the impact of treated slurry on plant germination and nitrogen (N) availability was also assessed. The by-products from the brewing and yeast industry failed to reduce the pH to 5. In fact, the bio-acidification of pig slurry was only possible with additives rich in carbon. Although slurry sanitization (<1000 CFU E.coli g 1 slurry) was not guaranteed by all treatments, a reduction in E.coli numbers was observed with all additives. The ammonium content of the treated slurry was significantly reduced (up to 20%) with treatments involving bio-acidification. N mineralization was evidenced for all additives used for slurry alkalinization but no N mineralization was observed when using acidification with H2SO4 or by-product spent acid. The phytotoxicity bioassay showed that most additives do not have a negative impact on germination. The results presented here suggest that agro-industrial by-products are capable of modifying the pH of pig slurry. Depending on the pH modification strategy and additive used, treated slurry may be safer and of higher fertilizing value than untreated (raw) slurry.
- Optimizing slurry managementPublication . Fangueiro, David; Elmahdi, Jihane; Nyang'au, Jared; Chrysanthopoulos, Stamatis; De Vries, Jerke; Sørensen, Peter
- Exploring social indicators in smallholder food systems: modeling children’s educational outcomes on crop-livestock family farms in MadagascarPublication . Thom, Amy E.; Bélières, Jean-François; Conradie, Beatrice; Salgado, Paulo; Vigne, Mathieu; Fangueiro, DavidPromoting smallholders’ sustainable development in Africa means addressing agronomic and economic factors but also highly relevant social influences shaping farmers’ production and affecting household well-being. Holistic, integrated analyses can help to meet this need, informing more effective policies and interventions for smallholder farming systems. The authors apply a transdisciplinary, quantitative approach to analyzing social impacts in the smallholder context, using milk-producing crop-livestock family farms in central Madagascar as a test case. First, stochastic frontier analysis is leveraged to confirm education as a social indicator linked to production efficiency. Then, linear regression is used for exploratory modeling of children’s educational outcomes. Findings from the Malagasy case emphasize the influence of rural infrastructure, parental education, chronic poverty, family planning, and crop-livestock diversification on children’s educational outcomes among one region’s farming households. Taken together, results suggest that Madagascar’s policymakers should consider comprehensive territorial planning for simultaneously promoting agricultural development and human well-being. This study illustrates how a transdisciplinary approach to social impacts analysis can integrate agronomic, economic, and social dynamics and help anticipate potential outcomes in support of smallholders’ sustainable development.
- A step towards the production of manure-based fertilizers: Disclosing the effects of animal species and slurry treatment on their nutrients content and availabilityPublication . Prado, Joana; Ribeiro, Henrique; Alvarenga, Paula; Fangueiro, DavidIn a context of climate change and circular economy, it is fundamental to produce animal manure-based fertilizers attractive to farmers who are reluctant to use heterogeneous materials, poorly characterized and with unbalanced nutrient contents, namely N:P ratios different from plant requirements. Hence, the aim of the present study was to assess the potential of different treated and non-treated animal manures to produce tailor-made manure-based fertilizers with known N:P ratios. Seven manures were considered: cattle, caprine and poultry solid manures, two contrasting cattle slurries and two contrasting swine slurries. Slurries were further treated by solid-liquid separation, acidification, and acidification followed by solid-liquid separation. Raw and treated manures were fully characterized to assess the effect of manure type and treatment on their nutrient contents and N:P ratios, to incorporate them in manure-based fertilizers with selected N:P ratio. The present results were essential to support the manure-based fertilizer production and identify which materials could be considered: it appears clearly that the pig slurry with all stages of production and the correspondent liquid fraction cannot be used due to their low nutrients content. It was shown that the solid fractions rich in P and with a NT:N–NH4+ ratio close to 1 are an excellent material to prepare manure-based fertilizers. Acidification, combined with solidliquid separation, produced a liquid fraction rich in both N and P and with a NT:PT ratio close to 1, with the additional benefit of a slow N-release material. Some of the manures or sub-products obtained after treatment provided the usual N:P ratio required by farmers and could be used directly as substitutes of mineral fertilizers. Nevertheless, the blending of some of these materials has a stronger potential to the production of specific manure-based fertilizer
- Assessment of the agronomic value of manure-based fertilizersPublication . Prado, Joana; Fangueiro, David; Alvarenga, Paula; Ribeiro, HenriqueProducing manure-based fertilizers (MBFs) with specific nutrient ratios is a solution to overpassing the imbalance of nitrogen and phosphorus in manures, and a way to recycle manure’s nutrients, promoting sustainable agricultural practices. Several MBFs with different tailored N:P ratios (0.5:1, 1:1 and 2:1) were produced to determine their agronomic value in a pot experiment with oat (0.5:1 ratio: cattle manure with pig slurry (CaM+PiS), cattle manure with poultry manure (CaM+PoM) and poultry manure with superphosphate (PoM+SP); 1:1 ratio: poultry manure with cattle slurry (PoM+CaS) and poultry manure with pig slurry (PoM+PiS); 2:1 ratio: cattle slurry with the liquid fraction of cattle slurry (CaS+CaS-LIQ), pig slurry with the liquid fraction of pig slurry (PiS+PiS-LIQ) and poultry manure with urea (PoM+U)). The performance of these MBFs was compared with conventional mineral fertilizers (MFs) in sandy soils (Haplic Arenosols) with different nutrient requirements. Oat fertilized with PoM+SP (0.5:1) and PoM+PiS (1:1) led to yields similar to those obtained with the use of MFs (6.3 and 7.2 mg DM, respectively). The MBFs PoM+SP and PoM+PiS, as well as PiS+PiS-LIQ (2:1), were agronomically equivalent to the MFs. N uptake with those MBFs was equivalent to that obtained with the MFs. Replacing MFs with MBFs in the basal fertilization of oat was demonstrated to be a solution to turn agriculture more sustainable by recycling nutrients efficiently
- Partial replacement of chemical fertilizers with animal manures in an apple orchard: Effects on crop performance and soil fertilityPublication . Esteves, Catarina; Fangueiro, David; Mota, Mariana; Martins, Miguel; Braga, Ricardo P.The combined use of chemical fertilisers with organic materials in crop fertilization is an essential approach to transition towards a more sustainable and resilient agriculture in Europe. In an apple orchard, chemical fertilisers (CF) were partially (25 to 57%) replaced with animal manure (cattle slurry - CS, acidified cattle slurry - ACS, cattle solid manure - CsM, and poultry manure - PM), based on the crop’s nitrogen (N) requirements. Apple production and soil properties were monitored during a 3-year experiment. At the end of the third year, leaf N was higher in the control treatment (CTRL, 100% CF). Apple production was, on average, higher in the CS treatment, although not significantly different from the CTRL. Fruit analysis showed that replacing CF with animal manures did not significantly impacted fruit quality (weight, ºBrix and firmness). Soil organic carbon (SOC), N and exchangeable potassium (K+) were significantly higher in the manure treatments. The increase in soil K+ in the manure treatments consequently increased soil K/magnesium (Mg) ratio, slightly mitigating K and Mg antagonism, as seen by the increase in fruit K. However, K content was still deficient in fruits and leaves in all treatments. It can be concluded that the partial replacement of chemical fertilisers by animal manures (CS, ACS and PM) had a positive effect on soil health with no decrease of apple production.
- Can dairy slurry application to stubble, without Incorporation into the soil, be sustainable?Publication . Silva, Arejacy; Carvalho, Mario; Coutinho, João; Vasconcelos, Ernesto; Fangueiro, DavidIn 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, apparent nutrient recovery (ANR) and soil chemical properties were assessed. ADS reached 94% equivalence to MS and performed similarly to IN for productivity, ANR and soil parameters showing to be a sustainable alternative to replace mineral nitrogen and a potential solution to enable dairy slurry application in CA without injection or incorporation into the soil.