University of Alcalá

About: University of Alcalá is a education organization based out in Alcalá de Henares, Spain. It is known for research contribution in the topics: Population & Context (language use). The organization has 10795 authors who have published 20718 publications receiving 410089 citations. The organization is also known as: University of Alcala & University of Alcala de Henares.

Soil and water conservation dilemmas associated with the use of green cover in steep vineyards

Abstract: A B S T R A C T Vineyards are customarily managed using tillage to eliminate competition from other plants. If the vineyards are on a slope, however, this process leads to considerable soil loss. The impacts of the practice on organic matter and the associated nutrient depletion can pose a threat to soil and water conservation. This paper considers three active rain fed vineyards in central Spain. Over two years, during which the erosivity of the rains was very low, we measured erosion rates between 35 and 179 g m 2 y 1 using erosion plots of 2 m 2 . The associated sediment had an organic matter Enrichment Ratio ranging from 1.4 to 2. Values similar to these were found for nitrogen and phosphorus. These findings indicate that alternative soil management practices, such as the use of vegetation cover, should be considered. A permanent cover consisting of Brachypodium distachyon was tested, as were covers of barley, rye and spontaneous vegetation cut in the spring. These tests resulted in reduced soil loss. The treatments exhibited erosion rates between 2 and 32 g m 2 y 1 . We also noted a decrease in the runoff coefficient. The average runoff coefficients for the study period were 5% for tilled soil, 0.9% for permanent covers and 1.4% for cut covers. We note that the infiltration benefits of tillage were only temporary because on an annual scale, the change in the soil structure led to sealing and increased runoff and erosion. Nevertheless, the moisture in the soil during the vineyard’s vegetative period was higher in traditionally tilled treatments. Although the transpiration through the permanent cover was offset by the ability of the cover to favor infiltration, the cover competed actively for water and resulted, on average, in 40% lower grape yields, with variations among the different vineyards. A similar decrease in yield (44%) was noted for the cover crop consisting of cut spontaneous vegetation. The cut cover crops of rye and barley did not significantly reduce grape yield.

Unpacking factors influencing antimicrobial use in global aquaculture and their implication for management: a review from a systems perspective

Abstract: Global seafood provides almost 20% of all animal protein in diets, and aquaculture is, despite weakening trends, the fastest growing food sector worldwide. Recent increases in production have largely been achieved through intensification of existing farming systems, resulting in higher risks of disease outbreaks. This has led to increased use of antimicrobials (AMs) and consequent antimicrobial resistance (AMR) in many farming sectors, which may compromise the treatment of bacterial infections in the aquaculture species itself and increase the risks of AMR in humans through zoonotic diseases or through the transfer of AMR genes to human bacteria. Multiple stakeholders have, as a result, criticized the aquaculture industry, resulting in consequent regulations in some countries. AM use in aquaculture differs from that in livestock farming due to aquaculture’s greater diversity of species and farming systems, alternative means of AM application, and less consolidated farming practices in many regions. This, together with less research on AM use in aquaculture in general, suggests that large data gaps persist with regards to its overall use, breakdowns by species and system, and how AMs become distributed in, and impact on, the overall social-ecological systems in which they are embedded. This paper identifies the main factors (and challenges) behind application rates, which enables discussion of mitigation pathways. From a set of identified key mechanisms for AM usage, six proximate factors are identified: vulnerability to bacterial disease, AM access, disease diagnostic capacity, AMR, target markets and food safety regulations, and certification. Building upon these can enable local governments to reduce AM use through farmer training, spatial planning, assistance with disease identification, and stricter regulations. National governments and international organizations could, in turn, assist with disease-free juveniles and vaccines, enforce rigid monitoring of the quantity and quality of AMs used by farmers and the AM residues in the farmed species and in the environment, and promote measures to reduce potential human health risks associated with AMR.

Debating the greening vs. browning of the North American boreal forest: differences between satellite datasets

Abstract: A number of remote sensing studies have evaluated the temporal trends of the normalized difference vegetation index (NDVI or vegetation greenness) in the North American boreal forest during the last two decades, often getting quite different results. To examine the effect that the use of different datasets might be having on the estimated trends, we compared the temporal trends of recently burned and unburned sites of boreal forest in central Canada calculated from two datasets: the Global Inventory, Monitoring, and Modeling Studies (GIMMS), which is the most commonly used 8 km dataset, and a new 1 km dataset developed by the Canadian Centre for Remote Sensing (CCRS). We compared the NDVI trends of both datasets along a fire severity gradient in order to evaluate the variance in regeneration rates. Temporal trends were calculated using the seasonal Mann-Kendall trend test, a rank-based, nonparametric test, which is robust against seasonality, nonnormality, heteroscedasticity, missing values, and serial dependence. The results showed contrasting NDVI trends between the CCRS and the GIMMS datasets. The CCRS dataset showed NDVI increases in all recently burned sites and in 50% of the unburned sites. Surprisingly, the GIMMS dataset did not capture the NDVI recovery in most burned sites and even showed NDVI declines in some burned sites one decade after fire. Between 50% and 75% of GIMMS pixels showed NDVI decreases in the unburned forest compared with <1% of CCRS pixels. Being the most broadly used dataset for monitoring ecosystem and carbon balance changes, the bias towards negative trends in the GIMMS dataset in the North American boreal forest has broad implications for the evaluation of vegetation and carbon dynamics in this region and globally.