Water Availability and Land Management Control Catchment‐Scale Agricultural Nitrogen and Phosphorous Use Efficiencies

In arable systems, large amounts of nutrients, particularly of nitrogen (N) and phosphorus (P), are not efficiently converted into harvestable products and are lost from agricultural systems, with negative consequences for agricultural productivity and the environment. These nutrient losses are mediated by hydroclimatic processes causing nutrient leaching and volatilization. We quantify over the period 1987–2012 how water availability through the evaporative ratio (actual evapotranspiration divided by precipitation) and irrigation, agricultural practices, and edaphic conditions jointly affect nutrient use efficiencies in 110 agricultural catchments in the United States. We consider N and P use efficiencies (nitrogen use efficiency [NUE] and phosphorous use efficiency [PUE]) defined as ratios of catchment-scale N and P in harvested products over their respective inputs, as well as the NUE/PUE ratio, as an indication of catchment-scale N and P imbalance. Both efficiencies increase through time because of changes in climate and agronomic practices. Setting all else at the median value of the data set, NUE and PUE increased with evaporative ratio by 0.5% and 0.2% when increasing the evaporative ratio by 20% and by 4.9% and 18.8% in the presence of irrigation. NUE was also higher in catchments where maize and soybean were dominant (increasing by 2.3% for a 20% increase in maize and soybean fractional area). Soil properties, represented by mineral soil texture and organic matter content, had only small effects on the efficiencies. Our results show that both climatic conditions and crop choice are important drivers of nutrient use efficiencies in agricultural catchments

Towards specific T–H relationships: FRIBAS database for better characterization of RC and URM buildings

FRIBAS database is an open access database (https://doi.org/10.5281/zenodo.6505442) composed of the characteristics of 312 buildings (71 masonry, 237 reinforced concrete and 4 mixed types). It collects and harmonizes data from different surveys performed on buildings in the Basilicata and Friuli Venezia Giulia regions (Southern and Northeastern Italy, respectively). Each building is defined by 37 parameters related to the building and foundation soil characteristics. The building and soil fundamental periods were experimentally estimated based on ambient noise measurements. FRIBAS gave us the opportunity to study the influence of the main characteristics of buildings and the soil-building interaction effect to their structural response. In this study, we have used the FRIBAS dataset to investigate how the building period varies as a function of construction materials and soil types. Our results motivate the need of going beyond a ‘one-fits-all’ numerical period–height (T–H) relationship for generic building typologies provided by seismic codes, towards specific T–H relationships that account for both soil and building typologies

Pathways from research to sustainable development: insights from ten research projects in sustainability and resilience

Drawing on collective experience from ten collaborative research projects focused on the Global South, we identify three major challenges that impede the translation of research on sustainability and resilience into better-informed choices by individuals and policy-makers that in turn can support transformation to a sustainable future. The three challenges comprise: (i) converting knowledge produced during research projects into successful knowledge application; (ii) scaling up knowledge in time when research projects are short-term and potential impacts are long-term; and (iii) scaling up knowledge across space, from local research sites to larger-scale or even global impact. Some potential pathways for funding agencies to overcome these challenges include providing targeted prolonged funding for dissemination and outreach, and facilitating collaboration and coordination across different sites, research teams, and partner organizations. By systematically documenting these challenges, we hope to pave the way for further innovations in the research cycle

Adhesion to carbon nanotube conductive scaffolds forces action-potential appearance in immature rat spinal neurons

In the last decade, carbon nanotube growth substrates have been used to investigate neurons and neuronal networks formation in vitro when guided by artificial nano-scaled cues. Besides, nanotube-based interfaces are being developed, such as prosthesis for monitoring brain activity. We recently described how carbon nanotube substrates alter the electrophysiological and synaptic responses of hippocampal neurons in culture. This observation highlighted the exceptional ability of this material in interfering with nerve tissue growth. Here we test the hypothesis that carbon nanotube scaffolds promote the development of immature neurons isolated from the neonatal rat spinal cord, and maintained in vitro. To address this issue we performed electrophysiological studies associated to gene expression analysis. Our results indicate that spinal neurons plated on electro-conductive carbon nanotubes show a facilitated development. Spinal neurons anticipate the expression of functional markers of maturation, such as the generation of voltage dependent currents or action potentials. These changes are accompanied by a selective modulation of gene expression, involving neuronal and non-neuronal components. Our microarray experiments suggest that carbon nanotube platforms trigger reparative activities involving microglia, in the absence of reactive gliosis. Hence, future tissue scaffolds blended with conductive nanotubes may be exploited to promote cell differentiation and reparative pathways in neural regeneration strategies

Hydro-climatic controls explain variations in catchment-scale nitrogen use efficiency

The efficiency of fertilizer conversion to harvestable products is often low in annual crops such that large amounts of nutrients are lost from fields with negative consequences for the environment. Focusing on nitrogen (N) use efficiency (NUE: the ratio of N in harvested products over the sum of all N inputs), we propose that hydrological controls can explain variations in NUE, because water mediates both the uptake of N by plants and N leaching. We assess these controls at the catchment scale, at which the water balance can be constrained by precipitation and runoff data and NUE can be quantified with census data. With this approach we test the hypotheses that a higher evaporative ratio (ET/P: the ratio of evapotranspiration over precipitation) increases N retention, thereby increasing NUE both across catchments at a given time and through time. With data from 73 catchments in the United States, encompassing a wide range of pedoclimatic conditions for the period 1988-2007, we apply a linear mixed effect model to test the effect of ET/P on NUE. Supporting our hypotheses, ET/P was positively related to NUE, and NUE increased through time. Moreover, we found an interaction between ET/P and time, such that the ET/P effect on NUE decreased in the period 1998-2007. We conclude that climatic changes that increase ET/P without negatively affecting yields, will increase N retention in the examined catchments

Successful Regrowth of Retinal Neurons When Cultured Interfaced to Carbon Nanotube Platforms

A shared dream of ophthalmologists,neurologists and bioengineers is to recover sight ability in diseased eyes via coupling retinal cells with artificial devices. In the engineering of ophto-prosthetic devices the material directly exposed to the biological milieu is crucial, it has to guarantee tight contacts between retinal neurons and the interface, while assuring cell survival with physiological network development. Carbon nanotubes have been applied in several areas of nerve tissue engineering and are emerging as a promising material for neuro-interfacing applications, given their outstanding physical properties. In the current work we have tested carbon nanotube ability to interface cultured murine and human retinal neurons. We cultured rat retinal neurons on carbon nanotube substrates and described their morphology and synaptic functions via immunofluorescence microscopy and patch-clamp recordings. In a second set of experiments, we explored viability and morphology of human retinal ganglion cells (RGC) when grown on carbon nanotube substrates. We show here carbon nanotube ability to sustain the proper development of rat neurons and, more importantly, of human RGCs. In addition, patch-clamp recordings on rat retinal cells were functional to demonstrate that carbon nanotubes do not perturb the physiological synaptic activity when compared to controls. This result, strengthen by the shown biocompatibility with human cells and the nanotube well described high electrical conductivity, makes these nanomaterials promising candidates to interface, stimulate or record eye nerve cells

Floods, soil and food – Interactions between water management and rice production within An Giang province, Vietnam

Rapid intensification of Vietnamese rice production has had a positive effect on the nation's food production and economy. However, the sustainability of intensive rice production is increasingly being questioned within Vietnam, particularly in major agricultural provinces such as An Giang. The construction of high dykes within this province, which allow for complete regulation of water onto rice fields, has enabled farmers to grow up to three rice crops per year. However, the profitability of producing three crops is rapidly decreasing as farmers increase their use of chemical fertilizer inputs and pesticides. Increased fertilizer inputs are partly used to replace natural flood-borne, nutrient-rich sediment inputs that have been inhibited by the dykes, but farmers believe that despite this, soil health within the dyke system is degrading. However, the effects of the dykes on soil properties have not been tested. Therefore, a sampling campaign was conducted to assess differences in soil properties caused by the construction of dykes. The results show that, under present fertilization practices, although dykes may inhibit flood-borne sediments, this does not lead to a systematic reduction in nutrients that typically limit rice growth within areas producing three crops per year. Concentrations of total nitrogen, available phosphorous, and both total and available potassium, and pH were higher in the surface layer of soils of three crop areas when compared to two crop areas. This suggests that yield declines may be caused by other factors related to the construction of dykes and the use of chemical inputs, and that care should be taken when attempting to maintain crop yields. Attempting to compensate for yield declines by increasing fertilizer inputs may ultimately have negative effects on yields

Do alternative irrigation strategies for rice cultivation decrease water footprints at the cost of long-term soil health?

The availability of water is a growing concern for flooded rice production. As such, several water-saving irrigation practices have been developed to reduce water requirements. Alternate wetting and drying and mid-season drainage have been shown to potentially reduce water requirements while maintaining rice yields when compared to continuous flooding. With the removal of permanently anaerobic conditions during the growing season, water-saving irrigation can also reduce CO _2 equivalent (CO _2eq ) emissions, helping reduce the impact of greenhouse gas (GHG) emissions. However, the long-term impact of water-saving irrigation on soil organic carbon (SOC)—used here as an indicator of soil health and fertility—has not been explored. We therefore conducted a meta-analysis to assess the effects of common water-saving irrigation practices (alternate wetting and drying and mid-season drainage) on (i) SOC, and (ii) GHG emissions. Despite an extensive literature search, only 12 studies were found containing data to constrain the soil C balance in both continuous flooding and water-saving irrigation plots, highlighting the still limited understanding of long-term impacts of water-saving irrigation on soil health and GHG emissions. Water-saving irrigation was found to reduce emissions of CH _4 by 52.3% and increased those of CO _2 by 44.8%. CO _2eq emissions were thereby reduced by 18.6% but the soil-to-atmosphere carbon (C) flux increased by 25% when compared to continuous flooding. Water-saving irrigation was also found to have a negative effect on both SOC—reducing concentrations by 5.2%—and soil organic nitrogen—potentially depleting stocks by more than 100 kg N/ha per year. While negative effects of water-saving irrigation on rice yield may not be visible in short-term experiments, care should be taken when assessing the long-term sustainability of these irrigation practices because they can decrease soil fertility. Strategies need to be developed for assessing the more long-term effects of these irrigation practices by considering trade-offs between water savings and other ecosystem services