Brief communication: Radar images for monitoring informal urban settlements in vulnerable zones in Lima, Peru

Lima, Peru's capital, has about 9.6 million inhabitants and keeps attracting more residents searching for a better life. Many citizens, without access to housing subsidies, live in informal housing and shack settlements. A typical social phenomenon in Lima is the sudden illegal occupation of areas for urban settlements. When such areas are unsafe against natural hazards, it is important to relocate such a population to avoid significant future losses. In this communication, we present an application of Sentinel-1 synthetic aperture radar (SAR) images to map the extension of a recent occupation of an area with unfavorable soil conditions against earthquakes.

Protection of Water Resources from Agriculture Pollution: An Integrated Methodological Approach for the Nitrates Directive 91–676-EEC Implementation

Nitrogen is a vital nutrient helpful to plants and crop growth. However, among the leading causes of water resources pollution is the excess nitrogen from agricultural sources. In European Union countries, the Nitrates Directive has been approved to reduce this problem monitoring of water bodies with regard to nitrate concentrations, designation of Nitrate Vulnerable Zones (NVZs), and establishing codes of good agricultural practices and measures to prevent and reduce water pollution from nitrates. In light of this, we propose an integrated methodological approach to better manage a environmental issue as the perimeter of NVZs with the prospective that our approach could be used in the future by other member states representing a Best Practice in that direction. The methodology is based on data integration applied in a GIS environment. Different available data representing the knowledge of the territory were harmonised, systematised and georeferenced, in order to increase the environmental framework, preserve the contamination of the water resource and give indications on the measures to be implemented to apply in the best way possible the Nitrates Directive. Finally, it was also possible to overcome the infringement procedure in progress for Italy and the Puglia region and proceed to new designation of NVZs.

Brief communication: Radar images for monitoring informal urban settlements in vulnerable zones in Lima, Peru

Lima city, Peru's capital, has about 9.6 million inhabitants and keeps attracting more residents searching for a better life. Many citizens, without access to housing subsidies, live in informal housing and shack settlements. A typical social phenomenon in Lima is the sudden illegal occupation of areas for urban settlements. When such areas are unsafe against natural hazards, it is important to relocate such a population to avoid significant future losses. In this communication, we present an application of Sentinel-1 SAR images to map the extension of a recent occupation of an area with unfavorable soil conditions against earthquakes.

The Potential of Digestate and the Liquid Fraction of Digestate as Chemical Fertiliser Substitutes under the RENURE Criteria

This study assessed how digestate and the liquid fraction (LF) of digestate would perform as candidate RENURE fertilisers (recovered nitrogen from manure) in nitrate vulnerable zones under the proposed criteria of the Joint Research Centre, namely, (i) a mineral nitrogen to total nitrogen ratio ≥ 90% (Nmin:TN ≥ 90%) or a total organic carbon to TN ratio ≤ 3 (TOC:TN ≤ 3); (ii) limits of ≤300 copper (Cu) mg kg−1 and ≤800 Zinc (Zn) mg kg−1. These criteria were applied to unpublished data (n = 2622) on digestate compositional properties, further amended with data from the literature (n = 180); digestate analysis from seven full-scale biogas facilities (n = 14); and biogas industry stakeholders (n = 23). The results showed that Cu and Zn mostly met the criteria, with compliance rates of 94.7% (of 1035 entries) and 95.0% (of 1038 entries), respectively. Just above 5% (of 1856 entries) met the Nmin/TN ≥ 90% criterion, while 36% (of 1583 entries) met the TOC/TN ≤ 3 criterion, while total compliance was 32% (of 1893 entries). When targeting the LF, total compliance increased noticeably, between 43 and 58% depending on DM range, indicating that LFs are better suited RENURE candidate fertilisers than unseparated digestate.

Durum Wheat Yield and N Uptake as Affected by N Source, Timing, and Rate in Two Mediterranean Environments

In nitrate vulnerable zones (NVZs), site-specific techniques are needed to match N availability with durum wheat (Triticum turgidum subsp. durum Desf.) requirements. Enhanced-efficiency fertilizers can improve efficient N supply and reduce leaching, contributing to sustainable agriculture. Two-year field experiments were carried out at two Mediterranean nitrate vulnerable zones in Central Italy (Pisa and Arezzo) to study the effects of nitrogen sources, timings, and application rates. The trial compared: (i) three N sources for the first topdressing application (urea, methylene urea, and urea with the nitrification inhibitor DMPP); (ii) two stages for the first topdressing N application (1st tiller visible—BBCH21 and 1st node detectable—BBCH31); (iii) two N rates: one based on the crop N requirements (Optimal—NO), the other based on action programme prescriptions of the two NVZs (Action Programme—NAP). Grain yield and yield components were determined, together with N uptake. The results showed that: (i) grain and biomass production were reduced with NAP at both locations; (ii) urea performed better than slow-release fertilizers; (iii) the best application time depended on the N source and location: in Pisa, enhanced-efficiency fertilizers achieved higher yields when applied earliest, while for urea the opposite was true; in Arezzo different N fertilizers showed similar performances between the two application timings. Different behaviors of topdressing fertilizers at the two localities could be related to the diverse patterns of temperatures and rainfall. Thus, optimal fertilization strategies would seem to vary according to environmental conditions.

Review of Two Mechanical Separation Technologies for the Sustainable Management of Agricultural Phosphorus in Nutrient-Vulnerable Zones

This work reviews two mechanical separation technologies (screw press and decanting centrifuge) which could be used in the dairy, beef, pig and anaerobic digestion sectors in nutrient-vulnerable zones in order to improve the sustainability of manure and anaerobic digestate management by decreasing agricultural phosphorus loss and reducing environmental impact on water quality. Capital and operating costs, separation efficiency and throughput, and management and processing of separated fractions, including transport costs, environmental impacts and the biosecurity of separated solids for export, were considered. Of the two technologies reviewed, screw press separation is a more cost-effective option (5-fold cheaper per tonne of feedstock) when lower amounts of export of phosphorus off farm are acceptable. For farms and those with anaerobic digesters managing larger volumes of manure/digestate, screw press separation is possible. However if higher levels of phosphorus removal are required, the use of decanting centrifugation is a viable option. Centralised processing facilities could also make use of decanting centrifuge technology to act as processing hubs for local farms within a distance that makes it economical for transport of manure/treated manure to/from the processor (the maximum distance for economical transport of raw manure and separated solids is approximately 70 km and 84 km, respectively). Both separation technologies could be integrated into agricultural manure and digestate management systems in order to provide a more sustainable approach to managing agricultural phosphorus loss and its associated impact on water quality. Screw press and decanting centrifuge separation could reduce phosphorous loss to water bodies by 34% and from 30 to 93%, respectively.

Vulnerability Assessment of Shallow Aquifers in Abuja using GIS and Hydrogeological Parameters

<p>One of the major challenges for the sustainable development of the federal capital territory of Abuja (Nigeria) is related to the access to safe fresh water resources. This area lies within the drought prone parts of the Sahel region. As in many regions of the world there has been growing competing demands for fresh water as a result of population growth and groundwater quality degradation. In this context, the paucity of data and in depth knowledge of aquifer features and groundwater flow makes groundwater management even more complex, with a severe impact on access to safe water resources for the local populations. To address this challenge, the purpose of the presented research is to generate information on aquifer settings and its vulnerability and on the qualitative and quantitative assessment of the available groundwater resources. Remote sensing and GIS were applied to improve the available information on groundwater resources of Abuja. Fundamental information such as recharge rate, availability and vulnerability of groundwater to pollution was determined. Aquifer vulnerability zones were delineated using the DRASTIC model by integrating layers of depth to groundwater, aquifer recharge, aquifer media, soil type, topography, impact of vadose zone and hydraulic conductivity.  The study area covers about 8000km². The elevation ranges from 62 to 843m a.s.l. with the highest elevations at the North Eastern parts and the lowest elevations at the South Western parts of the study area. There are three soil types in the area, the silty clay, silt loam and clay with clay being the predominant soil type. The five major rock types in the area include migmatite gneiss, schist and metasediment, sandstone and river alluvium, granite and quartzite. The aquifer type is phreatic and the depth to groundwater ranges from 2.8 to 21.9 m. The high recharge areas occurred mostly in highly fractured areas covered with metasedimentary rocks, migmatite gneiss and sandstones. The groundwater vulnerability zones in the study area were grouped into four classes: High, moderate, low and very low. The highly vulnerable zones are the North Eastern parts of the study area covering most parts of Bwari and parts of the municipal council areas and also the Southern parts of the study area covering parts of Kuje and Abaji. They constitute the highly fractured areas covered with silt loam soil type. The very low vulnerable zones are the North Western and Central parts covering mostly Gwgwalada and Kwali areas.  This study demonstrates that GIS and remote sensing techniques are efficient and cost effective tool for delineation of groundwater vulnerability zones. The information obtained will be used as a basis for a geochemical characterization of groundwater quality in the region with the overall goal of supporting new groundwater management plans in the region.</p><p> </p>