Nitrogen-neutrality: a step towards sustainability

We propose a novel indicator measuring one dimension of the sustainability of an entity in modern societies: Nitrogen-neutrality. N-neutrality strives to offset Nr releases an entity exerts on the environment from the release of reactive nitrogen (Nr) to the environment by reducing it and by offsetting the Nr releases elsewhere. N-neutrality also aims to increase awareness about the consequences of unintentional releases of nitrogen to the environment. N-neutrality is composed of two quantified elements: Nr released by an entity (e.g. on the basis of the N footprint) and Nr reduction from management and offset projects (N offset). It includes management strategies to reduce nitrogen losses before they occur (e.g., through energy conservation). Each of those elements faces specific challenges with regard to data availability and conceptual development. Impacts of Nr releases to the environment are manifold, and the impact profile of one unit of Nr release depends strongly on the compound released and the local susceptibility to Nr. As such, Nneutrality is more difficult to conceptualize and calculate than C-neutrality. We developed a workable conceptual framework for N-neutrality which was adapted for the 6th International Nitrogen Conference (N2013, Kampala, November 2013). Total N footprint of the surveyed meals at N2013 was 66 kg N. A total of US$ 3050 was collected from the participants and used to offset the conference’s N footprint by supporting the UN Millennium Village cluster Ruhiira in South- Western Uganda. The concept needs further development in particular to better incorporate the spatio-temporal variability of impacts and to standardize the methods to quantify the required N offset to neutralize the Nr releases impact. Criteria for compensation projects need to be sharply defined to allow the development of a market for N offset certificates Online supplementary data available from stacks.iop.org/ERL/9/115001/mmediainfo:eu-repo/semantics/publishedVersio

Biochars in soils : towards the required level of scientific understanding

Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar's effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar's contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil pH buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.Peer reviewe

Atrazine bound residues formation and dissipation in subtropical soil under swine wastewater application Dissipação e formação de resíduos ligados de atrazina em solo subtropical sob aplicação de água residuária da suinocultura

The effects of swine wastewater on atrazine dissipation and formation of bound residues in subtropical clay soil were investigated in this study. The experiment was carried out in laboratory, under room conditions, where samples of Rhodic Hapludox soil received 168.61 mg kg-1 of atrazine and were incubated for 60 days in the following treatments: T1 (sterilized soil + swine wastewater), T2 (sterilized soil + distilled water), T3 (Non sterilized soil + swine wastewater) and T4 (Non sterilized soil + distilled water). The extractable residues and bound residues of atrazine were extracted and analyzed by high performance liquid chromatography. The results showed no effect of swine wastewater on atrazine dissipation. However, the addition of swine wastewater favored the increase of bound residues, which can increase the persistence of atrazine in the environment and reduce its bioavailability.<br>Os efeitos da aplicação de água residuária da suinocultura (ARS) na dissipação de atrazina e formação de resíduos ligados em solo subtropical argiloso foram investigados neste trabalho. O experimento foi conduzido em laboratório, sob condições controladas, onde amostras de Latossolo Vermelho distroférrico receberam a aplicação de 168,61 mg kg-1 de atrazina e foram incubadas durante 60 dias, de acordo com os seguintes tratamentos: T1 (Solo esterilizado + ARS); T2 (Solo esterilizado + água destilada); T3 (Solo não esterilizado + ARS), e T4 (Solo não esterilizado + água destilada). Os resíduos extraíveis de atrazina e resíduos ligados foram extraídos e analisados por cromatografía líquida de alta eficiência. Os resultados mostraram que não houve efeito da aplicação de ARS na dissipação de atrazina. Entretanto, a adição de ARS ao solo favoreceu o aumento da formação de resíduos ligados, o que pode aumentar a persistência da atrazina no ambiente e diminuir sua biodisponibilidade

Multidimensional food security nexus in drylands under the slow onset effects of climate change

Hyperarid, arid, semiarid, and dry subhumid areas cover approximately 41% of the global land area. The human population in drylands, currently estimated at 2.7 billion, faces limited access to sufficient, affordable, and nutritious food. We discuss the interlinkages among water security, environmental security, energy security, economic security, health security, and food security governance, and how they affect food security in drylands. Reliable and adequate water supply, and the prevention of water contamination, increase the potential for ample food, fodder, and fiber production. Protecting woodlands and rangelands increases food security by buffering the slow onset effects of climate change, including biodiversity loss, desertification, salinization, and land degradation. The protection of natural lands is expected to decrease environmental contamination, and simultaneously, reduce the transfer of diseases from wildlife to humans. Biofuel production and hydroelectric power plants increase energy security but generate land-use conflicts, deforestation, and ecosystem degradation. Economic security generally positively correlates with food security. However, economic growth often degrades the environment, changes tenure rights over natural resources, and stimulates migration to urban areas, resulting in lower food and health security. Moreover, civil unrest, political instability, and armed conflicts disrupt local economies in drylands. Maintaining food security is crucial for health securityconversely, malnourished populations and unresponsive health systems decrease economic security, and adversely affect environmental, energy, and food security. Climate change is expected to deteriorate health security by spreading vector-borne diseases. Effective governance and timely interventions can substantially shorten periods of food insecurity, lower their intensities, and accelerate recovery from inevitable crises, and are therefore crucial in preventing humanitarian crises. Since global drylands population will nearly double by 2050, and since drylands are among the most susceptible areas to climate change, integrated multi-hazard approaches to food security are needed