Modelling agronomic properties of Technosols constructed with urban wastes

International audienceThe greening of urban and suburban areas requires large amounts of arable earth that is a non-renewable resource. However, concentration of population in cities leads to the production of high amounts of wastes and by-products that are nowadays partly recycled as a resource and quite systematically exported out of urban areas. To preserve natural soil resources, a strategy of waste recycling as fertile substitutes is proposed. Eleven wastes are selected for their environmental harmlessness and their contrasted physico-chemical properties for their potential use in pedological engineering. The aim is (i) to demonstrate the feasibility of the formulation of fertile substrates exclusively with wastes and (ii) to model their physico-chemical properties following various types, number and proportions of constitutive wastes. Twenty-five binary and ternary combinations are tested at different ratios for total carbon, Olsen available phosphorus, cation exchange capacity, water pH, water retention capacity and bulk density. Dose-response curves describe the variation of physico-chemical properties of mixtures depending on the type and ratio of selected wastes. If these mixtures mainly mimic natural soils, some of them present more extreme urban soil features, especially for pH and P Olsen. The fertility of the new substrates is modelled by multilinear regressions for the main soil properties

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Percolation theory and hydrodynamics of soil-peat mixtures

International audienc

Study of the macroporosity of reconstituted anthropic soils by image analysis

International audienc

Migration des solutes dans les laines

National audienc

Tree establishment practice in town and cities. Results from an European survey

International audienc

An innovative site sampling strategy to assess urban soil biodiversity

International audienceTo meet the challenge of the sustainable city, a better knowledge of the ecology of urban ecosystems is essential, with a major issue linked to the biological quality of soils in connection with land use and management practices. Improving the weak knowledge of soil biodiversity is indeed essential to tackle soil multifunctionality associated to urban greening. The Bises project (Biodiversity of urban soils and sustainable cities), deployed in four French cities with contrasting biopedoclimatic and historical situations (Montpellier, Nancy, Nantes and Paris), aims to understand the links between soil quality, soil biodiversity and the associated ecosystem functions and services. All the major families of organisms (macro, meso, microfauna and microorganisms) will be evaluated spatially in order to develop and aggregated indicators of the biological quality of urban soils. A multi-scale sampling strategy was implemented in order to select 48 sites per city representative of the use of urban vegetated space for ornamental (parks, road sides), or food production (family and shared gardens, urban micro-farms). Lawn-type plant cover was selected for non-productive spaces to ensure homogeneity. Close collaboration with city services enabled accessing to spatial mapping of vegetated areas in cities. The selection of site location for each type of use integrates parameters such as site area, position along the urban-rural gradient (from city center to periurban areas), age and history of site, management method for non-productive spaces (prestige=regular mowing, irrigation, fertilisation; rustic = one or two mowings per year) and type of valorisation of agricultural products (sales vs. not sales

Assessment of hydraulic properties of technosols using Beerkan and multiple tension disc infiltration methods

International audienc