Save Our Soils

Many researchers focus on how to intensify agriculture for a growing, hungry world. So far, they have largely dodged the question of how global soils will cope. Our planet’s soils are under threat, as witnessed in the past decade by dust-bowl conditions in northwest China, the desertification of grasslands in Inner Mongolia and massive dust storms across north-central Africa. Soil losses in some locations around the world are in excess of 50 tonnes per hectare in a year1: up to 100 times faster than the rate of soil formation. In other words, we are losing nearly a half-centimetre layer of this precious resource per year in some places (see graphic).At the same time, global growth in human population and wealth requires a major intensification of agricultural production to meet an expected 50% increase in demand for food by 2030, and possibly a doubling by 20502. These numbers do not bode well. Scientists need to develop a predictive framework for soil loss and degradation quickly, to evaluate potential solutions systematically and implement the best ones. There is a way forward. In the past four years, a global network of research field sites — Critical Zone Observatories — has been established. Multidisciplinary teams are focusing on the fundamentals of soil production and degradation, and aiming to create quantitative, predictive models. This programme has enormous potential. It can and should be accelerated, with stronger collaboration between national programmes and strong links to policy-makers

Contact angle hysteresis in the clay-water-air system of soils

The purpose of this research is to study the change in wettability of clays due to the influence of mesophilic soil microorganisms' activity when adding model contaminants: water-in-oil emulsion, glycerol and oleic acid. During the experiments, the objectives of this study were to specify peculiarities of wetting contact angle hysteresis of clays with substrates of different mineral composition and microbial activity. Hydrophilicity/hydrophobicity of the stimulator for microbial activity does not have a clear effect on clay properties. The surface heterogeneity mostly increases with time, perhaps, due to biofilm exudates whatever was a type of microbial stimulator. Chemical and geometric heterogeneities played comparable roles in the surface hydrophilic-hydrophobic balance. Results obtained prove that microbial communities and/or the Fe chemical state alteration (pyrite, hematite or goethite) were responsible for both hydrophilization and hydrophobization of the surface. The equation for the drop spreading rate was presented and verified by well comparison of experimental results with simulations.179-19

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

This review covers all of the common methods for the syntheses of aromatic and heterocyclic perfluoroalkyl sulfides, a class of compounds which is finding increasing application as starting materials for the preparation of agrochemicals, pharmaceutical products and, more generally, fine chemicals. A systematic approach is taken depending on the mode of incorporation of the SRF groups and also on the type of reagents used