The Complex Pathway towards Farm-Level Sustainable Intensification: An Exploratory Network Analysis of Stakeholders’ Knowledge and Perception

peer-reviewedFarm-level sustainable intensification of agriculture (SIA) has become an important concept to ensuring food security while minimising negative externalities. However, progress towards its achievement is often constrained by the different perceptions and goals of various stakeholders that affect farm management decisions. This study examines farm-level SIA as a dynamic system with interactive components that are determined by the interests of the stakeholders involved. A systems thinking approach was used to identify and describe the pathways towards farm-level SIA across the three main pillars of sustainability. An explanatory network analysis of fuzzy cognitive maps (FCMs) that were collectively created by representative groups of farmers, farm advisors and policy makers was performed. The study shows that SIA is a complex dynamic system, affected by cognitive beliefs and particular knowledge within stakeholder groups. The study concludes that, although farm-level SIA is a complex process, common goals can be identified in collective decision making

Evolution of trees and mycorrhizal fungi intensifies silicate mineral weathering.

Forested ecosystems diversified more than 350 Ma to become major engines of continental silicate weathering, regulating the Earth's atmospheric carbon dioxide concentration by driving calcium export into ocean carbonates. Our field experiments with mature trees demonstrate intensification of this weathering engine as tree lineages diversified in concert with their symbiotic mycorrhizal fungi. Preferential hyphal colonization of the calcium silicate-bearing rock, basalt, progressively increased with advancement from arbuscular mycorrhizal (AM) to later, independently evolved ectomycorrhizal (EM) fungi, and from gymnosperm to angiosperm hosts with both fungal groups. This led to 'trenching' of silicate mineral surfaces by AM and EM fungi, with EM gymnosperms and angiosperms releasing calcium from basalt at twice the rate of AM gymnosperms. Our findings indicate mycorrhiza-driven weathering may have originated hundreds of millions of years earlier than previously recognized and subsequently intensified with the evolution of trees and mycorrhizas to affect the Earth's long-term CO(2) and climate history

The oxidative transformation of green rust sulphate and its influence on the mobility of trace elements : applications to remediation processes

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

In situ studies of green rust formation using synchrotron-based X-ray scattering : helping to develop a new range of environmental materials.

The natural environment is rich in nanoparticulate mineral phases, such as iron and manganese oxides and oxyhydroxides, with unique chemical properties. Some of these minerals, for example Green Rusts, have the potential to be developed into a new generation of environmental remediation materials which could be utilized to clean up contaminated land. Advances in X-ray technologies at third-generation synchrotron sources (e.g. the Diamond Light Source) have helped to characterise the formation and crystallisation of highly reactive nanoparticles under simulated environmental conditions. In this article, Dr. Imad Ahmed, Dr. Sam Shaw, Ms. Gabriella Kakonyi and Prof. Liane G. Benning, describe how stateof- the-art in situ time-resolved synchrotron-based scattering and diffraction methods are used to determine the mechanisms and kinetics of green rust nanoparticle formation and growth

Formation of green rust sulfate : a combined in situ time-resolved X-ray scattering and electrochemical study.

The mechanism of green rust sulfate (GR-SO4) formation was determined using a novel in situ approach combining time-resolved synchrotron-based wide-angle X-ray scattering (WAXS) with highly controlled chemical synthesis and electrochemical (i.e., Eh and pH) monitoring of the reaction. Using this approach,GR-SO4 was synthesized under strictly anaerobic conditions by coprecipitation from solutions with known FeII/FeIII ratios (i.e., 1.28 and 2) via the controlled increase of pH. The reaction in both systems proceeded via a three-stage precipitation and transformation reaction. During the first stage,schwertmannite (Fe8O8(OH)4.5(SO4)1.75) precipitated directly from solution at pH 2.8−4.5. With increasing pH (>5), Fe2+ ions adsorb to the surface of schwertmannite and catalyze its transformation to goethite (α-FeOOH) during the second stage of the reaction. In the third stage, the hydrolysis of the adsorbed Fe2+ ions on goethite initiates its transformation to GR-SO4 at pH >7. The GR-SO4 then continues to crystallize up to pH ∼8.5. These results suggest that with an FeII/FeIII ratio of ≤2 in the initial solution the structural FeII/FeIII of the GR-SO4 will be close to that of the starting composition