Half of the applied fertilizers are not used globally and instead pollute the environment. Determining the degree of loss, which is crucial for prevention, is accomplished using models validated by measurements. For validation, knowledge of the concentration (χa) measured above the crop with the photoacoustic method is essential. In this regard, a summary article was published in which we described the models applicable to fertilized fields. We model material flux in the soil-plant-atmosphere system – specifically, the bi-directional exchange of ammonia – using an electrotechnical analogy. The ammonia flux (F), or current, is determined by the ratio of the concentration difference (Δχ) between two media and the resistance to exchange (R). The article discusses in detail the model concepts and the parameterizations of concentrations and resistances. Ammonia emitted by the soil is either directly released into the atmosphere (red line) or partly taken up by vegetation, i.e. recycled (purple line). The aim of our study is not only to measure and model ammonia loss, but also to determine rate of recycling.
The starting point of the study is that, even though the discourse related to the revitalization of brownfield areas has a long history in Hungarian development policy practice, its role in promoting the circular economy and environmental sustainability has appeared with little emphasis in Hungary so far, for which the article presents a few theoretical and practical arguments. In the study, the authors introduce a framework presenting the environmental, social and economic benefits of brownfield areas’ redevelopment, highlighting sustainability benefits along concrete examples.
