Transdisciplinary approaches that provide holistic views are essential to properly understand soil processes and the importance of soil to society and will be crucial in the future to integrate distinct disciplines into soil studies. A myriad of challenges faces soil science at the beginning of the 2020s. The main aim of this overview is to assess past achievements and current challenges regarding soil threats such as erosion and soil contamination related to different United Nations sustainable development goals (SDGs) including (1) sustainable food production, (2) ensure healthy lives and reduce environmental risks (SDG3), (3) ensure water availability (SDG6), and (4) enhanced soil carbon sequestration because of climate change (SDG13). Twenty experts from different disciplines related to soil sciences offer perspectives on important research directions. Special attention must be paid to some concerns such as (1) effective soil conservation strategies; (2) new computational technologies, models, and in situ measurements that will bring new insights to in-soil process at spatiotemporal scales, their relationships, dynamics, and thresholds; (3) impacts of human activities, wildfires, and climate change on soil microorganisms and thereby on biogeochemical cycles and water relationships; (4) microplastics as a new potential pollutant; (5) the development of green technologies for soil rehabilitation; and (6) the reduction of greenhouse gas emissions by simultaneous soil carbon sequestration and reduction in nitrous oxide emission. Manuscripts on topics such as these are particularly welcomed in Air, Soil and Water Research .

The manuscript presents results of the evaluation of compost from fish waste (FW) as a fertilizer for agricultural use. A pot experiment was conducted to compare the effects of compost from FW on the yield and macro and microelemental composition of ice lettuce (Lactuca sativa L.). In addition, the phytotoxicity degree of the compost and compost effects on seed germination and primary root growth were determined with white mustard (Sinapis alba L.). Compost used in the study consisted of FW and pine bark. Results of the evaluation enable concluding that the compost from FW is non-phytotoxic, mature, stable, and suitable for use in agriculture. Its addition to soil caused an increase in fresh and dry matter yield of leaves of ice lettuce (L. sativa L.). Fertilization had a significant effect on increased contents of nitrogen, phosphorus, potassium, sodium, calcium, and magnesium in leaves of the test plant. The average accumulation of microelements in ice lettuce (L. sativa L.) grown in the soil fertilized with compost from FW followed the descending order Fe > Cu > Ni > Zn > Mn, respectively. Soil fertilization with compost from FW improved the K:(Mg + Ca), K:Mg and K:Ca ratios but, simultaneously, deteriorated the Ca:P ratio.

Contamination of soil by copper (Cu) has become a serious problem throughout the world, causing the reduction of agricultural yield and harmful effects on human health by entering the food chain. A glasshouse pot experiment was designed to evaluate the potential use of halloysite as an immobilizing agent in the aided phytostabilization of Cu-contaminated soil, using Festuca rubra L. The content of Cu in plants, i.e., total and extracted by 0.01 M CaCl₂, was determined using the method of spectrophotometry. Cu content in the tested parts of F. rubra differed significantly when halloysite was applied to the soil, as well as with increasing concentrations of Cu. The addition of halloysite significantly increased plant biomass. Cu accumulated in the roots, thereby reducing its toxicity to the aerial parts of the plant. The obtained values of bioconcentration and translocation factors observed for halloysite treatment indicate the effectiveness of using F. rubra in phytostabilization techniques.

Slags are the final solid wastes from the steel industry. Their production from waste and associated materials is a proper implementation of the basic objectives and principles of the waste management. This study aims to investigate the chemical and selected significant geotechnical parameters of steel slag as the alternative materials used in road construction. These investigations are strongly desired for successful application in engineering. Young’s modules E, and resilient modules M_r showed that their values corresponding with requirements for subbase (principal or auxiliary) and riding surface as well. Tested mechanical properties were conducted in soaked and un-soaked (optimal moisture content) conditions. The designated high content of chromium and zinc are strongly associated with the internal crystal structure of steel slag. The results do not lead to threats when they are applied in roads’ structures. Mechanical characterization was obtained by performing California bearing ratio (CBR) tests for steel slag in fixed compaction and moisture content conditions. Moreover, cyclic loading of steel slag was conducted with the application of cyclic California bearing ratio (cCBR) apparatus to characterization of this material as a controlled low-strength material. Finally, field studies that consist of static load plate VSS tests were presented.