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Liming is a common practice in the treatment of acidic and metal contaminated soils, aiming at pH regulation, enhancing of the nutrient availability and attenuation of trace metals mobility. Replacement of natural limestone with alternative soil alkalizers found among waste materials represents a step towards sustainable resource management and reduced waste storage. In this study, waste seashells (SW) and red mud (RM) were applied in different doses to the soil sampled in the vicinity of mining and smelting complex. The soil was characterized by acidic reaction (pH 4.93), increased Cu concentration (219.2 mg/kg) and a very low level of P-supply (3.61 mg P2O5/100 g). The study aimed to quantify and compare additive-induced effects onto soil physicochemical properties, the status of macronutrients and distribution of trace metals. Targeted effect on soil pH was achieved with SW dose of 0.3% and RM dose of 2%. RM was found to be a source of available P and gave rise to the available P concentrations in the soil. Medium level of P-supply (15.60 mg P2O5/100 g) was achieved with RM dose of 5%, however, the increase in soil salinity and total trace elements concentrations have become significant adverse effects at such dose. The decrease in the ion-exchangeable content of Cu and other trace metals was in correlation with the increase in soil pH after the treatments. Redistribution of metal cations was mainly directed to carbonate/acid soluble and Fe, Mn-oxide bonded fraction after SW addition. Even though trace metals concentration has increased in the soil after application of the RM, they were principally found in the residual fraction. The results emphasize low amounts of contained trace elements and lower doses for achieving targeted effects on pH and metal mobility as the main benefits of SW treatments. On the other hand, moderate and controlled use of RM may represent multiple benefits in terms of simultaneous pH regulation, P-supply, and reduced trace metals mobility. © 2019 Elsevier B.V. This is the peer reviewed version of the following article: Egerić M, Smičiklas I, Dojčinović B, Sikirić B, Jović M, Šljivić-Ivanović M, Čakmak D. Interactions of acidic soil near copper mining and smelting complex and waste-derived alkaline additives. Geoderma. 2019;352:241–50. [http://dx.doi.org/10.1016/J.GEODERMA.2019.06.015] Published version: [https://vinar.vin.bg.ac.rs/handle/123456789/8345]

In addition to the benefits derived from nanotechnology, there is also concernabout the potential risks of engineered nanoparticles (ENPs) when released into the environment. Their possible accumulation and effects in agricultural soils and crops are closely linked to food and agriculture safety. Particular attention has been focused on the reuse of biosolids from wastewater treatment plants that are considered a cost-effective practice for the improvement of nutrients and organic matter in agricultural soils and, but also a sink of contaminants such as nanoparticles (NPs). TiO2NPs have a global production of about 10.000 tons/year and it are among the most extensively used ENPs. Moreover, dissimilar or inconclusive results have been reported concerning the impact of TiO2 NPs on the soil-crop system, thus more information regarding their behavior are necessary. This study aimed to evaluate the potential effects of TiO2 NPs (anatase and rutile) and larger particles (bulk) on the availability of soil nutrients and on the nutritional status of Pisum sativum plants, simulating low (80 mg/kg) and high load of TiO2 (800 mg/kg ) in a biosolid-amended soil. Treated soils were analyzed for N, P, K, Ca, Mg, Mn, Fe, Cu, Zn, soil microbial community, and plants grown in laboratory for 30d were analyzed for growth, pigments and mineral nutrition. Results showed that the treatment with TiO2 at macro- and nano-scale significantly reduced the availability of Mn, Fe and P in soils, this last more evident for the NPs treatments. Indeed, the soil bacterial diversity was reduced when the mixture of anatase and rutile were spiked in the biosolid-amended soil at high concentration. Moreover, the pea plants from treated soils showed an imbalance in the mineral nutrition, with reduction in the plant tissues of Mn and K and increase of N. This study pose a reflection on the use of biosolid, which could act as a vehicle for the spread and accumulation of ENPs in agro-ecosystems.

International audience; Phosphorus (P) availability in soils limits crop yields in many regions of the World, while excess of soil P triggers aquatic eutrophication in other regions. Numerous processes drive the global spatial distribution of P in agricultural soils, but their relative roles remain unclear. Here, we combined several global data sets describing these drivers with a soil P dynamics model to simulate the distribution of P in agricultural soils and to assess the contributions of the different drivers at the global scale. We analysed both the labile inorganic P (P ILAB), a proxy of the pool involved in plant nutrition and the total soil P (P TOT). We found that the soil biogeochemical background corresponding to P inherited from natural soils at the conversion to agriculture (BIOG) and farming practices (FARM) were the main drivers of the spatial variability in cropland soil P content but that their contribution varied between P TOT vs. P ILAB. When the spatial variability was computed between grid cells at half-degree resolution, we found that almost all of the P TOT spatial variability could be explained by BIOG, while BIOG and FARM explained 38% and 63% of P ILAB spatial variability, respectively. Our work also showed that the driver contribution was sensitive to the spatial scale characterizing the variability (grid cell vs. continent) and to the region of interest (global vs. tropics for instance). In particular, the heterogeneity of farming practices between continents was large enough to make FARM contribute to the variability in P TOT at that scale. We thus demonstrated how the different drivers were combined to explain the global distribution of agricultural soil P. Our study is also a promising approach to investigate the potential effect of P as a limiting factor for agroecosystems at the global scale.