Nutrient and toxic element soil concentrations during repeated mineral and compost fertilization treatments in a Mediterranean agricultural soil

Abstract

Agricultural soils of semi-arid Mediterranean areas are often subjected to depletion of their chemical, physical, and biological properties. In this context, organic fertilization, in addition to providing nutrients for a longer time in respect to mineral fertilization, improves many other characteristics related to soil fertility. Moreover, the combined use of organic and mineral fertilizers may promote a more sustainable crop production. However, a concern on the long-term use of organic fertilizers arises in relation to the possible accumulation of toxic elements in soil and their transfer to human beings. For this reason, a long-term study on nutrient and toxic element total concentrations and availabilities during fertilization treatments was carried out. In particular, mineral NPK fertilized soils, soils amended with biowaste compost, soils amended with biowaste compost plus mineral nitrogen, and unfertilized soils were analyzed for 11 chemical elements. The results highlighted that temporal variations in total and bioavailable concentrations of both nutrients and toxic elements, occurring also in unfertilized soils, are wider than those related to fertilization treatments. Anyway, soil amendments with biowaste compost, alone or in combination with mineral fertilizers, reduce Cu bioavailability but improve K, Fe, Mn, and Zn availabilities, excluding at the same time a long-term accumulation in soil. Total and bioavailable toxic element concentrations (apart from available Cd) do not vary in relation to fertilization treatments.

Effects of Compost Amendment on Glycophyte and Halophyte Crops Grown on Saline Soils: Isolation and Characterization of Rhizobacteria with Plant Growth Promoting Features and High Salt Resistance

“…Thousands of scientific publications, in the last three decades, deal with compost, illustrating the beneficial effects on soils depleted of its organic matter due to the reckless use of inorganic fertilizers [32]. The benefits of compost on soil chemical-physical-biological properties, and on crop productivity have been widely demonstrated [33][34][35]. In our pot experiment the positive effect on the seedlings growth and biomass was confirmed once more, in almost all the treated crops and groups.…”

Compost and Sewage Sludge for the Improvement of Soil Chemical and Biological Quality of Mediterranean Agroecosystems

“…CMP treatment was obtained adding to each mesocosm 494 g of BC (Table 1 and Table S1) produced by the Salerno (Italy) composting plant, from solid organic wastes and urban greening, in order to reach a final dose of 30 t/ha; this treatment often demonstrated to be the most advantageous in the Mediterranean area for edaphic community [31], as well as for crop yield and quality [8,17,18]. FNG treatment was obtained by adding to each mesocosm 987.5 g of SS (Table 1 and Table S1) produced by the Nocera Superiore (southern Italy) urban wastewater treatment plant (UWWTP), taking into account the quantity (5 t/ha) suggested by the regional legislation for the use of SS [32], as reported in the ISPRA Lombardia report [33].…”

“…Soil water content (after oven-drying at 105 • C for 48 h), and OM concentration (calcination in muffle, at 550 • C for 4 h, Nabertherm GmbH, Controller B 170) were determined using gravimetric methods. Total PTE (Cu, Mn, Ni, P, V, Zn) concentrations were determined as reported in Baldantoni et al (2016) [17].…”

“…Long-term soil amendments with biowaste compost, alone or in combination with mineral fertilizers (MFs), may represent a cost-effective, eco-friendly, and safe strategy [12,13]. Indeed this practice not only can have positive effects on crop yield [8] and edaphic community [14,15], but also can ensure crop quality [12,16], even when increases in soil potentially toxic element (PTE) bioavailability occur [17]. The physicochemical and biological properties of agroecosystem soils may be improved not only by BC, but also by SS application.…”

Influence of the Choice of Cultivar and Soil Fertilization on PTE Concentrations in Lactuca sativa L. in the Framework of the Regenerative Agriculture Revolution

“…Amendment with biowaste compost has been fostered in the Mediterranean area not only to improve physical, chemical and biological soil properties but also for its undeniable benefits linked to the recycling of organic wastes and the mitigation of climate changes [8][9][10][11][12][13]. Even if recycling back byproducts from food production, processing and consumption into the food system represent key points of circular and sustainable agriculture [4], concerns regarding the potential introduction of persistent contaminants or the enhancement of their availability to the biota still exist [14][15][16][17][18]. The same applies to the selection of different species and cultivars, able to achieve high yields by enhancing the efficiency of soil utilization, but potentially accumulating large amounts of persistent pollutants, with possible threats for food security and environmental health [19][20][21].…”