Synergistic effect of organic and inorganic fertilization on the soil inoculum density of the soilborne pathogens Verticillium dahliae and Phytophthora spp. under open-field conditions

Abstract Background The increasing demand of food causes an excessive exploitation of agricultural lands, often inducing phenomena of soil sickness accompanied by the development of soilborne diseases. The use of residual biomasses together with inorganic fertilizers can be considered a good agricultural practice for controlling the inoculum density of soilborne phytopathogens since soil conditioners can release inorganic nitrogen, polyphenols and fatty acids that, especially in vitro, have demonstrated various degree of suppressiveness against such pathogens. Further, soil organic amendments can also modify the population of soil culturable bacteria and fungi that, in turn, can affect the soilborne diseases in several ways. With this study, the authors aim to evaluate the impact of the synergistic application of different biomasses and inorganic fertilizers on the soil inoculum density of Verticillium dahliae and Phytophthora spp. during two potato cycles under open-field conditions. The biomasses used for the fertilization of the potato crop were olive pomace residues (OPR), composts from municipal solid wastes (CMW), spent mushroom compost (SMC), and livestock manure-based compost (BRX). Results The inoculum density of Verticillium dahliae appeared inhibited by BRX due to its low C/N ratio that caused a quicker release of inorganic nitrogen with respect to the others soil conditioners. In contrast, OPR was conducive to the aforementioned soilborne pathogen since that biomass was characterized by a very high percentage of unsaturated fatty acids that, rather, stimulate the inoculum density of V. dahliae. Finally, polyphenols did not influence the same pathogen because they apparently turned into no toxic compounds very quickly. The inoculum density of Phytophthora spp. was reduced equally by all the biomasses used in combination with the inorganic fertilizers, regardless of their composition and quantity, mainly because of the development of general microbial suppression. Therefore, the chemical characteristics of the soil conditioners apparently did not affect the inoculum density of Phytophthora spp. Conclusions The results of this work underline the behavioral diversity of the different pathogens towards the different means adopted. Phytophthora spp. are sensitive to any kind of biomasses combined with inorganic fertilizers while the inoculum density of Verticillium dahliae should be reduced using soil conditioners characterized by low C/N ratio and low quantity of unsaturated fatty acids

Influence of chemical and mineralogical soil properties on the adsorption of sulfamethoxazole and diclofenac in Mediterranean soils

Abstract Background The irrigation with treated wastewaters can be a way for the introduction of organic contaminants in soils. However, their adsorption onto soils can allow a control of their bioavailability and leaching. The adsorption is influenced by properties of contaminants (water solubility, chemical structure) and soils (organic matter content, pH, mineralogy). This study aimed to investigate the effect of mineralogical composition, organic matter content and others parameters of soils on the adsorption of sulfamethoxazole (SMX) and diclofenac (DCF), two contaminants of emerging concerns (CECs), in real cases (Altamura, Sibari and Noci soils). Results The isotherms data showed that the adsorption of the two CECs closely matched the Freundlich model, even if the DCF could also fit the linear one. The only exception was the adsorption of SMX on the soil of Sibari, for which Langmuir's model fitted better. In all cases, the Kd values were the highest for Altamura soil according mainly to its content of organic carbon. Positive correlations were found between Kd value of DCF and the soil organic carbon and Al oxyhydroxides content, suggesting their roles in its adsorption, while SMX showed only a slight positive correlation with the soil organic carbon content. Finally, between the two CECs studied, DCF was more adsorbed than SMX also because of the lower water solubility of the former. Conclusions The good interaction between DCF and soil organic carbon suggests the organic amendment of soils before the application of treated watewaters. The low adsorption of SMX onto soils suggests greater leaching of this compound which is, therefore, potentially more dangerous than DCF. For this reason, the application of a filtration system with appropriate adsorbent materials before the application of wastewater to soils should be expected. Graphical Abstrac

Validation of a modified QuEChERS method for the extraction of multiple classes of pharmaceuticals from soils

Abstract Background The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method can be employed for multi-residue analyses instead of traditional extraction methods due to its advantages in terms of extraction time and required equipment. A modified version of the QuEChERS method has been developed for quantifying eight pharmaceuticals belonging to different classes in three real soils with different chemical properties. Firstly, the soils have been polluted with all contaminants and the recoveries were determined by liquid chromatography tandem–mass spectrometry. Due to similar recoveries from the three soils, the validation of the method has been carried out only on a soil by determining linearity, recovery, precision, limit of detection (LOD) and limit of quantification (LOQ) values. A matrix-matched calibration for the soil has been adopted in order to avoid the matrix effect and three levels of fortification (50, 100 and 500 µg L−1) were used. Results The recovery of all pharmaceuticals, with the exception of tetracycline, from any soil was between 72 and 113%. In the validation procedure, recoveries of fortified samples ranged from 80 to 99%, the relative standard deviations ranged between 1.2 and 11.8%, and the LOQ between 20 and 36.9 μg kg−1. Conclusion The results of the present study confirmed the validity of the modified QuEChERS method for the extraction of pharmaceuticals from soils in the range 50–500 μg kg−1. Graphical Abstrac

Potential of native and bioprocessed brewers' spent grains as organic soil amendments

IntroductionThe use of novel soil amendments and the exploitation of plant growth-promoting microorganisms are considered promising tools for developing a more sustainable agriculture in times when ensuring high-yield productions with limited resources is essential. MethodsIn this study, the potential of brewers' spent grain (BSG), the major by-product of the brewing industry, as organic soil amendment, was investigated. Bioprocessed BSG, obtained by an enzymatic treatment coupled with fermentation, together with native BSG, were used as amendments in a pot-trial. An integrated analytical approach aimed at assessing the modification of the physicochemical properties of a typical Mediterranean alkaline agricultural soil, and the plant growth-promoting effect on escarole (Cichorium endivia var. Cuartana), was carried out. ResultsThe use of biomasses led to soil organic content and total nitrogen content up to 72 and 42% higher, compared to the unamended soils. Moreover, the lower pH and the higher organic acids content doubled phosphorus availability. Although the number of leaves per plant in escaroles from pots amended with native and bioprocessed BSG did not show any difference compared to plants cultivated on unamended pots, the average fresh weight per escarole head, was higher in pots amended with bioprocessed BSG. DiscussionHence, the results collected so far encourage BSG application for agricultural purpose, while solving the problem of disposing of such abundant side stream.Peer reviewe

miRNA deregulation and relationship with metabolic parameters after Mediterranean dietary intervention in BRCA-mutated women

BackgroundBreast cancer onset is determined by a genetics-environment interaction. BRCA1/2 gene alterations are often genetically shared in familial context, but also food intake and hormonal assessment seem to influence the lifetime risk of developing this neoplasia. We previously showed the relationship between a six-months Mediterranean dietary intervention and insulin, glucose and estradiol levels in BRCA1/2 carrier subjects. The aim of the present study was to evidence the eventual influence of this dietary intervention on the relationship between circulating miRNA expression and metabolic parameters in presence of BRCA1/2 loss of function variants.MethodsPlasma samples of BRCA-women have been collected at the baseline and at the end of the dietary intervention. Moreover, subjects have been randomized in two groups: dietary intervention and placebo. miRNA profiling and subsequent ddPCR validation have been performed in all the subjects at both time points.ResultsddPCR analysis confirmed that five (miR-185-5p, miR-498, miR-3910, miR-4423 and miR-4445) of seven miRNAs, deregulated in the training cohort, were significantly up-regulated in subjects after dietary intervention compared with the baseline measurement. Interestingly, when we focused on variation of miRNA levels in the two timepoints, it could be observed that miR-4423, miR-4445 and miR-3910 expressions are positively correlated with variation in vitaminD level; whilst miR-185-5p difference in expression is related to HDL cholesterol variation.ConclusionsWe highlighted the synergistic effect of a healthy lifestyle and epigenetic regulation in BC through the modulation of specific miRNAs. Different miRNAs have been reported involved in the tumor onset acting as tumor suppressors by targeting tumor-associated genes that are often downregulated

Phytodecontamination of water systems from phenolic endocrine disruptors and the regulation role of natural organic matter

In the last decades an increasing number of natural and synthetic compounds have been recognized as endocrine disruptors (EDs) because of their hormone-like activity and capacity to alter the normal hormonal functions of animals and humans. Among EDs, there are phenolic compounds widely present in terrestrial and aquatic systems, such as bisphenol A, 4-nonylphenol (NP), 4- tert-octylphenol, estrone, ethynilestradiol and so on. Estrogenic effects of these molecules have been ascertained on mollusks, crustaceans, fishes, amphibians and mammals starting from concentrations of 1 μgL−1. Thus, the removal of EDs from polluted media is a priority goal in order to avoid risks for the ecosystem health. Nowadays, several physico-chemical methods are mainly used for the removal of EDs from liquid and solid matrices. Nevertheless, these methods are expensive, difficult to apply and may produce a negative impact on the environment. Recently, most of studies on soil and water remediation from EDs address more sustainable techniques using bacteria, fungi, microbial enzymes and plants. Phytoremediation uses photoautotrophic organisms to uptake, transform, volatilize or stabilize pollutants present in waters, sediments, soils and atmosphere. As this technology is solar driven and exploits natural sources, it is consequently environmentally safe and cost-effective. A fundamental role in the phytoremediation process is played by natural organic molecules, mainly dissolved organic matter and humic substances. These compounds are ubiquitous in all terrestrial and aquatic environments and they interact at various extent with all contaminants deriving from agricultural, industrial and urban activities. Natural organic matter has a relevant biological activity and may also regulate the decontamination capacity of plants and other organisms, such as algae and fungi. In this review, some results of phytodecontamination studies conducted using herbaceous plant species which are presented and discussed. Further, the modulation role of natural organic matter on the phytodecontamination process is highlighted

Chemical and spectroscopic investigation of different soil fractions as affected by soil management

The interaction of organic matter with the finest soil fractions (<20 μm) represents a good way for its stabilization. This study investigates the effects of conventional (CT), minimum (MT), and no (NT) tillage, fertilization, and non-fertilization, and soil depth (0–30, 30–60, and 60–90 cm) on the amount of organic carbon (OC) in four soil fractions. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) was performed to obtain information about the OC quality and the mineralogical composition of these fractions. The CT shows the highest amount of the finest fraction while the fertilization enhances the microbial community with the increase of soil micro-aggregates (250–53 μm). The coarse fraction (>250 μm) is highest in the upper soil layer, while the finest fraction is in the deepest one. The greatest OC content is observed in the topsoil layer and in the finest soil fraction. DRIFT analysis suggests that organic components are more present in the finest fraction, calcite is mainly localized in the coarse fraction, quartz is in micro-aggregates and 53–20 μm fraction, and clay minerals are in the finest fraction

Effects of a 2-Year Application of Different Residual Biomasses on Soil Properties and Potato Yield

The increasing food demand encourages the overuse of agricultural lands and natural resources that often is not economic, social, and environmentally sustainable. This overuse can lead to the soil sickness, which causes the decline of the soil fertility through the development of soil-borne diseases, the depletion of nutrients, and the loss of soil organic matter. Addition of residual biomasses is a good agricultural practice for improving soil properties and enhancing crop production, in the framework of a sustainable development. The study is performed in a 2 years field experiment using olive pomace residues (OPR), composts from municipal solid wastes (CMW), spent mushroom compost (SMC), and livestock manures based compost (BRX) for the fertilization of the potato crop. The aim of the study is to test the impact of different biomasses available in Apulia region, Italy, on soil fertility and potato growth. The application of BRX shows the highest potato yield in both seasons while OPR, CMW, and SMC significantly increases soil total nitrogen and organic carbon compared to BRX and un-amended plots (CON). All treatments, except SMC, reduce the soil exchangeable K content, therefore, the application of BRX, OPR, and CMW should include the use of K based fertilizer to balance the high crop demand of K. Finally, SMC appears the best compromise for managing soil fertility and obtaining high potato yield

Fertilization promotes microbial growth and minimum tillage increases nutrient-acquiring enzyme activities in a semiarid agro-ecosystem

Microorganisms respiratory and enzymatic activities provide sensitive indicators of changes in soil properties, such as those caused by interactive effects of tillage and fertilization regimes or other agricultural practices. However, the rapid, adaptive microbial growth, respiratory and enzymatic responses to changes in soil environments induced by specific agricultural practices are not well understood. Thus, to explore these adaptations we compared effects of contrasting environments on functional microbial traits (growth and enzyme kinetic parameters) in a Mediterranean agro-ecosystem. These environments differed in long-term disturbance (no, minimum, or conventional tillage), nitrogen-richness (fertilization with 90 kg N ha−1 versus no fertilization), and resource scarcity (increasing with soil depth in 0–30, 30–60 and 60–90 cm layers). Reducing soil disturbance from conventional to minimum tillage promoted microbial growth through shorter Tlag and larger active biomass fraction and induced increases in N- and P-acquiring enzyme activities by increasing nutrients limitation. Fertilization stimulated increases in fast-growing microorganisms with low substrate-affinity enzyme systems, microbial biomass, enzymatic activities, and turnover rates of soil organics. In contrast, increasing scarcity of resources with soil depth strongly reduced microbial biomass and activity. A lack of correlation between soil and enzymatic stoichiometric ratios raises concern regarding the applicability of eco-enzymatic stoichiometric indexes in Mediterranean agro-ecosystems. We conclude that decomposition and turnover of organic substrates under contrasting agricultural practices are mediated by microbial communities with distinct functional traits (active fraction, growth parameters) and enzyme properties (Vmax, Km), which need to be considered in smart land use regimes

Effect of crop rotation, fertilization and tillage on mail soil properties and its water extractable organic matter

The excessive use of fertilizers and frequent and deep tillage are not considered good agricultural practices since they increase the production costs and reduce soil fertility. Water extractable organic matter (WEOM) is the fraction of soil organic matter responsible for nutrients transport and bioavailability. The aim of this work was to investigate the effect of a 2-year rotation of faba bean–wheat, cultivated for a decade, and the agricultural practices (conventional vs. no tillage, fertilization vs. no fertilization) on selected soil parameters and WEOM quality. Results showed that the soil organic carbon (SOC) and the total nitrogen (TN) content increased after the wheat and the faba bean, respectively. Plots managed with conventional tillage showed WEOM with higher OC content with respect to no tillage plots. A higher WEOM OC content was observed also in the fertilized plots. The WEOM of fertilized and faba bean plots derived from the decomposition of the native SOC, while the microbial community decomposition was the main origin of WEOM after wheat