Density-based fractionation of soil organic matter: effects of heavy liquid and heavy fraction washing

Physical fractionation methods used in soil organic matter (SOM) research commonly include density-based procedures with heavy liquids to separate SOM pools with varying turnover rates and functions. Once separated, the heavy SOM pools are often thoroughly rinsed with water to wash off any residues of the heavy liquids. Using four soils with contrasting properties, we investigated the effects of using either sodium polytungstate (SPT) or sodium iodide (NaI), two of the most commonly used heavy liquids, on the distribution of organic carbon (C) and total nitrogen (N) in free light, intra-aggregate light, and mineral-associated heavy SOM pools isolated by a common fractionation scheme. We also determined the effects of washing the mineral-associated heavy SOM fractions on the recovery of organic C and total N after separation. Because of its smaller viscosity compared to that of NaI, SPT consistently yielded greater intra-aggregate and smaller mineral-associated soil organic C contents. We also confirm that some commercial SPT products, such as the one used here, can contaminate organo-mineral heavy pools with N during density-based fractionation procedures. We do not recommend the repeated washing of heavy fractions separated with Na-based heavy liquids, as this can mobilize SOM

Adsorption and degradation of three pesticides in a vineyard soil and in an organic biomix

none5noA soil and an organic biomix (soil/vine branch/garden compost 20/40/40) were used in this lab experiment to evaluate adsorption and degradation parameters for three pesticides (chlorpyrifos, metalaxyl and cymoxanil) used in a vineyard. Adsorption in the biomix material was higher than in the soil for the three pesticides and chlorpyrifos was the most adsorbed pesticide. The role of the organic carbon is essential for enhancing the adsortion of the three pesticides, especially for the most apolar chlorpyrifos. Degradation was generally faster in the biomix material than in the soil although the process was slower in the case of chlorpyrifos if compared with the other two chemicals, due to a more toxic eect of this pesticide on soil microflora and a larger adsorption of this pesticide on the organic biomix that reduces its availability for dissipation. Amendment with cheap and available organic wastes or a grass-covered management of soil in the vineyard could reduce the impact of pesticides in the vineyard ecosystem and contribute to the sustainable management of chemicals in the environment.openCostantino Vischetti, Elga Monaci, Cristiano Casucci, Arianna De Bernardi, Alessandra CardinaliVischetti, Costantino; Monaci, Elga; Casucci, Cristiano; DE BERNARDI, Arianna; Cardinali, Alessandr

Copper monitoring in vineyard soils of central Italy subjected to three antifungal treatments, and effects of copper sub-lethal doses on the earthworm Eisenia fetida.

none6The extensive employment of copper-based fungicides has increased copper concentration in vineyard soils. The present study’s objectives were to monitor copper concentration in two vineyard soils during two cropping seasons and study the ecotoxicological effects on the earthworm Eisenia fetida. Total, soluble, and bioavailable copper fractions were measured at the end of two cropping seasons and different depths in two vineyards of central Italy, characterised by three anticryptogamic control methods: copper compounds, chitosan, and combined treatments of them. A laboratory experiment to assess the effects on Eisenia fetida was conducted with soil samples collected in the vineyards with a mean copper concentration of 60 mg/kg and two higher concentrations of 90 and 150 mg/kg. Results showed low levels of total copper concentration in the first 20 cm of soils, regardless of antifungal treatment, highlighting prudent management of the vineyards under study, but the soluble fractions showed a significant increase in all samples during the two cropping seasons. At the dose of 150 mg/kg, earthworms suffer during the first two days, showing weight loss and DNA damage, but they are able to recover until day 28, showing no permanent harm at this copper concentration in soil.openArianna De Bernardi, Enrica Marini, Cristiano Casucci, Luca Tiano, Fabio Marcheggiani, Costantino VischettiDE BERNARDI, Arianna; Marini, Enrica; Casucci, Cristiano; Tiano, Luca; Marcheggiani, Fabio; Vischetti, Costantin

Production of Beauregard Sweet Potato in vertical farming under different fertilization technologies

Ipomoea batatas, popularly known as sweet potato, is a species of the Convolvulaceae family, with probable origin between Mexico and northern South America. Among the genotypes with economic potential, the biofortified cultivar Beauregard (Ipomoea batatas) stands out due to its rusticity and easy handling. Controlled-release fertilizers were mostly used in studies developed in other countries, and their study being necessary in Brazilian soil and climatic conditions. This study aimed to evaluate the development of Beauregard biofortified cultivar, submitted to different fertilization technologies in vertical farming system. The plantlets received different doses of controlled-release fertilizer: 0.0 (control); 30; 60; 90; 120g and a dose of 40g per pit of NPK 13-13-28 of ready solubility. At 180 days, biometric and production parameter data were collected and submitted to regression analysis and variance analysis followed by the Scott-Knott test for mean separation. The application of controlled-release fertilizer showed a positive effect on the production of the studied cultivar, favoring the performance of the plants and promoting the increase especially in height, length of branches and number of leaves. The base application of controlled-release fertilizer at a dose of 30g per plant and traditional NPK fertilizer at a dose of 40g per plant promote higher yields of dry mass of shoots and root when compared to unfertilized plants in the cultivation of sweet potatoes in vertical farming

Biogas production and electricity generation from a quail manure wastewater treatment system per water depth

Coturniculture, as an activity which demands low investment and quick return, is shown to be a possibility for the rural family producer. Concomitant to this, we highlight the fact that the use of liquid quail farming waste, aimed at generating energy by anaerobic digestion, can mean a viable and promising technology for obtaining biogas from confined animal production systems. The growing demand for energy establishes that new energy sources are better used, and a great opportunity for their growth may be the use of biomass in anaerobic digestion systems, in which the organic substrate is degraded and transformed into energy and biofertilizer. The method applied was Biochemical Potential of Methane, through benchtop bioreactors with a volume of 250 mL, and in mesophilic conditions. Waste was used as inoculum from the manure tank of the quail egg production farm. Thesubstrates used to compose the treatments were liquid quail farming waste from the water depth treatment system, with 15, 30 and 45 days of deposition. In the results obtained, it was verified that the best mono digestion used was inoculum+substrate of 30 days of deposition, with water retention time of 45 days, showing a higher production accumulated in biogas (0.00078476 Nm3) and CH4 (0.000575 Nm3) as well as the highest biogas potential of 0.0043 Nm3 (kg substrate)-1. When converted into electrical energy,  by means of a motor generator, using as fuel the biogas produced by the liquid quail farming waste, the value of 104.64 kwh (45 days)-1 was obtained.A coturnicultura, enquanto atividade que demanda baixo investimento e tem rápido retorno, mostra-se como possibilidade para o produtor rural familiar. Concomitantemente a isso, destaca-se o fato de que a utilização dos dejetos líquidos da coturnicultura, visando à geração de energia por digestão anaeróbia, pode significar uma tecnologia viável e promissora para a obtenção de biogás originado dos sistemas de produção de animais confinados. A crescente demanda por energia estabelece que novas fontes energéticas sejam mais aproveitadas, e uma grande oportunidade para o crescimento destas pode ser o uso da biomassa em sistemas de digestão anaeróbia, em que o substrato orgânico é degradado e transformado em energia e biofertilizante. O método aplicado foi o Potencial Bioquímico de Metano, por meio de biorreatores em bancada com volume de 250 mL,e em condições mesófilas se utilizou como inóculo o dejeto do tanque da esterqueira da granja de produção de ovos de codornas, os substratos utilizados para compor os tratamentos foram dejetos líquidos da coturnicultura do sistema de tratamento por lâmina d’água, com 15, 30 e 45 dias de deposição. Nos resultados obtidos, constatou-se que a melhor monodigestão utilizada foi inóculo+substrato de 30 dias de deposição, com tempo de retenção hídrica de 45 dias, apresentando maior produção acumulada de biogás (0,00078476 Nm3) e CH4 (0,000575 Nm3), bem como o maior potencial de biogás 0,0043 Nm3 (kg substrato)-1; e, quando convertido em energia elétrica, por meio de motogerador, utilizando como combustível o biogás produzido pelo dejetos líquidos da coturnicultura, obteve-se o valor 104,64 kwh (45 dias)-1

Effect of contrasting crop rotation systems on soil chemical and biochemical properties and plant root growth in organic farming: First results

Organic farming is claimed to improve soil fertility. Nonetheless, among organic practices, net C-inputs may largely vary in amount and composition and produce different soil conditions for microbial activity and plant-root system adaptation and development. In this study, we hypothesised that, in the regime of organic agriculture, soil chemical and biochemical properties can substantially differ under contrasting crop rotation systems and produce conditions of soil fertility to which the plant responds through diverse growth and production. The impact of 13 years of Alfalfa-Crop rotation (P-C) and Annual Crop rotation (A-C) was evaluated on the build up of soil organic carbon (SOC), active (light fraction organic matter, LFOM; water soluble organic carbon, WSOC) and humic fraction (fulvic acids carbon, FAC; humic acids carbon, HAC), soil biochemical properties (microbial biomass carbon, MBC; basal respiration, dBR; alkaline phosphatase AmP; arylsulfatase ArS; orto-diphenoloxidase, o-DPO) and the amount of available macro-nutrients (N, P, and S) at two different soil depths (0-10 cm and 10-30 cm) before and after cultivation of wheat. We also studied the response of root morphology, physiology and yield of the plant-root system of wheat. Results showed that the level of soil fertility and plant-root system behaviour substantially differed under the two crop rotation systems investigated here. We observed high efficiency of the P-C soil in the build up of soil organic carbon, as it was 2.9 times higher than that measured in the A-C soil. With the exception of o-DPO, P-C soil always showed a higher level of AmP and ArS activity and an initial lower amount of available P and S. The P-C soil showed higher rootability and promoted thinner roots and higher root density. In the P-C soil conditions, the photosynthesis and yield of durum wheat were also favoured. Finally, cultivation of wheat caused an overall depletion of the accrued fertility of soil, mainly evident in the P-C soil, which maintained a residual higher level of all the chemical and biochemical properties tested

Biogas production and electricity generation from a quail manure wastewater treatment system per water depth

A coturnicultura, enquanto atividade que demanda baixo investimento e tem rápido retorno, mostra-se como possibilidade para o produtor rural familiar. Concomitantemente a isso, destaca-se o fato de que a utilização dos dejetos líquidos da coturnicultura, visando à geração de energia por digestão anaeróbia, pode significar uma tecnologia viável e promissora para a obtenção de biogás originado dos sistemas de produção de animais confinados. A crescente demanda por energia estabelece que novas fontes energéticas sejam mais aproveitadas, e uma grande oportunidade para o crescimento destas pode ser o uso da biomassa em sistemas de digestão anaeróbia, em que o substrato orgânico é degradado e transformado em energia e biofertilizante. O método aplicado foi o Potencial Bioquímico de Metano, por meio de biorreatores em bancada com volume de 250 mL,e em condições mesófilas se utilizou como inóculo o dejeto do tanque da esterqueira da granja de produção de ovos de codornas, os substratos utilizados para compor os tratamentos foram dejetos líquidos da coturnicultura do sistema de tratamento por lâmina d’água, com 15, 30 e 45 dias de deposição. Nos resultados obtidos, constatou-se que a melhor monodigestão utilizada foi inóculo+substrato de 30 dias de deposição, com tempo de retenção hídrica de 45 dias, apresentando maior produção acumulada de biogás (0,00078476 Nm3) e CH4 (0,000575 Nm3), bem como o maior potencial de biogás 0,0043 Nm3 (kg substrato)-1; e, quando convertido em energia elétrica, por meio de motogerador, utilizando como combustível o biogás produzido pelo dejetos líquidos da coturnicultura, obteve-se o valor 104,64 kwh (45 dias)-1

Assessing the effectiveness of a three-stage on-farm biobed in treating pesticide contaminated wastewater

Agricultural point source pesticide pollution arising from contaminated machinery washings and accidental spillages pose a significant threat to river water and groundwater quality. In this study, we assess the effectiveness of a three-stage on-farm biobed for treating pesticide contaminated waste water from a large (20 km2) commercial arable estate. The facility consisted of an enclosed machinery wash-down unit (stage 1), a 49 m2 lined compost-straw-topsoil biobed (stage 2), and a 200 m2 drainage field with a trickle irrigation system (stage 3). Pesticide concentrations were analysed in water samples collected fortnightly between November 2013 and November 2015 from the biobed input and output sumps and from 20 porous pots buried at 45 cm and 90 cm depth within the drainage field. The results revealed that the biobed removed 68–98% of individual pesticides within the contaminated washings, with mean total pesticide concentrations reducing by 91.6% between the biobed input and output sumps. Drainage field irrigation removed a further 68–99% of individual pesticides, with total mean pesticide concentrations reducing by 98.4% and 97.2% in the 45 cm and 90 cm depth porous pots, respectively. The average total pesticide concentration at 45 cm depth in the drainage field (57 µg L-1) was 760 times lower than the mean concentration recorded in the input sump (43,334 µg L-1). There was no evidence of seasonality in the efficiency of biobed pesticide removal, nor was there evidence of a decline in removal efficiency over the two-year monitoring period. However, higher mean total pesticide concentrations at 90 cm (102 µg L-1) relative to 45 cm (57 µg L-1) depth indicated an accumulation of pesticide residues deeper within the soil profile. Overall, the results presented here demonstrate that a three-stage biobed can successfully reduce pesticide pollution risk from contaminated machinery washings on a commercial farm