RESUMO
Agricultural waste can have a catastrophic impact on climate change, as it contributes significantly to greenhouse gas (GHG) emissions if not managed sustainably. Swine-digestate-manure-derived biochar may be one sustainable way to manage waste and tackle GHG emissions in temperate climatic conditions. The purpose of this study was to ascertain how such biochar could be used to reduce soil GHG emissions. Spring barley (Hordeum vulgare L.) and pea crops in 2020 and 2021, respectively, were treated with 25 t ha-1 of swine-digestate-manure-derived biochar (B1) and 120 kg ha-1 (N1) and 160 kg ha-1 (N2) of synthetic nitrogen fertilizer (ammonium nitrate). Biochar with or without nitrogen fertilizer substantially lowered GHG emissions compared to the control treatment (without any treatment) or treatments without biochar application. Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions were directly measured using static chamber technology. Cumulative emissions and global warming potential (GWP) followed the same trend and were significantly lowered in biochar-treated soils. The influences of soil and environmental parameters on GHG emissions were, therefore, investigated. A positive correlation was found between both moisture and temperature and GHG emissions. Thus, biochar made from swine digestate manure may be an effective organic amendment to reduce GHG emissions and address climate change challenges.
RESUMO
Biochar has been proven to influence soil hydro-physical properties, as well as the abundance and diversity of microbial communities. However, the relationship between the hydro-physical properties of soils and the diversity of microbial communities is not well studied in the context of biochar application. The soil analyzed in this study was collected from an ongoing field experiment (2019-2024) with six treatments and three replications each of biochar (B1 = 25 t·ha-1 and B0 = no biochar) and nitrogen fertilizer (N1 = 160, N2 = 120 kg·ha-1, and N0 = no fertilizer). The results show that biochar treatments (B1N0, B1N1, and B1N2) significantly improved the soil bulk density and total soil porosity at different depths. The B1N1 treatment substantially enhanced the volumetric water content (VMC) by 5-7% at -4 to -100 hPa suction at 5-10 cm depth. All three biochar treatments strengthened macropores by 33%, 37%, and 41%, respectively, at 5-10 cm depth and by 40%, 45%, and 54%, respectively, at 15-20 cm depth. However, biochar application significantly lowered hydraulic conductivity (HC) and enhanced carbon source utilization and soil indices at different hours. Additionally, a positive correlation was recorded among carbon sources, indices, and soil hydro-physical properties under biochar applications. We can summarize that biochar has the potential to improve soil hydro-physical properties and soil carbon source utilization; these changes tend to elevate fertility and the sustainability of Cambisol.
RESUMO
Environmentally persistent free radicals (EPFRs) have been considered as emerging contaminants due to their detrimental effects on human health. The adverse health impacts are attributed to oxidative stress induced by EPFRs through the formation of reactive oxygen species (ROS). In soils, it may also increase the degradation process of polymeric organic matter and/or undesired organic pollutants through hydroxyl radical activity. The biochar pyrolysis process entails the thermal decomposition of organic compounds in the biomass, with the carbonization conditions and feedstock type facilitating the formation of EPFRs. When biochar is used to amend soil, these radicals may promote the formation of ROS, and thus influence the transformation of organic and inorganic contaminants in soil and impact the rhizosphere. Agricultural soils are being amended with biochar to mainly increase carbon content and facilitate the plant growing conditions. Therefore, agricultural soils may become a source of EPFRs. However, the fate and transformations of EPFRs in soils after biochar amendment are not well understood or studied. This paper presents the first (to our knowledge) studies of EPFRs behaviour in agricultural soil with different input of biochar, cultivation types and residence time period. Different cultivation types, addition of fertilisers and variation in biochar input, on the one hand, and presence of metals in soil, biochar and fertilizers, on the other hand, provide different conditions for EPFRs formation, accumulation and fate in agricultural soils. Two significant factors have been found to determine the fate of EPFRs in soil: transition metal content (particularly those in reaction available form) and cultivation level of soil. Cultivation significantly decreased presence of EPFRs, both carbon-centered and oxygen-centered, in relatively short periods of time, while metal presence (and particularly through fertilizer supplementation) increases the half-life of radicals and transforms organic matter to more oxygen-centered EPFRs. The amount of biochar addition plays a secondary role as the EPFRs content in the soils is in a longer term primarily controlled by the other two factors.
RESUMO
This study examined the effect of study time, biochar dose, and fertilization-tillage system on the improvement of sandy loam physical-chemical properties and triticale grain yield. The soil properties (water holding capacity (WHC), wettability, moisture content (MC), organic matter content (SOM), pH, and electrical conductivity (EC) were monitored in short time intervals (after 3, 6, 12, and 24 months). Soil was tilled in two methods (shallow ploughless tillage and direct drilling), fertilized with nitrogen, phosphorus, and potassium (NPK) fertilizers, and amended with three hydrophobic pine wood biochar doses (0 t/ha; 5 t/ha; 15 t/ha). It was found that 15 t/ha biochar dose had the highest effect on the soil's physical-chemical properties improvement (SOM increased by 33.7%, pH-by 6.84%, EC-by 23.4%, WHC-by 8.48%, and MC-by 21.8%) compared to the variants without biochar. Direct drilling, fertilization with NPK fertilizers and 15 t/ha biochar dose significantly influenced the rise of soil's physical-chemical properties and triticale yield (3.51 t/ha).
RESUMO
With the increase of urbanization and human consumption, the extraction of potentially toxic elements (PTEs) causes higher risk of them to enter sources of human food and potable water. Adsorption has been studied extensively as phenomena to reduce element mobility in both natural and engineered systems. The need to adapt the adsorption models to simulate the adsorption increases as the variety of adsorbents of natural origin is getting bigger and bigger due to their sustainability, availability and low costs. Adsorption of PTEs was analysed in the case of biochar which is a widely studied adsorbent, however, the studies are often limited to standard adsorption equilibrium and kinetic procedures without further analyses into the adsorbate and adsorbent contact zone. Zn(II), Cu(II) and Mn(II) were chosen study due to their nutritional and toxicological features. Diagnostic methods were used to differentiate the metal behaviour during adsorption and dynamic intraparticle model was further employed to simulate the kinetic conditions. Harkins-Jura isotherm model and pseudo-second kinetic model were determined to fit the adsorption of PTEs on biochar. According to the adsorption efficiency and capacity, PTEs fell into the following sequence: Cu(II) > Mn(II)>Zn(II). It was observed that the kinetics of Cu(II) decreased in the solution by about 1.7 times more than of Zn(II) and about 2.3 times more than of Mn(II). Cu(II) decreased faster and more suddenly than Mn(II) and Zn(II) in the solution on the particle surface and in the solution inside the particle.
