Willingness to Adopt Biochar in Agriculture: The Producer’s Perspective

Most research on biochar has focused either on the mechanistic or the biophysical aspects, and there has been relatively little research into the social applicability and acceptance of biochar as a soil enhancer in agriculture. However, whether to adopt biochar in their practice is ultimately the farmers’ decision, and their willingness to do so is crucial. Here, we show the producer’s perspective on adopting biochar, using Polish farmers as a case study. Poland is an interesting case study because biochar has only recently attracted the attention of researchers, entrepreneurs, and other stakeholders there. We performed standardized, semi-structured interviews with 161 Polish farmers to evaluate the socioeconomic potential of biochar application in practice. We found that 27% of the respondents claimed to be familiar with biochar. The respondents with a technical, non-agricultural level of education were most familiar with the term ‘biochar’ (36%), followed by the group of respondents with a higher-level agricultural education (31%). It was surprising that among the latter respondents, the majority (69%) did not know the term ‘biochar’, either in the context used for this study or in any other context. Twenty percent of the respondents expressed an interest in using biochar, while 43% were not willing to adopt it in their agricultural practice (37% ‘did not know yet’). If a farmer was familiar with the concept of sustainable agriculture, the probability of familiarity with biochar increased by 16% (p < 0.05). In addition, farmers interested in using biochar indicated that sustainable agriculture might improve the financial situation of their farms (52%). The perceived benefits of biochar that drive the willingness to adopt it included improved soil quality and increased income due to increased yields, while the constraints on its adoption were associated mainly with high costs. Our results also point to the necessity of information flow as well as engaging farmers in participatory research to adjust the research to their needs. Furthermore, our results highlight the importance of transparency with the farmers and appropriate dissemination and presentation of both the positive and the negative aspects of biochar adoption. We urge those studying biochar to engage in more interdisciplinary research and to go beyond laboratory and field research. Many innovations, even those that work, will not be adopted if socioeconomic considerations are not incorporated into the research

Biochar as a soil amendment

Biochar is a carbonaceous product of biomass pyrolysis under limited oxygen conditions. Due to the very good sorption properties material is used as a soil amendment. In recent years, much attention has been paid to biochar as a potential tool improving soil properties and fertility. The most important benefits of its use in agriculture is a significant increase of sorption capacity, reduced nutrient leaching, as well as slow release of macro- and microelements essential for plant growth, liming effect, increased water holding capacity, improved biological properties, resulting in an increase in crop yields. The aim of the study is to summarize the knowledge about the impact of biochar on soil environment, as well as identify areas and directions for future research on biochar application in soils impacted by human activitie

Influence of Different Microplastic Forms on pH and Mobility of Cu2+ and Pb2+ in Soil

Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy metal mobilization/immobilization processes. In order to better understand the problem, three commonly found forms of microplastics in soil (fibers, fragments and microbeads) were mixed with Cu2+- or Pb2+-contaminated soil and incubated at 22 &deg;C for 180 days. In soil samples pH and the content of water and acid exchangeable species of metals were analyzed. The results of this study showed that the presence of microplastics in HM-contaminated soil affected metal speciation, increasing the amount of easily exchangeable and potentially bioavailable forms of Cu2+ or Pb2+ in the tested soil. Soil pH also increased, confirming that microplastic particles affect soil properties relevant to the sorption/desorption process of metal cations. Overall, the smallest microplastic particles (&le;1 mm), such as fibers or glitter microbeads, had a greater impact on the change in the sorption and desorption conditions of metals in tested soil than larger particles. The findings of our study show that microplastic form, shape and size should be considered as important factors that influence the soil properties and mobility of heavy metals in soil

Characterization and Sodium Cations Sorption Capacity of Chemically Modified Biochars Produced from Agricultural and Forestry Wastes

Excessive amounts of sodium cations (Na+) in water is an important limiting factor to reuse poor quality water in agriculture or industry, and recently, much attention has been paid to developing cost-effective and easily available water desalination technology that is not limited to natural resources. Biochar seems to be a promising solution for reducing high loads of inorganic contaminant from water and soil solution, and due to the high availability of biomass in agriculture and forestry, its production for these purposes may become beneficial. In the present research, wheat straw, sunflower husk, and pine-chip biochars produced at 250, 450 and 550 °C under simple torrefaction/pyrolysis conditions were chemically modified with ethanol or HCl to determine the effect of these activations on Na sorption capacity from aqueous solution. Biochar sorption property measurements, such as specific surface area, cation exchange capacity, content of base cations in exchangeable forms, and structural changes of biochar surface, were performed by FTIR and EPR spectrometry to study the effect of material chemical activation. The sorption capacity of biochars and activated carbons was investigated by performing batch sorption experiments, and adsorption isotherms were tested with Langmuir’s and Freundlich’s models. The results showed that biochar activation had significant effects on the sorption characteristics of Na+, increasing its capacity (even 10-folds) and inducing the mechanism of ion exchange between biochar and saline solution, especially when ethanol activation was applied. The findings of this study show that biochar produced through torrefaction with ethanol activation requires lower energy demand and carbon footprint and, therefore, is a promising method for studying material applications for environmental and industrial purposes

Microplastic Pollution in EU Farmland Soils: Preliminary Findings from Agricultural Soils (Southwestern Poland)

Agricultural soils are considered as “hot-spots” of plastic particles; however, due to a lack of standardized method of microplastic determination in soils, as well as no legal regulations requiring the monitoring of the soil environment in the context of microplastic contamination, the data on MP abundance and occurrence in European soils are very limited. In this first study of MPs pollution in agricultural soils in Poland, we developed a method of microplastic extraction from soil samples with different properties (particle size distribution, clay and organic matter content) and used optical microscopy for MP determination and quantification. In this study, we analyzed 44 soil samples from five sampling site locations with differing soil type, agricultural activity, including farmland soils on floodplains and past records of sewage sludge and compost applications. We found evidence that 93% of cultivated soils in the SW part of Poland contained MPs. The content of MP varied between soil types and present/former use of the land. Loamy and clay soils contained more MPs, 1540 ± 912 particles per kg soil and 933 ± 682 particles per kg, respectively, compared with sandy soils at 383 ± 188 particles per kg of soil. The highest MP concentrations were determined in soils amended with sewage sludge, wastewaters and green-waste composts (up to 4050 ± 2831 particles per kg of soil). The wide distribution of MPs with a dominance of plastic fibers (up to 60% of determined MP types) can be associated with agricultural sources such as soil mulching, the use of organic fertilizers, seed coating or unintentional waste dumping and air deposition

Influence of Different Microplastic Forms on pH and Mobility of Cu²⁺ and Pb²⁺ in Soil

Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy metal mobilization/immobilization processes. In order to better understand the problem, three commonly found forms of microplastics in soil (fibers, fragments and microbeads) were mixed with Cu2+- or Pb2+-contaminated soil and incubated at 22 °C for 180 days. In soil samples pH and the content of water and acid exchangeable species of metals were analyzed. The results of this study showed that the presence of microplastics in HM-contaminated soil affected metal speciation, increasing the amount of easily exchangeable and potentially bioavailable forms of Cu2+ or Pb2+ in the tested soil. Soil pH also increased, confirming that microplastic particles affect soil properties relevant to the sorption/desorption process of metal cations. Overall, the smallest microplastic particles (≤1 mm), such as fibers or glitter microbeads, had a greater impact on the change in the sorption and desorption conditions of metals in tested soil than larger particles. The findings of our study show that microplastic form, shape and size should be considered as important factors that influence the soil properties and mobility of heavy metals in soil

Effect of Six Different Feedstocks on Biochar’s Properties and Expected Stability

Biochar (BC) is often proposed as a tool for climate change mitigation, due to the expected long lifetime in the environment. However, BC’s stability can vary depending on feedstock type and the presence of labile carbon fractions. In this study, we verify the recent methods with new possible tools for biochar stability assessment on six different biochars derived from commonly available Europe biomass sources. Elemental composition (CHNO), dissolved organic carbon (DOC) and water-soluble carbonates content (WSC), volatile organic compounds (VOCs) composition, and mid-infrared spectra (MIR) were performed to estimate the persistence of biochars. Under similar conditions of pyrolysis, biochar properties can vary depending on a feedstock origin. Less aromatic structure and higher contents of labile carbon fractions (DOCs and WSC) in food waste biochars affected the lower stability, while biochars derived from high lignocellulose materials (straw, wood, and grass) were strongly carbonized, with persistent, aromatic structure. Labile carbon pool content (DOC, WSC) and spectral analysis can be useful tools for biochar stability assessment, giving similar information to the standard molar ratio method. Biochars obtained from agriculture and forestry management biomass should be considered as highly stable in soil and are appropriate for long-term carbon sequestration purposes

Humic Substances as Indicator of Degradation Rate of Chernozems in South-Eastern Poland

Unfavourable quantitative and qualitative changes of soil organic matter result from degradation processes, such as water erosion connected with intense arable land use. In order to take adequate preventive action, the proper indicators of soil quality or degradation are urgently needed. In particular, tests considering the soil organic matter quality seem to be beneficial for soil monitoring. In this paper, we performed organic matter fractionation using the Tyurin and IHSS procedures on eight profiles of chernozemic soils (non-degraded, eroded, forest and accumulative soils). The study conducted confirmed the applicability of using humic and fulvic fractions in order to determine the pedogenesis processes and degradation rates of chernozemic soils. For example, the HA/FA ratio was higher in non-eroded and accumulative soils, compared with eroded or forest profiles. These findings were supported by statistical discrimination performed on the mid-infrared spectra of humic acids extracted from the selected profiles. Groups of samples were divided into classes depending on land usage or degradation rate. Considering the results, fractions of humic substances can be recommended as useful tools for the assessment of soil transformation

The Effects of Rabbit-Manure-Derived Biochar Co-Application with Compost on the Availability and Heavy Metal Uptake by Green Leafy Vegetables

The use of organic amendments to enhance plant growth is increasing due to horticulture activities and vegetable cultivation in urban areas. Consequently, as organic amendments impact heavy metal solubility and plant uptake of unknown contaminants, the risk of human exposure to potentially toxic elements from contaminated soils and compost is increasing. Biochar co-application with compost may reduce the risk-related increased metal uptake by edible plants. To verify this thesis, a greenhouse experiment was established to examine the effects of rabbit-manure-derived biochar (RBC) on Cu, Cr, Cd and Pb uptake by five green leafy vegetables (lettuce&mdash;Lactuca sativa L., spinach&mdash;Spinacia oleracea L., corn salad&mdash;Valerianella locusta L., kale&mdash;Brassica oleracea L., mustard greens&mdash;Brassica juncea L.) cultivated in compost substrate and soil amended with a 30% (v/w) mix of compost and biochar. The results indicated that the addition of biochar decreased Cu, Cr, Cd and Pb availability in the tested substrates, reducing the uptake of Cd in spinach by 61% and Pb in mustard greens by 73%. The application of RBC also had some adverse effects, such as enhanced accumulation of Cr by kale, lettuce and mustard greens cultivated in compost. Compost co-application with biochar to soil decreased the availability of metals, reducing the content of Pb and Cd in tissues of the tested vegetables, while uptake of Cu and Cr was enhanced in spinach and lettuce by 20%. In conclusion, the application of compost and biochar can be beneficial in improving the quality of urban soil used for horticulture purposes. However, more attention by gardeners should be paid to soil and compost testing in terms of heavy metal contamination and possible adverse effects of organic amendments application for green leafy vegetable cultivation

The Effect of Biochar Used as Soil Amendment on Morphological Diversity of Collembola

Biochar was reported to improve the chemical and physical properties of soil. The use of biochar as a soil amendment have been found to improve the soil structure, increase the porosity, decrease bulk density, as well increase aggregation and water retention. Knowing that springtails (Collembola) are closely related to soil properties, the effect of biochar on morphological diversity of these organisms was evaluated. The main concept was the classification of springtails to the life-form groups and estimation of QBS-c index (biological quality index based on Collembola species). We conducted the field experiment where biochar was used as soil amendment in oilseed rape and maize crops. Wood-chip biochar from low-temperature (300 &deg;C) flash pyrolysis was free from PAH (polycyclic aromatic hydrocarbon) and other toxic components. Results showed that all springtail life-form groups (epedaphic, hemiedaphic, and euedaphic) were positively affected after biochar application. The QBS-c index, which relates to springtails&rsquo; adaptation to living in the soil, was higher in treatments where biochar was applied. We can recommend the use of Collembola&rsquo;s morphological diversity as a good tool for the bioindication of soil health