Effects of biochar, N-enriched biochar and urea on tomato seed germination, vegetative growth, and fruit traits.

Background: Agronomic uses of biochar have been intensely explored in the last 15 years. Recently, a new generation of biochar-based fertilizers has been developed. Raw biochar (BCH), nitrogen-enriched biochar (N + BCH) or urea were added to a coir fiber-based substrate for tomato cultivation, to assess seed germination, growth and fruiting of two cultivars (Cuarenteno and Moneymaker).

Soil fertility and plant nutrition in an organic olive orchard after 5 years of amendment with compost, biochar or their blend.

The agronomic use of compost and biochar as soil amendments may exhibit contrasting results in terms of soil fertility and plant nutrition. The effects of the biennial application of biochar, compost and a blend of compost:biochar (90:10; % dw:dw) on the agronomical performance of an organically managed and well established 25-year-old olive orchard was assessed 5 years after the initial application. The agronomical evaluation was based on the assessment of the soil physical, chemical, and biological characteristics, and the assessment of the soil fertility by both crop production and nutritional status of the orchard, and the bioassay with olive plantlets.

Role of dry watercourses of an arid watershed in carbon and nitrogen processing along an agricultural impact gradient.

In the Mediterranean arid region such as Southeast (SE) Spain, a considerable part of the fluvial network runs permanently dry. Here, many dry watercourses are embedded in catchments where agriculture has brought changes in carbon (C) and nitrogen (N) availability due to native riparian vegetation removal and the establishment of intensive agriculture. Despite their increasing scientific recognition and vulnerability, our knowledge about dry riverbeds biogeochemistry and environmental drivers is still limited, moreover for developing proper management plans at the whole catchment scale.

Nitrogen availability in biochar-based fertilizers depending on activation treatment and nitrogen source.

Different activation and N-doping treatments were used to produce biochar-based fertilizers (BBFs) with increased N concentration and slow N release. Pristine biochars were produced by pyrolysis of olive tree pruning feedstock at low and high temperatures (400 and 800 °C). These biochars were activated either by ultrasonication, or oxidation with hydrogen peroxide (HO) or nitric acid (HNO) to increase their N retention potential.

Application of biostimulant products and biological control agents in sustainable viticulture: A review.

Current and continuing climate change in the Anthropocene epoch requires sustainable agricultural practices. Additionally, due to changing consumer preferences, organic approaches to cultivation are gaining popularity. The global market for organic grapes, grape products, and wine is growing.

Paracetamol degradation pathways in soil after biochar addition.

Little is known about the effect of biochar on the degradation of paracetamol in soil, considering the ubiquity of this pollutant in the environment. Given the importance of the electrochemical properties of biochar for contaminant remediation, we investigated the influence of raw and designer redox-active biochars on paracetamol degradation in soil. Metabolite quantification indicated that a minimum of 53% of the spiked paracetamol was transformed in biochar-amended soil, resulting in the accumulation of different degradation products.

Overcoming biochar limitations to remediate pentachlorophenol in soil by modifying its electrochemical properties.

In this study, we produced modified biochars with enhanced electrochemical properties to increase PCP remediation in soil. Although all biochars enhanced PCP remediation in aerobic conditions, only a few did in anaerobic soil. The most successful modifications were (i) the preloading of biomass with 10% w/w FeCl, to obtain a biochar rich in redox-active metals (B-Fe); (ii) the oxidation of a conductive biochar pyrolyzed at 1000 ºC with 0.

Biochar as electron donor for reduction of N2O by Paracoccus denitrificans.

Biochar (BC) has been shown to influence microbial denitrification and mitigate soil N2O emissions. However, it is unclear if BC is able to directly stimulate the microbial reduction of N2O to N2. We hypothesized that the ability of BC to lower N2O emissions could be related not only to its ability to store electrons, but to donate them to bacteria that enzymatically reduce N2O.

From Lab to Field: Role of Humic Substances Under Open-Field and Greenhouse Conditions as Biostimulant and Biocontrol Agent.

The demand for biostimulants has been growing at an annual rate of 10 and 12.4% in Europe and Northern America, respectively. The beneficial effects of humic substances (HS) as biostimulants of plant growth have been well-known since the 1980s, and they can be supportive to a circular economy if they are extracted from different renewable resources of organic matter including harvest residues, wastewater, sewage sludge, and manure.

Copper immobilization by biochar and microbial community abundance in metal-contaminated soils.

Biochar (BC) is gaining attention as a soil amendment that can remediate metal polluted soils. The simultaneous effects of BC on copper (Cu) mobility, microbial activities in soil using metallophytes have scarcely been addressed. The objective of this study was to evaluate the effects of biochar BCs on Cu immobilization and over soil microbial communities in a Cu-contaminated soil evaluated over a two-year trial.

Properties of biochar derived from wood and high-nutrient biomasses with the aim of agronomic and environmental benefits.

Biochar production and use are part of the modern agenda to recycle wastes, and to retain nutrients, pollutants, and heavy metals in the soil and to offset some greenhouse gas emissions. Biochars from wood (eucalyptus sawdust, pine bark), sugarcane bagasse, and substances rich in nutrients (coffee husk, chicken manure) produced at 350, 450 and 750°C were characterized to identify agronomic and environmental benefits, which may enhance soil quality. Biochars derived from wood and sugarcane have greater potential for improving C storage in tropical soils due to a higher aromatic character, high C concentration, low H/C ratio, and FTIR spectra features as compared to nutrient-rich biochars.

Influence of biochar addition on the humic substances of composting manures.

Application of biochar (10% v/v) to a manure composting matrix was investigated to evaluate its effect on the chemical composition of humic substances during the composting process. The characteristics of the humic acid (HA) and fulvic acid (FA) fractions were analyzed in compost mixtures originating from two different manures (poultry manure (PM) and cow manure (CM)). The C contents of HA and FA from the manure compost/biochar blends (PM+B and CM+B) were higher than those from PM and CM, with an enhanced recalcitrant fraction, as determined by thermogravimetric analysis.

Biochar improves N cycling during composting of olive mill wastes and sheep manure.

The use of biochar has been revealed to have beneficial effects during the composting of manures and other N-rich materials by reducing N losses and enhancing the rate of the process. However, the impact of biochar has not been explored in other complex organic matrices with low N nitrogen that may hinder the composting process. The main novelty of this work was to study the impact of a small amount of biochar (4%) on the composting process of olive mill wastes, which are characterised by a recalcitrant lignocellulosic composition with reduced nitrogen (N) availability.

Physical and chemical properties of biochars co-composted with biowastes and incubated with a chicken litter compost.

Two experiments were conducted where three biochars, made from macadamia nutshell (MS), hardwood shaving (WS) and chicken litter (CL), were co-composted with chicken manure and sawdust, and also incubated with a chicken litter based commercial compost. Biochars were added at the rates of 5% and 10% in the co-composting and 10% and 20% in the incubation experiment. The rates of biochar had no consistent effect on the change in element contents of composted- or incubated-biochars.

Application of compost of two-phase olive mill waste on olive grove: effects on soil, olive fruit and olive oil quality.

Composting is a method for preparing organic fertilizers that represents a suitable management option for the recycling of two-phase olive mill waste (TPOMW) in agriculture. Four different composts were prepared by mixing TPOMW with different agro-industrial by-products (olive pruning, sheep manure and horse manure), which were used either as bulking agents or as N sources. The mature composts were added during six consecutive years to a typical "Picual" olive tree grove in the Jaén province (Spain).

Maturity indices in co-composting of chicken manure and sawdust with biochar.

Several maturity indices were evaluated for in-vessel co-composting of chicken manure and pine sawdust with three different biochars. All the seven mixtures (piles) contained chicken manure and sawdust. Six of these piles contained biochar; each biochar was added at two rates, 5% and 10% wet weight.

Fourier transform infrared spectroscopy and partial least square regression for the prediction of substrate maturity indexes.

Traditional methods to evaluate the stability and maturity of organic wastes and composting matrices are laborious, time-consuming and generate laboratory chemical wastes. This study focused on the development of partial least square (PLS) regression models for the prediction of the stability and maturity of compost-based substrates based on Fourier transform infrared (FTIR) spectroscopy. The following parameters, selected as conventional maturity indexes, were modeled and used as dataset: dissolved organic carbon (DOC), C/N and NH4(+)/NO3(-) ratios, cation exchange capacity (CEC), degree of polymerization (DP), percentage of humic acid (PHA), humification index (HI) and humification ratio (HR).

Matrix effect on the performance of headspace solid phase microextraction method for the analysis of target volatile organic compounds (VOCs) in environmental samples.

Solid phase microextraction (SPME) is a fast, cheap and solvent free methodology widely used for environmental analysis. A SPME methodology has been optimized for the analysis of VOCs in a range of matrices covering different soils of varying textures, organic matrices from manures and composts from different origins, and biochars. The performance of the technique was compared for the different matrices spiked with a multicomponent VOC mixture, selected to cover different VOC groups of environmental relevance (ketone, terpene, alcohol, aliphatic hydrocarbons and alkylbenzenes).

Biochar and denitrification in soils: when, how much and why does biochar reduce N₂O emissions?

Agricultural soils represent the main source of anthropogenic N2O emissions. Recently, interactions of black carbon with the nitrogen cycle have been recognized and the use of biochar is being investigated as a means to reduce N2O emissions. However, the mechanisms of reduction remain unclear.

Influence of biochar addition on methane metabolism during thermophilic phase of composting.

CH(4) is known to be generated during the most active phase of composting, even in well-managed composting piles. In this manuscript, we studied the influence of biochar on the CH(4) metabolism during composting of cattle manure and local organic wastes. We evaluated the presence of methanogens and methanotrophs in the composting piles quantified by the level of mcrA encoding methyl coenzyme M reductase alpha subunit and pmoA encoding particulate methane monooxygenase.

Biochemical changes and GHG emissions during composting of lignocellulosic residues with different N-rich by-products.

Nitrogen availability plays a critical role in the biodegradation of organic matter during composting. Although the optimal initial C/N is known to be around 25-30, the chemical form in which N is present influences microbial activity and therefore degradation rate and gaseous losses. This study was conducted to evaluate the influence of N availability on the composting of a mixture of lignocellulosic materials.

Chemical and biochemical characterisation of biochar-blended composts prepared from poultry manure.

The aim of this study was to assess the effect of a 2% (v/v) addition of biochar on the quality of a composting mixture prepared with poultry manure and different local organic wastes (rice husk and apple pomace). Compost quality was evaluated in terms of typical stabilisation indices, the microbial biomass and selected enzymatic activities related to the C, N and P cycles. The main effects of biochar were a 10% increase in C captured by humic substance extraction and a 30% decrease of water-soluble C, due to an enhanced degradation rate and/or the sorption of these labile compounds into the biochar.

Biochar influences the microbial community structure during manure composting with agricultural wastes.

The influence of biochar derived from a hardwood tree (Quercus serrate Murray) on the dynamics of the microbial community during the composting of poultry manure (PM) and cow manure (CM) was evaluated by phospholipid fatty acid analysis (PLFAs). Changes in the PLFA patterns were related to key composting properties (C/N ratio, temperature, and bulk density) as the major drivers of the dynamics of the microbial community. At the beginning of the process, the fungal biomass was significantly greater in PM and CM than in the respective co-composted materials with biochar (PMB and CMB); this difference declined gradually during the process.

Greenhouse gas emissions during composting of two-phase olive mill wastes with different agroindustrial by-products.

The evolution of CO(2), CH(4) and N(2)O were monitored in five composting mixtures prepared from two-phase olive mill waste (TPOMW) and different agroindustrial by-products in order to assess the effect of the initial composition and the N source on greenhouse gas emission. Surface gas fluxes were measured using a closed static chamber and compared to the changes in different organic matter fractions (organic and watersoluble C) and N forms (NH(4)(+) and NO(3)(-)). CH(4) emissions depended on the organic matter mineralisation dynamics and the incorporation of manure in the starting mixture.

A simple automated system for measuring soil respiration by gas chromatography.

An automated dynamic closed chamber system for CO(2) sampling and analysis was developed for the measurement of soil respiration under laboratory conditions. The system is composed by a gas chromatograph linked to a fully computerised sampling system composed by 16 sample jars and 2 multiposition valves. Besides CO(2), the system can automatically and simultaneously measure CH(4), N(2)O and other gases of environmental interest.