Biochar is considered a promising option for the development of sustainable agroecosystems, due to its diverse agronomic and environmental benefits. In this context, the aim of this study was to carry out a bibliometric analysis on biochar research in Brazil within an agricultural context, including investigating the raw materials most employed for its production in the country. The analysis was conducted based on a search for scientific articles (peer-reviewed papers) at the Web of Science database (WoS Core Collection) from 2003 to 2020 specifically in Brazil. A performance analysis was carried out by applying a descriptive and metric approach concerning research constituents (authors, institutions, countries and keywords) and science mapping to clarify scientific collaborations and cognitive and intellectual structure patterns regarding the biochar domain in Brazilian research, using the VOSviewer software. The obtained studies were also analyzed individually to classify the different raw materials employed in biochar production. A total of 261 scientific articles met the screening criteria, indicating that the beginning of biochar publications in Brazil took place in 2003, increasing until 2015 and peaking in 2021. Institutions and authors with the highest publication contributions were the Brazilian Agricultural Research Corporation (EMBRAPA) (Novotny E.), São Paulo University (USP) (Cerri C.) and Federal Lavras University (UFLA) (Melo L.). The United States, Spain, Australia, Germany and the Netherlands present the most collaborations on biochar research with Brazil. The biochar domain was highly associated with the following keywords: biochar, pyrogenic carbon, pyrolysis, charcoal, immobilization, black carbon, soil fertility and soil and characterization. Raw materials of plant origin were the most employed in biochar research in Brazil, with wood residues being the most studied and residues originated from the sugar-energy industry (straw, bagasse and filter cake) identified as exhibiting high potential for future studies. Poultry litter is the most promising animal waste for biochar production, while the use of biosolids can be innovative, contributing to the consolidation of biochar as an option for serious urban waste sanitary management problems.

Type D bovine botulism outbreaks associated with poultry litter are increasingly reported in European countries, but the circumstances of exposure to Clostridium botulinum toxins remain unclear. In spring 2015, a large type D/C bovine botulism outbreak affected a farm with dairy and poultry operations. Epidemiological and laboratory investigations strongly suggest that the outbreak was caused by feeding cattle with insufficiently acidified grass silage that was contaminated by type D/C C. botulinum spores. The source of the spores remains unclear, but could have been a stack of poultry litter stored in the grass silage pasture before harvesting. The presence of putrefied poultry carcasses mixed in with the litter is relatively unlikely considering the careful daily removal of poultry carcasses. These findings reinforce the importance of proper ensiling of feed materials and highlight the need for safe disposal of poultry litter, even in the case of good management of poultry deadstock, in order to prevent bovine botulism.

In the context of determining the sustainable carrying capacity of dry-Mediterranean herbaceous rangelands, we examined the effect of animal density on cattle nutrition, which is fundamental to animal performance and welfare. The effects on dietary components of low (0.56 cows/ha; L) and high (1.11 cows/ha; H) animal densities were monitored for three consecutive years in grazing beef cows. In the dry season (summer and early autumn), cows had free access to N-rich poultry litter (PL) given as a dietary supplement. In each season, near-IR spectroscopy (NIRS) was used to predict the chemical composition of herbage samples (ash, NDF, CP, in vitro dry matter digestibility (IVDMD) and metabolizable energy (ME) content from IVDMD). Near-IR spectroscopy was applied also to faecal samples to determine the chemical composition of the diet selected by the animal, as well as the contents of ash, NDF and CP in the faeces themselves. A faecal-NIRS equation was applied to estimate the dietary proportion of PL. Seasonal categories were green, dry without PL supplementation and dry with it. We found no effects of animal density on nutrition during the green season but effects were apparent when cows consumed dry pasture. Ash content predicted by faecal NIRS was higher in the diet than in plant samples clipped from pasture, which infers that cows ingested soil. Dietary and faecal ash contents were higher (P<0.05) at the H, implying greater soil intake in these animals. During the dry period, dietary contents of ME were higher in L than in H (P<0.05). Poultry litter supplementation was associated with a marked increase (P<0.01) in dietary and faecal CP contents. Poultry litter represented 0.45 and 0.59 of the diet in treatments L and H, respectively (P<0.05). Consequently, treatment H had higher faecal protein (P<0.05). A tendency of higher dietary protein (P=0.08) and lower dietary NDF (P=0.10) in treatment H was probably related to greater PL ingestion. Given that high and sustained rates of poultry litter consumption are detrimental to animal health, the above results cast doubts on the long-term sustainability of the higher of the animal densities tested. Although it may be sustainable vis-à-vis the vegetation, treatment H may have exceeded the boundaries of what is acceptable for cow health. Chemical information revealed with NIRS can be used to evaluate whether animal densities are compatible with animal health and welfare standards and can play a role in determining the carrying capacity of Mediterranean rangelands.

Composting is the enhanced biological decomposition of organic materials in a primarily aerobic environment. During the process, microorganisms break down organic materials to stable, usable organic substances in a process which consumes oxygen and releases heat, water, and CO2. Under controlled conditions, the composting process is described in two phases, primary and secondary. Chemical and physical properties of the raw wastes affect the rate of composting. Particle size and surface area of the waste material influence the type of microorganisms involved and the degree of biological activity in the composting process. Composting allows safe disposal of birds and manure and reduces environmental degradation. Composting of poultry manure and dead birds is still a debatable topic, however, with some scientists in favour of composting due to its overwhelming advantages while others are against composting due to certain disadvantages/environmental hazards. The present article is an effort to encompass the overall composting process, its applications as well as troubleshooting various associated issues.

Exporting northwest Arkansas excess turkey and broiler litter to partially fertilize nutrient-deficient cropland in eastern Arkansas can be more cost effective than to supply all crop nutrients with chemical fertilizer only, given current high fertilizer prices. Cost savings are greater if litter is baled in ultraviolet resistant plastic and transported via truck, since backhaul opportunities reduce truck rates, or alternatively, if raw litter is shipped via a truck-barge combination. Rice is the crop that allows for greater savings according to a mathematical programming model implemented in General Algebraic Modeling System (GAMS).

This paper identifies optimal combinations of nitrogen in the form of urea, fresh litter and composted litter for rice production. Traditional cost minimization techniques using data from experimental results conducted at three sites in Arkansas during 1991 have been employed. Comparisons between different scenarios indicate that the trade-off between the use of poultry litter and urea nitrogen depends on such factors as soil fertility, the yield response to litter application and the relative prices of nitrogen and litter. The use of litter is more economical at high target yields than at low target yields.

Concerns about nutrient loads into our waters have focused attention onpoultry litter applications. Like many states with a large poultry industry,Georgia recently designed a subsidy program to facilitate the transportationof poultry litter out of vulnerable watersheds. This paper uses atransportation model to examine the necessity of a poultry litter subsidy toachieve water protection goals in Georgia. We also demonstrate therelationship between diesel and synthetic fertilizer prices and the value ofpoultry litter. Results suggest that a well-functioning market would be ableto remove excess litter from vulnerable watersheds in the absence of asubsidy.

Conversion of poultry litter to energy can serve as a renewable energy source and provide an alternative to land application in areas where poultry production is intensive. Economies of size may limit a farmer's ability to economically use on-farm conversion. Capital costs can be spread across several poultry farmers to convert poultry litter to energy in a centralized facility. This research determined influences on the amount of litter poultry producers will to sell to a centralized conversion facility, on their willingness to invest in a conversion cooperative, and on the prices for litter required to divert litter from current uses.

The poultry industry is one of the largest and fastest growing agro-based industries in the world. This can be attributed to an increasing demand for poultry meat and egg products. However, a major problem facing the poultry industry is the large-scale accumulation of wastes including manure and litter which may pose disposal and pollution problems unless environmentally and economically sustainable management technologies are evolved. Most of the litter produced by the poultry industry is currently applied to agricultural land as a source of nutrients and soil amendment. However environmental pollution, resulting from nutrient and contaminant leaching can occur when poultry litter is applied under soil and climatic conditions that do not favour agronomic utilisation of the manure-borne nutrients. This review examines the composition of poultry litter in relation to nutrient content and environmental contaminants, its value as a nutrient source, soil amendment, animal feed and fuel source, and cost-effective innovative technologies for improving its value. Poultry litter provides a major source of nitrogen, phosphorus and trace elements for crop production and is effective in improving physical and biological fertility, indicating that land application remains as the main option for the utilisation of this valuable resource. The alternative use of poultry litter; as an animal feed and fuel source, is limited by contaminants, and high moisture content, respectively. The review proposes best management practices to mitigate environmental consequences associated with air and water quality parameters that are impacted by land application in order to maintain the continued productivity, profitability, and sustainability of the poultry industry.

The application of poultry litter on land over many years may lead to excessive quantities of nutrients in soils and water contamination. In a watershed in Oklahoma and Arkansas, litter applications by large numbers of poultry producers have led the state of Oklahoma to bring a lawsuit against poultry integrators under the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Oklahoma alleges that poultry waste is being disposed of as a hazardous substance, and that the poultry integrators are facilitating the disposal by placing birds at facilities that deposit litter on fields that do not need additional nutrients. Oklahoma is requesting that the integrators be ordered to pay for all monetary damages suffered and incurred by the state to remedy such wrongful conduct. The state also seeks a permanent injunction requiring the defendants to abate their pollution-causing conduct and other relief, including punitive and exemplary damages. While poultry litter may not appear to be a hazardous substance, in 2005 a federal district court found that it was a substance regulated by CERCLA. Thus, the poultry industry and producers might avoid liability by qualifying for a CERCLA exception. Two are available: federally permitted releases and normal applications of fertiliser. However, despite qualifying under these exceptions, it is incumbent on producers and the industry to recognise that public concerns about environmental contamination require greater efforts. All producers should be employing best management practices and limit applications of litter to only those amounts needed for crop production. Additional voluntary and mandatory oversight might be advantageous in precluding shirkers from engaging in unacceptable practices that contaminate land and water resources.

This paper discusses materials used as bedding or litter for the rearing of broilers and turkeys in the U.S.A. The U.S. poultry industry has historically used pine shavings as the litter of choice for many years. Sawdust has replaced pine shavings in many areas, however, not by choice, but because pine shavings have become increasingly difficult to obtain. Regionally, rice hulls, straw, and peanut hulls can be found in use by poultry producers for litter. Re-cycled paper products have received a lot of research and development, but have not had a great deal of acceptance by the poultry industry. Sand is another alternative bedding that is currently being tested in southern climates. Alternative litter materials for poultry will continue to be researched and evaluated, and pine shavings or sawdust will probably continue to be used as the benchmark comparison. However, while bird performance will always be a threshold criterion, cost and availability will ultimately determine the adoption of new or alternative litter materials by poultry growers and the poultry industry.

We coupled a nonlinear mathematical programming model with sensitivity analysis and evaluated some economic barriers to adoption of low-input agriculture by farmers in Richmond County, Virginia. Collection of primary data made the model more realistic. We analyzed potential barriers to adoption, including poultry litter price, yields, labor requirements, and variable input costs. We found the adoption of low-input practices to be sensitive to the price of poultry litter and relatively insensitive to yields, labor requirements, and variable costs. However, when several of these barriers are combined, the model predicts that farmers would use conventional practices. Therefore analysis of the farm as a system rather than practice by practice is important when identifying the effects of economic barriers.

A case study in eastern Virginia provides evidence that both environmental and farm profit goals may be satisfied by alternative nitrogen (N) management strategies for grain production. We used a linear programming framework with an N mass balance model to calculate returns from several options for providing N to crops. Replacing single applications of inorganic N fertilizer with split applications or with additions of organic N were found to reduce the potential for N loss from cropland and to increase net returns. For some N management strategiesy however, adoption may require financial and educational assistance. As a result, water quality policies may benefit by including such incentives.