Açai seed biochar improves soil quality and black pepper seedling development in the Amazon region.

Sustainable management of the Amazon rainforest is fundamental for supporting life on earth because of its crucial role in sequestering carbon. One of the species grown in the forest is açaí (Euterpe oleracea), which is an important food and income source for its inhabitant. The acai seed, resulting from the processing of the fruit, is a solid organic residue, which has been an agent of undesirable environmental impacts such as natural landscape modifications, clogging sewers and water courses, eutrophication of surface waters.

Nickel sources affect soil biological properties but do not affect sorghum growth.

Nickel (Ni) is an essential element, but it can be phytotoxic in high concentration, which may be caused by high availability in soil solution. The objective of this study was to evaluate the effect of sources and doses of Ni applied to a dystrophic Red Latosol cultivated with sorghum on i) the availability of the metal in the soil; ii) the impact on biological and biochemical properties of the soil; iii) the absorption and distribution in sorghum plants; and iv) crop productivity. The experiment was carried out within a completely randomized design with two nickel sources [nickel(II) nitrate, Ni(NO) and nickel(III) oxide, NiO], three doses (35, 70, and 140 mg Ni kg soil), plus controls without Ni, with 3 replications.

Microbial communities in the rhizosphere of maize and cowpea respond differently to chromium contamination.

Chromium (Cr) contamination can affect microorganisms in the soil, but the response of the microbial community in the rhizosphere of plants grown in Cr-contaminated soils is poorly understood. Therefore, this study assessed the microbial community, by amplicon sequencing, in the rhizosphere of maize and cowpea growing in uncontaminated (∼6.0 mg kg Cr) and Cr-contaminated soils (∼250 mg kg Cr).

Dynamics of bacterial and archaeal communities along the composting of tannery sludge.

The process of composting has been proposed as a biological alternative to improve the quality of tannery sludge (TS) by the action of microbial communities. However, there is limited knowledge about the dynamic of these microbial communities during the composting process. This study assessed the responses of bacterial and archaeal communities during TS composting using the 16S rRNA sequencing.

Microbial co-occurrence network and its key microorganisms in soil with permanent application of composted tannery sludge.

Soil microbial communities act on important environmental processes, being sensitive to the application of wastes, mainly those potential contaminants, such as tannery sludge. Due to the microbiome complexity, graph-theoretical approaches have been applied to represent model microbial communities interactions and identify important taxa, mainly in contaminated soils. Herein, we performed network and statistical analyses into microbial 16S rRNA gene sequencing data from soil samples with the application of different levels of composted tannery sludge (CTS) to assess the most connected nodes and the nodes that act as bridges to identify key microbes within each community.

Long-term effect of composted tannery sludge on soil chemical and biological parameters.

Composting has been recommended as a suitable alternative for recycling wastes and could improve tannery sludge (TS) before its use. However, the long-term application of composted tannery sludge (CTS) may bring concerns about its effects on soil properties and, consequently, on plants and environment, mainly when considering Cr contamination. In this study, we summarize the responses of soil chemical and biological parameters in a 10-year study with yearly applications of CTS.

Phytotoxicity and cytogenotoxicity of composted tannery sludge.

Tannery sludge (TS) contains high levels of organic matter and chemical elements, mainly chromium (Cr). This can increase its toxicity, rendering it unsuitable for application to soil. However, composting has been proposed as an alternative method for detoxifying TS before its addition to soil.

Dynamics of archaeal community in soil with application of composted tannery sludge.

Application of composted tannery sludge (CTS) could promote a shift in the structure of soil microbial communities. Although the effect of CTS on bacterial community has been studied, it is unclear how the composition and diversity of archaeal community respond to CTS amendment and which environmental factors drive the community over time. Here, we hypothesize that the Archaea structure and composition respond to CTS amendment over the time.

Land use impact on potentially toxic metals concentration on surface water and resistant microorganisms in watersheds.

Soil and water resources must be conserved and protected. However, the management of production activities causes a change in the quality of these natural resources due to accumulation in soil of potentially toxic metals. The objective of the present study was to identify the variety and paths of potentially toxic metals (PTMs), such as cadmium, lead, copper, chromium, nickel and zinc, which are associated spatially and temporally to soil and water.

Time-dependent effect of composted tannery sludge on the chemical and microbial properties of soil.

Composting has been suggested as an efficient method for tannery sludge recycling before its application to the soil. However, the application of composted tannery sludge (CTS) should be monitored to evaluate its effect on the chemical and microbial properties of soil. This study evaluated the time-dependent effect of CTS on the chemical and microbial properties of soil.

Agricultural management of an Oxisol affects accumulation of heavy metals.

Soil contamination may result from the inadequate disposal of substances with polluting potential or prolonged agricultural use. Therefore, cadmium (Cd), chromium (Cr) and nickel (Ni) concentrations were assessed in a Eutroferric Red Oxisol under a no-tillage farming system with mineral fertilizer applications, a conventional tillage system with mineral fertilizer application and a conventional tillage system with sewage sludge application in an area used for agriculture for more than 80 years. We evaluated the spatial distributions of these elements in the experimental area and the effect of the different management practices on the soil retention of these metals.

Soil microbial properties after 5 years of consecutive amendment with composted tannery sludge.

Composting has been recognised an alternative method to tannery sludge recycling and afterwards to be used in agriculture. As the tannery sludge contains salts and chromium, the application of composted tannery sludge (CTS) should be performed carefully to minimise negative effects on soil microbial properties. Therefore, this study evaluated the effects of 5-year repeated CTS amendment on soil microbial biomass (SMB) and enzyme activities in a tropical soil.

Evaluation of biochemical and redox parameters in rats fed with corn grown in soil amended with urban sewage sludge.

The increased production of urban sewage sludge requires alternative methods for final disposal. A very promising choice is the use of sewage sludge as a fertilizer in agriculture, since it is rich in organic matter, macro and micronutrients. However, urban sewage sludge may contain toxic substances that may cause deleterious effects on the biota, water and soil, and consequently on humans.

Concentrations of Cu, Fe, Mn, and Zn in tropical soils amended with sewage sludge and composted sewage sludge.

Sewage sludge may be used as an agricultural fertilizer, but the practice has been criticized because sludge may contain trace elements and pathogens. The aim of this study was to compare the effectiveness of total and pseudototal extractants of Cu, Fe, Mn, and Zn, and to compare the results with the bioavailable concentrations of these elements to maize and sugarcane in a soil that was amended with sewage sludge for 13 consecutive years and in a separate soil that was amended a single time with sewage sludge and composted sewage sludge. The 13-year amendment experiment involved 3 rates of sludge (5, 10, and 20 t ha(-1)).

Effect of different tannery sludge compost amendment rates on growth, biomass accumulation and yield responses of Capsicum plants.

Composting has been recognized as one of the most cost effective and environmentally sound alternatives for organic wastes recycling from long and composted wastes have a potential to substitute inorganic fertilizers. We investigated the potential of composted tannery sludge for ornamental purposes and to examine the effects of two different composts and concentrations on ornamental Capsicum growth. The two composts were produced with tannery sludge and the composition of each compost was: compost(1) of tannery sludge (C(1)TS) - tannery sludge+sugarcane straw and cattle manure mixed in the ratio 1:3:1 (v:v:v); compost(2) of tannery sludge (C(2)TS) - tannery sludge+"carnauba" straw and cattle manure in the ratio 1:3:1 (v:v:v).