Total Carbon, Organic Carbon, and Organic Matter

Ernani

et al. 2016

Pesq. agropec. bras.

-The objective of this work was to assess the risk of phosphorus losses by runoff through an index based on the degree of P saturation (DPS), in cropland soils of Southern Brazil. Sixty-five highly representative cropland soils from the region were evaluated. Three labile P forms were measured (Mehlich-1, Mehlich-3, and ammonium oxalate), and four P sorption indexes were tested (phosphorus single sorption point and Fe+Al determined with the three extractors). Water-extractable P (WEP) was used as an index of P susceptibility to losses by surface runoff. The DPS was determined from the ratio between labile P and each sorption index. DPS values obtained from the ratio between Mehlich-1 P and the single P sorption point ranged from 1 to 25%, whereas those from Mehlich-1 P and Fe+Al (ammonium oxalate) ranged from 1 to 55%. All DPS types were highly correlated with WEP. From a practical stand point, the DPS obtained with both P and Fe+Al extracted with Mehlich-1 can be used to estimate the risk of P losses by runoff in soils of Southern Brazil.Index terms: eutrophication, runoff, single P sorption point, water quality. Limite do grau de saturação de fósforo para minimizar perdas de P por escorrimento superficial em solos agrícolas do Sul do BrasilResumo -O objetivo deste trabalho foi avaliar o risco de perdas de fósforo por escorrimento superficial por meio de um índice baseado no o grau de saturação de P (GSP) no solo, em solos agrícolas do Sul do Brasil. Foram avaliados 65 solos agrícolas representativos da região. Três formas lábeis de P foram medidas (Mehlich-1, Mehlich-3 e oxalato de amônio), e quatro índices de adsorção de P foram testados (adsorção de P em único ponto e Fe+Al obtido com os três extratores). O P extraível em água (PEA) foi utilizado como índice de suscetibilidade do P a perdas por escoamento superficial. O GSP foi obtido a partir do quociente entre a forma lábil de P e cada índice de adsorção. Os valores do GSP obtidos a partir do quociente entre P Mehlich-1 e a adsorção de P em único ponto variaram de 1 a 25%, enquanto os entre P Mehlich-1 e Fe+Al (oxalato de amônio) variaram de 1 a 55%. Todos os tipos de GSP estiveram altamente correlacionados ao PEA. Do ponto de vista de uso prático, o GSP obtido com P e Fe+Al extraídos com Mehlich-1 pode ser usado para estimar o risco de perda de P por escorrimento superficial em solos do Sul do Brasil.Termos para indexação: eutrofização, escorrimento superficial, P em único ponto, qualidade de água.

Section: Methodsmentioning

confidence: 99%

Degree of phosphorus saturation threshold for minimizing P losses by runoff in cropland soils of Southern Brazil

Ernani

et al. 2016

Pesq. agropec. bras.

Applied and Environmental Soil Science

“…Soil texture was determined using the hydrometer method according to Gee and Bauder [18]. OM was determined using the wet oxidation method according to Sparks et al [19]. CEC was determined by displacement of cations from soil samples with 1 N ammonium acetate, and determination was done using Flame Photometer (Palemio and Rhoades 1977).…”

Section: Soil Watermentioning

confidence: 99%

Sustainable Management of Calcareous Saline-Sodic Soil in Arid Environments: The Leaching Process in the Jordan Valley

Batarseh

2017

A leaching experiment of calcareous saline-sodic soil was conducted in Jordan Valley and aimed to reduce the soil salinity ≤ 4.0 dS m −1 . The quantification of salt removal from the effective root zone was done using three treatment scenarios. Treatment A contained soil amended with gypsum leaching with fresh water (EC = 1.1 dS m −1 ). Treatments B and C contained nonamended soil, but B was leached with fresh water only while treatment C's soil was washed with saline agricultural drainage water (EC = 8 dS m −1 ) at the start of the experiment and continued with fresh water to reach the desired soil salinity. All treatments were able to reduce the soil salinity to the desired level at the end of the experiment; however, there were clear differences in the salt removal efficiencies among the treatments which were attributed to the presence of direct source of calcium ion. The soil amended with gypsum caused a substantial decline in soil salinity and drainage water's electrical conductivity and drained the water twice as fast as the nonamended soil. It was found that utilizing agricultural drainage water and gypsum as a soil amendment for calcareous saline-sodic soil reclamation can beneficially contribute to sustainable agricultural management in the Jordan Valley.

“…For aged biosolids 1, Arulrajah et al (2011) reported a TVS of~27% and total organic carbon of 17·4% (with standard deviation of 2·3%), indicating a conversion factor relating TVS to total organic carbon for this particular material of~1·55. Traditionally, for natural soils, a conversion factor of 1·724 is used, on the assumption that organic matter contains an average of 58% organic carbon (Nelson and Sommers, 1996), although there is no universal conversion factor value, with it varying from soil to soil and also depending on the type of organic matter present. (Basim, 1999) Alum WTR 8 (Basim, 1999) Alum lime WTR 1 (Basim, 1999) Alum lime WTR 2 (Raghu and Hsieh, 1986) Alum with polymer WTR 1 (Basim, 1999) Polymer WTR 1 (Basim, 1999) Lime sludge 1 (Raghu and Hsieh, 1986) Passing: dry mass % (Stone et al, 1998) Sewage sludge 6b (Stone et al, 1998) Sewage sludge 6c (Stone et al, 1998) Sewage sludge 6d (Stone et al, 1998) Sewage sludge 6e (Stone et al, 1998) Biosolids 4 (GLSEC, 2003) Aged biosolids 1 Passing: dry mass % 2011; Maghoolpilehrood et al, 2013;Wanigaratne and Udamulla, 2012) plot below the A-line and are classified as organic silt of high to extremely high plasticity.…”

Section: Organic Matter Contentmentioning

confidence: 99%

Geotechnics of municipal sludges and residues for landfilling

O’Kelly

2016

Geotechnical Research

This paper presents a comprehensive review of reported field and laboratory investigations and theoretical work concerning the geotechnical behaviour/properties of water treatment residue (WTR), biosolids and sewage sludge materials, which are by-products of municipal water and wastewater treatment processes. After describing the backgrounds to the generation of these materials and various disposal options (with a focus on landfilling), including associated geotechnical issues, their physical, geotechnical index, compaction, undrained strength and effective-stress strength properties are described, including the effects of oxidation, biodegradation and viscous gellike pore fluid for biosolids/sewage sludge material. Characteristic compressibility, consolidation and permeability behaviour/properties are also presented for these materials and linked with microstructure and the chemicals added during the treatment processes. The paper then focuses on various geotechnical issues pertinent to landfill (monofill) disposal of these materials, including undrained strength requirements, design strength, on-site and laboratory strength measurements and water content-strength correlations. Since such correlations are material specific, with the geotechnical properties of biosolids, sewage sludge and WTR materials varying between water/wastewater treatment plants, they cannot be applied more widely with confidence. Alternative approaches to predicting undrained strength are described, including a power-law strength relationship with water content, which can be applied more generally. , 2008a). The type and amount of chemicals added depends on the nature of the source water, but primarily on its turbidity and hardness. The coagulants cause the colloidal particles present to aggregate into flocs (with the polyelectrolyte also acting as a binding agent to increase their inherent shear strength) that are more readily separated out by settling processes, removing not only the impurities but also the chemical additives. NotationThe residue so formed is categorised as aluminium sulfate (alum) or iron WTR material depending on the coagulant salt, with the former being the most widely used coagulant in the water treatment industry. Lime-softening sludge, composed of typically 80-95 wt% calcite (Raghu and Hsieh, 1986), is the result of softening hard water before its distribution as drinking water.Biosolids and sewage sludge materials are highly organic residue by-products of municipal waste water treatment, with the organic fraction originating principally from human faeces (primary sludge) and bacterial biomass (secondary sludge) and the inorganic fraction derived from materials such as soil, sediment and inorganic residuals (Haynes et al., 2009). According to the US Environmental Protection Agency (EPA) (2015), sewage sludge refers to the solids separated out during the treatment processes, whereas biosolids refers to treated sewage sludge material that meets regulatory pollutant-and pathogen-control requirements for land applica...