Applied and Environmental Soil Science The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Dissolution of Metals from Biosolid-Treated Soils by Organic Acid Mixtures Thu, 14 Apr 2016 06:12:05 +0000 Results for the solubilization of metals from biosolid- (BSL-) treated soils by simulated organic acid-based synthetic root exudates (OA mixtures) of differing composition and concentrations are presented. This study used two BSL-treated Romona soils and a BSL-free Romona soil control that were collected from experimental plots of a long-term BSL land application experiment. Results indicate that the solubility of metals in a BSL-treated soil with 0.01 and 0.1 M OA mixtures was significantly higher than that of 0.001 M concentrations. Differences in composition of OAs caused by BSL treatment and the length of growing periods did not affect the solubility of metals. There were no significant differences in organic composition and metals extracted for plants grown at 2, 4, 8, 12, and 16 weeks. The amount of metals extracted tended to decrease with the increase of the pH. Results of metal dissolution kinetics indicate two-stage metal dissolution. A rapid dissolution of metals occurred in the first 15 minutes. For Cd, Cu, Ni, and Zn, approximately 60–70% of the metals were released in the first 15 minutes while the initial releases for Cr and Pb were approximately 30% of the total. It was then followed by a slow but steady release of additional metals over 48 hours. Won-Pyo Park, Bon-Jun Koo, Andrew C. Chang, Thomas E. Ferko, Jonathan R. Parker, Tracy H. Ward, Stephanie V. Lara, and Chau M. Nguyen Copyright © 2016 Won-Pyo Park et al. All rights reserved. Oil and Gas Production Wastewater: Soil Contamination and Pollution Prevention Sun, 20 Mar 2016 07:59:43 +0000 During oil and natural gas production, so-called “produced water” comprises the largest byproduct stream. In addition, many oil and gas operations are augmented via injection of hydraulic fracturing (HF) fluids into the formation. Both produced water and HF fluids may contain hundreds of individual chemicals, some known to be detrimental to public health and the environment. Oil and gas production wastewater may serve a range of beneficial purposes, particularly in arid regions, if managed correctly. Numerous treatment technologies have been developed that allow for injection, discharge to the land surface, or beneficial reuse. Although many papers have addressed the effects of oil and gas production wastewater (OGPW) on groundwater and surface water quality, significantly less information is available on the effects of these fluids on the soil resource. This review paper compiles fundamental information on numerous chemicals used and produced during oil and gas development and their effects on the soil environment. Additionally, pollution prevention technologies relating to OGPW are presented. An understanding of the effects of OGPW on soil chemical, physical, and biological properties can provide a foundation for effective remediation of OGPW-affected soils; additionally, sustainable reuse of oil and gas water for irrigation and industrial purposes may be enhanced. John Pichtel Copyright © 2016 John Pichtel. All rights reserved. Long-Term Dynamics of Urban Soil Pollution with Heavy Metals in Moscow Sun, 06 Mar 2016 07:20:49 +0000 Results of 21-year-long (1989–2010) observations of the concentrations and the spatial distribution patterns of nine heavy metals (HMs) in topsoils of the Eastern district of Moscow are presented. The quantitative parameters of soil pollution include the annual increase rates of HM concentrations in several land-use zones. The maps of geochemical anomalies were compiled using the data collected in 1989, 2005, and 2010. The growth of the total volume of industrial and vehicles’ emissions between 1989 and 2005 caused significant deposition of Pb, Zn, Cu, and Cd. The additional input of Cd to the soils is attributed to the application of sewage sludge as fertilizers. The relative increment of concentrations was the highest for Pb, Co, Cu, Ni, and Cr. In 2005–2010, the relative annual increment rate was the highest for Cr, Cd, Co, and Ni, and it increased by an order of magnitude as compared to the previous period. By contrast, Pb and Cu concentrations decreased owing to the soil reclamation, the exclusion of leaded gasoline as a fuel for vehicles and closing some hazardous enterprises. Joint analysis of snow and soil geochemical maps allows identification of the zones of actual, permanent, and relict pollution. N. E. Kosheleva and E. M. Nikiforova Copyright © 2016 N. E. Kosheleva and E. M. Nikiforova. All rights reserved. Using Cosmic-Ray Neutron Probes to Monitor Landscape Scale Soil Water Content in Mixed Land Use Agricultural Systems Mon, 29 Feb 2016 09:24:10 +0000 With an ever-increasing demand for natural resources and the societal need to understand and predict natural disasters, soil water content (SWC) observations remain a critical variable to monitor in order to optimally allocate resources, establish early warning systems, and improve weather forecasts. However, routine agricultural production practices of soil cultivation, planting, and harvest make the operation and maintenance of direct contact point sensors for long-term monitoring challenging. In this work, we explore the use of the newly established Cosmic-Ray Neutron Probe (CRNP) and method to monitor landscape average SWC in a mixed agricultural land use system in northeast Austria. The calibrated CRNP landscape SWC values compare well against an independent in situ SWC probe network (MAE = 0.0286 m3/m3) given the challenge of continuous in situ monitoring from probes across a heterogeneous agricultural landscape. The ability of the CRNP to provide real-time and accurate landscape SWC measurements makes it an ideal method for establishing long-term monitoring sites in agricultural ecosystems to aid in agricultural water and nutrient management decisions at the small tract of land scale as well as aiding in management decisions at larger scales. Trenton E. Franz, Ammar Wahbi, Mariette Vreugdenhil, Georg Weltin, Lee Heng, Markus Oismueller, Peter Strauss, Gerd Dercon, and Darin Desilets Copyright © 2016 Trenton E. Franz et al. All rights reserved. Combining Geoelectrical Measurements and CO2 Analyses to Monitor the Enhanced Bioremediation of Hydrocarbon-Contaminated Soils: A Field Implementation Wed, 17 Feb 2016 11:35:56 +0000 Hydrocarbon-contaminated aquifers can be successfully remediated through enhanced biodegradation. However, in situ monitoring of the treatment by piezometers is expensive and invasive and might be insufficient as the information provided is restricted to vertical profiles at discrete locations. An alternative method was tested in order to improve the robustness of the monitoring. Geophysical methods, electrical resistivity (ER) and induced polarization (IP), were combined with gas analyses, CO2 concentration, and its carbon isotopic ratio, to develop a less invasive methodology for monitoring enhanced biodegradation of hydrocarbons. The field implementation of this monitoring methodology, which lasted from February 2014 until June 2015, was carried out at a BTEX-polluted site under aerobic biotreatment. Geophysical monitoring shows a more conductive and chargeable area which corresponds to the contaminated zone. In this area, high CO2 emissions have been measured with an isotopic signature demonstrating that the main source of CO2 on this site is the biodegradation of hydrocarbon fuels. Besides, the evolution of geochemical and geophysical data over a year seems to show the seasonal variation of bacterial activity. Combining geophysics with gas analyses is thus promising to provide a new methodology for in situ monitoring. Cécile Noel, Jean-Christophe Gourry, Jacques Deparis, Michaela Blessing, Ioannis Ignatiadis, and Christophe Guimbaud Copyright © 2016 Cécile Noel et al. All rights reserved. Transport Processes in Porous Media by Self-Potential Method Tue, 26 Jan 2016 14:16:38 +0000 A controlled diffusion/infiltration column experimental activity was carried out with the aim of monitoring the leakage of a salty water plume by time-lapse self-potential (SP) measurements. In particular, three tracer tests with different NaCl concentrations (6.00, 1.00, and 0.25 g L−1) were performed and all the measured SP signals showed a sharp reduction corresponding to the arrival of saline front with negative electrical potential values (− mV, − mV, and − mV) which decrease with increasing volume of tracer introduced into the column. Then, measured self-potential values were converted into salt concentration ones by the Planck-Henderson equation and sand diffusion and longitudinal dispersivity () values were estimated by modelling the transport equations in the COMSOL Multiphysics environment. Finally, the results show that measured and estimated NaCl concentrations are well correlated. Valeria Giampaolo, Daniela Calabrese, and Enzo Rizzo Copyright © 2016 Valeria Giampaolo et al. All rights reserved. A Rationale for Pollutograph Evaluation in Ungauged Areas, Using Daily Rainfall Patterns: Case Studies of the Apulian Region in Southern Italy Sun, 24 Jan 2016 08:40:09 +0000 In the context of the implementation of sustainable water treatment technologies for soil pollution prevention, a methodology that try to overcome the lack of runoff quality data in Puglia (Southern Italy) is firstly tackled in this paper. It provides a tool to obtain total suspended solid (TSS) pollutographs in areas without availability of monitoring campaigns. The proposed procedure is based on the relationship between rainfall characteristics and pollutant wash-off. In particular, starting from the evaluation of the observed regional rainfall patterns by using a rainfall generator model, the storm water management model (SWMM) was applied on five case studies located in different climatic subareas. The quantity SWMM parameters were evaluated starting from the drainage network and catchments characteristics, while the quality parameters were obtained from results of a monitoring campaign conducted for quality model calibration and validation with reference to the pollutograph’s shape and the peak-time. The research yields a procedure useful to evaluate the first flush phenomenon in ungauged sites and, in particular, it provides interesting information for designing efficient and sustainable drainage systems for first flush treatment and diffuse pollution treatment. Angela Gorgoglione, Andrea Gioia, Vito Iacobellis, Alberto Ferruccio Piccinni, and Ezio Ranieri Copyright © 2016 Angela Gorgoglione et al. All rights reserved. Role of Inorganic and Organic Fractions in Animal Manure Compost in Lead Immobilization and Microbial Activity in Soil Wed, 06 Jan 2016 11:05:47 +0000 This study aimed to identify how the ratio of inorganic-to-organic components in animal manure compost (AMC) affected both lead immobilization and microbial activity in lead-contaminated soil. When AMC containing 50% or more inorganic fraction with high phosphorous content was applied to contaminated soil, the amounts of water-soluble lead in it were suppressed by over 88% from the values in the soil without compost. The residual fraction under sequential extraction increased with the inorganic fraction in the AMC; however, in those AMCs, the levels of microbial enzyme activity were the same or less than those in the control soil. The application of AMC containing 25% inorganic fraction could alter the lead phases to be more insoluble while improving microbial enzyme activities; however, no suppression of the level of water-soluble lead existed during the first 30 days. These results indicate that compost containing an inorganic component of 50% or more with high phosphorus content is suitable for immobilizing lead; however, in the case where low precipitation is expected for a month, AMC containing 25% inorganic component could be used to both immobilize lead and restore microbial activity. Masahiko Katoh, Wataru Kitahara, and Takeshi Sato Copyright © 2016 Masahiko Katoh et al. All rights reserved. Gully Morphology and Rehabilitation Measures in Different Agroecological Environments of Northwestern Ethiopia Sun, 27 Dec 2015 12:07:32 +0000 Gully erosion is a serious threat to the society and environment of the study, primarily caused by surface runoff and dramatically accelerated due to rugged topography and human induced factors. Intensive measurements of gully characteristics were undertaken to investigate the morphologies of gully, while aiming for sustainable gully rehabilitation; therefore, a total of 63 gully samples from three different agroecologies were randomly observed. The morphological variability of measured gullies was evaluated and the resulting CVs had been between 0.27 and 0.39 except for gully length, which had highest variability (CV = 1.10). The highest gully length (2,400 m) and highest lower width (6 m) were observed on Dembia district, which might be due to the loose and pulverized condition of the soil. The correlation matrices for many parameters of gully morphology in different districts of Semien Gondar showed several sets of significant relationships. Some of the assessed gullies showed that appropriate physical gully control structures integrated with vegetative measures have resulted in a significant reduction of soil loss and stabilized the gully from further enlargement. There could be various justifications for the success of these structures; however, the most important measures were vegetative management and exclusion of cattle. Hailu Kendie Addis, Belayneh Adugna, Muuz Gebretsadik, and Baye Ayalew Copyright © 2015 Hailu Kendie Addis et al. All rights reserved. Cadmium Phytoremediation Potential of Napiergrass Cultivated in Kyushu, Japan Thu, 24 Dec 2015 14:26:24 +0000 Napiergrass (Pennisetum purpureum Schumach), a C4 tropical species, has been used for forage since it has high dry matter productivity, sustainability over several years in low-altitudinal sites of Kyushu, and little damage from serious pests. Recently, this grass has gained attention due to its potential as a bioethanol feedstock and for phytoremediation. Napiergrass cultivar Wruk Wona was grown as an annual crop in cadmium- (Cd-) contaminated soils under two cutting frequencies. Annual dry matter yield was not affected significantly by cutting frequency, but the concentration and uptake of Cd were higher when cut twice rather than only once, due to high Cd content of the herbage from the second cutting. Therefore, the soil Cd concentration was reduced by 4.6% when managed by cutting twice in a single year of Napiergrass cultivation. Yasuyuki Ishii, Kotomi Hamano, Dong-Jin Kang, Sachiko Idota, and Aya Nishiwaki Copyright © 2015 Yasuyuki Ishii et al. All rights reserved. Determination of Tetracycline and Fluoroquinolone Antibiotics at Trace Levels in Sludge and Soil Thu, 17 Dec 2015 05:58:18 +0000 This work describes the development of a sensitive analytical method to determine simultaneously traces of tetracycline and fluoroquinolone antibiotics in sludge and soil, based on PLE extraction, followed by SPE purification and finally an analysis by LC-MS/MS. Recoveries were greater than 87% in the case of fluoroquinolones and between 25.4 and 41.7% for tetracyclines. Low relative standard deviations (<15%) were obtained in both matrices. The limits of quantification were comprised between 1.1 and 4.6 ng/g and between 5 and 20 ng/g in soil and sludge, respectively. The method was then successfully applied to the analysis of the target antibiotics in sludge as well as soil that received spreading. The substances most frequently found and with the highest levels were fluoroquinolones with concentrations exceeding 1,000 ng/g in several samples of sludge and up to 16 ng/g in soil. Marie-Virginie Salvia, Maëva Fieu, and Emmanuelle Vulliet Copyright © 2015 Marie-Virginie Salvia et al. All rights reserved. Aggregate Indices Method in Soil Quality Evaluation Using the Relative Soil Quality Index Wed, 25 Nov 2015 11:27:38 +0000 This paper presents a new approach to assess the soil quality by aggregate indices using the Relative Soil Quality Index (RSQI) proposed by Ho Ngoc Pham. RSQI is integrated from the individual indices into a simple formula for overall assessment of the soil quality. RSQI is different from other approaches. Particularly, the individual indices and the weighting factors of Pham are calculated from the analytical laboratory data and the environmental standards, respectively, and not self-regulated as in methods of some other authors. In this paper, the authors applied the RSQI to assess the Soil Environmental Quality of rice intensive cultivation areas through a case study in Haiduong province in 2013. The RSQI is calculated for sampling points in 12 districts and simulated the Soil Environmental Quality on GIS map. The results show that the Soil Environmental Quality of rice intensive cultivation areas in Haiduong is predominantly divided into three levels: good, moderate, and poor. According to the report of General Statistics Office for Haiduong province, rice intensive cultivation areas in 2013 achieved a relatively high average rice yield of 5.90 tonnes per hectare; it means actual soil properties are in line with results of the research. Ho Ngoc Pham, Hai Xuan Nguyen, Anh Ngoc Nguyen, and Diep Ngoc Tran Copyright © 2015 Ho Ngoc Pham et al. All rights reserved. Sodium Contents in Dairy Cow Urine and Soil Aggregate Sizes Influence the Amount of Nitrogen Lost from Soil Thu, 12 Nov 2015 09:49:35 +0000 Cow urine deposition on pasture soils is a major source of N-related environmental impacts in the dairy farming systems. The urine-N can potentially be lost to the ground water as nitrate () and to the atmosphere as nitrous oxide (N2O). These N-related environmental impacts are possibly related to the sodium (Na+) concentrations in urine. We sampled a pasture soil and separated it into three aggregate size groups (0–3, 3–5, and 5–7 mm). Then, cow urine with variable Na+ concentrations (4.3–6.1 g Na+ L−1) was added to the soil cores. We treated the cores with simulated heavy rains and measured the amounts of calcium (Ca2+), Na+, potassium (K+), and inorganic-N leached from the soils. N2O emission rates were also determined throughout the experimental period. Increasing Na+ concentration in urine decreased the loss of (−20%), after repeatedly applied simulated rain treatments (30 mm × 3), whereas it increased the loss of ammonium (31%) and K+ (19%). For the loss of Ca2+ and the emissions of N2O, the effect of the Na+ concentrations was unclear. Field level studies and studies focusing on the mechanisms behind the changes in nutrient losses are needed. Toru Hamamoto and Yoshitaka Uchida Copyright © 2015 Toru Hamamoto and Yoshitaka Uchida. All rights reserved. Impact of Soil Compaction on Bulk Density and Root Biomass of Quercus petraea L. at Reclaimed Post-Lignite Mining Site in Lusatia, Germany Thu, 15 Oct 2015 08:01:59 +0000 The impact of soil compaction on bulk density and root biomass of Quercus petraea L. was assessed after 85 years of reclamation of post-lignite mining soil at Welzow-South, in Lusatia, Germany. Bulk density of core soils sampled from 20 to 25 cm, 100 to 105 cm, and 200 to 205 cm depths and oven-dried biomass of Q. petraea roots sampled from 0 to 30 cm and at successive depths of 20 cm, up to 210 cm depth at compacted and uncompacted sites were determined. Bulk density was significantly higher at 20 to 25 cm ( g cm−3) and 100 to 105 cm ( g cm−3) depths of the compacted site. Likewise, compaction induced significant greater root biomass within the 0 to 70 cm depth with higher bulk density; root biomass at this depth was 2-fold greater compared to the uncompacted site. Root biomass decreased with soil depth and showed significant relationship with depth at both sites. The result indicates that, after 85 years of reclamation, the impact of soil compaction persisted as evident in higher bulk density and greater root biomass. Eric K. A. Twum and Seth Nii-Annang Copyright © 2015 Eric K. A. Twum and Seth Nii-Annang. All rights reserved. Impact of Brick Kilns’ Emission on Soil Quality of Agriculture Fields in the Vicinity of Selected Bhaktapur Area of Nepal Thu, 08 Oct 2015 11:58:26 +0000 The study was conducted to evaluate soil quality and impact of brick kiln on different physicochemical parameters of soils of agricultural field, located in the vicinity of Bhaktapur, Nepal. The study was carried out by determining the physicochemical characteristics of soil, soil fertility, and heavy metal contamination of soil. During the entire study period, water absorptivity of soil ranged from 2.4 to 3.3 mg/L, pH varies from 5.885 to 7.64, and organic carbon content and organic matter varied from 0.277 to 0.93%, from 0.477% to 1.603%, respectively. Nutrient content, that is, sulfate and nitrate concentration, in the soil ranged from 0.829 to 3.764 mol/L and from 0.984 to 29.99 mol/L, respectively. The findings revealed that concentrations of heavy metals (chromium and lead) were within permissible limit, although the levels were higher in soil at 50 m and decrease farther from brick kiln. However, the physical parameters and nutrient content were deficient in soil at 50 m while increasing gradually at distances of 100 m and 150 m. The variation of result obtained for physical parameters supports the fact that quality of soil in terms of heavy metal content and nutrient content was directly proportional to the distance from the kiln; that is, the quality of soil increased with increasing distance. Gunjan Bisht and Sanjila Neupane Copyright © 2015 Gunjan Bisht and Sanjila Neupane. All rights reserved. Aluminum-Tolerant Pisolithus Ectomycorrhizas Confer Increased Growth, Mineral Nutrition, and Metal Tolerance to Eucalyptus in Acidic Mine Spoil Thu, 01 Oct 2015 13:33:21 +0000 Ectomycorrhizal fungi (ECM) may increase the tolerance of their host plants to Al toxicity by immobilizing Al in fungal tissues and/or improving plant mineral nutrition. Although these benefits have been demonstrated in in vitro (pure culture) or short-term nutrient solution (hydroponic) experiments, fewer studies have examined these benefits in the field. This study examined the growth, mineral nutrition, and Al levels in two Eucalyptus species inoculated with three Pisolithus ecotypes that varied in Al tolerance (in vitro) and grown in mine spoil in the greenhouse and field. All three ecotypes of Pisolithus improved Eucalyptus growth and increased host plant tolerance to Al in comparison to noninoculated plants. However, large variations in plant growth and mineral nutrition were detected among the Pisolithus-inoculated plants; these differences were largely explained by the functional properties of the Pisolithus inoculum. Seedlings inoculated with the most Al-tolerant Pisolithus inoculum showed significantly higher levels of N, P, Ca, Mg, and K and lower levels of Al than seedlings inoculated with Al-sensitive ecotypes of Pisolithus. These findings indicate an agreement between the fungal tolerance to Al in vitro and performance in symbiosis, indicating that both ECM-mediated mineral nutrient acquisition and Al accumulation are important in increasing the host plant Al tolerance. Louise Egerton-Warburton Copyright © 2015 Louise Egerton-Warburton. All rights reserved. Characterization of Potential Plant Growth Promoting Rhizobacteria Isolated from Maize (Zea mays L.) in Central and Northern Benin (West Africa) Sun, 06 Sep 2015 09:04:04 +0000 Our study aims to characterize Plant Growth Promoting Rhizobacteria (PGPR) isolated from maize roots in five agroecological zones of central and northern Benin. Sixty samples were collected at the rate of four samples per village and three villages per agroecological zone. Rhizobacteria strains were isolated from these samples and biochemically characterized. These strains were analyzed for some of their PGPR traits like ammonia production and hydrogen cyanide following conventional methods. Microbiological investigation of these samples has shown that maize rhizospheres in central and northern Benin contain a high diversity of microorganisms. A total of nine species of maize Plant Growth Promoting Rhizobacteria were identified. Those PGPR include five Bacillus species (B. polymyxa, B. pantothenticus, B. anthracis, B. thuringiensis, and B. circulans), three Pseudomonas species (P. cichorii, P. putida, and P. syringae), and Serratia marcescens. The microbial diversity does not depend on the soil types. The microbial density, generally high, varies according to both soil types and agroecological zones. All Serratia strains (100%) have produced ammonia, whereas 80% of Bacillus and 77.77% of Pseudomonas produced this metabolite. The hydrogen cyanide was produced by all isolates (100%) independent of their genus. These results suggest the possibility to use these rhizobacteria as biological fertilizers to increase maize production. Nadège A. Agbodjato, Pacôme A. Noumavo, Farid Baba-Moussa, Hafiz A. Salami, Haziz Sina, Alphonse Sèzan, Honoré Bankolé, Adolphe Adjanohoun, and Lamine Baba-Moussa Copyright © 2015 Nadège A. Agbodjato et al. All rights reserved. Soil Carbon Accumulation and CO2 Flux in Experimental Restoration Plots, Southern Iceland: Comparing Soil Treatment Strategies Sun, 23 Aug 2015 12:12:14 +0000 Experimental plots were established on severely eroded land surfaces in Iceland in 1999 to study the rates and limits of soil carbon sequestration during restoration and succession. The carbon content in the upper 10 cm of soils increased substantially during the initial eight years in all plots for which the treatments included both fertilizer and seeding with grasses, concomitant with the increase in vegetative cover. In the following five years, however, the soil carbon accumulation rates declined to negligible for most treatments and the carbon content in soils mainly remained relatively constant. We suggest that burial of vegetated surfaces by aeolian drift and nutrient limitation inhibited productivity and carbon sequestration in most plots. Only plots seeded with lupine demonstrated continued long-term soil carbon accumulation and soil CO2 flux rates significantly higher than background levels. This demonstrates that lupine was the sole treatment that resulted in vegetation capable of sustained growth independent of nutrient availability and resistant to disruption by aeolian processes. Lawrence H. Tanner, Morgan Nivison, Olafur Arnalds, and Kristin Svavarsdóttir Copyright © 2015 Lawrence H. Tanner et al. All rights reserved. Biosolids Soil Application: Agronomic and Environmental Implications 2014 Mon, 11 May 2015 06:49:14 +0000 Silvana Torri, Rodrigo Studart Corrêa, Giancarlo Renella, Alejandro Vadecantos, and Leonid Perelomov Copyright © 2015 Silvana Torri et al. All rights reserved. Surface-Applied Biosolids Enhance Soil Organic Carbon and Nitrogen Stocks but Have Contrasting Effects on Soil Physical Quality Tue, 05 May 2015 13:46:37 +0000 Mid- to long-term impacts of land applying biosolids will depend on application rate, duration, and method; biosolids composition; and site-specific characteristics (e.g., climate, soils). This study evaluates the effects of surface-broadcast biosolids application rate and duration on soil organic carbon (SOC) stocks, soil aggregate stability, and selected soil hydraulic properties in a municipally operated, no-till forage production system. Total SOC stocks (0–45 cm soil) increased nonlinearly with application rate in perennial grass fields treated for 8 years with 0, 20, 40, or 60 Mg of Class B biosolids (DM) ha−1 yr−1 (midterm treatments). Soil organic C stocks in long-term treatment fields receiving 20 years of 20 Mg ha−1 yr−1 were 36% higher than those in midterm fields treated at the same rate. Surface-applying biosolids had contrasting effects on soil physical properties. Soil bulk density was little affected by biosolids applications, but applications were associated with decreased water-stable soil aggregates, increased soil water retention, and increased available water-holding capacity. This study contrasts the potential for C storage in soils treated with surface-applied biosolids with application effects on soil physical properties, underscoring the importance of site-specific management decisions for the beneficial reuse of biosolids in agricultural settings. Virginia L. Jin, Kenneth N. Potter, Mari-Vaughn V. Johnson, R. Daren Harmel, and Jeffrey G. Arnold Copyright © 2015 Virginia L. Jin et al. All rights reserved. Residual Effects of Lime- and Clay-Amended Biosolids Applied to Coarse-Textured Pasture Soil Tue, 05 May 2015 13:45:51 +0000 This study investigated whether there was residual effect of application of lime- and clay-amended biosolids (LaBC®) on ryegrass growth and soil microbial biomass in a coarse-textured, acid pasture soil. Reapplied LaBC® increased fertiliser-use efficiency and plant growth in this glasshouse experiment. Soil management history was established with a single application of LaBC® (50 t ha−1 wet weight equivalent) with or without inorganic fertiliser (NPK) prior to growing annual ryegrass for 5 cycles. In cycle 6 there was no residual nutrient effect of the original application of LaBC® but there was a residual liming effect of the previously applied LaBC®. A nutrient effect of reapplied LaBC® in plant growth cycle 6, had little residual benefit in cycle 7. The residual concentration of inorganic N remaining in this coarse-textured acid soil after a single application of LaBC® was negligible and did not appear to be a risk to the environment when applied at 50 t ha−1 wet weight equivalent. Sanjutha Shanmugam and Lynette K. Abbott Copyright © 2015 Sanjutha Shanmugam and Lynette K. Abbott. All rights reserved. Potential for Recycling Nutrients from Biosolids Amended with Clay and Lime in Coarse-Textured Water Repellence, Acidic Soils of Western Australia Tue, 05 May 2015 11:27:04 +0000 Application of biosolids in soils is an efficient method of recycling nutrients from biosolids and it is considered even safer when it is modified after mixing and diluting with other suitable soil organic amendments. A variety of soil organic amendments, such as green manures and composts, are used for modifying and co-composting with biosolids. However, these may not be considered as appropriate biosolids disposal and remedial measures for soils with unique problems such as low soil pH, water repellence nature, and poor water and nutrient retention capacities due to soil textural issues. Historically, soil amendments such as lime, clay, and recently biochar are being applied for such problematic soils at Western Australia and these researches focused mostly on improvement in soil physical and chemical properties. However, studies with potential for applying modified biosolids with these amendments are not complete yet. This review focused on identifying such gaps in these studies from over 170 peer-reviewed key research and review articles published over decades to latest in these areas. Sanjutha Shanmugam and Lynette K. Abbott Copyright © 2015 Sanjutha Shanmugam and Lynette K. Abbott. All rights reserved. Agronomic Efficiency of Biosolid as Source of Nitrogen to Banana Plants Tue, 05 May 2015 08:39:27 +0000 Sewage sludge (SS) or biosolid has been studied as source of nutrient for several different plant species. It also contributes to soil fertility recycling organic matter and plant nutrients. This followup work examines a three-year (2001–2004) field experiment designed to evaluate the response of banana plants (Cavendish subgroup) to the application of biosolid as source of nitrogen. The treatments consisted of control (mineral PK, no N), three rates of sludge, and two rates of mineral NPK fertilizer. Plant and soil N concentration, fruit yield, plant height, stem diameter, and foliar endurance index were measured. Fruit yield with mineral fertilization or sludge applications did not differ statistically . Application of biosolid resulted in statistically significant higher agronomic efficiency in comparison to mineral fertilizers. The concentration of soil mineral nitrogen increased using mineral fertilizer or sludge until 0.80 m after three years of application. The effect of the source of N was smaller than the effect of the rate. Biosolid can be used as source of N for banana growers. Luiz Antonio Junqueira Teixeira, Ronaldo Severiano Berton, Aline Reneé Coscione, Luis Alberto Saes, and Marcio Koiti Chiba Copyright © 2015 Luiz Antonio Junqueira Teixeira et al. All rights reserved. Influence of NaCl-Induced Salinity and Cd Toxicity on Respiration Activity and Cd Availability to Barley Plants in Farmyard Manure-Amended Soil Tue, 05 May 2015 06:38:10 +0000 The objective of this study was to evaluate the Cd availability and toxicity as affected by NaCl-induced salinity and farmyard manure addition. The Cd availability and toxicity were investigated in greenhouse pot and incubation experiments were conducted on a calcareous loamy sand soil contaminated with Cd (0.5, 1.5, 3, 6, 12, and 24 mg kg−1 of soil) and amended with two rates of 0.0 and 30 g farmyard manure (FYM) kg−1. Barley seeds (Hordeum vulgare L.) were sown in pots and irrigated with water containing different levels of salinity (0, 30, 60, and 120 mM NaCl). The results revealed that the DTPA-extractable Cd and its content in barley plant shoots tended to increase in line as Cd was applied and salt levels increased. Elevated decreases in the soil basal respiration with increased Cd applied and NaCl-induced salinity were found. However, applying FYM significantly reduced Cd availability and increased plant growth and soil respiration activity. The results clearly showed that adding farmyard manure as soil organic amendment decreased the availability of Cd to barley plants and mitigated the toxicity of both Cd and salinity to soil microbial activity. Adel R. A. Usman Copyright © 2015 Adel R. A. Usman. All rights reserved. Effectiveness of Extractants for Bioavailable Phosphorus in Tropical Soils Amended with Sewage Sludge Mon, 04 May 2015 12:18:41 +0000 Urban wastes such as sewage sludge can be an economically viable alternative source for providing macro- and micronutrients to plants in tropical conditions. Sewage sludge is normally rich in phosphorus (P), which is present in soils mainly in organic forms, so that it is very important to establish methods for estimating its availability to plants. This study aimed to test three extractants that simulate P-uptake by maize (Zea mays) cropped in plots after 13 consecutive years of fertilization with sewage sludge, in a cycle of fertilized sugarcane (Saccharum L.) amended with sewage sludge and organic compost. Soil samples were collected at depths of 0–10, 10–20, and 20–40 cm in March 2010 from the two experimental areas. Soil P was extracted via ion exchange resin, Mehlich-I, and 0.025 M H2SO4 and determined via colorimetry. Maize and sugarcane diagnostic leaves were collected in the experiments, subjected to nitric-perchloric digestion, and the leaf-P content was determined via colorimetry. No significant correlations were found between phosphorus extracted from soils and phosphorus concentrations in diagnostic leaves. Resin extracted larger amounts of P in the short-term experiment, while acidic extractants yielded larger amounts in the long-term experiment. Roberta Corrêa Nogueirol, Wanderley José de Melo, Edna Ivani Bertoncini, and Luís Reynaldo Ferracciú Alleoni Copyright © 2015 Roberta Corrêa Nogueirol et al. All rights reserved. Seasonal Dynamics of N, P, and K in an Organic and Inorganic Fertilized Willow Biomass System Mon, 04 May 2015 12:09:19 +0000 The seasonal variations in soil nutrient supply and bioavailability were assessed in a willow biomass crop (Salix miyabeana, SX64) treated with 150 and 200 kg available N ha−1 of commercial fertilizer (CF), biosolid compost (BC), dairy manure (DM), and control (CT0) at Delhi, NY. Plant root simulator probes were used to measure nutrient supply (inside) and bioavailability (outside) of root exclusion cylinders. Measurements were made in September 2008 and May, August, and October of 2009. Soil moisture content (θd) and foliar nutrient concentrations were also determined. The BC treatments increased soil P supply more than CF and CT0. The supply of and K in the soil increased in August but their bioavailability increased in May and October. Soil and P supply and bioavailability were both high in May. Foliar N and K concentrations were significantly high in May and low in August which could be due to dilution effect caused by increased soil moisture foliar dry weight. Foliar P concentrations increased in September and October. The observed higher soil mineralization and plant uptake in May suggest that in high soil conditions willow biomass crops can level and minimize leaching out of the root zone into groundwater. Amos K. Quaye, Timothy A. Volk, and Jeff J. Schoenau Copyright © 2015 Amos K. Quaye et al. All rights reserved. N Mineralisation from Bioresources Incubated at 12.5°C Mon, 04 May 2015 11:59:45 +0000 Soils treated with lime-amended biosolids (LAB), poppy seed waste (PSW), anaerobically digested biosolids (ADB) and poppy mulch (PM) and incubated at 12.5°C for 56 days released 45%, 36%, 25%, and −8%, respectively, of total applied N as plant available nitrogen (PAN) by the end of the incubation. The mineralisation rates were contrary to expectations based on the C : N ratios of the four products: LAB (5 : 1), PSW (7 : 1), ADB (3 : 1), and PM (16 : 1). PM showed a significant negative priming effect over the incubation period. These results have implications for production agriculture in temperate regions where application and incorporation of bio-resources traditionally occurs in autumn and spring when soil and air temperatures are relatively low. Current application times may not be suitable for nitrogen release to satisfy crop demand. S. W. Ives, L. A. Sparrow, W. E. Cotching, R. B. Doyle, and S. Lisson Copyright © 2015 S. W. Ives et al. All rights reserved. Soil Microbial Community Structure and Target Organisms under Different Fumigation Treatments Thu, 26 Mar 2015 09:57:07 +0000 Producers of several high-value crops in California rely heavily on soil fumigants to control key diseases, nematodes, and weeds. Fumigants with broad biocidal activity can affect both target and nontarget soil microorganisms. The ability of nontarget soil microorganisms to recover after fumigation treatment is critical because they play an important role in sustaining the health of agricultural and natural soil systems. Fumigation trial was conducted in Parlier, CA, and the study focuses on the effects of different rates of Telone C35 and also methyl bromide fumigation with polyethylene (PE) and totally impermeable film (TIF) tarps on target and nontarget soil microorganisms using field samples. Results indicated that the populations of target organisms, such as Fusarium oxysporum and Pythium spp., were reduced at all rates of fumigants. Phospholipid fatty acid (PLFA) analysis indicated that all major nontarget soil microbial groups such as Gram positive bacteria, Gram negative bacteria, fungi, and arbuscular mycorrhizal fungi (AMF) were affected by methyl bromide (MeBr) fumigation treatment. In general, the effects of Telone C35 (299 L/ha) under PE tarp had the least impact on microbial community structure and better effect on controlling target microorganisms and, therefore, indicated the better option among fumigation treatments. Sadikshya R. Dangi, James S. Gerik, Rebecca Tirado-Corbalá, and Husein Ajwa Copyright © 2015 Sadikshya R. Dangi et al. All rights reserved. Phosphorus Status, Inorganic Phosphorus Forms, and Other Physicochemical Properties of Acid Soils of Farta District, Northwestern Highlands of Ethiopia Mon, 16 Mar 2015 16:24:43 +0000 Soil acidity and low availability of P limit crop production in the highlands of Ethiopia. The objective of this study was to determine the P status, distribution and forms of inorganic P and relate them to selected chemical properties of eight representative acidic surface soil samples from Farta District. Soil pH (H2O) varied between 4.74 and 5.50. The moderate to high CEC suggests that besides kaolinite, the soils also contain expandable 2 : 1 clay minerals. Though the total P content was high, the available Olsen P content was very low or low in all soils except one. In most soils, the abundance of inorganic P fractions was as follows: P bound by oxalate extractable iron (-P) reductant soluble Fe-P occluded Al-Fe-P P bound by oxalate extractable aluminum (-P) calcium bound P (Ca-P). Olsen P had a very strong positive correlation () with -P (), -P (), and oxalate extractable P (). Though Fe bound P reserves were quite abundant and the degree of P saturation of + (median 3.3%) was moderate, the extremely low P saturation of (median 0.5%) explains the P deficiency of the soils. Asmare Melese, Heluf Gebrekidan, Markku Yli-Halla, and Birru Yitaferu Copyright © 2015 Asmare Melese et al. All rights reserved. Artificial Neural Networks for Estimating Soil Water Retention Curve Using Fitted and Measured Data Mon, 16 Mar 2015 13:31:20 +0000 Artificial neural networks for estimating the soil water retention curve have been developed considering measured data and require a large quantity of soil samples because only retention curve data obtained for the same set of matric potentials can be used. In order to preclude this drawback, we present two ANN models which tested the performance of ANNs trained with fitted water contents data. These models were compared to a recent new ANN approach for predicting water retention curve, the pseudocontinuous pedotransfer functions (PTFs), which is also an attempt to deal with limited data. Additionally, a sensitivity analysis was carried out to verify the influence of each input parameter on each output. Results showed that fitted ANNs provided similar statistical indexes in predicting water contents to those obtained by the pseudocontinuous method. Sensitivity analysis revealed that bulk density and porosity are the most important parameters for predicting water contents in wet regime, whereas sand and clay contents are more significant in drier conditions. The sensitivity analysis for the pseudocontinuous method demonstrated that the natural logarithm of the matric potential became the most important parameter, and the influences of all other inputs were reduced to be not relevant, except the bulk density. Tirzah Moreira de Melo and Olavo Correa Pedrollo Copyright © 2015 Tirzah Moreira de Melo and Olavo Correa Pedrollo. All rights reserved.