A Comparison of Super-Valid Restricted and Row–Column Randomization

In complete block experiments, treatments are often randomized within blocks without any other restrictions. When the blocks are rows of plots and the blocks are laid out in parallel so that also columns of plots are formed, there might be random effects of both rows and columns. In this situation, a row–column design is a natural choice. Super-valid restricted randomization is another option. This article compares these randomization procedures for small complete block experiments (5–10 treatments in 3–6 blocks). Validity of a randomization procedure is defined for mixed-effects models. The two randomization procedures are compared with regard to average variance in pairwise comparisons. Row–column randomization is recommended when either there are at least four replicates, or the number of replicates is three and intercolumn variance is not known to be small. These conclusions assume a model with fixed effects of treatments and random effects of rows and columns, and estimation using the REML method and the Kenward and Roger approximation.     

The Odd–Even Behaviour of Dicarboxylic Acids Solubility in the Atmospheric Aerosols

The solubility and the enthalpy of dicarboxylic acids have been determined in water at intervals between 278.5 and 543.5 K. At 298.15 K, the values derived were: Δ_sol H _m (m?=?1.33 mol kg^?1)?=?29.80 kJ mol^?1for oxalic acid; Δ_sol H _m (m?=?16.03 mol kg^?1)?=?12.82 kJ mol^?1 for malonic acid; Δ_sol H _m (m?=?0.75 mol kg^?1)?=?28.20 kJ mol^?1 for succinic acid; Δ_sol H _m (m?=?8.77 mol kg^?1)?=?48.01 kJ mol^?1 and Δ_sol H _m (m?=?0.17 mol kg^?1)?=?40.30 kJ mol^?1 for glutaric and adipic acid respectively. The solubility value exhibits a prominent odd–even effect with respect to terms with even number of carbon atoms with the odd carbon numbers showing much higher solubility. Observations made in the atmospheres suggest that this odd–even effect may have implications for the relative abundance of these acids in aerosols.     

Soil‐Test Methods for Florida Sands Treated with an Aluminum–Water Treatment Residual and Various Phosphorus Sources

Use of aluminum (Al)–rich water treatment residuals (Al‐WTR) has been suggested as a practice to immobilize excessive phosphorus (P) in Florida soils that could represent an environmental hazard. Fertilizer P requirements can differ in WTR‐amended and unamended soil, so careful selection of soil‐testing methodology is necessary. Acidic extractants can dissolve WTR sorbed P and overestimate plant‐available P. We evaluated the suitability of the Mehlich 1 P (M‐1P) and other agronomic soil‐test procedures in an Al‐WTR‐treated Florida soil. Bahiagrass (paspalum notatum Fluggae), ryegrass (Lolium perenne L.), and a second bahiagrass crop were grown in succession in a Florida topsoil amended with four sources of P at 44 kg P ha^?1 (P‐based rates) and 179 kg PAN ha^?1 [nitrogen (N)–based rates] and three WTR rates (0, 10, and 25 g kg^?1 oven‐dry basis). Both water‐extractable P (WEP) and iron (Fe) strip P (ISP), but not M‐1P, values of soil sampled at planting of each grass were greater in the absence than in the presence of WTR. Total plant P uptake correlated with WEP (r² = 0.82^***) and ISP (r² = 0.75^***), but not M‐1P (r² = 0.34^***). Correlations of the dry‐matter yield, P concentration, and P uptake of the first bahiagrass were also better with WEP and ISP than with M‐1P values. However, regression of plant responses with M‐1P improved after the first crop of bahiagrass. Both WEP and ISP values were better predictors of available soil P than M‐1P in a field study with same four P sources surface applied to established bahiagrass at the same two P rates, with and without WTR. Both WEP and ISP are recommended as predictors of P adequacy in soils treated with WTR, especially for soils recently (< 5 months) treated with Al‐WTR.     

The Effect of Treatment with Hydrogen Peroxide and the Mehra–Jackson Reagent on X-ray Diffraction Patterns of Clay Fractions

X-ray diffraction patterns of clay fractions from the AEL and EL horizons of pale-podzolic soil before and after treatment with 10% H₂O₂ and the Mehra–Jackson reagent in different sequences have been examined. The successive treatment with 10% H₂O₂ and then with the Mehra–Jackson reagent causes dissolution of Al-hydroxy-interlayers in pedogenic chlorites and the respective increase in the content of labile minerals because of a dramatic decrease in pH upon the treatment with hydrogen peroxide. The rate of these changes depends on the degree of chloritization of pedogenic chlorites in the initial samples. The result of the reverse sequence of the treatments of clay fractions (initially with the Mehra–Jackson reagent and then with hydrogen peroxide) is opposite: the chloritization of labile minerals becomes more intensive. It is provided by pH values that do not drop below 7.5 at any treatment stage. At particular stages, pH values favors the mobilization of Al compounds and their subsequent polymerization in the interlayer space of labile structures. We suppose that hydroxyl-aluminosilicate layers may be formed in the interlayer space upon this treatment sequence.     

Treatment of Olive Oil Mill Wastewater by Silica–Alginate–Fungi Biocomposites

Olive oil mill wastewater (OMW) generates a wide variety of pollutants depending on the production process and other factors such as olive varieties and cultivation system. Efforts to mitigate the impact of these effluents in the environment have been made by developing more efficient treatment systems in terms of removal of chemical oxygen demand (COD), color, organic compounds, and toxicity. This study is the first that reports the potential of a treatment of OMW by biocomposites of silica?Calginate?Cfungi (Pleurotus sajor caju and Trametes versicolor). The treatment by biocomposites can be considered as a three-step process responsible for the removal of the compounds: (1) adsorption of reactants on the monolithic structure and diffusion to the biological active sites, (2) biodegradation by the fungi, and (3) diffusion of the products resulting from the biodegradation. Both treatments tested showed potential capacity to remove organic compounds, color, COD, and toxicity. The T. versicolor biocomposites were the most effective and responsible for the reduction in color (from 38.4 to 44.9?%), COD (from 42.8 to 63.8?%), and total phenolic content (from 85.3 to 88.7?%) after 29?days of treatment. The toxicity reduction on Portuguese OMW was minimal, but the use of composites on the Moroccan OMW caused a 9.5- to 19-fold reduction in toxicity. Furthermore, the biocomposites showed potential for re-utilization for more 29?days of treatment.     

Leaching and Transformation of Nitrogen Fertilizers in Soil After Application of N with Irrigation： A Soil Column Method

A soil column method was used to compare the effect of drip fertigation （the application of fertilizer through drip irrigation systems, DFI） on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation （SFI）, and to study the leaching loss and transformation of three kinds of nitrogen fertilizers （nitrate fertilizer, ammonium fertilizer, and urea fertilizer） in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N （NH4^＋-N ＋ NO3^--N） in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control （without urea addition）, on the first day when soils were fertigated with urea, there were increases in NH4^＋-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4^＋-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4^＋-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4^＋-N fixation or volatilization in the soil during the fertigation process.     

Cavity spot of carrots ‐ an association with soil ammonium

Abstract

Cavity spot incidence on sixteen samples of carrots from four fields was found to be correlated with soil ammonium (r = + .78***) and pH (r = ‐ .63**). The calcium concentration in the carrots related to soil ammonium (r = ‐ .65**), but not to cavity spot incidence. Soil nitrate and ammonium were positively associated with each other (r = + .63**), and their ratio (NH₄/NO₃) was very highly correlated with exchangeable manganese (r = + .93***) suggesting that anaerobicity was present.     

A Laboratory Column Study on the Biodegradation of Toluene and Methyl tert–Butyl Ether: The Effect of Substrate Interactions

Soil vapor extraction (SVE) is one of the most effective remediation technologies for soil and groundwater contamination. Soil particles can be mobilized by air perturbation during SVE, resulting in the differentiation of porous media, which has not been well addressed. This paper developed a numerical method to study the flow pattern and quantify the change of porous media for the first time. Based on the mass equilibrium and Darcy’s law, a two-phase water–air flow model was constructed with integration of saturation, relative permeability, and capillary pressure during SVE. Relationship between porosity and saturation was deduced and coupled with the two-phase flow model for quantifying change of porous media in real time. Results reveal that both porosity and permeability increase sharply in the early stage of SVE then gradually to a quasi-steady state. These increases in vadose zone tapered off with distance from the SVE screen and the steady period occurred later as well. The influence radius of a single SVE well and the change degree in porosity and permeability of media were proportional to the extraction vacuum and the driving coefficient C, which is more sensitive than extraction vacuum according to the simulation results. Knowledge from this modeling exercise provides a useful tool to estimate the change of remediated zone and assess the environmental risk of remedial activities at real-world contamination sites.     

Distribution and Availability of Heavy Metals in Raw and Acidulated Phosphate Rock–Amended Soils

Abstract

The effectiveness of the application of raw (PR‐1), and partially acidulated phosphate rock (PR), at 25% (PR‐25) and at 50% (PR‐50), was investigated to reduce extractability and plant uptake of Pb, Cd, Cu, Ni, and Zn in three calciorthids soils.Furthermore, the effects of soil treatments on metal extractability were evaluated by sequential extraction. Similarly, such effects were assessed on the phytoavailability of metals of maize (Zea mays L.) through a pot experiment. Water‐soluble and exchangeable metal fractions (the bioavailable fractions) were influenced distinctively by PR treatments and soil properties. In addition, decrease of soluble and exchangeable metal fractions was compensated by an increase in metal extracted from other fractions. Most bioavailable soil metals correlated significantly with their associated level in plant tissue. Finally, plant metal uptake decreased with PR treatments, suggesting that PR application was likely to be effective in controlling metal immobilization in these soils.     

Nonparametric Threshold Model of Zero-Inflated Spatio-Temporal Data with Application to Shifts in Jellyfish Distribution

There is increasing scientific interest in studying the spatial distribution of species abundance in relation to environmental variability. Jellyfish in particular have received considerable attention in the literature and media due to regional population increases and abrupt changes in distribution. Jellyfish distribution and abundance data, like many biological datasets, are characterized by an excess of zero counts or nonstationary processes, which hampers their analyses by standard statistical methods. Here we further develop a recently proposed statistical framework, the constrained zero-inflated generalized additive model (COZIGAM), and apply it to a spatio-temporal dataset of jellyfish biomass in the Bering Sea. Our analyses indicate systematic spatial variation in the process that causes the zero inflation. Moreover, we show strong evidence of a range expansion of jellyfish from the southeastern to the northwestern portion of the survey area beginning in 1991. The proposed methodologies could be readily applied to ecological data in which zero inflation and spatio-temporal nonstationarity are suspected, such as data describing species distribution in relation to changes of climate-driven environmental variables. Some supplemental materials including an animation of jellyfish annual biomass and web appendices are available online.     

Interaction of Magnesium–Iron–Carbonic-Layered Double Hydroxides with As(III)

Static granular bed reactor (SGBR) and upflow anaerobic sludge blanket (UASB) reactor were demonstrated at mesophilic condition for the treatment of pulp and paper mill wastewater. The hydraulic retention times (HRTs) were varied from 4 to 24 h following 29-day start-up period. The overall chemical oxygen demand (COD) removal efficiency of the SGBR was higher than the UASB during this study. At 4 h HRT, the COD removal was greater than 70 % for the SGBR and 60 % for the UASB. Biomass yield and volatile fatty acids concentration of SGBR were slightly less than UASB at organic loading rates ranging from 1.2 to 5.1 kg/m³/day. The results indicated that the SGBR system can be considered a viable alternative system for anaerobic treatment for pulp and paper wastewater.     

Removal of Cyanide and Zinc–Cyanide Complex by an Ion-Exchange Process

Removal efficiencies of cyanide and a zinc–cyanide complex in solutions were studied by using an ion-exchange process at pH 10.0 and 12.0. An anion-exchange resin, AMBERLITE® IRA-402 Cl, was used to perform packed bed continuous experiments. For the initial 200 mg/l cyanide solution, the packed bed gave a cyanide effluent concentration of 0.2 mg/l at 80 bed volumes for both pH 10.0 and 12.0. Comparatively, in the mixture of 200 mg/l cyanide and 100 mg/l zinc, packed bed volumes were obtained as 80 and 90 at pH 10.0 and 12.0, respectively, to have 0.2 mg/l cyanide effluent concentrations. The packed beds were exhausted at 250 and 400 bed volumes for cyanide and zinc–cyanide complex solutions, respectively. Speciation calculations in Zn(II)/cyanide/OH^? were used to interpret the results. The exchange capacities of the resin were determined as ～1.2 and ～0.9 meq/ml resin for cyanide and zinc–cyanide complex solutions, respectively, and were independent of pH in the studied pH range.     

Potassium Release in an Aeric Haplaquept as Influenced by Long-Term Rice–Rice Cropping with Different Rates of Fertilizers and Manuring

Different fractions of potassium (K) and the kinetics of K release as influenced by 21 cycles of rice–rice cropping with different rates of fertilizers and manuring were investigated on an Aeric Haplaquept (kaolinitic Inceptisol) soil profile from Bhubaneswar, India. The neutral 1 N ammonium acetate–extractable K in the surface soil layer (0–15 cm) increased from its initial value of 11.2 mg K kg^?1 to 14.8, 14.2, and 17.5 mg K kg^?1 soil in different treatments. However, the nonexchangeable K content in the surface soil layer dropped considerably to a level of 4.8–20.0 mg K kg^?1 soil. Cumulative nonexchangeable K release after 121 h of extraction with 0.01 M calcium chloride (CaCl₂) was <14 mg K kg^?1. The first-order kinetic model best described the nonexchangeable K release. The decrease in pH and increase in iron (Fe) content indicated the possibilities of K supply to plants through the dissolution of soil minerals.     

Evaluation of the Physical–Chemical Characteristics of Wastewater After Disinfection with Peracetic Acid

Water, Air, &; Soil Pollution - The use of peracetic acid (PAA) in the disinfection of sanitary effluents has been proposed by various authors. However, there are still doubts about its...     

Distribution and Accumulation of Copper and Cadmium in Soil–Rice System as Affected by Soil Amendments

The effects of seven amendments on the distribution and accumulation of copper and cadmium in a soil–rice system were investigated using a pot experiment. Results showed that application of limestone, calcium magnesium phosphate (Ca–Mg–P fertilizer), calcium silicate (silicon fertilizer), Chinese milk vetch, pig manure, and peat significantly decreased the concentrations of Cu and Cd in rice roots by 24.8–75.3% and 9.7–49.9%, respectively. However, no significant difference was observed between zinc sulfate (zinc fertilizer) and the control treatment. The concentrations of Cu and Cd in different parts of rice followed the order: root > straw > grain, and all amendments restrained the transfer of Cu and Cd from rice root to stem. Copper and Cd concentrations in rice stems at the tillering stage were the highest, and then decreased from the tillering stage to the heading stage. However, they increased again at the ripening stage. The results also showed that application of amendments changed Cu and Cd solubility in soil and decreased their bioavailability, which resulted in the reduction of Cu and Cd uptake by rice. Significant correlations between the concentrations of Cu and Cd in soil solutions and in rice stems were found. The result demonstrated that limestone has the best efficiency among all the amendments used in reducing Cu and Cd contamination to rice production.     

Treatment of High Ammonium–Nitrogen Wastewater from Composting Facilities by Air Stripping and Catalytic Oxidation

Composting municipal wastewater sludge may generate composting wastewater (acid washer water and tunnel wastewater) with high ammonium–nitrogen (NH₄–N) concentration; this kind of wastewater is usually generated in a rather small daily amount. A procedure of air stripping with catalytic oxidation was developed and tested with pilot-scale and full-scale units for synthetic disposal of the high NH₄–N wastewaters from composting facilities. In air stripping, around 90% NH₄–N removal efficiency was reliably achieved with a maximum of 98%. A model to describe the stripping process efficiency was constructed, which can be used for process optimization. After catalytic oxidation, the concentrations in the outlet gas were acceptable for NH₃, NO_X, NO₂, and N₂O, but the NH₃ and N₂O concentrations limited the feasible loading range. The treatment costs were estimated in detail. The results indicate that air stripping with the catalytic oxidation process can be applied for wastewater treatment in composting facilities.     

Vertical Distribution of Sulfur Fractions in a Continuously Fertilized Acid Alfisol Under Maize​–Wheat Cropping System

Vertical distribution of sulfur fractions was studied in a long-term fertilizer experiment at the experimental farm of Department of Soil Science, Himachal Pradesh Agricultural University, Palampur (India), comprising various combinations of fertilizer and amendments. Initially, available nitrogen (N) was high, and phosphorus (P), potassium (K), organic carbon were optimum. Different forms, viz., available, water-soluble, heat-soluble, organic, and total sulfur were significantly affected by continuous cropping and decreased with depth. However at surface layer, 100% NPK(-S) resulted in 67%, 70%, 34%, 47%, and 48% reduction in these fractions, respectively, as compared to 100% NPK. Among all, organic sulfur was recorded highest. Hundred percent NPK + farmyard manure (at par with 100% NPK + lime) recorded highest maize and wheat yield. Hundred percent NPK(-S) recorded 39% and 44% reduction in grain yield of maize and wheat as compared to 100% NPK, respectively. Sulfur fractions were positively and significantly correlated with yield of maize?–wheat which shows the importance of sulfur fertilization.     

Combining X-ray computed tomography with relevant techniques for analyzing soil–root dynamics – an overview

The study of below-ground features of roots and soil and their interactions is essential for understanding the configuration and diversities in such a dynamic environment. X-ray computed tomography is recognized as a tool for visualizing the physical interactions in the soil. In many studies, it has been used as a stand-alone tool to describe soil and root parameters. However, in recent times, attempts to couple it with other complementary tools are gaining rapid interest among researchers. The paper therefore provides an overview of the major application of combining X-ray computed tomography with other relevant methods in analyzing the structural characteristics of roots and soil media. The relevance of using this multidisciplinary approach for unraveling the mysteries surrounding root–soil dynamic interactions is stressed. The current and future trends of such studies are also pointed out.     

Distribution of Forms of Zinc and Their Association with Soil Properties and Uptake in Different Soil Orders in Semi‐arid Soils of Punjab,India

Abstract

Profiles of semi‐arid–zone soils in Punjab, northwest India, were investigated for different forms of zinc (Zn), including total, diethylenetriamine penta‐acetic acid (DTPA)-extractable, soil solution plus exchangeable (Zn), Zn adsorbed onto inorganic sites, Zn bound by organic sites, and Zn adsorbed onto oxide surfaces. Irrespective of the different fractions of Zn present, its content was higher in fine‐textured Alfisols and Inceptisols than in coarse‐textured Entisols. In general, the higher content of Zn was observed in the surface horizon and then decreased in the subsurface horizons. However, none of the forms of Zn exhibited any consistent pattern of distribution. Organic matter and size fractions (clay and silt) had a strong influence on the distribution of different forms of Zn. Based upon the linear coefficient of correlation, the soil solution plus exchangeable Zn, adsorbed onto inorganic sites, and DTPA‐Zn increased with increase in organic carbon but decreased with increase in pH and calcium carbonate content. Total Zn increased with increase in clay and silt content. Among the different forms, Zn bound by organic sites, water soluble plus exchangeable Zn and Zn adsorb onto oxide (amorphous surfaces) were all correlated with DTPA extractable Zn. The uptake of Zn was more in recent floodplain Entisols than very fine textured Alfisols and Inceptisols. Among the different forms soil solution +exchangeable and DTPA‐extractable Zn was positively correlated with total uptake of Zn.     

Sodium hydroxide-tetraborate in comparison with sodium pyrophosphate as an extractant of “complexes” characteristic of spodic horizons

Sodium hydroxide-tetraborate at pH 9.7 was found not to be a suitable extractant of the amorphous substances characteristic of podzolic B horizons as defined in Canada. Similarly, it does not appear to be a useful basis of a criterion for differentiating spodic horizons as defined in the United States. Hydroxide-tetraborate extracted very little Al and Fe from about half of the podzolic B horizons tested. Compared with pyrophosphate, it extracted from 2 to 50% as much Fe and from 10 to 70% as much Al. Furthermore, hydroxide-tetraborate extracted only small proportions of the Fe and Al from synthetic Fe- and Al-fulvic acid products tested.Evidence regarding the relative specificaties for organic-complexed Al and Fe of hydroxide-tetraborate and sodium pyrophosphate is considered. Deductions about the genesis of podzolic soils based upon experiments with hydroxide-tetraborate are discussed in relation to other evidence.