EFFECTS OF ORGANIC MATTER CONTENT ON EXCHANGEABLE Al AND pH-DEPENDENT ACIDITY OF VERY ACID SOILS

1977 ◽  
Vol 57 (2) ◽  
pp. 221-222 ◽  
Author(s):  
P. B. HOYT

Twenty-nine soil samples were selected within a field for similar pH (4.60–4.72) but with widely varying organic matter contents (3.5–20.5%). Exchangeable Al decreased while pH-dependent acidity increased with increasing organic matter content. The implication of these relationships for liming practices is discussed.

1976 ◽  
Vol 56 (3) ◽  
pp. 129-138 ◽  
Author(s):  
A. J. MACLEAN

The Cd concentration in 10 plant species grown in a neutral surface soil (0.65 ppm Cd) varied from 0.18 ppm in potato tubers to 0.99 ppm in soybean roots on a dry matter basis. Addition of 5 ppm Cd increased the concentrations in the plants markedly and they were particularly high in lettuce (10.36 ppm) and tobacco leaves (11.57 ppm). Cd concentrations tended to be lower in the edible portion (seed, fruit, tubers) than in other plant parts. Added Cd affected yields in only a few instances. But in another experiment, Cd added at a rate of 5 ppm to five soils decreased the yield of lettuce in most instances. In a comparison of results for two similarly managed sandy loam soils, nearly neutral in reaction but differing in organic matter content (2.17 vs. 15.95% organic C), the concentration of Cd was lower in lettuce grown in the soil with the higher amount of organic matter. The Cd content of the lettuce was reduced by liming some of the acid soils. Addition of Cd increased the concentration of Zn in the plants appreciably, but added Zn did not affect Cd uptake. In an incubation experiment comprising five soils, DTPA (diethylenetriamine-pentaacetic acid) extractable Cd decreased with liming of three Cd-treated acid soil samples. In comparisons of two sandy loam soils and of surface and subsoil layers of a sand, extractable Cd increased with higher amounts of soil organic matter.


2009 ◽  
Vol 33 (5) ◽  
pp. 1481-1488 ◽  
Author(s):  
Vanusa Maria Feliciano Jacomino ◽  
Kerley Alberto Pereira de Oliveira ◽  
Maria Helena Tirollo Taddei ◽  
Maria Célia Siqueira ◽  
Maria Eleonora Deschamps Pires Carneiro ◽  
...  

Phosphogysum (PG) or agricultural gypsum, a solid waste from the phosphate fertilizer industry, is used as soil amendment, especially on soils in the Cerrado region, in Brazil. This material may however contain natural radionuclides and metals which can be transferred to soils, plants and water sources. This paper presents and discusses the results of physical and chemical analyses that characterized samples of PG and compares them to the results found in two typical soils of the Cerrado, a clayey and sandy one. These analyses included: solid waste classification, evaluation of organic matter content and of P, K, Ca, Mg, and Al concentrations and of the mineralogical composition. Natural radionuclides and metal concentrations in PG and soil samples were also measured. Phosphogypsum was classified as Class II A - Not Dangerous, Not Inert, Not Corrosive and Not Reactive. The organic matter content in the soil samples was low and potential acidity high. In the mean, the specific 226Ra activity in the phosphogypsum samples (252 Bq kg-1) was below the maximum level recommended by USEPA, which is 370 Bq kg-1 for agricultural use. In addition, this study verified that natural radionuclides and metals concentrations in PG were lower than in the clayey Oxisol of Sete Lagoas, Minas Gerais, Brazil. These results indicated that the application of phosphogypsum as soil amendment in agriculture would not cause a significant impact on the environment.


2004 ◽  
Vol 5 (1) ◽  
pp. 31 ◽  
Author(s):  
Ana María Serralde O. ◽  
María Margarita Ramírez G.

<p>Mediante el seguimiento de cultivos experimentales en suelos ácidos de los Llanos Orientales, durante un periodo de cinco años consecutivos (1997-2001), se evaluaron las poblaciones nativas de hongos micorrícicos arbusculares (MA) asociados con dos variedades de maíz: ICA- Sikuani V-110 y la variedad regional criolla Clavito, analizando su comportamiento bajo distintos tratamientos con abono orgánico (gallinaza), abono verde (Caupí) y testigo sin aplicación de materiales orgánicos, para un total de seis tratamientos. De 7.924 esporas analizadas se aislaron veinticuatro morfotipos identificados morfológica y molecularmente. Se determinó la relación de las condiciones del suelo (pH, los contenidos de materia orgánica, P, K, Al+++ y % saturación Al) con el comportamiento de las poblaciones de MA. Con la aplicación del Análisis de Regresión Múltiple (Stepwise), se obtuvieron coeficientes significativos (P≤ 0.001 y R2 ≥ 83) para todas las variables y se seleccionaron como variables predictivas principales el pH y la materia orgánica del suelo, que presentaron coeficientes significativos para cinco y cuatro de los siete modelos establecidos, respectivamente. La técnica molecular empleada basada en la Reacción en Cadena de la Polimerasa (PCR), con el uso de primers específicos, permitió la identificación confirmatoria de las esporas aisladas de los géneros <em>Glomus, Entrophospora </em>y <em>Gigaspora</em>. Además, mediante el uso de esta metodología se logró identificar la presencia del género <em>Glomus</em>en raíces de maíz altamente colonizadas.</p><p> </p><p><strong>Mycorrhiza populations analysis in corn (<em>Zea mays</em>) cultivated in acid soils under different agronomic treatments</strong></p><p>A study was carried out to evaluate the populations of native arbuscular mycorrhizas (AM) fungi on established crops on acid soils of the Colombian Eastern Plains, for a period of five years (1997-2001). Fungi spores were isolated from the crop-fungi association of two maize cultivars: ICASikuani V-110 and the regional cultivar Clavito. The mycorrhizal behavior was evaluated under six different organic fertilization treatments, which included green manure (cowpea), chicken manure and a control treatment (no application). From a total of 7924 spores, 24 different types of mycorrhiza were characterized using morphological and molecular analysis. The relation between soil conditions (pH, organic matter contents, P, K, Al+++ and % Al saturation) and AM fungi populations was analysed using a Stepwise Multiple Regression model. According to the regression coefficients obtained (P≤ 0.001 y R2 ≥ 0.83), soil pH and organic matter content were the independent variables that explained most of the variation observed in AM populations. The molecular methodology was based on the Polymerase Chain Reaction (PCR) and the use of specific primers allowed to identify spores from <em>Glomus</em>, <em>Entrophospora </em>and <em>Gigaspora</em>. This methodology also provided the identification of fungi from the <em>Glomus </em>genera in highly colonized maize roots.</p>


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 863D-863
Author(s):  
Adou Rahim Alimi Assimiou ◽  
Léon E. Parent

In Quebec, potato crops are largely grown on light acid soils altered by podzolization. In the plow layer, abundance of sesquioxides, low pH and low organic matter content produce high P-fixing capacity. Liming to pH not exceeding 5.6, organic matter additions and banding of P fertilizers are practices to improve the P status in the soil–plant system. Plant response to treatments could be diagnosed by yield evaluation and foliar analysis. Agricultural lime, dolomitic limestone and basalt were applied to an acid soil (pH 4.6). Ordinary superphosphate, biosuperphosphate, triple superphosphate, and diammonium phosphate impregnated with humic peat were banded at two rates. Highest tuber yield was 40 t·ha–1. There was no response to liming materials as pH did not exceed 4.9. There was a significant response to P fertilizers. Nutrient balance assessment of the foliage by Compositional Nutrient Diagnosis indicated a critical “d” value of 1.5 and a critical P index of 0.8.


2004 ◽  
Vol 61 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Pedro Luís da Costa Aguiar Alves ◽  
José Marques Júnior ◽  
Antonio Sergio Ferraudo

In the soil, herbicides are submitted to absorption, leaching and degradation by physical, chemical and biological processes or absorbed by plants. All these processes are dependent on soil class and weather conditions and affect the product efficiency on weed control. The objective of this work was to investigate the influence of soil attributes on sulfentrazone efficiency for controlling purple nutsedge (Cyperus rotundus L. ). Soil samples from LVAd (Typic Haplustox), LVd, LVdf and LVef (Typic Haplustox and Typic Eutrustox), NVe (Rhodic Kandiustalf), and LVd (Typic Haplustox) were collected under two crop conditions aiming to have different clay, Fe oxides, and organic matter contents. The soil samples were submitted to granulometric, chemical and mineralogical characterization. A bioassay was used to evaluate the efficacy of sulfentrazone (1.6 L c.p. ha-1) to control purple nutsedge on pre-emergence. The sulfentrazone behaved differently among the studied soil classes. The product efficiency decreased when the soil Fe oxide content increased, following the order: LVAd, LVd, NVe, LVef and LVdf. Clay content, ranging from 240 to 640 g kg-1, and organic matter content, ranging from 12 to 78 g kg-1, did not influence sulfentrazone efficiency.


Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 209-225 ◽  
Author(s):  
P. Pereira ◽  
X. Úbeda ◽  
J. Mataix-Solera ◽  
M. Oliva ◽  
A. Novara

Abstract. Fire is a natural phenomenon with important implications on soil properties. The degree of this impact depends upon fire severity, the ecosystem affected, topography of the burned area and post-fire meteorological conditions. The study of fire effects on soil properties is fundamental to understand the impacts of this disturbance on ecosystems. The aim of this work was to study the short-term effects immediately after the fire (IAF), 2, 5, 7 and 9 months after a low-severity spring boreal grassland fire on soil colour value (assessed with the Munsell colour chart), soil organic matter content (SOM) and soil water repellency (SWR) in Lithuania. Four days after the fire a 400 m2 plot was delineated in an unburned and burned area with the same topographical characteristics. Soil samples were collected at 0–5 cm depth in a 20 m × 20 m grid, with 5 m space between sampling points. In each plot 25 samples were collected (50 each sampling date) for a total of 250 samples for the whole study. SWR was assessed in fine earth (< 2 mm) and sieve fractions of 2–1, 1–0.5, 0.5–0.25 and < 0.25 mm from the 250 soil samples using the water drop penetration time (WDPT) method. The results showed that significant differences were only identified in the burned area. Fire darkened the soil significantly during the entire study period due to the incorporation of ash/charcoal into the topsoil (significant differences were found among plots for all sampling dates). SOM was only significantly different among samples from the unburned area. The comparison between plots revealed that SOM was significantly higher in the first 2 months after the fire in the burned plot, compared to the unburned plot. SWR of the fine earth was significantly different in the burned and unburned plot among all sampling dates. SWR was significantly more severe only IAF and 2 months after the fire. In the unburned area SWR was significantly higher IAF, 2, 5 and 7 months later after than 9 months later. The comparison between plots showed that SWR was more severe in the burned plot during the first 2 months after the fire in relation to the unburned plot. Considering the different sieve fractions studied, in the burned plot SWR was significantly more severe in the first 7 months after the fire in the coarser fractions (2–1 and 1–0.5 mm) and 9 months after in the finer fractions (0.5–0.25 and < 0.25 mm). In relation to the unburned plot, SWR was significantly more severe in the size fractions 2–1 and < 0.25 mm, IAF, 5 and 7 months after the fire than 2 and 9 months later. In the 1–0.5- and 0.5–0.25 mm-size fractions, SWR was significantly higher IAF, 2, 5 and 7 months after the fire than in the last sampling date. Significant differences in SWR were observed among the different sieve fractions in each plot, with exception of 2 and 9 months after the fire in the unburned plot. In most cases the finer fraction (< 0.25 mm) was more water repellent than the others. The comparison between plots for each sieve fraction showed significant differences in all cases IAF, 2 and 5 months after the fire. Seven months after the fire significant differences were only observed in the finer fractions (0.5–0.25 and < 0.25 mm) and after 9 months no significant differences were identified. The correlations between soil Munsell colour value and SOM were negatively significant in the burned and unburned areas. The correlations between Munsell colour value and SWR were only significant in the burned plot IAF, 2 and 7 months after the fire. In the case of the correlations between SOM and SWR, significant differences were only identified IAF and 2 months after the fire. The partial correlations (controlling for the effect of SOM) revealed that SOM had an important influence on the correlation between soil Munsell colour value and SWR in the burned plot IAF, 2 and 7 months after the fire.


Author(s):  
C. O. Olukanni ◽  
A. A. Audu ◽  
M. Waziri

The aim of this research is to determine the insecticide and herbicide residues and their degradation products in Kura irrigation farmland soils. The analyses were carried out during the planting (before harvest) and after the harvesting periods. The insecticide residue analyses were undertaken using Gas chromatography-mass spectrometry (GC/MS) after extraction with a mixture of n-hexane and acetone (1:1) in a soxhlet extractor. The pH levels of the soil samples and the soil organic matter were also determined using standard analytical methods. The acidity and organic matter content of most of the soil samples increased slightly after harvest. The compounds detected as residues include 1-octadecene, 9-heptadecanone, (E)-3-eicosene, (Z)-5-nonadecene, heptadecane, 1-docosene, 1-nonadecene and 1-eicosene. Out of these residues, 1-octadecene and (E)-3-eicosene were detected during planting and after the harvesting periods, showing that they are the most persistent of the residues in the soil samples. The residues detected before harvest were totally different from the residues detected after harvest. This shows that the pesticides, after some time, degraded in the soil into completely different compounds and the total residues were detected in high percentages.


1969 ◽  
Vol 39 (2) ◽  
pp. 65-76
Author(s):  
Fernando Abruña-Rodríguez ◽  
José Vicente-Chandler

The exchange capacity of the organic matter in typical soils of Puerto Rico was evaluated from: (1) The variation in the exchange capacity of soil samples following destruction of the organic matter, (2) titration curves of extracted organic matter, (3) and the correlations between exchange capacity and organic-matter content of soil samples. The first method was the most practical and gave fairly accurate results. The second method gave results which were in all cases too high. The third method, though probably the most accurate, is impractical. Results obtained with the first and third methods were similar. The exchange capacity of the organic matter varied rather widely, but was generally between 100 and 150 m.e. per 100 gm. On the average it accounted for about 25 percent of the total exchange capacity of the soils studied. The organic matter removed by flotation had the highest exchange capacity and the more readily oxidizable portions generally appeared to be the most active. This suggests the importance of conserving the more readily lost portions of the soil organic matter. A considerable portion of the soil organic matter was extremely resistant to oxidation, had a narrow C:N ratio, and apparently little exchange capacity. This suggests a close association between the organic matter and the inorganic soil colloids. The marked resistance to oxidation of a considerable portion of the organic matter may partly explain the high contents found even in continuously cultivated soils in Puerto Rico.


Separations ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 12
Author(s):  
Renli Ma ◽  
John R. Dean

The former St. Antony’s Lead Works site, now the central part of an urban recreational park (Walker Riverside Park) in the east end of Newcastle upon Tyne (England, UK), has been assessed based on the Pb concentration in topsoil according to recently derived Category 4 Screening Level (C4SL) for public open space–park (POSpark, 1300 mg/kg). The site was divided into eight sampling areas following its physical layout. In total 79 soil samples were collected, characterised for acidity and organic matter content, and analysed by energy dispersive X-ray fluorescence (ED-XRF). The Pb levels in most of the samples, particularly those from the fringes of the site, are below the generic guideline value (down to 70 mg/kg). More than 16% of the samples from nearly all sampling areas, especially those sampling points around the former horizontal condenser flue and main chimney, contain levels of Pb significantly exceeding the limit (up to 206,000 mg/kg). No correlation is found between the Pb concentration in soil samples and their acidity (mostly neutral, pH 7.0 ± 0.5) or organic matter content (15.5 ± 4.1%). Using the Contaminated Land Exposure Assessment (CLEA) model (version 1.071), the site-specific risk assessment criteria (SSAC) for Lead (C4SL child), 2862 mg/kg, is obtained based on adjusted exposure frequency and occupancy period. Nearly 9% of the individual sample Pb concentrations (n = 79) across sample locations B, C, D and H are still above the specific value. Further statistical evaluation based on 95% upper confidence limit confirms that the site still represents a potential human health risk. This is because Pb concentrations, from two areas in the centre of the site (sample locations B and C), are greatly over the SSAC specific threshold (sample mean at location B is 12,350 mg/kg and at location C is 11,745 mg/kg).


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