Decomposition of plant material in Australian soils .IV. Decomposition in situ of 14C labeled and 15N labeled legume and wheat materials in a range of southern Australian soils

Soil Research ◽  
1987 ◽  
Vol 25 (1) ◽  
pp. 95 ◽  
Author(s):  
M Amato ◽  
JN Ladd ◽  
A Ellington ◽  
G Ford ◽  
JE Mahoney ◽  
...  

14C- and 15N-labelled wheat straw, and tops or roots of a pasture legume (either Medicago littoralis or Trifolium subterraneum) were incorporated into topsoils at 12 field sites in southern Australia. These sites were representative of soil types widely used for wheat growing in each region. The soils varied markedly in their physical and chemical properties (e.g. pH, texture and organic matter content). Based on amounts of residual I4C (averaged for all sites), the legume tops decomposed more extensively than did wheat straw, especially soon after incorporation. To a lesser extent the legume tops decomposed more extensively than legume roots, and T. subterraneum tops more than M. littoralis tops; root decomposition for both legumes was similar. For example, after 1 year, the residual organic 14C from wheat straw, M. littoralis tops, T. subterraneum tops and legume roots accounted for 48%, 41%, 38% and 54% of their respective inputs. After two years, residual 14C of wheat straw accounted for 30% of the input. Differences in decomposition due to climate and soil properties were generally small, but at times were statistically significant; these differences related positively with rainfall and negatively with soil clay content, but showed no relationship with pH or soil organic C and N. Some N was mineralized from all plant materials, the greatest from legume tops, the least from wheat straw. After 1 year, residual organic 15N accounted for 56%, 63% and 78% respectively of input l5N from legume tops and roots and from wheat straw. The influence of climate and soil properties on amounts of residual organic I5N was small and generally was consistent with those found for residual 14C. AS an exception, the residual organic 15N from wheat straw was negatively related to soil organic N levels, whereas residual I5N of legume tops and roots and residual 14C of all plant materials were not influenced by soil organic matter levels. These results are discussed in terms of the turnover of N in soils amended with isotope labelled plant materials of different available C:N ratios.

Jurnal Solum ◽  
2010 ◽  
Vol 7 (1) ◽  
pp. 27
Author(s):  
Asmar Asmar ◽  
Amrizal Saidi ◽  
Masliyunas Masliyunas

A research about relationship between soil properties and crop yield was conducted in Pandai Sikek, Tanah Datar Region, center for cabbage and carrot production, West Sumatra in 2004 and 2005.  Soil samples were collected from rainfed paddy soils by purposive random sampling.  Soil samples were analyzed in Soil Laboratory, Agriculture Faculty and Agriculture Polytechnique Laboratory, Andalas University.  Several soil physical properties analysed were soil bulk density and total soil pores by using gravimetric method, permeability with de Boodt method, soil water content at several pF values using pressure plate apparatus, and soil strength by using penetrometer.   Soil chemical parameters analysed were soil pH using pH-meter, organic-C using Walkley and Black, available P using Bray II, and cation exchange capacity using NH4-leaching at pH 7.0, and N-total using Kjehdhal method.  Crop productions were sampled from a 3x3 m2 of soil sampling area.  The result showed that soils planted by cabbage and carrot had good soil physical properties, such as having balanced pore size distribution.  The chemical properties of the soils were good as well, except N, K- and Ca-exchangeable which were very low.  The other soil properties were quite good.  Soil physical properties gave different response on both crops.  Carrots were more response aeration pore and soil organic matter content, then cabbage was more response on BV, TSP, and slow drainage pores.  While soil chemical properties did not give significant response.  Both crops responded on Ca, but cabbage was more response on N-total, and carrot on CEC and saturated cationKey Words: Soil Physical Properties, Soil Fertility, Crop Productivity


Author(s):  
Amita M Watkar ◽  

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.


Author(s):  
Trina Stephens

Land‐use change can have a major impact on soil properties, leading to long‐term changes in soilnutrient cycling rates and carbon storage. While a substantial amount of research has been conducted onland‐use change in tropical regions, empirical evidence of long‐term conversion of forested land toagricultural land in North America is lacking. Pervasive deforestation for the sake of agriculturethroughout much of North America is likely to have modified soil properties, with implications for theglobal climate. Here, we examined the response of physical, chemical and biological soil properties toconversion of forest to agricultural land (100 years ago) on Roebuck Farm near Perth, Ontario, Canada.Soil samples were collected at three sites from under forest and agricultural vegetative cover on bothhigh‐ and low‐lying topographic positions (12 locations in total; soil profile sampled to a depth of 40cm).Our results revealed that bulk density, pH, and nitrate concentrations were all higher in soils collectedfrom cultivate sites. In contrast, samples from forested sites exhibited greater water‐holding capacity,porosity, organic matter content, ammonia concentrations and cation exchange capacity. Many of these characteristics are linked to greater organic matter abundance and diversity in soils under forestvegetation as compared with agricultural soils. Microbial activity and Q10 values were also higher in theforest soils. While soil properties in the forest were fairly similar across topographic gradients, low‐lyingpositions under agricultural regions had higher bulk density and organic matter content than upslopepositions, suggesting significant movement of material along topographic gradients. Differences in soilproperties are attributed largely to increased compaction and loss of organic matter inputs in theagricultural system. Our results suggest that the conversion of forested land cover to agriculture landcover reduces soil quality and carbon storage, alters long‐term site productivity, and contributes toincreased atmospheric carbon dioxide concentrations.


Author(s):  
Juliana Vantellingen ◽  
Sean C. Thomas

Log landings are areas within managed forests used to process and store felled trees prior to transport. Through their construction and use soil is removed or redistributed, compacted, and organic matter contents may be increased by incorporation of wood fragments. The effects of these changes to soil properties on methane (CH<sub>4</sub>) flux is unclear and unstudied. We quantified CH<sub>4</sub> flux rates from year-old landings in Ontario, Canada, and examined spatial variability and relationships to soil properties within these sites. Landings emitted CH<sub>4</sub> throughout the growing season; the average CH<sub>4</sub> emission rate from log landings was 69.2 ± 12.8 nmol m<sup>-2</sup> s<sup>-1</sup> (26.2 ± 4.8 g CH<sub>4</sub> C m<sup>-2</sup> y<sup>-1</sup>), a rate comparable to CH<sub>4</sub>-emitting wetlands. Emission rates were correlated to soil pH, organic matter content and quantities of buried woody debris. These properties led to strong CH<sub>4</sub> emissions, or “hotspots”, in certain areas of landings, particularly where processing of logs occurred and incorporated woody debris into the soil. At the forest level, emissions from landings were estimated to offset ~12% of CH<sub>4</sub> consumption from soils within the harvest area, although making up only ~0.5% of the harvest area. Management practices to avoid or remediate these emissions should be developed as a priority measure in “climate-smart” forestry.


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.


2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.


2009 ◽  
Vol 6 (3) ◽  
pp. 245 ◽  
Author(s):  
Achouak El Arfaoui ◽  
Stéphanie Sayen ◽  
Eric Marceau ◽  
Lorenzo Stievano ◽  
Emmanuel Guillon ◽  
...  

Environmental context. The wide use of pesticides for pest and weed control contributes to their presence in underground and surface waters, which has led to a continuously growing interest in their environmental fate. Soils play a key role in the transfer of these compounds from the sprayer to the water as a result of their capacity to retain pesticides depending on the soil components. The knowledge of soil composition should enable one to predict pesticide behaviour in the environment. Abstract. Eight calcareous soils of Champagne vineyards (France) were studied to investigate the adsorption of the herbicide terbumeton (TER). A preliminary characterisation of the soil samples using X-ray diffraction (XRD), elemental and textural analyses, revealed a wide range of soil properties for the selected samples. The adsorption isotherms of TER were plotted for all samples. The determination of soil properties, which significantly correlated with the Kd distribution coefficient, allowed identification of organic matter and CaCO3 as the two main soil components that govern the retention of the herbicide. Organic matter was the predominant phase involved in the retention but its role was limited by the presence of calcite. Finally, the ratio of CaCO3 content to organic matter content was proposed as a useful parameter to predict the adsorption of terbumeton in chalky soils. The evolution of Kd as a function of this ratio was successfully described using an empirical model.


Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 368-372 ◽  
Author(s):  
Josef Kozak ◽  
Jerome B. Weber

Adsorption of five phenylurea herbicides, metobromuron [3-(p-bromophenyl)-1-methoxy-1-methylurea], monolinuron [3-(p-chlorophenyl)-1-methoxyl-1-methylurea], linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea], chlorbromuron [3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea], and CGA-15646 [3-(3-chloro-4-methylphenyl)-1,1-dimethylurea] by eight selected soils of Czechoslovakia were studied. Constants from Freundlich and Langmuir equations were calculated and correlated with the major soil properties. Freundlich K values ranged from 1.84 to 128, and the Freundlich equation was better fitted to the adsorption isotherms than was the Langmuir equation. Soil organic-matter content was the most important factor influencing the range of adsorption.


1974 ◽  
Vol 54 (1) ◽  
pp. 7-14 ◽  
Author(s):  
L. S. CROSSON ◽  
R. PROTZ

Many soil mapping units (MU) have not been adequately sampled to provide a true measure of their variability; therefore, their descriptions must be regarded as incomplete, and valid statistical comparisons cannot be made with other closely related MU. The number of samples required to detect the differences in means of 18 soil properties between Brantford and Beverly Silt Loam MU were calculated and they ranged from 4 at the 80% probability level (10 at the 95% probability level) for organic matter content of the Ap horizon to several thousand for pH of the Ap horizon. Calculation of required sample numbers indicated that sufficient samples had been collected to make valid statistical comparisons between seven of the soil properties. All seven properties were found to be significantly different between the two MU at the 95% probability level. However, only two of the properties, hue and organic matter content of the Ap horizon, had distinctly different modal values between the two MU and neither of these properties is easily measured in the field. Therefore, it was concluded that the 18 soil properties examined were impractical and unreliable criteria for separating the MU in the field. But, the MU separations can be readily and validly made on the basis of landscape position.


1991 ◽  
Vol 71 (3) ◽  
pp. 377-387 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
K. E. Bowren ◽  
L. Townley-Smith ◽  
M. Schnitzer

The effects of crop rotation and various cultural practices on soil organic matter and some biochemical characteristics of a heavy-textured, Orthic Black Chernozem with a thick A horizon were determined after 31 yr at Melfort, Saskatchewan. Treatments investigated included: fertilization, cropping frequency, green manuring, and inclusion of grass-legume hay crops in predominantly spring wheat (Triticum aestivum L.) systems. The results showed that neither soil organic C nor N in the top 15 cm of soil, nor hydrolyzable amino acids, nor C mineralized in 14 d at 20 °C were influenced by fertilization. However, the relative molar distribution (RMD) of the amino acids reflected the influence of fertilization and the phase (Rot-yr) of the legume green manure rotation sampled. Some characteristics assessed increased marginally with increasing cropping frequency but differences were less marked than results obtained earlier in a heavy-textured Black Chernozem with a thin A horizon at Indian Head, Saskatchewan. The relationship between soil organic matter or C mineralization versus estimated crop residues, residue C, or residue N returned to the land over the 31-yr period, were not significant in the Melfort soil. This contrasts with our findings for the thin Black soil. We speculate that the lack of soil organic matter response in the Melfort soil was due to its very high organic matter content (about 64 t ha−1C and 6.5 t ha−1N in the top 15 cm). We also hypothesized that the amino acid RMD results, which differed from most of those reported in the literature, may be reflecting the more recent cropping history of the soil. This aspect requires further research into the composition and distribution of the humic materials in this soil. Key words: Amino acids, relative molar distribution, C respiration, green manures, fertilization


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