Soil dry aggregate size distribution: effects of soil type and land use (original) (raw)
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Land Use Pattern Influences the Aggregate Stability of Soil
Soil samples collected from four land use patterns namely forest, tea garden, cultivated and uncultivated land were used for analyzing the physic-chemical parameters and aggregate stability of the soil. Result showed that among the different soil analyzed, soil texture varied from loamy sand to clay loam with mean clay content in order of cultivated> forest> tea garden> uncultivated land. Bulk density (BD) of the soil showed significant negative correlation with organic matter content, soil porosity, percent base saturation and maximum water holding capacity (MWHC). Maximum water holding capacity was higher in forest soil followed by tea garden soil and the minimum in uncultivated soil. Forest, tea garden and cultivated soils were strongly acidic to moderately acidic in nature, while uncultivated soils were slightly acidic.All soils were non-saline and have low to medium cation exchange capacity (CEC) ranged from 3.70 to 15.48 Cmol(P)kg. The results of aggregate stability indicated that majority of the soils +-1 showed high values of mean weight diameter (MWD) in both dry and wet sieving.Meanweight diameter and water stable aggregates were greater in forest and tea garden soils compared to cultivated soil. Mean weight diameter (dry sieving)maintained significant positive correlation withorganic carbon content and cation exchange capacity.Correlations were drawn between the physic-chemical properties of soil and also among the different physical properties of soils.
The ability of soil aggregates to resist the forces of water and/or wind, the potential to degrade, crust and/or seal is referred to aggregate stability. Little is known about the effect of soil texture and period of soaking on aggregate stability for cultivated soil of four major textural classes in southeast, Nigeria which was the objective of our study. Soil samples representing a range of agricultural soils of four contrasting textural classes of sandy loam; sandy clay loam; clay loam and loam under five different period of soaking namely; 0, 30, 60, 90 and 120 minutes were studied using wet and dry sieve techniques. The indices evaluated include; mean weight diameter wet and dry, water stable aggregates >2.00mm (WSA1); water stable aggregates 2.00mm-1.00mm (WSA2); water stable aggregates 1.00mm-0.5mm (WSA3); 0.5mm-0.25mm (WSA4); < 0.25 mm (WSA5). Results generated from the study showed that the studied soil types are poor in organic carbon (OC), organic matter and sodium (Na) contents. Their cation exchange capacity (CEC) values are of moderate values of which ranged from 4.67-8.80 cmolkg-1. The relationship study indicated that WSA1 correlated significantly and positively with WSA2 and mean weight diameter wet (MWDW), but negatively with WSA4 and WSA5 with r values of-0.306 and-0.695 respectively. WSA2 was observed to have significant positive correlation with WSA3, WSA4 and MWDW. WSA3 and WSA4 did not correlate significantly with MWDW but has positive correlation with each other with r value of 0.794. WSA5 was found to correlate significantly but negatively withWSA1-WSA5 (2.00mm-0.25mm). Mean weight diameter of wet aggregates correlated positively and significantly with degree of aggregation (DA) and state of aggregation (SA) at 0-120 minutes, this result was equally true for DA and SA correlation result at times studied. The correlation matrix of mean weight diameter of dry aggregates (MWDD) with MWDW, DA and SA indicated negative correlation in all the time studied, except at 30 minutes where it showed positive correlation with DA with r value of 0.639 and at 90 minutes were it was not significant with DA and SA. The correlation between aggregate stability indices studied and Na, CEC at various periods of soaking was not significant and OM content was low. Though not statistically significant, hydraulic conductivity (HC) and bulk density (BD) showed positive correlation with MWDW, DA and SA in all the soaking period while field capacity (FC) and total porosity (TP) showed negative correlation but not statistically significant with MWDW, DA and SA, but has positive correlation with MWDD. The findings from this study is of evidence that the period of soaking had some contributions to the stability of soil aggregates and soil properties especially with the trend in the correlation matrix between MWDD and MWDW, DA and SA.
Vulnerability of soil aggregates in relation to soil properties
Stability of soil structure represents an indicator of soil quality. The aim of this paper was to assess the effect of soil properties on structure vulnerability in an Orthic Luvisol. The aggregates were most vulnerable to fast wetting (mean K v1 = 9.99, i.e. this effect can decrease the aggregate size 9.99 times). Lower destruction was caused by slow wetting and drying (K v2 = 3.70) and mechanical forces (K v3 = 1.67). Fine silt (particles of 0.0020.01 mm) was the most important soil characteristic decreasing aggregate vulnerability (H = 0.334, 0.248, and 0.393 for K v1 , K v2 , and K v3 , respectively). Silt (0.010.05 mm) increased vulnerability to fast wetting (H = 0.318). Very fine sand (0.050.1 mm) increased vulnerability to mechanical impacts (H = 0.307). Organic carbon decreased vulnerability only slightly. Humus quality was rather related to porosity. Higher moisture of samples in time of collection increased aggregate vulnerability. Multiple regression, used for description of the effect of basic soil properties, provided the best model for K v1 (4 2 = 27.45%), the poorest for K v2 (4 2 = 7.23%).
Soil structure and their management in farming system: A review
2018
Soil structure applies an important effect on edaphic circumstances and the atmosphere. It is normally expressed as the degree of structural stability in soil. Soil structure stability or soil aggregation fallouts from the rearrangement, flocculation and cementation of soil particles. It is facilitated by soil organic carbon (SOC), biota, ionic bridging, clay and carbonates. The complex interactions of these aggregates can be synergistic or disrupting to aggregation. The clay-sized soil particles are commonly associated with soil aggregation by redisposition and flocculation, though swelling clay can upset aggregates. The organic matter creates from plants, animals and microorganisms, and their exudates. It improves soil aggregation from side to side the attachment of primary soil particles. The helpfulness of SOC in forming stable soil aggregates is associated to its rottenness rate, which in turn is inclined through its physical, chemical and microbial population act since defense...
Ekologia, 2011
CITATIONS 5 READS 168 8 authors, including: Some of the authors of this publication are also working on these related projects: The impacts of fire on plant ash behaviour and properties in relation to soil mineralogy and morphology, water repellency and soil aggregate stability View project POSTFIRE, Soil quality, erosion control and plant cover recovery under different post-fire management scenarios View project Abstract Dlapa P., Chrenková K., Hrabovský A., Mataix-Solera J., Kollár J., Šimkovic I., Juráni B.: The effect of land use on the soil aggregate stability in the viticulture district of Modra (SW Slovakia). Ekológia (Bratislava), Vol. 30, No. 4, p. 397-404, 2011.
P a g e | 334 DEVELOPMENT OF AN INDEX OF SOIL AGGREGATE STABILITY
Soil aggregate stability is an important parameter affecting soil credibility and soil crusting potential, and plays a key role in ecosystem functioning as it affects water, gas and nutrient fluxes and storage and, therefore, influences the activity and growth of plants in the soil. Laboratory determination of this property is often viewed as unreliable due to inequity resulting from the common measurement techniques. As a result, a laboratory investigation was carried out on soils from two different fields (uprooted and un-uprooted oil palm fields) to develop an index for estimating soil aggregate stability using sodium chloride (NaCl) conductivity. The results of the study showed a good agreement between wet-sieved aggregate stability and relative conductivity from both study sites, with coefficient of determination from the 1:1 plots (between wet-sieved aggregate stability and relative conductivity) were 0.98 and 0.92 for the uprooted and un-uprooted oil palm fields, respectively.
Soil aggregation under different management systems
Revista Brasileira de Ciência do Solo, 2012
Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT) and conventional tillage (CT), since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile) in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI), mean weighted diameter (MWD), mean geometric diameter (MGD) in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC), flocculation index (FI) and bulk density (Bd)) and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH). The results indicated that more intense soil preparation (M &l...
2014
The present study was carried out to clarify the effects of some soil physical and chemical specifications on soil aggregates size distribution and stability under different tillage methods. Conventional tillage cause to break soil aggregates especially in loamy soils consequently increase soil sensitivity to water and winderosion. On the other hand, soil aggregate size distribution and aggregate stability are the two important physical properties of the soil with profound effects on soil health. Thus, soil sensitivity to destruction might be a criterion for evaluating soil agronomic capacity that may be defined by its stability i.e. physical structure. In an experiment carried out in 2011-12 crop season at agricultural education and research farm of Tehran University, Karaj. Iran (35048'N, 510'E, and 1321m above sea level) using randomized complete block design in split-plot arrangement with three replications physical soil parameters of aggregates size distribution and sta...
Journal of Plant Nutrition and Soil Science, 2010
Conversion of meadow and forest ecosystems to agricultural land generally leads to changes in soil structure. This comparative study presents the composition and stability of structural aggregates in humus horizons (0-30 cm) of noncarbonate silty-clay Fluvisols in the Kolubara River Valley, W Serbia. Aggregates collected from under a native forest were compared to aggregates from meadows and arable fields which underwent crop rotation for > 100 y. The results show that size distribution and stability of structural aggregates in the humus horizons of arable soil are significantly impaired due to long-term anthropogenization. In the humus horizons, the content of the agronomically most valuable aggregates (0.25-10 mm) decreased by a factor of ≈ 2, from 68%-74% to 37%-39%, while the percentage of cloddy aggregates (>10 mm) increased by a factor of ≈ 2, from 23%-31% to 48%-62%, compared to forest aggregates. The long-term-arable soil had significantly (p < 0.05) lower aggregate stability, determined by wet sieving, than meadow and forest soils. The lowest aggregate stability was found in aggregates > 3 mm. Their content is ≈ 2.5-3 times lower in arable soil (13%-16%) than in forest soil (32%-42%) at a depth of 0-20 cm. The largest mean weight diameters of dry aggregates (dMWD) with a range between 12.6 and 14.7 mm were found in arable soil, vs. 9.5-9.9 mm in meadow and 6.5-8.3 mm in forest. The arable soil had significantly lower mean weight diameters of wet-stable aggregates (wMWD) and a lower structure coefficient (Ks) than forest and meadow soils. The dispersion ratio (DR) of arable soil was significantly higher than that of forest and meadow soils. Forest and meadow showed a significantly higher soil organic-matter content (SOM) by 74% and 39%, respectively, compared with arable soil, while meadow uses decreased the SOM content by 57% compared with forest at a depth of 0-10 cm. In conclusion, the results showed that long-term conventional tillage of soils from natural forest and meadow in the lowland ecosystems of W Serbia degraded soil aggregate-size distribution and stability and reduced SOM content, probably resulting in lower productivity and reduced crop yields.