Soil Shrinkage Relationships of Texas Vertisols: I. Small Cores

Yule, D. F.; Ritchie, J. T.

doi:10.2136/sssaj1980.03615995004400060031x

Cited by 100 publications

(58 citation statements)

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“…Therefore, clay and sand were the most important determinant parameters for bulk density or soil compaction. Observations from our study are well corroborated by several workers [46][47][48][49][50], who observed, from different areas and soil types, that the higher the amount of sand in the soil, the greater the bulk density, while the higher the amount of clay, the lower the bulk density. PCA was used to determine if there were similarity clusters of soils from different farms and sub-counties with respect to soil properties.…”

Section: Quantification Of Bare Ground Coveragesupporting

confidence: 91%

Conservation Farming and Changing Climate: More Beneficial than Conventional Methods for Degraded Ugandan Soils

et al. 2017

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Abstract:The extent of land affected by degradation in Uganda ranges from 20% in relatively flat and vegetation-covered areas to 90% in the eastern and southwestern highlands. Land degradation has adversely affected smallholder agro-ecosystems including direct damage and loss of critical ecosystem services such as agricultural land/soil and biodiversity. This study evaluated the extent of bare grounds in Nakasongola, one of the districts in the Cattle Corridor of Uganda and the yield responses of maize (Zea mays) and common bean (Phaseolus vulgaris L.) to different tillage methods in the district. Bare ground was determined by a supervised multi-band satellite image classification using the Maximum Likelihood Classifier (MLC). Field trials on maize and bean grain yield responses to tillage practices used a randomized complete block design with three replications, evaluating conventional farmer practice (CFP); permanent planting basins (PPB); and rip lines, with or without fertilizer in maize and bean rotations. Bare ground coverage in the Nakasongola District was 187 km 2 (11%) of the 1741 km 2 of arable land due to extreme cases of soil compaction. All practices, whether conventional or the newly introduced conservation farming practices in combination with fertilizer increased bean and maize grain yields, albeit with minimal statistical significance in some cases. The newly introduced conservation farming tillage practices increased the bean grain yield relative to conventional practices by 41% in PPBs and 43% in rip lines. In maize, the newly introduced conservation farming tillage practices increased the grain yield by 78% on average, relative to conventional practices. Apparently, conservation farming tillage methods proved beneficial relative to conventional methods on degraded soils, with the short-term benefit of increasing land productivity leading to better harvests and food security.

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Section: Quantification Of Bare Ground Coveragesupporting

confidence: 91%

Conservation Farming and Changing Climate: More Beneficial than Conventional Methods for Degraded Ugandan Soils

et al. 2017

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“…It has been reported that vertisols may have BD values as high as 2.1 g·cm -3 [35]. It has been also shown that at the swelling limit, the gravimetric water content decreases and BD values increase with depth [36].…”

Section: Physical Propertiesmentioning

confidence: 99%

Morphological and Physico-Chemical Characteristics and Classification of Vertisol Developed on Deltaic Plain

Dengi̇z

Sağlam²,

Sarıoğlu³

et al. 2012

OJSS

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The name of Vertisol is derived from Latin "vertere" meaning to invert. This case restricts development of soil horizons in profile. These soils have the capacity to swell and shrink, inducing cracks in the upper parts of the soil and distinctive soil structure throughout the soil. The formation of these specific features are caused by a heavy texture, a dominance of swelling clay in the fine fraction and marked changes in moisture content. The swell-shrink behavior is attributed to the wetting and drying of the soil mass. In this study, morphology, physico-chemical characteristics and classification of vertisols that were formed on alluvial delta plains, were investigated. Those soils formed on the Bafra Plain found in the Kızılırmak Delta and located in the central Black Sea region of Turkey. All studied Vertisols are characterised by a dark colour in surface soil, a heavy clayey texture, hardpan formation under top soil (high bulk density a high compaction) and very high COLE values. In addition, they have deep wide-opened desiccation cracks at the surface, slickensides at the middle part of the profiles and a poor differentiation of their horizons. Physico-chemically, the studied soils are slightly basic to very basic, non-saline and poor in organic matter, which is slightly higher in the surface horizon. In addition, cation exchange capacity, sum of exchangeable bases and base saturation of soils are very high. On the basis of morphological and physicochemical analysis, soil profiles were classified as Sodic Haplustert, Typic Calciaquert, Sodic Calciustert according to Soil Taxonomy (Soil Survey Staff, 1975 and1999) and as Sodic Vertisol and Calcic Vertisol according to FAO/ISRIC (2006) classification systems.

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“…In general, the shrinkage curve of an aggregated soil is non-single valued because the volume of (macro) cracks between primary aggregates depends on sampling, sample preparation, sample size, and drying regime [7][8][9][10][11][12]. How-consider the effects of soil structure on shrinkage curve, Chertkov [4][5][6] used the reference shrinkage curve that by definition only corresponds to soil clay shrinkage without inter-aggregate cracking and can be predicted in a single valued manner.…”

Section: Introductionmentioning

confidence: 99%

Step-by-Step Transition from Clay to Soil Shrinkage Curve

Chertkov¹

2008

TOMECHJ

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Clay and soil containing it have shrinkage curves that are qualitatively different in shape. The objective of this work is to qualitatively show with maximum simplicity, how a clay shrinkage curve turns into a soil shrinkage curve. Because of the crack volume the measured shrinkage curve is not the single-valued feature of a soil. We use a concept of the reference shrinkage curve that is only stipulated by soil shrinkage without cracking, single-valued, and qualitatively similar to an observed shrinkage curve. We also use new concepts of an intra-aggregate soil structure: (i) a deformable, but non-shrinking surface layer of aggregates that loses water during shrinkage; and (ii) lacunar pores (micro-cracks) inside an intra-aggregate clay that increase in volume during shrinkage. Then, through a series of consecutive steps, illustrating each step by a separate graphic presentation, we move from a clay shrinkage curve to a soil shrinkage curve with predicted qualitative features that coincide with those experimentally observed in numerous soil shrinkage publications. We thereby demonstrate the qualitative physical impact of the intra-aggregate structure on soil shrinkage.

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Soil Shrinkage Relationships of Texas Vertisols: I. Small Cores

Cited by 100 publications

References 0 publications

Conservation Farming and Changing Climate: More Beneficial than Conventional Methods for Degraded Ugandan Soils

Conservation Farming and Changing Climate: More Beneficial than Conventional Methods for Degraded Ugandan Soils

Morphological and Physico-Chemical Characteristics and Classification of Vertisol Developed on Deltaic Plain

Step-by-Step Transition from Clay to Soil Shrinkage Curve

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