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首页> 外文期刊>Australian Journal of Soil Research >Variation in soil strength, bulk density and gravel concentration along a toposequence in Abeokuta, south-western Nigeria.
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Variation in soil strength, bulk density and gravel concentration along a toposequence in Abeokuta, south-western Nigeria.

机译：尼日利亚西南部Abeokuta地区土壤强度，堆积密度和砾石浓度随地形的变化。

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This study was carried out at Abeokuta, south-western Nigeria, to understand the variation in soil strength, gravel distribution, and bulk density along a toposequence. In 2003, a 120-m transect on a fallowed land was sampled at every 1 m for topsoil bulk density measurement by excavation (3278 cm3 pits), while soil strength was measured at every soil depth increment of 25 mm to 0.50 m depth. Total dry ( rho < sub>t) and fine earth (<2 mm) ( rho < sub>f) bulk densities were determined. Soil water content was also determined. Gravel was divided into classes of 2-4, 4-8, 8-16, and >16 mm. In 2006, four 100-m transects were considered; two each on adjacent fallowed and cultivated lands. Soil strength and water content were measured. The fine earth fraction of topsoil ranged from 62 to 90.6%. Gravel in the 2-4 mm class was dominant with a range of 0.8-35.7%. Thus, cores <=50 mm could be used in the topsoil to obtain reliable estimates of bulk density. Total bulk density ( rho < sub>t) was reduced by 4-19% when corrected for gravel to obtain rho < sub>f. Soil strength of the lower slope was highest in 2003 (1981-4482 kPa) and lowest in 2006 (1546 kPa). In spite of the apparent significant influence of water content on soil strength, the relationship was weakly expressed by regression analysis, as only 35% of variation in soil strength was explained by water content at 0.10-0.15 m soil depth in 2003. No relationship was found in 2006; the cultivated segment had higher soil strength (2045 kPa) than the fallowed segment (1970 kPa) even though the water contents were similar. Also, only the 2-4 mm gravel significantly influenced rho < sub>t. Land use, soil depth, and slope position significantly affected soil strength. Root-limiting soil strength (>2000 kPa) would certainly be encountered below 0.20 m soil depth in the wet season irrespective of land use. Management of this gravelly landscape must be based on the heterogeneous nature of soil physical properties along the toposequence, and this could be made effective by grouping the soils according to slope position and taking interest in the few portions of the landscape with extreme values of gravel distribution and high soil strength.
机译：这项研究是在尼日利亚西南部的Abeokuta进行的，目的是了解土的强度，砾石分布和堆积密度沿一定顺序的变化。 2003年，在一个休耕地上每1 m采样一个120 m的样带，用于通过开挖（3278 cm3坑）来测量表土的土壤堆积密度，而在每25mm到0.50 m深度的每一个土壤深度增量中测量土壤强度。测定总干重（rho t ）和细土（<2 mm）（rho f ）堆积密度。还确定了土壤含水量。砾石分为2-4、4-8、8-16和> 16毫米的类别。 2006年，考虑了四个100 m的断面;在相邻的休耕地上各两个。测量土壤强度和水含量。表土的细土含量在62％至90.6％之间。 2-4毫米级别的碎石占主导地位，范围为0.8-35.7％。因此，≤50mm的岩心可用于表层土壤，以获得可靠的堆积密度估算值。校正砾石以获得rho f 后，总堆积密度（rho t ）降低了4-19％。下坡的土壤强度在2003年最高（1981-4482 kPa），在2006年最低（1546 kPa）。尽管含水量对土壤强度有明显的显着影响，但回归分析未能很好地表达这种关系，因为2003年土壤深度在0.10-0.15 m时，仅解释了35％的土壤强度变化。发现于2006年;即使含水量相似，耕作段的土壤强度（2045 kPa）也比休耕段（1970 kPa）高。另外，只有2-4 mm的砾石对rho t 有显着影响。土地利用，土壤深度和斜坡位置会严重影响土壤强度。不论土地使用如何，在湿季土壤深度低于0.20 m时，肯定会遇到限制根的土壤强度（> 2000 kPa）。对该砾石景观的管理必须基于沿后序的土壤物理性质的异质性，这可以通过根据坡度位置对土壤进行分组并利用砾石分布的极值对景观的少数部分感兴趣来使其有效和高土壤强度。

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