SOIL Studies

SOIL Studies

2017, Vol 6, Num, 1     (Pages: 036-043)

Variation of Aggregate Stability and Soil Development with Different Slope and Land Cover under Semi Moist Humid Climate Conditions

Tülay TUNÇAY 1 ,Orhan DENGİZ 2

1 Toprak, Gübre ve Su Kaynakları Merkez Araştırma Enstitüsü Müdürlüğü, Ankara
2 Ondokuz Mayıs Üniversitesi, Ziraat Fakültesi, Toprak Bilimi ve Bitki Besleme Bölümü, Samsun

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The aim of this study is to examine the changes in soil development and water-resistant aggregate stability on the same parent material, but with different slopes, land cover and land use under semihumid climatic conditions. It was carried out on the soil formed on the basaltic parent material in different topographical positions within the Dağköy area of Engiz Country, which is located at the south of the Samsun-Bafra Highway. In this context, six soil profiles were selected on north and south transect direction and examined. According to the study results, the lands located on sloped fields were classified in the Lithic Ustorthent subgroup of the Entisol order, while the lands on the lowersloped fields and the hill/plateau plains were classified as Typic Haplustert, Vertic Haplustept and Typic Haplustept, belonging to the Inceptisol and Vertisol orders. The formation of different soils on the same parent material in the study area – in other words, young and mature soils co-existing in a local area – suggests that topography or local relief has a significant impact on the material and time involved in the soil formation process. In addition, factors including the frequency and variety of vegetation on the land have also been shown to have an important effect. It is seen that in the maturation of the soil and in the process that keeps the soil young, the soil transport and accumulation, especially in the soils located on the slopes due to water movement, is as effective as the formation that occurs on the spot. A significant difference was determined between the upper layer water-resistant aggregate values of Typic Haplustert and Vertic Haplustept soils used as dry agriculture – at the flat and foothill fields – compared to the values of the Typic Haplustept soil used as pasture on the upper plains, and this difference is thought to be caused in particular by agricultural use of the soils and by their organic matter content. In the soil classified as Lithic Ustorthent on the sloped land under the forest and pasture lands, the aggregate values were about the same level, ranging from 63.28% to 70.16%.


Keywords : Soil formation, soil classification, aggregate stability, land use-land cover, topographic position