Macro morphological features of vertisols in semi-arid climate, in Rahad Area, Eastern Sudan

Bushra Mohamed Meheissi

Net Journal of Agricultural Science
Published: August 29 2017
Volume 5, Issue 3
Pages 105-113

Abstract

The study area lies in the eastern part of the Central Clay Plain of Sudan. The plain is dominated by the vertisols; which is cracking clayey soils with a dark colour. The study objective was to investigate macro morphological features of vertisols in semi-arid climate in eastern Sudan. The paper is limited to the description of surface and macro morphological features of vertisols. These features are: mulch of the soil surface, gray nodules, cracking, colour, texture, structure, calcium carbonates CaCO₃, calcareousness, consistence, porosity, and subsoil vertic features. The mulch thickness ranges from 1 to 5 cm. The soil cracks were observed throughout the area with width ranging from 1 to 7 cm; and depth of more than 60 cm. The gray nodules (CaCO₃) are common or abundant on the soil surface with different shapes and sizes. The colour is dark brown (10YR3/3) (70%), followed by very dark grayish brown (2.5Y 3/2) (30%). The texture class of these soils is heavy clay; where the clay percent is more than 60%. Soil structure of more than 95% of the soils have moderate grade of structure on the top, weak grade beneath, and massive at lower depths. Soil consistence is hard dry; friable moist, and very sticky and very plastic wet. The parallel-epipedal structural aggregates appear between 40 and 50 cm of the profile soil depth. The slickenside appears at 60 cm and downwards with distinct feature below the cracking zone. Soil pores are common to few; very fine, fine micro pores, and very few medium meso pores. The macro pores exist at deeper moist subsoil where biological activity present. Calcium carbonates (CaCO₃) are few to common and occurred in a wide variety of forms as concretions and soft segregates, and increases with soil depth.

Keywords: Macro morphology, vertisols, semi arid, Rahad.

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