The study of cracks on vertisol soils (Black Cotton Soil ) has great significance for understanding the processes of soil degradation,plant nutrient uptake,and drawing strategic agricultural plans, as well as for engineering works and the development of re-vegetation techniques. An abundance of stable soil aggregates is an important indicator of good soil structure for sustainable crop production. This study aimed at a better understanding of the cracking phenomena inVertisols in order to be able to obtain a simple field technique that may reduce water losses through evaporation from cracks, yet retainstheir beneficial effects on soil profile, to estimate the development of cracks and their morphology during drying sequence, particle size distribution, its chemical and physical properties and to assess the causal relationships between the amount of soil moisture in vertisol and cracks developed and propagated.The study used a fractal approach and experiment where core-compost soil samples from a field site that has dark-clay soils mostly with very little vegetation cover were transported to the lab.The samples were left under natural conditions for four days to allow them to reach their plastic limit and the moisture content was measured using an Eijkelkamp 4-pin soil moisture sensor ML3 attached to a penetrologger display. The results indicated that moisture content reduced as the soil become drier. However, most soil samples also indicated constant moisture retention capacity (samples 1, 2, 4, 5, & 10) with a lower rate of drying hence the low development of cracks in such soil samples. Meanwhile, soil samples (3, 6, 7, 8, & 9) were found with low water holding capacity enabling cracks to develop. The results further revealedsilt soils had about 50% particle size distribution and sand soils had the lowest particle size distribution (18.35%). The pH of the vertisol soilwas found to be 8 which is extremely alkaline. Magnesium was very high in this soil compared to Calcium, Nitrate nitrogen, and phosphorus. However, humus content was found very low (2%)and considered to be of low fertility grade soils. In this case, the ability of the dark-clay vertisol to crack is attributed to the high chemical properties of the nutrient elements. Therefore, in order to assess the best type of soil that is favorable for engineering works, settlements, agriculture, and for livestock, soils must first be tested for various sustainable land uses without impacting and changing the soil structure.

Keywords : Particlesize distribution, soil nutrient elements, surface cracking, remolded vertisol, drying sequence, soil moisture content, black cotton soil, Rajaf Payam, South Sudan.