Distribution of Selected Soil Nutrients in Aggregate Sizes of Soils Under Different Geologic Formations in Southeast Nigeria

Abstract

Soil nutrients which are major factors to crop yield and food security could be loss to erosion as a result of structural break down leading to water pollution and low crop yield. Soils of southeast Nigeria like others in the humid tropical area are prone to degradation and are low in nutrient status. Therefore the study was conducted in other to investigate the distribution of selected soil nutrients in aggregate sizes under different geologic formations namely Asu River Group (ARG), Coastal Plain Sand (CPS), Falsebedded Sand Stone (FBS) and Bende Ameki Group (BAG) in Southeast Nigeria. At a depth of 0-15 cm, three replicate soil samples were taken from each formation. Collected samples were air dried, crushed and sieved using 2 mm mesh, properly labelled and analysed using standard methods. Samples for aggregate stability were not crushed after air drying. Core samplers were also used to collect samples for bulk density determination. Wet sieving method was used in separating samples into different sieve sizes of 2, 1, 0.5, and 0.25) was significantly higher in soils of Umuna (59.18%) under False bedded Sand Stone and least at soils of Obinze (26.27%) under Coastal Plain Sand and followed the order: FBS >ARG > BAG > CPS. Result also showed that soil organic carbon had significant (P < 0.05) positive relation with water stable aggregates WSA (r= 0.50), pH water (r= 0.53), total nitrogen (r=0.79), effective cation exchange capacity (r = 0.51) of the studied soils.

Keywords

• aggregates
• geologic formation
• soil nutrients
• lithology
• organic matter
• soil erosion