ABSTRACT
Land evaluation studies was carried out in Kolokuma/Opokuma Local Government area of Bayelsa State to map, classify and determine the capability groupings most appropriate for the establishment of suitable system (s) specific for the soils of the area.
The Area was georeferenced with a rigid grid format of semi detailed soil survey system was applied at 1000 m x 500 m and a total of 891 points were obtained. The coordinates of each points were recorded and loaded into hand held Garmin GPS (global position system) for groundtruthing and auger boring. Twelve (12) profiles were dug, described and soil samples collected according to established guidelines, processed and analyzed in the laboratory by standard methods. The pedons were designated as Pedons 1 to 12.
Three major soil types were present: Alfisols,/Lixisols, Inceptisols/Cambisols and Ultisols/Acrisol, Pedon 1 is Ultisol/Acrisols (3074.3 ha), Pedons 4 and 12 are Alfisols/Lixisols with (9371.7ha), while Pedons 2, 3, 5, 6, 7, 8, 9, 10 and 11 are Inceptisols/Cambisols occupying (31,837 ha). Land evaluation, results showed that Land Capability Classification had 4 classes for arable crop production: class II (2227 ha), Class III (10,026.7 ha), Class IV (7075.5 ha) and class VII (19812.2 ha). Fertility Capability Classification has three (3) Units: LLmg occupying 32,049.7 ha with Loamy Topsoil, Loamy Subsoil and Condition Modifiers of m and g; CCmg occupying 5197.5 ha with Topsoil Clay, subsoil Clay and Condition Modifiers m and g and LSmg occupying 891 ha with Loamy Topsoil and Sandy subsoil and Condition Modifiers of m and g. The Index of capability scores ranked from 0.245% to 6.912%. Land Capability classification correlated positively with Index of Capability while Fertility Capability Classification did not correlate with any of them. Suitability of the soils for the cultivation of oil palm, yam and plantain, the results revealed that no part of the study area was highly suitable, (S1 class) for oil palm, yam and plantain cultivation. Oil palm was moderately suitable (S2), occupying 18300.5 ha and (S3) occupying 19,837.2 ha marginally suitable. Suitability for Yam results showed that 594 ha was moderately suitable (S2) and 12,791.4 ha marginally suitable (S3), while 24,575.1ha was currently not suitable (N1). For plantain, 32,013.9 ha was marginally suitable (S3) while 6123 ha was currently not suitable (N1). Kolokuma/Opokuma Local Government area predominantly has soils that are classified as Alfisols/Lixisols, Incepitsols/Cambisols and Ultisols/Acrisols. The capability groupings are either LCC or IC and FCC, while the soils of the LGA are suitable for the cultivation of oil palm, yam and plantain at varying degrees of suitability.
