CHARACTERIZATION AND CLASSIFICATION OF SOILS SUPPORTING OIL PALM (Elaesis guineensis) CULTIVATION IN OBIO AKPA COMMUNITY, AKWA IBOM STATE, NIGERIA

ABSTRACT

Characterization and classification of soils supporting oil palm production in Obio Akpa, Akwa Ibom Sate of Nigeria was carried out from the morphological, physical and chemical properties of the soils. Free survey in line with land system approach was employed. Profile pits were dug and studied; soil samples from genetic horizons were analytically examined. Result of the findings revealed that the textural composition of the soils ranged from loamy sand to sandy loam on top soils and sandy clay loam in subsoil. Soil pH varied from very strongly acidic to moderately acidic (4.5- 6.0). Organic carbon ranged from very low to high (0.03 – 4.60 %). Total Nitrogen was very low to moderate (0.02 -0.20%). Effective Cation Exchange capacity rated low to high (2.50 – 30.60 Cmol/kg).Percentage base Saturation was very low to moderate (10-60%).Available phosphorus was low to moderate (3.80 – 13.26 Mgkg-1). Exchangeable cation was very low. The soil dominantly had argillic B- horizon (Bt) and cambic diagnostic subsurface horizon. The findings also revealed that pedon3 had acquic moisture regime because it is formed under poor drainage condition. The result indicated that pedons1 and 2, were classified as Typic Hapludults(USDA) or Haplic Acrisols(WRB) while pedon3 was classified as Typic Tropaquept(USDA) or Fluvic Cambisol(WRB). The soils were evaluated for oil palm cultivation. Hartley’s land and Soil Requirement and Suitability Rating for oil palm was employed. The results showed that although certain land qualities/ characteristics (e.g. mean annual temperature, rainfall and soil depth) were highly suitable for oil palm cultivation but because of low fertility status of the soil, pedons (1 and 2) were rated moderate Suitable(S2) while  pedon 3 with poor drainage was rated marginally suitable(S3) for oil palm cultivation. The low level of OC, N and P in these pedons makes application of organic and inorganic fertilizers necessary. In the alternative, it should be allowed to undergo long term fallow so as to improve organic matter build up in the area through litter falls, which will in turn increase ECEC of the soils.

Keywords: Soil Characterization, Soil classification, Soil Suitability Evaluation

CHAPTER ONE

INTRODUCTION

Soil is a mixture of minerals, organic matter, gases, liquids and countless organisms that together support life on earth. Soil is a natural body called the pedosphere which has important function such as a medium for plant growth (Brady and Weil, 2007).It is a natural medium for plant growth which supplies 90% of all the human food, livestock feed, fibre and fuels (FAO,1999).Characterization of soils is helpful in the appraisal of soil productivity (Ufot et al, 2001). The quest for wise use of soils calls for their characterization as a pre-requisite to proper land evaluation for various competing uses of land and knowledge of the soil properties is essential as this can affect crop yield and influence potential management for sustainable productivity (onwerenmadu et al; 2011).

Describing of soil profile, characterization, classification and mapping is a major concern in today’s world especially to pedologists, therefore to be able to attend to this standard, various techniques such as soil survey mapping, soil suitability classification, evaluation and profile pit description, technologies such as; computer soil test kit, Geographical information system (GIS), Global positioning system(GPS) and satellite imageries are being employed in modern soil survey work for characterization and classification of soils.

Ufot(2012) stated that apart from the use of modern technology in soil survey for the purpose of soil characterization and classification, the primary sources of information for soil classification are based on soil profile pit description, soil sampling and routine soil analysis. According to Ufot et al;(2001), pedology investigation and soil taxonomy is based on soil characteristics and cannot be discussed in isolation of soil genesis, presence or absence of soil diagnostic horizons. The morphological, physical, chemical and biological processes of soils are used as criteria for soil taxonomy. The soil moisture, temperature, colour, texture, structure of the soil, mineralogical properties, organic matter, soil nutrient status, clay, slit, sand, soil pH, the percentage exchangeable cations, base saturation, iron, Aluminum oxides, soil depths and other environmental factors are necessary in soil classification(Soil survey staff, 2010)

Nigerian soils derived from basic rocks have higher content of micro-nutrients than those derived from acid rocks (chude et al;1993). It is not so much in abundance or the total content of these micronutrient elements as the availability, that is crucial to plant growth, since micronutrient in most soils are ordinarily insoluble and are not easily available to plants

According to Ajiboye and Ogunwale(2010), earlier studies conducted on the soils of various regions of Nigeria and subsequent classifications were based majorly on the parent materials at the higher category classes. Soil classification study is a major building blocks for understanding the soil, classifying it and getting the best understanding of the environment. It categorizes soils on the basis of their characteristic, the USDA soil taxonomy (soil survey staff, 1975 and 1999) and the FAO UNESCO soil classification system (FAO, 2001) are the two most used classification system in Nigeria (Esu, 1999). Esu and Akpan-Idiok (2010), characterized the morphological and physio-chemical properties of alluvial soils and classified them according to the USDA soil taxonomy system( soil survey staff, 1999) and the FAO/UNESCO/ISRIC World Reference Base for Soil Resources (WRB) classification system (FAO, 2001). The soils met the requirement as entisols and vertisols.

Oil palm (Elaesis guineensis) is a tropical tree crop which is mainly grown for industrial production of vegetable oil. It is a typical crop of the humid tropical lowlands. The tree requires a deep soil, a relatively stable high temperature and continuous moisture throughout the year. Decrease in oil palm production in the study area has become a serious problem to dwellers, deforestation is in the increase despite the use of inorganic and organic fertilizers.

Palm plantation owners reports that output of production is still low compared to the input, some marginal lands not meant for oil palm production are now being used in order to increase the supply of oil palm product in the market. Due to the losses recorded by oil palm farmers in the study area probably because of inadequate soil information supporting oil palm production and management, it is of paramount importance to conduct soil survey of the area for the purpose of characterization and classification of soils supporting oil palm production in the area as to ensure food security and wealth creation.

  1. Objectives of the Study

The aim of the study was to characterize and classify soils supporting oil palm production in Obio Akpa community.

The specific objectives included:

  1. To determine physical and chemical characteristic of soil of the study area.
  2. To classify soils supporting oil palm production in Obio- Akpa Community Akwa Ibom State, using USDA Soil Taxonomy and correlate with WRB soil classification system for effective management purposes.