INFLUENCE OF TWO LAND USE SYSTEMS ON SOIL PROPERTIES AND MICROBIAL BIOMASS IN COASTAL PLAIN SANDS OF AKWA IBOM STATE, NIGERIA

Godwin Umoren Akpan and Ubong Samuel Udoma

ABSTRACT

A research to investigate the influence of two land use systems (Organic farming (OF) and conventional farming (CF)) on soil properties and microbial biomass was carried out between 2019 and 2021 at the Department of Soil Science and Land Resources Management, University of Uyo, Nigeria. Soil samples were collected from three local government Areas (Ikot Ekpene, Uyo and Itu) where these agricultural practices are located at three different depths (0-10, 10-20 and 20-30cm). The soil samples were conveyed to the Soil Science Laboratory for the assay of soil physico chemical properties and microbial biomass. The results showed that sand particle ranged from 771.30 – 849.60 gkg^-1 with a mean of 738.89 ± 22.72 gkg^-1 , silt fraction ranged from 2.50-14.30 gkg^-1  with a mean of 9.40 ± 3.74 gkg^-1 , Clay fraction ranged from 136.40 – 220.40 gkg^-1  with a mean of 181.43 ± 25.25 gkg^-1 soil giving a textural class as Sandy loam in Organic farm (OF), whereas in Conventional farm, sand fractions ranged from 802.0 – 938.0 gkg^-1  with the mean of 867.32 ± 44.49 gkg^-1 , silt fraction ranged from 6.0 – 49.20 gkg^-1  with a mean of 25.94 ± 15.28 gkg^-1  and Clay fractions ranged from 49.0 – 174.0 gkg^-1  with a mean of 106.73 ± 35.81 gkg^-1  giving rise to Loamy sand texture. Saturated hydraulic conductivity (ksat) in OF soil ranged from 0.67 – 1.78Cmhr^-1 with a mean of 1.13 ± 0.33 Cmhr^-1 , Bulk density (BD) ranged from 669.0 – 132.0 Mgg^-3 with a mean of 1007.89 ± 17.0 Mgg^-3 and total porosity of 50.15 – 74.75% with a mean of 61.97%, For conventional soil (Ksat range) from 0.55 – 1.43 Cmhr^-1 with a mean of 1.02 ± 0.35 Cmhr^-1, BD ranged from 578.0 – 1461.0 Mgg^-3 and TP ranged from 44.87 – 78.19% with the mean of 58.87 ± 11.8%. Chemical properties of the soil revealed that OF soil had very high organic carbon (23.91 gkg^-1) while CF had medium (14.91 gkg^-1 ), OF soil had medium total nitrogen (1.04 gkg^-1 ), CF had low (0.65 gkg^-1 ), available P was high in OF soil, while CF soil had medium, exchangeable Ca was high in both OF and CF soils while exchangeable Mg was high in OF soil and low in CF soil, K was low in OF and very low in CF soil respectively. pH was slightly acid in OF and acid in CF soils respectively. Microbial biomass Carbon (MBC) was higher in OF soil than CF soil. Microbial biomass Nitrogen (MBN) was very low in the two land use types with a wide coefficient of variability (CV) of 34.93% in CF soil, Microbial biomass phosphorus (MBP) also had wide CV in CF soil (50%) compared to the OF soil with (21.12%). The application of organic manure to soils significantly enhanced both soil physical and chemical properties. The OF soil resulted in reduction in Bulk density and increased soil pH.

Keywords: Land Use Systems, Coastal Plain Sands, Microbial Biomass.