Impact of the use of Inorganic Fertilizers to the Soils of the Ebonyi State Agro-Ecology, South-Eastern Nigeria.

Abstract

There is the fear that long term application of inorganic fertilizers to the soils of the Ebonyi state Agro- ecology could have contributed to the soils productivity constraints.  A study was therefore conducted in the major crop production communities, representing the major soils of the state, to assess the impact of long term use of inorganic fertilizers on the soils.  Soil samples were collected from fifteen different farm locations that have the records of continuous application of inorganic fertilizers and analyzed for their physical characteristics, chemical properties, and microbial population. The Results of the analysis indicated that the soils were very strongly Acidic to strongly acidic (4.0-5.6), whereas exchangeable acidity (EA) was very high across the entire locations. Organic carbon (OC) ranged from low to high (0.51-1.84); Cation Exchange Capacity (CEC) was very low across the locations (1.65-4.5), whereas base saturation ranged from very low to low (42.06-50.10). Total Nitrogen and exchangeable phosphorus ranged from moderate to medium (0.09-0.19 and 5, 70-24.8); potassium, calcium, magnesium and sodium ranged from very low to low (0.05-0.32; 0.86-5.10; 0.30-2.0 and 0.09-0.25) respectively across the locations. The soil microbial populations were however stable and consistent with normal microbial population for natural agricultural soils. The application of lime and complementary use of organic manure and mineral fertilizers were recommended as a sound fertility management strategy for these soils.

Key Words: Inorganic Fertilizers; Soil Acidity; Nutrient elements; Microbial population; Soil fertility.