Micronutrient Concentrations of Cassava Continuously Cultivated Soils in Ezinihitte Mbaise LGA Imo State, Nigeria

The study was conducted to determine the concentrations of micronutrients (Copper (Cu), Zinc (Zn), Iron (Fe), Molybdenum (Mo) and Manganese (Mn)) in soils of Ezinihitte Mbaise LGA Imo State. The research was conducted in cassava continuously cultivated areas Obizi, Eziudo, Onisha and Udo in Ezinihitte to trace the role of micronutrient in the decline of Cassava yield in the area. Samples were collected randomly using soil auger from each locations at a depth of 0-30 centimeter (cm). Control (reference) soils were collected the same way but from fallow land of 5years old. Samples were treated and analyzed routinely and micronutrients (Cu, Zn, Fe, Mo and Mn) determined using Atomic Adsorption Spectrophotometer (AAS). The result (table 1) revealed that Samples have same soil texture -Loamy Sand (LS) but differ in pH significantly (p<0.05). The samples are acid soils of moderately acidity, and levels ranges from 5.00 to 5.44 (lowest to highest) with mean value of 5.21. For % Nitrogen N, % Organic Matter (OM), % Base Saturation (BS), Available Phosphorus (Av. P), Potassium (K), Magnesium (Mg), Calcium (Ca), Sodium (Na), EA (Ea) and Effective Cation Exchange capacity (ECEC). They were significantly affected by cultivation and have mean values (P -1.57, N -1.33, K-1.60, OM 2.79, BS-74.3, Mg-2.46, Ca-1.47, K-0.15, Na-0.13, Ea-1.48 and ECEC-5.47) (table 1). This is a common characteristics of moderate to low fertility soils. The micronutrient levels were also significantly different. Cassava cultivation affected micronutrients levels significantly at p<0.05 (table2). The decrease were observed in all samples, and were significantly lower when compared with control. For Zn, Cu, Mo, Fe and Mn, the mean values are 6.05 Zn, 1.60 Cu, 1.09 Mo. 4.61 Fe and 4.90 Mn respectively. Micronutrients though significantly different between samples, and lower when compared with control, all (including control) were at low levels at which deficiency can occur when compared with critical nutrient levels (table 3).