Evaluating Changes In Fertility Status Of An Alfisol Under Different Growth Stages Of Cassava (Manihot Esculenta Crantz)
Key words: Alfisol, cassava, evaluating, fertility, growth, status
Abstract: Evaluating changes in soil nutrient status under different growth stages of cassava, makes possible determination of the most critical stage in its vegetative growth phase, when its demand for nutrients is highest. Determining the most critical stage in cassava vegetative growth phase, when its nutrient demand is highest, will enhance properly timed fertilizer application in such a way the application will coincide with the most critical stage in cassava vegetative phase when its demand for nutrients is highest. In view of this, a two – year field experiment was designed to assess changes in nutrient status of an Alfisol under different growth stages of cassava during 2010 and 2011 cropping seasons at the Teaching and Research Farm of the Ekiti State University, Ado – Ekiti, Ekiti State, Nigeria. The experiment was laid out in a randomized complete block design with three replicates. The different growth stages of cassava when changes in nutrient status of Alfisol were evaluated included: 3, 6, 9, and 12 months after planting (MAP). The results indicated existence of significant (P = 0.05) differences among the different growth stages of cassava as regards their effects on chemical properties of Alfisol. During 2010 cropping season, the significant decreases in soil organic carbon (SOC) under growth stages of cassava were from 0.96 g kg-1 for ISNSPTC to 0.88, 0.80, 0.72 and0.64 g kg-1 for ages 3, 6, 9 and 12 MAP, respectively. Similarly, during 2011 cropping season, the significant decreases in soil organic carbon (SOC) under growth stages of cassava were from 0.96 g kg-1 for ISNSPTC to 0.80, 0.73, 0.66 and0.58 g kg-1 for ages 3, 6, 9 and 12 MAP, respectively. During 2010 cropping season, the significant decreases in total N under growth stages of cassava were from 0.68 g kg-1 for ISNSPTC to 0.57, 0.50, 0.43 and0.35 g kg-1 for ages 3, 6, 9 and 12 MAP, respectively. During 2011 cropping season, the significant decreases in total N under growth stages of cassava were from 0.68 g kg-1 for ISNSPTC to 0.54, 0.47, 0.41 and0.32 g kg-1 for ages 3, 6, 9 and 12 MAP, respectively.
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