Influence of Lime and Gypsum Application on Soil Properties and Tuber Initiation of Cassava(manihot Esculenta Crantz.) in a Degraded Ultisols in Agbani, Enugu Southeastern Nigeria

The experiment was carried out to examine the influence of Lime and Gypsum on soil physicochemical properties in a degraded ultisol during 2013 and 2014 Rainy season in Agbani, Enugu Southeastern Nigeria (60 29’N and 70 54’E). A Randomized Complete Block Design (RCBD) using Lime and Gypsum as treatments at the rate of Lime 5000 kgha-1, Gypsum 2500 kgha-1, Lime 5000 kgha-1 + Gypsum 2500 kgha-1 and Control, replicated five (5) times using cassava (TMS 0304) as test crop that was adopted. At 90 DAP in each of the season, the results showed a significant treatment difference in pH when treated with Lime 5000 kgha-1 (7.6), Gypsum 2500 kgha-1 (7.5), Lime 5000 kgha-1 + Gypsum 2500 kgha-1 (7.5) and Control 6.7. Post soil Ca2+ content of the soil was highly influenced by Lime 5000 kgha-1 (4.7 cmol/kg), Gypsum 2500 kgha-1 (3.6 cmol/kg), Lime 5000 kgha-1 + Gypsum 2500 kgha-1 (5.2 cmol/kg) and Control (2.4 cmol/ kg). Available P was also significantly influenced by Lime 5000 kgha-1 (13.9 cmol/kg), but Gypsum 2500 kgha-1 and Control had no influence on the available P (7.6 cmol/kg) whereas Lime 5000 kgha-1 + Gypsum 2500 kgha-1 reduced it to 5.7 cmol/kg. Base saturation was significantly increased by Lime 5000 kgha-1 to 75.3 %, Gypsum 2500 kgha-1 to 91.6 %, Lime 5000 kgha-1 + Gypsum 2500 kgha-1 to 93.0 % and Control to 72.8 %). The results indicated a significant treatment effect on Bulk density. It was reduced by Lime 5000 kgha-1 to 1.60 gcm-3, Gypsum 2500 kgha-1 to 1.52gcm-3, Lime 5000 kgha-1 + Gypsum 2500 kgha-1 to 1.44 gcm-3 while Control stagnated it to 1.68 gcm-3. Similarly total porosity was influenced by Lime 5000 kgha-1 (39.7 %), Gypsum 2500 kgha-1 (42.9 %), Lime 5000 kgha-1 + Gypsum 2500 kgha-1 (45.90 %) and Control (36.8 %) while saturated hydraulic conductivity (35.7 cm/hr, 37.6 cm/hr, 41.4 cm/hr and 31.9 cm3 /hr) was also significantly influenced by Lime 5000 kgha-1, Gypsum 2500 kgha-1, Lime 5000 kgha-1 + Gypsum 2500 kgha-1 and Control respectively. At 90 DAP in each of the seasons, there were significant treatment influences on cassava tuber initiation which resulted to mean tuber yield of 2.6 kg by Lime 5000 kgha-1, 3.9 kg by Gypsum 2500 kgha-1, 6.2 kg by Lime 5000 kgha-1 + Gypsum 2500 kgha-1 and 2.1 kg by Control. However this significant treatment influence found at 5 % level of probability can be attributed to the influence of the treatments on the physical properties of the soil which increased the soil and vegetative functionality of the study site. Key words: lime, Gypsum, soil properties, tuber initiation, degraded ultisol