EFFECTS OF INTEGRATED APPLICATION OF UREA AND SAWDUST ASH ON SOIL AND PLANT NUTRIENTS AND OKRA (Abelmoscus esculentus (L.) Moench) PERFORMANCE

Abstract

Trials were conducted at Emmanuel Alayande College of Education, Teaching and Research Farm, Lanlate, Southwest Nigeria in 2012 and 2013 to investigate effects of combined applications of Sawdust Ash (SDA) and Urea (U) as fertilizer in okra production. There were six treatments replicated three times in a Randomized Complete Block Design (RCBD). The treatments were; a control, Urea at 240 kgha-1, 180 kgha-1 Urea + 1 .5tha-1SDA, 120kgha-1 Urea + 3.0 tha-1 SDA, 60 kgha-1 Urea + 4.5 tha-1 SDA and 6 tha-1 SDA alone. Soil chemical properties, plant nutrients content, growth and yield parameters were evaluated. Data were analyzed using Analysis of Variance (ANOVA) and Duncan Multiple Range Test were used to compare the treatment means. The test soil was marginal in organic matter, inadequate in available P and slightly acidic. SDA and its combination with Urea increased soil N, available P, exchangeable K, Ca and Mg significantly. Urea increased plant N, P, K and Ca in 2012 and 2013. SDA and its combinations with Urea increased plant N, P, K, Ca and Mg significantly. SDA and its combinations with reduced rates of Urea significantly increased number and weight of fruits. The 60 kgha-1 urea + 4.5 tha-1 SDA increased pod weight significantly in both years. Relative to control, Urea alone, 180 kgha-1 Urea + 1.5 tha-1 SDA, 120 kgha-1 Urea + 3.0 tha-1 SDA, 60 kgha-1 Urea + 4.5 tha-1 SDA, and 6.0t/ha-1SDA increased pod weight by 29, 32, 37, 52 and 39% respectively. Combination of 60kgha-1 Urea + 4.5 tha-1SDA is recommended.