Combined Application of Ureaand Sawdust Ash in Okra Production Effects on Yield and Nutrients Availability

Trials were conducted at Emmanuel Alayande College of Education Teaching and Research Farm Lanlate, southwest Nigeria in 2012 and 2013 to investigate the effects of combined applications of sawdust ash (SDA)and urea (U) as fertilizer in okra production. There were five treatments and control, replicated three times in randomised complete block design. Treatments were a control, urea at 240 kg/ ha, 180kg/ha U+1.5t/ha SDA, 120kg/ha U+3.0t/ha SDA, 60kg/ha U+4.5t/ha SDA and 6t/ha SDA. 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 Urea increased plant N, P, K and Ca in 2012 and 2013. SDA and its combinations with a reduced rate of urea significantly increased the number and weight of pods. Relative to control, urea, 1.5 t/ha SDA +180 kg/ha U, 3.0 t/ha SDA +120 kg/ha U,4.5 t/ha SDA + 60 kg/ha U, and 6.0 t/ha respectively increased pods weight by 29. 31, 37, 52, and 38%. Combination 4.5 t/ha SDA + 60 kg /ha U is recommended. SDA reduced the need for urea by 75 %.