Combined influence of ash and poultry manure on soil reaction and performance of maize (Zea mays) in a coarse-textured acid soil of South-East, Nigeria

Crop production can be limited by soil acidity. A two-factor factorial experiment involving three levels each of ash and poultry manure  (PM) was conducted to determine the effects of ash and PM on soil reaction and performance of maize in an acid soil. The ash comprised  of mixture of ash from wood, cocoa husk and palm bunch. The levels of ash (0.00, 3.00, 6.00 t ha–1 ) and PM (0.00, 4.00, 8.00 t ha–1 ) were  combined to obtain nine treatment combinations (control, 3.00 ash and 0.00 PM, 3.00 ash and 4.00 PM, 3.00 ash and 8.00 PM, 0.00 ash and  4.00 PM, 3.00 ash and 0.00 PM) which were replicated thrice. The experiment was laid out in a randomized complete block design.  Soil samples were collected at 3, 6, 9 and 12 weeks after planting (WAP), plant height measured at 3, 5, 7, and 9 WAP while cob oven-dry  weight was measured after oven-drying harvested cobs at maturity. Analysis of variance was conducted on the data collected using  GenStat version 14. The highest plant height of 132.50 cm at 12 WAP and the highest oven-dry cob weight of 7.15 t ha–1 were obtained  from plots treated with 6.00 and 8.00 t ha-1 of ash and PM, respectively, and these were significantly (p ≤ 0.05) different from the other  treatments. The lowest exchangeable acidity of 1.33 cmol kg–1 which varied significantly (p ≤ 0.05) from the other values observed at the  other plots was obtained at the plot treated with the combination of 6.00 and 4.00 t ha–1 of ash and PM, respectively at 12 WAP. The  combination of ash and PM at 3.00 and 8.00 t ha–1 gave the highest pH of 6.80, and this was significantly (p ≤ 0.05) different from the other treatments. Therefore, ash and PM at varying levels of combination can simultaneously ameliorate soil acidity and improve maize  performance; however, the best combination of ash and PM application which showed the potential to produce optimum effect in  simultaneously ameliorating soil acidity and increasing maize performance was the combination of 6.00 tonnes of ash and 8.00 tonnes of  PM.