Sole and complementary effect of animal manures and wood ash on maize production and P uptake in tropical soils

Information on the sole and complementary effect of wood ash and animal manures on phosphorus (P) and maize growth in literature is scarce. Therefore, this study was carried out to determine the sole effect of animal manures, wood ash, and their combined effect on P uptake and maize performance, in some alfisols of southwest Nigeria. Treatments included control, poultry manure (PM), poultry manure + wood ash (PMWA), cattle manure (CM), cattle manure + wood ash (CMWA), and wood ash (WA). Sole manures were applied at a rate of 5 tha⁻¹, wood ash at a rate of 90 kg P ha⁻¹ while mixtures of animal manure and wood ash were applied at 90 kg P ha⁻¹and 5 tha⁻¹ to soils under screen house and field conditions after which maize seeds were sown. Agronomic parameters of maize were measured fortnightly. Data collected were analyzed, and significant treatments were separated using the Duncan multiple range test. Result indicated that Maize plant height increased by 35, 33, 32, 31, 26, and 22% respectively with the single application of CMWA, PMWA, CM, PM, and WA from the 2nd to 8th weeks after planting. Furthermore, an increase of 28%, 29%, 31%, 35% and 48%, 41%, 30%, 27%, respectively, was recorded in CM, CMWA, PM, and PMWA amended pots relative to the control and WA in the screen house experiment. At 8 weeks after planting (WAP), the amendment effect was significant across all the experimental soils; an increase of 35%, 7%, and 182% in stem girth was recorded with the application of CM, respectively, relative to the control soil from Alabata, Obada, and Owode. The increase in leaf area from the 2nd week to the 8th week was in the order control (54%) < WA (58%) < CMWA (85%) < CM (87%) < PM (88%) < PMWA (114%) in the screen house. Furthermore, leaf area observed in CM, CMWA, PM, and PMWA was 178, 142, 115, and 102% higher than the control treatment. The residual effect of amendments on maize height indicated that maize plant heights in CM, CMWA, PM, and PMWA amended pots were 92, 51, 82, and 67% higher than the control. The application of PMWA significantly increased the dry matter yield of maize by 66, 135, 663, and 59% when compared to the control CM, CMWA, and PM, respectively. Phosphorus uptake in amended pots was the highest in PMWA amended pots for all the soils except soil from Obada in the first cycle of the screen house experiment. However, in the second cycle of the screen house experiment, CM had a residual effect on dry matter and P uptake in comparison to all other amendments. The percent mean increases of maize plant height from 2 to 12WAP of the field trial in plots are CMWA (26%), WA (29%), CM (30%), PMWA (30%), and PM (31%). The percent mean increases of maize stem girth were CMWA (263%), WA (316%), CM (290%), PMWA (291%), and PM (368%), and the percent mean increases of maize leaf area were WA (46%), CM (47%), PM (52%), CMWA (53%), and PMWA (54%) over the 12 weeks of the field experiment. All amendments significantly increased cob + grain yield, grain yield, and shoot yield above the control in the first and second cycle of the field experiment. Shoot P uptake was similar for all amendments in the first cycle while significant increases of 270%, 127%, and 296% were recorded in CMWA and PMWA applied plots comparative to control, PM, and WA, respectively, in the second cycle. However, the application of CMWA significantly increased grain P uptake than the control. Animal manures, wood ash, and their mixtures can increase agronomic parameters of maize, yield, and P uptake in maize under screen house and field experiments. The sole and complementary application of wood ash and animal manures is therefore recommended for maize production.