Field trials were carried out in the rainforest agroecological zone of Nigeria to assess the usefulness of the CERES-maize model as a decision support tool for optimizing growth and yield production of maize crop through varying application of organic manure as well as recommended Nitrogen Phosphorus Potassium (NPK) 20:10:10 fertilizer rate. The experiment was laid in a Randomized Complete Block Design (RCBD) in three (3) replications. The trial was conducted in the 2016 growing season at the Teaching and Research Farm, Federal University of Technology, Akure to calibrate and evaluate the performance of three maize cultivars (Suwan-1-SR-Y, ART/98/SW1 and ART/98/SW6 respectively) using sunshine organic manure applied at the rate of 0, 60, 90 and 120 kg N ha -1 and NPK 20:10:10 applied at a recommended rate of 70 kg N ha -1 . Model performance across fertilizer management was evaluated using some statistical indicators such as Mean Square error (RMSE), Mean bias error (MBE), and R 2 to measure its efficacy. Results showed that the model predicts accurately maize grain yield and total biomass with NPK 20:10:10 at 70 kg N ha -1 better than different rates of sunshine organic manure application for all the maize cultivars. The result further showed good agreement between the model predicted and observed data with low RMSE of ≤ 1 day for anthesis and ≤ 5 days for physiological maturity while the total leaf number ranged from 1.9 to 2.7. Model accuracy for predicting grain yield and total biomass was also good, for both the calibration and validation with lowest RMSE and NRMSE of the observed mean values.

Organomineral formulations are low input technology fertilizers, which combine the attributes of both organic and inorganic fertilizers. A completely randomized design (CRD) pot experiment was conducted in the screen house of the Department of Crop, Soil and Pest Management, of the Federal University of Technology, Akure, to evaluate the residual effects of neem Azadirachta indica A. Juss. (Sapindales: Meliaceae) seed based fertilizer and NPK 20:10:10 on the growth, yield and nutritional quality of Basella alba L. (Caryophyllales: Basellaceae). Results showed that the plots previously treated with neem seed-based fertilizer especially at 150-300 kg/ha enhanced the growth, yield and nutritional quality of B. alba, and increased these parameter significantly (P < 0.05) compared to the NPK treated and the untreated soil samples. It was therefore concluded that the Neem seed based fertilizer can serve as a viable alternative to NPK chemical fertilizers especially in rotational cropping systems owing to its prolonged soil action.