Effect of Organic and Inorganic Fertilizers and Their Combinations on the Growth and Yield of Maize in the Semi-Deciduous Forest Zone of Ghana.

A study was conducted to characterize poultry manure and two composted materials (Household waste plus poultry manure and Market waste plus faecal sludge mixes in 3:1 ratio) based on their nutrient content and water holding capacity and to evaluate the influence of organic and inorganic fertilizers and their combination on the growth and yield of maize (Zea mays) in pot and field experiments at Soil Research Institute of CSIR, Kwadaso, Kumasi, Ghana. The treatments were studied in a complete randomized design (CRD) in the pot experiment and in a randomized complete block design (RCBD) in the field experiment with three replications each. The results were analysed by ANOVA and the standard error of differences (SED) was used to separate the means. Regression analysis was used to establish relationships between measured parameters. The experimental results showed that poultry manure was high in nutrients containing 2.06 % N, 0.52 % P and 0.73 % K whilst the composted materials were moderate in N and K but low in P. Percentage moisture of poultry manure at three stages; saturation, field capacity and 16 DAS were 119.51 %, 92.68 % and 63.41 % respectively which were higher than the values obtained under the composted materials. Water use efficiency (WUE) increased significantly with increasing dry matter production in the pot experiment. The combined treatments had WUE values higher than the values obtained by the sole organic or inorganic treatments alone. There were no significant differences (P > 0.05) in the vegetative growth of maize for the various treatments; however, the combined treatments gave higher values of plant height, girth, leaf area and number of leaves than organic and inorganic fertilizers used separately. Generally vegetative growth increased rapidly in all the treatments from 28 to 56 days after planting. The field experiment showed trends that were similar to those observed in the pot experiment. The combined applications produced yields, which were significantly higher than organic or inorganic alone and the control. The highest grain and stover yields of 8.0 tons ha-1 and 8.9 tons ha-1 respectively was recorded by the combined treatment of poultry manure with mineral fertilizer at a rate of 60 kg ha-1 N poultry manure and 60-40-40 kg ha-1 NPK mineral fertilizer, with the control recording the lowest grain and stover yields of 2.10 tons ha-1 and 4.30 tons ha-1 respectively. The combined treatments had significantly higher nutrient uptake values than the sole organic and inorganic fertilizers alone. The highest nutrient uptake values of 142.09 kg ha-1 N, 41.10 kg ha-1 P and 50.87 kg ha-1 K was recorded by the combined treatment of household waste and poultry manure mix compost with mineral fertilizer high rate. Differences in soil nutrient concentrations after harvest were marginal for all the treatments. Soil pH and total N decreased in all the treatments while percentage C and available P and K increased generally. Residual nutrients sustained maize plant growth and had yields, which were approximately 50% lower, with the sole application of mineral fertilizer as well as poultry manure high rate performing better than the combined applications contrary to what was observed in the major season.

Source: KNUST