GROWTH AND YIELD OF SUNFLOWERS UNDER ORGANIC VS. INORGANIC FERTILIZATION IN THE DERIVED SAVANNAH

A field experiment was conducted at the Department of Crop Science Teaching & Research Farm, University of Nigeria, Nsukka to determine the effects of poultry manure and NPK 20:10:10 on the growth and seed yield of sunflower (Helianthus annuus L.) in Nsukka, southeastern Nigeria. The factors were poultry manure at the rates of 0, 5, 10, and 15 t ha−1 and NPK 20:10:10 at 0, 100, 200, and 300 kg ha−1. The experiment was laid out in a 4 × 4 factorial in a randomized complete block design with three replications. Parameters measured were plant height, stem girth, number of leaves, days to 50% and 100% flowering, head diameter, head weight and seed weight per plant. Stem girth, number of leaves, head diameter and head weight increased at the application of poultry manure. Plant height and seed weight were significantly (p < 0.05) affected by poultry manure application. Application of 15 t ha−1 poultry manure gave similar seed yield per plant as 10 t ha−1 but higher than the other rates. Days to 50% and 100% flowering decreased at the application of poultry manure. All parameters were significantly affected by NPK 20:10:10, increasing with increase in the rate of NPK 20:10:10. The application of 300 kg ha−1 NPK 20:10:10 produced the highest seed yield compared to other rates. The 0 kg ha−1 NPK 20:10:10 (control) gave the lowest value for all parameters measured and the highest days to 50% and 100% flowering. Poultry manure and NPK 20:10:10 interaction consistently showed non-significant effects; however, applying them at 15 t ha−1 and 300 kg ha−1, respectively gave the highest values for all parameters. Therefore, they should be combined at these rates, otherwise sole application of either poultry manure at 15 t ha−1 or NPK 20:10:10 at 300 kg ha−1 is recommended for optimum growth and production of sunflower in the derived savannah ecological zone