Study of the Effect of NPK Fertiliser Rates on the Performance of Rice in Ebonyi State

Rice is the most consumed cereal in Nigeria, and optimising mineral fertiliser application for improved productivity in the lowland ecologies of South East Nigeria is critical for household food security and farmer income. This study examined the effect of varying NPK fertiliser rates on the growth and yield of rice (Oryza sativa L.) in Abakaliki, Ebonyi State, South East Nigeria. A field trial was conducted during the 2023 wet season at the Ebonyi State University Teaching Farm using a randomised complete block design with four treatments (0 kg NPK ha-1, 100 kg NPK ha-1, 200 kg NPK ha-1, and 300 kg NPK ha-1) and three replications. FARO 44 rice variety was transplanted at 21 days after seeding. Growth parameters (plant height, tiller number, and leaf area) and yield parameters (panicle number per plant, grain weight, and grain yield) were assessed. Results showed that 200 kg NPK ha-1 produced the highest grain yield of 4.56 tonnes per hectare, significantly higher than the control (2.18 t ha-1) and the 100 kg ha-1 treatment (3.41 t ha-1). Application of 300 kg NPK ha-1 did not produce a statistically significant increase over the 200 kg ha-1 rate, suggesting a yield ceiling at that input level under the prevailing soil conditions. The study concludes that 200 kg NPK ha-1 is the most productive and economically rational fertiliser rate for lowland rice in Ebonyi State and recommends its adoption with periodic soil testing to adjust nutrient rates.