ISSN 2167-0447
International Journal of Agricultural Sciences ISSN 2167-0447 Vol. 5 (7), pp. 878-885, September, 2015. © International Scholars Journals
Full Length Research Paper
Effect of nitrogen rates on the growth and yield of three rice (Oryza sativa L.) varieties in rain-fed lowland in the forest agro-ecological zone of Ghana
Buri Mohammed Moro*, Issaka Roland Nuhu, Essien Ato and Biney Nathanial
CSIR – Soil Research Institute (SRI), Academy Post Office, Private Mail Bag, Kwadaso – Kumasi, Ghana.
Corresponding Author.E-mail: [email protected]. Tel. 231-880005361.
Accepted 28 July, 2015
Abstract
Nitrogen is not only a major nutrient but most often the most limiting nutrient element in lowland ecologies. With the introduction of improved soil and water management ('sawah system) for lowland rice production, a study was conducted to determine the optimum nitrogen rate required. A randomized complete block design arranged in a split plot consisting of five levels of nitrogen as main treatments and three improved rice varieties as sub-treatments was adopted. Results showed that total number of tillers per m2 increased significantly with increasing levels of N as was total dry matter production. However, total number of panicles did not show the same relationship. Total biomass yield increased significantly and linearly with increasing levels of N. Paddy yield significantly increased from 1.7t ha-1(control) to a maximum of 9.4t ha-1 (90kgN ha-1) before declining to 5.8 t ha-1 (150kgN ha-1) in the order: 0 < 30 < 60 < 150 < 120 < 90kgN ha-1respectively. This result significantly and positively reflected on grain harvest index (GHI) in the order: 0.27 < 0.38 < 0.46 < 0.47 < 0.57 < 0.68 for 0, 30, 60, 150, 120 and 90kgNha-1respectively. Nitrogen at 90 kgN ha-1was therefore recommended.
Key words: Forest agro-ecology, Ghana, rain-fed lowland, nitrogen fertilization, yield.