Department of Crop Science, University of Calabar, Calabar, Nigeria
Binang, W.B., Department of Crop Science, University of Calabar, Calabar, Nigeria; Ntia, J.D., Department of Crop Science, University of Calabar, Calabar, Nigeria; Shiyam, O.J., Department of Crop Science, University of Calabar, Calabar, Nigeria
The mangrove swamp soils of the Cross River estuaq are suitable for intemive rice cultivation because of ample water supply, large level units and high Inherent fedility. However, because water is abundant, rainfall does not determine the sowing period. Field studes were conducted in 2006 and 2007 at Obufa Esuk Orok adlacent the University of Calabar Teachng and Research Fann to determine the best seeding date for two salt-tolerant rice varieties grown on a mangrove swamp soil in the Cross River estuary, southeastern Nigeria. Two mangrove rice varieties namely ROC 5 and CK 73 were raised in nurseries on 6 December, 8 January, 4 Febmary and 4 March, of each year and 30 day-old seedlings tramplanted at a plant spacing of 20×20 cm and at 2 seedlings per h11 Treatments comprised factorial combinations of four seeding dates and two varieties laid out in a split-plot design; the main- plot being the date of seeding and the sub-plot the variety. Significant varietal differences were obsenred, with CK 73 performing better than ROC 5. During the 2006 and 2007 growing seasom, paddy yield of 4.35 and 5.14 t ha-1 obtained from sowing in Febmary was higher than yieldvalues for December, January andMarchplantings by 145,276 and 18.2% (2006) and 37.9, 41.8 and 18.9% (2007). Seeding conditions in December through January were unfavorable because in the absence of water control, the frequent and unpredictable tidal water flow washed away seeds and seedlings, leading to poor germination, seedling establishment and reduction of the crop's tillering capacity and panicle formation. These conditiom were ameliorated in February- and March and the favorable solar radation levels and temperature regime that subsisted in April and May when the Febmary sown crop matured accounted for the superiority of this seeding period. It would however, be muitable to seed late-maturing varieties at this period because they would mature during the peak rains when natural drying conditions would be unfavorable. © 2012 Asian Network for Scientific Information.