ABSTRACT

Four field experiments each in two cropping seasons were conducted at the Teaching and Research Farm of the University of Calabar, Calabar, between 2005 and 2007 to study the effect of sowing date on the growth and yield of two varieties of rice (FARO 44 and FARO 52); to determine the effect of nitrogen sources and rates on the growth and yield of rice; to evaluate the effects of intercrop ratio on the productivity of rice cultivar FARO 15 / Muduga intercrop system, and to ascertain the most suitable time to introduce component cultivars and the effect of spatial arrangement on rice cultivar mixture. The experiment on the effect of sowing date and variety was laid out as a split plot in randomized complete block design. The experimental design for nitrogen sources and rates studies was factorial in randomized complete block design. The experimental design for the intercrop studies involving intercrop ratio was a simple randomized complete block while that of time of introduction of component cultivars and spatial arrangement was laid out as factorial in randomized complete block. For each experiment, replication was thrice. Results indicated that optimum planting date for rice is May or June. Planting early in April resulted in yield depression of 37% in 2005 and 42% in 2006 while delay in planting up to July resulted in yield depression of 34% in 2005 and 2006. FARO 52 out yielded FARO 44 by 24% in 2006 and 31% in 2007. The moderate fertilizer rate of 50kgN/ha gave optimum yield under the condition of the experiment but a higher economic return would be obtained by adopting the application rate of lOOkgN/ha.Nitrogen source did not produce any significant effect on grain yield. Rice cultivars FARO 15 and Muduga can be successfully intercropped. On the basis of combined grain yield and gross monetary value, the best crop combinations were at the ratios of 1:4 and 2:3 Muduga to FARO 15, while the optimum time of introducing FARO 15 was 2 weeks before Muduga.