Abstract

The effects of cassava/legume intercrop-rice relay and weed management practices on weed infestation, growth and yield of rice were investigated at Badeggi, Southern Guinea Savanna of Nigeria in 2011 to 2013 cropping seasons. The treatments consisted of factorial combination of cassava (IIT 427) intercrop with: Mucuna or Velvet bean [Mucuna pruriens (L.) DC.], Cowpea [Vigna unguiculata (L.) Walp.], Soybean [Glycine max (L.) Merr.], Hyacinth bean [Lablab purpureus (L.) Sweet.] and Porcupine Jointvetch (Aeschynomene histrix Poir.) and weed management practices: (i) application of propanil at 1.44 kg a.i ha-1 plus 2,4-D at 0.80 kg a.i ha-1 (Orizo Plus®) at the rate of 2.24 kg a.i ha-1 at three weeks after transplanting (WAT) rice followed by hoeing at 6 WAT, (ii) two hoeing at 3 and 6 WAT, (iii) one hoeing at 3 WAT, and (iv) weedy check with sole cassava and natural fallow as control laid in a split plot arranged in a randomized complete block with three replications. Across cassava/legumes intercrops, cassava/mucuna had lower weed density and dry matter, cassava/Aeschynomene and cassava/cowpea produced comparable taller rice plants, more rice panicles and paddy yield, and cassava/Aeschynomene produced greater number of rice tillers. Irrespective of the weed management practices, two hoeing at 3 and 6 WAT gave better weed control, taller rice plants, greater number of tillers and panicles, and higher paddy yield comparable to application of Orizo Plus® at 3 WAT followed by one hoeing at 6 WAT. This study suggests that sustainable weed control with Mucuna intercrop and rice productivity with Aeschynomene and cowpea intercrops can be achieved with two hoeing at 3 and 6 WAT or application of Orizo Plus® at 3 WAT followed by hoeing at 6 WAT in this agro-ecology of Nigeria.

Key words: Intercrops, legumes, Oryza sativa L., paddy yield, weed suppression.