Performance of Upland Rice Fitted into Lowland Rice–Vegetable/Cowpea Sequence in Rainfed Inland Valley

The inland valleys (IVs) have the potential of growing three crops in sequence within a year without supplemental irrigation. Considerable opportunity exists for growing the third crop between main crop and dry season cropping. This is a niche that has not been exploited. Field experiments were conducted at the University of Agriculture, Abeokuta, Nigeria in 2000–2003 to determine the growth and yield performance of upland rice ( Oryza sativa L.) in lowland rice–upland rice–fallow, lowland rice–upland rice–cowpea [ Vigna unguculata (L.) Walp], and lowland rice–upland rice–vegetable sequences in an IV. Lowland rice–upland rice–fallow, lowland rice–upland rice–cowpea, lowland rice–upland rice–okra ( Abelmoschus esculentus L.), lowland rice–upland rice–amaranth ( Amaranth cruentus ), lowland rice–fallow–fallow, lowland rice–fallow–cowpea, lowland rice–fallow–okra, and lowland rice–fallow–amaranth sequences, which ran concurrently constituted a cropping cycle. The first, second, and third crops in all the cropping cycles were planted in May, October and January, respectively. The grain yields of preceding lowland rice in the various sequences with or without upland rice were similar. The preceding lowland rice variety BW 311‐9 enhanced the height and grain yield performance of upland rice. The grain yields of the two upland rice varieties in the existing niche were similar in the three‐crop sequence but substantially lower than the obtainable yield in an upland ecology. Upland rice crop could be grown in between the lowland rice and vegetable/cowpea without reducing the yields of lowland rice and vegetable. Inclusion of upland rice in the sequence decreased the overall benefit/cost ratio of triple cropping. Thus, two‐crop sequence, which is currently being practiced by the traditional farmers, should be adhered to, until a suitable crop or technology is identified.