EVALUATION OF PLANT SPACING, SEEDLING AGE, AND IRRIGATION METHODS UNDER THE SYSTEM OF RICE INTENSIFICATION IN THE BAKOLORI IRRIGATION SCHEME, NORTHERN NIGERIA

Production of rice, an important staple food crop in Nigeria, remains about 40% below the demand of its growing population. The System of Rice Intensification (SRI) represents an opportunity for increasing rice yields in a sustainable manner. The Bakolori Irrigation Scheme (BIS) in northern Nigeria is a large irrigation site with more than 80% of its command area under rice production. Using Farmer Field School approach, three sets of participatory on-farm trials were conducted in 2018 and 2019 under the World Bank-funded TRIMING project to evaluate the effects on paddy yield with four plant spacings (20 cm x 20 cm, 25 cm x 25 cm, 30 cm x 30 cm, farmers' practice); seven seedling ages (9, 11, 13, 14, 16, 18, >21 days); and two irrigation practices (alternate-wetting-and-drying vs. continuous flooding). This was to assess what would be the best practices under given agroecological conditions. For each trial, all SRI principles were applied with the treatment being tested being varied. In each of five BIS sectors, 5 to 7 farmers were selected to conduct trials on their fields. Each treatment was laid out in a basin of 60 square meters (60 m2), with total trial N=260. Data were collected on total number of tillers/plant and tillers/m2, number of productive tillers/plant and per m2, non-productive tillers, number of spikelets/panicle, and paddy yield. From two years of trials, it was found that transplanting rice seedlings at a spacing of 25 cm x 25 cm gave the best paddy yield (11.4 t/ha) while lowest yield (6.2 t/ha) was obtained under farmers' practice. In the second set of trials, highest yields were obtained from plots transplanted with 11-day-old seedlings (10.2 t/ha), 88% higher than yields under farmers' practice. The third set of trials resulted in paddy yields of 10.5 t/ha under alternate wetting and drying, exceeding yields with continuous flooding by 128%. Similar trends were observed for the other growth and yield parameters collected from the trials. Based on these results, plant spacing of 25 cm x 25 cm, seedling age of 11 days old, and irrigation by alternate wetting and drying cycle was recommended for BIS and other irrigation schemes in northern Nigeria