EFFECTS OF NITROGEN RATES AND PRECEDING CROPS ON THE GROWTH AND PRODUCTIVITY OF UPLAND RICE IN INLAND VALLEY

The study was conducted to determine the effects of upland rice and lowland preceding varieties, and
N fertilization on growth and productivity upland rice grown the same year in two locations in the
inland valley of Nigeria. The experiment was split plot design with two preceding lowland rice
-1 varieties (Jasmine and Funaabor-2) as main plots and five levels of N (0, 30, 60, 90 and 120 kg N ha )
for the succeeding upland rice as split plot treatments with 3 replications. Results showed that upland
rice grown after FUNAABOR-2 variety gave significant (p < 0.05) number of leaves, chlorophyll
2
content, number of tillers, dry matter, panicle per m , panicle weight and grain yield than Jasmine
variety was the preceding crop. Rice grown after Funaabor-2 exhibited 54% grain yield increments
compared to growing Jasmine in Igbogila. The effects of preceding lowland rice varieties on the yield
-1 components and grain yield of upland rice was pronounced more in Alabata (671 kg ha ) than Igbogila
-1 -1 (1077 kg ha ). Similarly, linear responses to N application from 0-120 kg ha were observed on the
growth and yield components of rice in both locations. Thus, Cultivation of Funaabor-2 and
-1 increasing the rate of N application from 90 to 120 kg ha is recommended to boost rice growth and
yield, increase profitability and to enhance long-term sustainability of the cropping system in inland
valley.

本研究旨在明确旱地稻（upland rice）与前茬低地稻（lowland rice）品种，以及氮肥施用，对同年种植于尼日利亚内陆河谷两个试验点的旱地稻生长与生产性能的影响。本试验采用裂区设计（split plot design），主区设置2个前茬低地稻品种：茉莉（Jasmine）与FUNAABOR-2；裂区处理为后续种植的旱地稻施加的5个氮肥水平：0、30、60、90及120 kg·ha⁻¹纯氮，共设置3次重复。结果表明，以FUNAABOR-2为前茬作物的旱地稻，其叶片数、叶绿素含量、分蘖数、干物质积累量、每平方米穗数、穗重及籽粒产量均显著（p < 0.05）高于以Jasmine为前茬的处理。在Igbogila试验点，以FUNAABOR-2为前茬的水稻籽粒产量较Jasmine前茬提升54%。前茬低地稻品种对旱地稻产量构成因子与籽粒产量的影响，在Alabata试验点（671 kg·ha⁻¹）较Igbogila试验点（1077 kg·ha⁻¹）更为显著。同样，两个试验点均观测到，在0~120 kg·ha⁻¹的施氮范围内，氮肥施用对水稻生长及产量构成因子呈线性响应。据此，本研究建议种植FUNAABOR-2品种，并将施氮量从90 kg·ha⁻¹提升至120 kg·ha⁻¹，以提升水稻生长与产量水平，提高种植收益，并增强尼日利亚内陆河谷种植系统的长期可持续性。