Growth and Yield Response of Masakwa Sorghum (Sorghum bicolor (L.) Moench) Cultivars to Supplementary Irrigation in a Nigeria Sahel Savanna Vertisols

Abstract

Masakwa sorghum, a post-rainy season crop is commonly grown using residual moisture without supplementary irrigation on heavy clay soils or Vertisols during cool harmattan period. Field experiments were conducted to determine response of masakwa sorghum cultivars to supplementary irrigation during 2020/2021 and 2021/2022 dry seasons in sahel savanna vertisols in Monguno Local Government Area of Borno State NE Nigeria. Four irrigation treatments applied at 0.3, 0.6, 0.9 and 1.2 liters/stand constituted the irrigation treatments, while Adja’ama and Tumbuna constituted the cultivars. The treatments were replicated three times in a Randomized Complete Block Design. Plant heights were significantly higher for 0.3, 0.6 or 0.9 liters (P<0.01) than 1.2 liters at 4 WAT, 0.6 and 0.9 liters (P<0.05) than 0.3 or 1.2 liters at 8 WAT, and 0.3 liter (P<0.01) than 0.6 or 1.2 liters at 10 WAT. Panicle length was significantly (P<0.01) greater for 0.6 and 0.9 liters, while grain yield per plant was significantly (P<0.01) greater for 0.3 liter than the other irrigation levels. Grain yield per hectare was significantly (P<0.01) greater when irrigation was applied at flower inception (0.9 liter), while the cultivar Tumbuna significantly (P<0.01) produced superior grain yield than Adja’ama. Straw yield per plant was significantly (P<0.01) greater for 1.2 liters, but harvest index was significantly (P<0.01) greater for 0.3 liter than the other treatments. The economic returns from the irrigation levels were negative as the marginal rate of returns: – N2.64, – N 0.82 and – N 0.23 for 1.2, 0.9 and 0.6 liters per stand, respectively, however, the farmer practice (0.3 liters at transplanting only) realized the net benefit of N 42,960.00 per hectare. It is apparent therefore that the flower inception is the most critical stage for moisture stress in masakwa sorghum; however, there is no economic benefit of supplementary irrigation of the sorghum cultivars after transplanting as observed from the current study.