Phosphorus (P) deficiency resulting from P fixation is a major constraint limiting sustainable rice cultivation in sub-Saharan Africa. Soil texture also affects P availability and use efficiency. In a factorial experiment, we evaluated the combined effect of soil texture (sand, clay loam, and clay) and P treatments P-dipping (Pdip) and two other broadcasted P fertilizer levels (Brod1 and Brod2) on the growth of NERICA 4 rice in the initial growth stages. Across all soil textures and P treatments, total plant biomass ranged from 1.06 to 4.63 g pot⁻¹. The Pdip treatment significantly increased shoot and root biomass relative to control from 1.27 to 1.98 and 0.23 to 0.38 g pot⁻¹, respectively. Mean photosynthetic rate values under Pdip (20.1 μmol m⁻² s⁻¹), Brod2 (19.5 μmol m⁻² s⁻¹), and Brod1 (19.3 μmol m⁻² s⁻¹) treatments showed significant 42%, 37%, and 36% increases over control, regardless of soil texture. In a striking contrast, P-dipping significantly promoted growth of root length under clay soil, but without a commensurate increase in shoot P uptake. Contrary to our hypothesis, the interactive effect of soil texture and P-dipping influenced NERICA 4 shoot and root physiological and morphological characteristics under clay loam soil texture as opposed to clay.

Cassava plants’ response to waterlogging must be monitored in an accurate and timely manner to mitigate the adverse effects of waterlogging stress. Under waterlogging conditions, root hypoxia reduces water uptake and stomatal closure limits transpiration, which often results in increased leaf temperature due to reduced evaporative cooling. However, how this relationship changes in cassava leaves under waterlogged conditions remains poorly known. This study hypothesized that a cooler canopy is more critical for better performance under waterlogging stress in various cassava genotypes. Two cassava cultivars were subjected to twelve days of waterlogging. Results revealed a significant decrease in photosynthetic rate, stomatal conductance, and transpiration, and an increase in leaf temperature and ΔT, reflecting impaired stomatal regulation and reduced evaporative cooling. Strong negative correlations between ΔT and photosynthetic parameters were observed presenting ΔT as a reliable, nondestructive indicator of cassava’s physiological responses under hypoxic conditions. Findings indicate that maintaining cooler canopies may contribute to enhanced tolerance and survival under waterlogging. ΔT can be used as a practical screening tool for identifying and selecting waterlogging-tolerant cassava genotypes. However, further studies involving contrasting cultivars and additional parameters such as leaf relative water content, and leaf anatomy are recommended to validate and strengthen reported findings.

Phosphorus (P) deficiency is a major constraint limiting sustainable rice cultivation in sub-Saharan Africa—partly due to the deeply weathered soils that have low pH and contain high P-fixing Fe and Al oxides. Soil texture also affects P availability and use efficiency. In this study, we evaluated the combined effect of soil texture (sand, clay loam, and clay) and P treatments (P-dipping and two other P fertilizer levels) on growth of NERICA 4 rice in the initial growth stages. In a factorial experiment, we measured the interaction effects of soil texture and P treatments on shoot parameters and root morphology. Both treatments had significant interaction effects on all measured parameters, except shoot biomass, and affected the photosynthetic rate, with the highest mean values obtained under clay loam soil texture and P-dipping treatment, respectively. The treatments also affected rice root morphology. In a striking contrast, whereas mean root length under clay was significantly higher than that under clay loam texture, mean shoot P uptake under clay loam soil was significantly higher than that under clay soil texture. The interactive effect of soil texture and P-dipping influenced NERICA 4 shoot and root physiological and morphological characteristics under clay loam soil texture.

Cassava plants’ response to waterlogging must be monitored in an accurate and timely manner to mitigate the adverse effects of waterlogging stress. Under waterlogging conditions, root hypoxia reduces water uptake and stomatal closure limits transpiration, which often results in increased leaf temperature due to reduced evaporative cooling. However, how this relationship changes in cassava leaves under waterlogged conditions remains poorly understood. This study hypothesized that more negative ΔT values reflect enhanced transpirational cooling, which is a key determinant of superior physiological performance under waterlogging stress among cassava genotypes. Two cassava cultivars were subjected to twelve days of waterlogging. Results revealed a significant decrease in photosynthetic rate (p < 0.001), stomatal conductance (p < 0.001), and transpiration rate (p < 0.001), as well as an increase in leaf temperature (p < 0.001) and ΔT (p < 0.001), reflecting impaired stomatal regulation and reduced evaporative cooling. Strong negative correlations between ΔT and photosynthetic parameters (Pn (p < 0.001, r = −0.91), gs (p < 0.001, r = −0.91), and E (p < 0.001, r = −0.87)) were observed, presenting ΔT as a reliable, nondestructive indicator of cassava’s physiological responses under hypoxic conditions. Findings indicate that maintaining cooler canopies may contribute to waterlogging-tolerant cassava genotypes, and that ΔT can act as a screening parameter for waterlogging-tolerant genotypes. However, further studies with contrasting genotypes and additional parameters are recommended for validation.