Effect of Soil–Rice Husk Growing Media Ratios on Nursery Establishment and Post-Transplant Field Performance of Napier Grass (Pennisetum purpureum)

Abstract This study evaluated the effect of five soil–rice husk growing-media ratios on the nursery establishment and subsequent field performance of Napier grass ( Pennisetum purpureum ) tillers at the Sokoine University of Agriculture horticultural section, Morogoro, Tanzania. Sole soil, sole rice husk, and soil: rice husk mixtures (75:25, 50:50 and 25:75) were arranged in a completely randomized design with three replications. Tiller number, plant height, stem girth, leaf length and leaf width were recorded at three-day intervals for 22 days in the nursery and for 27 days after field transplanting. Media containing rice husk consistently outperformed sole soil. By the final nursery assessment, the 75:25 (soil:rice husk) mixture produced the tallest plants (58.5 ± 12.9 cm) against only 11.1 ± 19.2 cm for sole soil, and this advantage persisted after transplanting (67.4 ± 6.6 cm versus 15.2 ± 26.3 cm at 27 days after transplanting). One-way analysis of variance confirmed significant treatment effects (p < 0.05) on plant height, leaf length and leaf width at both stages, and on stem girth in the field. Sole soil and sole rice husk also showed highly erratic, often failed, germination across replicates. The results indicate that blending soil with a high proportion of rice husk markedly improves substrate porosity, tiller establishment and early vigour, and reduces apparent transplant shock, offering smallholder farmers a low-cost, locally available alternative nursery medium for Napier grass propagation.