Effect of Biofertilization with a Mixture of Arbuscular Mycorrhizal Fungi and Natural Phosphate from Tilemsi on the Growth and Grain Yield of Sorghum (Sorghum bicolor L. Moench) in the Field in Koumantou

Abstract

Sorghum is an important food-security crop in Mali, but productivity is often constrained by poor soil fertility, particularly low phosphorus availability. Arbuscular mycorrhizal fungi and locally available natural phosphate may provide an alternative or complementary approach to mineral fertilisation. This study evaluated the effect of biofertilisation with a mixture of arbuscular mycorrhizal fungi and Tilemsi natural phosphate on sorghum growth and grain yield under field conditions in Koumantou, Bougouni region, Mali. The experiment used a randomised block design with five treatments and four replications: an uninoculated and unfertilised control, mineral fertiliser, Tilemsi natural phosphate, arbuscular mycorrhizal fungal inoculum, and the inoculum combined with Tilemsi natural phosphate. The fungal inoculum comprised Rhizophagus irregulare, Glomus aggregatum, and Glomus mosseae. Plant height and stem diameter were measured during growth, while panicle length, panicle weight, dry aboveground biomass, grain yield, and 1000-grain weight were assessed at harvest. The experimental soil was acidic and low in organic matter, nitrogen, potassium, and available phosphorus. Fertilised and inoculated treatments generally improved growth compared with the control. At 100 days after emergence, plant height ranged from 195.06 cm in the control to 216.28 cm under mineral fertiliser; the combined treatment reached 214.03 cm. Dry aboveground biomass was highest under the combined treatment (39.31 g) compared with the control (22.44 g). Grain yield was also numerically higher under the combined treatment than under the control. These findings suggest that arbuscular mycorrhizal fungi combined with Tilemsi natural phosphate may support sorghum growth in phosphorus-poor field conditions.