Interaction between phosphorus fertilizer and arbuscular mycorrhizal fungal inoculants on yield components of cassava in northern Guinea savanna alfisols of Nigeria

Abstract

Field experiment was carried out in the Northern Guinea Savanna agro-ecology of Nigeria to examine the interaction between Phosphorus (P) fertilizer and Arbuscular Mycorrhizal Fungal (AMF) inoculants on cassava yield components. The experiment was laid in a split plot design with P fertilizers as main plot and AMF inoculants as subplots. There were three rates of P (0, 17.5, and 35 kg P₂O₅ ha^-1) and three levels of AMF inoculants (Control, Glomygel and Mycodrip). The result showed a significant interaction between P and AMF in root/shoot ratio and mycorrhizal response ratio. Highest root/shoot was recorded with combination of 17.5 P₂O₅ ha^-1+ control which depict increased sink strength. However, at 0 kg P₂O₅ ha^-1, Glomygel and Mycodrip were 65.5% and 21.5% respectively greater than control. Mycorrhizal response was also shown to be highest with application of 0 kg P₂O₅ ha^-1 + Glomygel showing much influence of the inoculants where no P was applied. Single effects of P and AMF showed that dry yield components were significantly (p<0.01) increased. The root dry weight was increased by 3.21 and 5.16 t ha^-1as a result of application of 17.5 kg P₂O₅ ha^-1 and 35 kg P₂O₅ ha^-1respectively over application of 0 kg P₂O₅ ha^-1. Glomygel and Mycodrip inoculants recorded 28% and 4% total plant dry yield increment respectively over control. This study shows that both P and AMF increased dry yield of cassava in Northern Guinea Savanna of Nigeria. The reproducibility at scale and in time is required for proper recommendation.

Keywords: AMF inoculants, Cassava, Alfisol, Mycorrhizal response, P fertilizers.