Leucaena leucocephala and Zeolite-based Fertilizers on the Tuber Yield of Purple Yam (Dioscorea alata L.) grown on San Manuel Series

Purple yam (Dioscorea alata L.) is an important staple and cash crop valued for its nutritional content, cultural significance, and potential to enhance food security and rural livelihoods in tropical regions. This study was conducted to assess the influence of zeolites and Leucaena leucocephala on the soil chemical properties of San Manuel series planted with Dioscorea alata, and to evaluate the interaction effect between soil amendments with varying NPK nutrient levels. Results showed that zeolites and Leucaena leucocephala had no significant effect on the soil chemical properties. The Leaf Area Index (LAI) of the yams was not significantly different among the treatments but recorded the highest LAI in yams applied with 80-5-90 NP2O5K20 kg ha-1 with an index of 91 cm² and 94 cm² for A1 and A2, respectively. The tuber yield showed significant differences among treatment means, with yam plants applied with Leucaena leucocephala (A2) being significantly higher than those applied with zeolites (A1). The average yield of yams applied with Factor A2 was 11.1 t ha-1, which was significantly higher than A1 that recorded 8.0 t ha-1. Similarly, the interaction effect between zeolites: fertilizers, and Leucaena leucocephala: fertilizers, significantly increased the yield. The positive control for fertilizers with an application rate of 160-10-180 NP2O5K20 kg ha-1 (B1) resulted in the highest yield with 14.3 t ha-1, which was significantly higher than those fertilizers applied with B0 – control (6.8 t ha-1), B2 -120-7.5-135 NP2O5K20 kg ha-1 (8.1 t ha-1), and B3- 80-5-90 NP2O5K20 kg ha-1 (8.9 t ha-1). This implies that increasing the number of fertilizers with soil amendment (Factor A2) significantly increased the tuber yield. Keywords: Leucaena leucocephala, NPK, soil chemical properties, zeolites