Interactive effects of banana stem ash and potassium-solubilizing fungi on peanut (Arachis hypogaea L.) growth and yield

Abstract

Peanut (Arachis hypogaea L.) productivity in Indonesia averages approximately 1.0 t ha⁻¹, far below its potential yield of 3.5 t ha⁻¹, mainly due to poor pod filling associated with low soil potassium (K) availability. This study evaluated the integrated application of banana stem ash (BSA) containing 23.6% K₂O and potassium-solubilizing fungi (PSF), including Aspergillus unguis, Metarhizium carneum, and Meyerozyma caribbica, as a locally available nutrient-management strategy to enhance peanut yield. A split-plot design with three replications was applied, consisting of three BSA dosages (0, 500, and 1,000 kg ha⁻¹) and four fungal inoculation treatments. Growth, yield components, and K content in plant tissues and soils were measured at flowering and harvest. Data were analyzed using analysis of variance (ANOVA), followed by the least significant difference (LSD) test at 5%. Results showed that BSA at 1,000 kg ha⁻¹ combined with M. carneum increased dry pod weight per plant by 48.2% (24.95 g vs. 16.84 g in the uninoculated control without BSA), while M. caribbica raised the proportion of filled pods to 85.09% compared with 53.86% in the uninoculated control without BSA. Soil available K₂O increased from 21.82 to 25.94 mg 100 g⁻¹ under the highest BSA dose. These outcomes indicate a significant positive interaction between BSA and PSF for dry pod weight, whereas other variables were mainly influenced by BSA and/or PSF main effects. Because no conventional K-fertilizer control was included, the integrated use of PSF and BSA should be considered a potential complementary approach for improving peanut yield, soil K status, and nutrient-management sustainability in Indonesia.