Physiological Indicator for Egg Plant Growth in Red Yellow Podzol Soil with Beneficial Reuse of Pollutant Materials

Background: Red-yellow Podzol soil is generally regarded as infertile and covers approximately 45.7 million hectares in Indonesia, accounting for about 29.7% of the national land area. Despite these limitations, this soil type can be utilized for agricultural production through the application of appropriate soil amendments and alternative nutrient sources. Methods: A two-factor experiment was conducted at the experimental station of the Faculty of Agriculture, Islamic University of Riau, Indonesia. The first factor examined the effect of Pekanbaru city wastewater on eggplant (Solanum melongena L.), while the second factor was the pplication rate of palm kernel shell ash. Observed parameters included net assimilation rate (NAR), mean relative growth rate (MRGR), dry matter weight and total plant biomass. Result: Net assimilation rate and mean relative growth rate served as physiological indicators of dry matter accumulation. The combined application of city wastewater and palm kernel shell ash showed a significant interactive effect on eggplant growth. Increases in NAR were consistently followed by increases in MRGR, resulting in a significant enhancement of dry matter production. The application of palm kernel shell ash contributed to the amelioration of excessive iron and aluminum availability in red-yellow Podzol soil, thereby improving nutrient uptake efficiency. Overall, the integrated use of city wastewater and palm kernel shell ash significantly increased eggplant dry matter yield on red-yellow Podzol soil.