The Effect of SP-36 and KCl Fertilizer on Peanut (Arachis hypogaea L.) Productivity of Katana 1 Variety

Background: Peanut (Arachis hypogaea L.) productivity remains relatively low, partly due to declining soil fertility and suboptimal fertilizer management. Although phosphorus and potassium are essential for plant growth and yield, appropriate SP-36 and KCl fertilizer rates for the Katana 1 variety remain insufficiently investigated. This study evaluated the individual and interactive effects of SP-36 and KCl fertilizer rates on peanut growth and yield to identify optimal application rates. Methodology: A field experiment was conducted in Gogorante Village, Ngasem District, Kediri Regency, using a factorial Randomized Block Design with three replications. Treatments comprised four SP-36 rates (0, 100, 200, and 300 kg ha⁻¹) and four KCl rates (0, 50, 100, and 150 kg ha⁻¹). Days to flowering, pod number, dry pod weight, and harvest index were evaluated using analysis of variance, followed by Tukey's Honestly Significant Difference test at the 5% significance level. Findings: No significant interaction between SP-36 and KCl was observed across the measured parameters. SP-36 significantly influenced flowering time, pod number, and dry pod weight, whereas KCl significantly affected dry pod weight and harvest index. SP-36 at 200 kg ha⁻¹ produced the best flowering and pod number responses, while 300 kg ha⁻¹ maximized dry pod weight. KCl at 150 kg ha⁻¹ produced the highest dry pod weight and harvest index. Contribution: These findings provide field-based evidence supporting improved phosphorus and potassium fertilizer management for Katana 1 peanut cultivation and offer practical guidance for optimizing fertilization strategies to enhance productivity under comparable growing conditions