Determination of potassium (K) fertilizer requirement for pepper (Capsicum annuum L.) on inceptisols soil

Abstract

Background and Objective: Research on soil test calibration has been conducted through field experiment on pepper responses to potassium (K) fertilization at various K soil nutrient status. The objectives of this study were to determine class of K soil nutrient availability and calculate recommended K fertilizer for pepper cultivation on inceptisols soil. Methodology: This study used single location approach, where the treatment were randomized according to split-plot design with three replications and conducted in SP-1 Prafi Manokwari from December, 2012 to July, 2013. The treatment of the main plot is prepare K soil nutrient status through K fertilizer application with 5 doses, namely: 0 X (Very low), 1/4 X (low), 1/2 X (medium), 3/4 X (high) and X (very high). Dose X is application of K fertilizer as much as 367.54 kg K ha-1 to achieve very high K content in the soil. Treatment on subplot is the dose of K fertilizer, namely: 0, 40, 80, 160 and 320 kg K2O ha-1. Results: The results showed that K fertilization on soil with very low-medium K soil status has significant effect on the growth and yield of pepper, while high and very high K soil status has not significant effect. Class of K soil nutrient availability based on two extractors for very low, low, medium, high and very high, respectively are as follows: Morgan Vanema (<114, 114 to <228, 228 to <460, = 460 and >460 ppm K) and HCl 25% (<5960, 5960 to <6645, 6645 to <8100, = 8100 and >8100 ppm K). Conclusion: The maximum dose of K fertilizer recommended for pepper cultivation on inceptisols with K nutrient availability very low, low and moderate are: 165.00, 148.50 and 127.50 kg K2O ha-1, respectively, while high-very high class of K nutrient availability does not require fertilization.