Pengaruh Pemberian Kompos Kulit Kopi, Pupuk Kalium dan CaCO3 Terhadap Ketersediaan Hara K, Ca dan Pertumbuhan Tanaman Kacang Kedelai (Glycine Max L.) pada Tanah Ultisol

Abstract

This study aims to determine the effect of coffee peel compost, potassium fertilizer and CaCO3 on the availability of nutrients K, Ca and plant growth of Soybean (Glycine max L.) on Ultisol soil. The research was conducted in Greenhouse, Research and Technology Laboratory, Faculty of Agriculture, University of North Sumatra and BSIP Laboratory from January to April 2024. This research used Randomized Group Design (RAK) with 3 treatment factors and 3 replications. The first factor is coffee skin compost consisting of 2 levels of treatment, namely: (B0) control without coffee skin compost, (B1) coffee skin compost 91 tons/ha. The second factor is Potassium fertilizer with 2 treatment levels, namely (K0) control without KCl fertilizer, (K1) 50kg/ha KCl fertilizer. The third factor is CaCO3 with 2 treatment levels, namely (C0) control without CaCO3, (C1) CaCO3 3.14 tons/ha. The observed variables were soil CEC, soil K-dd, soil Ca-dd, number of branches, root dry weight, crown dry weight, leaf K content, leaf K uptake, leaf Ca content, plant Ca uptake. The results showed that the application of coffee skin compost increased CEC, K-dd, and Ca nutrient uptake. The application of CaCO3 increased Ca nutrient uptake. The combination of coffee skin compost and KCl fertilizer increased root dry weight, K nutrient content and uptake. The combination of coffee skin compost and CaCO3 increased Ca-dd, number of branches, crown dry weight, K nutrient uptake and Ca nutrient content. The combination of KCl and CaCO3 fertilizer increased CEC and crown dry weight.