FORMULASI PUPUK ORGANIK BERBAHAN SLUDGE, ARANG SEKAM, KOMPOS, DAN AGEN KHELAT TERHADAP PERTUMBUHAN TANAMAN KANGKUNG (Ipomoea reptans)

Abstract

Limbah sludge industri bumbu masak berpotensi dimanfaatkan sebagai pupuk organik karena mengandung bahan organik dan unsur hara. Namun, pemanfaatannya terkendala oleh kadar air yang tinggi dan kontaminasi logam berat yang melampaui ambang batas Kepmentan No. 261/2019. Penelitian ini bertujuan mengevaluasi formulasi pupuk organik berbasis sludge (75%) yang dikombinasikan dengan arang sekam, kompos, dan agen khelat (EDTA dan asam sitrat) terhadap karakteristik sifat tanah dan pertumbuhan kangkung (Ipomoea reptans). Penelitian menggunakan Rancangan Kelompok Acak Lengkap (RKAL) satu faktor dengan 10 perlakuan agen khelat EDTA dan asam sitrat dengan parameter pengamatan meliputi sifat kimia tanah, biologi tanah, serta variabel vegetatif dan generatif tanaman. Hasil penelitian menunjukkan bahwa pemberian EDTA dan asam sitrat pada berbagai dosis tidak memberikan pengaruh nyata terhadap sifat biologi tanah, sifat kimia tanah, maupun pertumbuhan kangkung. Secara numerik, asam sitrat 50% menghasilkan populasi mikrob tertinggi, sedangkan EDTA 125% menghasilkan tinggi tanaman dan diameter batang tertinggi, namun tidak berbeda nyata dengan perlakuan lainnya. Formulasi berbasis sludge, arang sekam, dan kompos mampu mendukung pertumbuhan kangkung, tetapi penambahan agen khelat pada dosis yang digunakan belum memberikan pengaruh yang nyata terhadap sifat tanah maupun pertumbuhan tanaman.

Seasoning industry sludge waste has potential for use as an organic fertilizer due to its organic matter and nutrient content. However, its utilization is constrained by high moisture content and heavy metal contamination exceeding the threshold limits established by the Indonesian Ministry of Agriculture Decree No. 261/2019. This study aimed to evaluate an organic fertilizer formulation based on sludge (75%) combined with rice husk biochar, compost, and chelating agents (EDTA and citric acid) on soil characteristics and the growth of spinach (Ipomoea reptans). The experiment was conducted using a Randomized Complete Block Design (RCBD) with a single factor consisting of ten treatments of EDTA and citric acid at different dosages. Observed parameters included soil chemical properties, soil biological properties, and vegetative and generative growth variables of the plant. The results showed that the application of EDTA and citric acid at various dosages did not significantly affect soil biological properties, soil chemical properties, or spinach growth. Numerically, the 50% citric acid treatment produced the highest microbial population, while the 125% EDTA treatment resulted in the greatest plant height and stem diameter; however, these values were not significantly different from those of the other treatments. The sludge-based fertilizer formulation combined with rice husk biochar and compost was able to support the growth of spinach, but the addition of chelating agents at the applied dosages did not produce a significant effect on soil properties or plant growth.