Analisis Pupuk Tabur Dengan Variasi Penambahan Asam Humat Terhadap Pertumbuhan Sawi Hijau (Brassica juncea L.)

Abstract

Research on the analysis of the effect of varying humic acid additions to granular fertilizer on the growth of mustard greens (Brassica juncea L.) was conducted with the objectives of (1) analyzing the effect of humic acid variation on plant growth, and (2) determining whether the N, P, and K content of humic acid-enriched fertilizers meets the Indonesian National Standard (SNI 2803-2024). Humic acid is known to improve the physical, chemical, and biological properties of soil and enhance the availability of nutrients for plants. This study employed a Completely Randomized Design (CRD) with a non-factorial model consisting of five treatments: no fertilizer, reference fertilizer, and modified granular fertilizers with the addition of 1, 2, and 3 grams of humic acid, each replicated three times. Observed parameters included leaf number, plant height, and fresh weight as growth indicators, as well as nitrogen, phosphorus, and potassium content in the fertilizer, analyzed using the Kjeldahl method, UV-Vis spectrophotometry, and flame photometry. The results showed that the addition of humic acid, particularly at a dose of 3 g, significantly improved the growth of mustard greens and simultaneously enhanced soil quality, as indicated by increases in pH (from 5.13 to 6.85), organic C content (from 1.05% to 3.53%), total nitrogen (from 0.20% to 0.68%), available phosphorus (from 14.28 ppm to 25.30 ppm), exchangeable potassium (from 0.30 me/100g to 0.75 me/100g), and cation exchange capacity (from 10.67 me/100g to 26.10 me/100g). The NPK content in the formulated fertilizer—N: 0.20% (dose 1), 0.32% (dose 2), 0.40% (dose 3); P: 6.20% (dose 1), 6.40% (dose 2), 6.65% (dose 3); K: 6.40% (dose 1), 6.60% (dose 2), 6.85% (dose 3)—met the standards of SNI 2803-2024. Therefore, humic acid-based granular fertilizer has strong potential to be developed as an environmentally friendly and sustainable fertilization solution in support of modern agriculture.