<![CDATA[Blotong atau filter cake merupakan kotoran nira tebu dari proses pembuatan gula. Namun, blotong dapat dimanfaatkan menjadi pupuk organik karena kandungan hara dalam blotong cukup tinggi. Misalnya kandungan C, N, P, dan K yang dapat menjadi sumber hara serta meningkatkan kualitas tanah. Penelitian ini bertujuan untuk mengetahui peningkatan unsur hara C, N, P, dan K pada tanah setelah pemberian pupuk blotong. Metode yang digunakan dalam penelitian ini yaitu metode Walkley and Black untuk penetapan hara C, metode Kjeldahl untuk penentuan hara N, dan metode Bray I untuk penentuan hara P dan K. Perlakuan pemupukan dilakukan dalam skala kecil, dimana tanah perkebunan direparasi dalam wadah polybag berukuran 50 cm x 50 cm. Pemupukan dilakukan selama 4 minggu dengan takaran variasi pupuk setara 0 ton/ha, 10 ton/ha, 25 ton/ha, dan 60 ton/ha. Hasil penelitian menunjukkan bahwa pupuk blotong dapat meningkatkan kadar hara pada tanah perkebunan. Perlakuan 0 ton/ha diperoleh hasil kadar C, N, P, dan K berturut-turut sebesar 1,12%; 0,12%; 102,7588 ppm, dan 101,320 ppm. Perlakuan 10 ton/ha diperoleh hasil kadar berturut-turut sebesar 1,18%; 0,13%; 122,9938 ppm, dan 145,610 ppm. Perlakuan 25 ton/ha diperoleh hasil kadar berturut-turut sebesar 1,22%; 0,14%; 144,8662 ppm, dan 260,960 ppm. Perlakuan 60 ton/ha kadar berturut-turut sebesar 2,58%; 0,15%; 190,6140 ppm, dan 380,180 ppm. Hal tersebut menunjukkan bahwa takaran setara 60 ton/ha cukup untuk meningkatkan kandungan hara C, N, P, dan K tanah dalam waktu 4 minggu. Kata kunci: Blotong, tanah, C-organik, N, P, K ABSTRACT Blotong or filter cake is sugar cane sap dirt from the sugar-making process. However, blotong can be used as an organic fertilizer because the nutrient content in blotong is relatively high. For example, the contents of C, N, P, and K can be a source of nutrients and improve soil quality. This study aimed to determine the increase in nutrients C, N, P, and K in the soil after applying blotong fertilizer. There were methods used in this study, such as the Walkley and Black method for determining C nutrients, the Kjeldahl method for determining N nutrients, and the Bray I method for determining P and K nutrients. Fertilization treatment was carried out on a small scale, where who repaired the plantation soil in polybags measuring 50 cm x 50 cm. Fertilization is carried out for four weeks with varying doses of fertilizer equivalent to 0 tons/ha, 10 tons/ha, 25 tons/ha, and 60 tons/ha. The results showed that blotong fertilizer could increase the nutrient content of the plantation soil. Treatment of 0 ton/ha resulted in C, N, P, and K of 1.12%, 0.12%, 102.7588 ppm, and 101.320 ppm, respectively, while the 10 ton/ha treatment yielded 1.18%, 0.13%, 122.9938 ppm, and 145.610 ppm, respectively. Moreover, the 25 ton/ha treatment produced a grade of 1.22%, 0.14%, 144.8662 ppm, and 260.960 ppm, respectively, whereas the treatment of 60 tons/ha of 2.58%, 0.15%, 190.6140 ppm, and 380.180 ppm successively. These results showed that the equivalent dose of 60 tons/ha was sufficient to increase the contents of C, N, P, and K nutrients in the soil within four weeks. Keywords: blotong, soil, C-organic, N, P, K]]>
