Pemanfaatan Biochar Batang Kelapa Sawit Sebagai Amandemen Tanah Ultisol Perkebunan Kelapa Sawit

Abstract

Biochar berasal dari bahan baku batang kelapa sawit (BKS) dipirolisis terpisah berdasarkan tinggi batang relatif (bawah, tengah, dan atas) dan campuran. Pirolisis yang dilakukan adalah pirolisis lambat dengan kisaran suhu 300 – 400 °C menggunakan tungku reaktor drum (drum retort kiln). Biochar dianalisis dengan analisis difraksi sinar-X (XRD), scanning electronic microscopy (SEM) yang digabungkan dengan spektrometer sinar-X dispersif energi (EDX), spektroskopi inframerah transformasi Fourier (FTIR), analisis proksimat dan analisis unsur. Biochar batang kelapa sawit (BBKS) bagian bawah batang memiliki puncak intensitas tertinggi yang diukur dengan XRD mengandung 62,05% karbon tetap, 69,21% karbon, 26,28% oksigen dan kadar abu paling rendah 7,83%. Ukuran pori terbesar dengan jumlah pori paling banyak dan kadar abu paling tinggi 12,34% ditemukan pada BBKS dari bagian batang atas. Studi ini menunjukkan BBKS yang dihasilkan dengan drum retort kiln sesuai standar International Biochar Iniative (IBI) dan Europian Biochar Certificate (EBC) untuk digunakan sebagai amandemen tanah untuk aplikasi pertanian. Penelitian dilanjutkan pada pembibitan awal (Pre-nursery) dengan media tanah ultisol di rumah kaca. Biochar batang kelapa sawit yang berasal dari bagian atas, tengah, dan bawah diaplikasi pada tingkat: 1, 2, 3, dan 4% (b/b) selama 12 minggu. Hasil penelitian menunjukkan bahwa aplikasi biochar sebesar 2% (b/b) optimal meningkatkan serapan N, P, K dan pertumbuhan bibit kelapa sawit. Aplikasi sampai tingkat 2% (b/b) digunakan pada percobaan lapangan pada tanaman kelapa sawit menghasilkan di tanah Ultisol. Perlakuan pada percobaan lapangan ini adalah: B0 (tanpa biochar); B1 (aplikasi biochar 1%); B2 (aplikasi biochar 2%). Hasil penelitian menunjukkan penambahan BBKS sampai 2% (B2) secara signifikan meningkatkan sifat kimia tanah meliputi pH, C-organik, KTK, Kejenuhan Basa, Ca-dd, Mg-dd, K-dd, Boron dan P-tersedia. Sifat fisika tanah meningkatkan total porositas dan kapasitas air tersedia meningkat masing-masing sebesar 2,8 dan 3%, menurunkan BD sebesar 3–5% per persen. Untuk sifat biologi tanah meningkatkan total mikroba pelarut P dan respirasi mikroorganisme tanah secara signifikan. Serta signifikan meningkatkan kandungan unsur hara daun seperti N, P, K, Ca, B dan berat 1 berondolan. Biochar derived from oil palm trunks (OPT) was pyrolyzed separately based on relative trunk height (bottom, middle, and top) and mixed. Slow pyrolysis was performed at a temperature range of 300–400°C using a drum retort kiln. Biochar was analyzed using X-ray diffraction (XRD), scanning electronic microscopy (SEM) combined with an energy-dispersive X-ray spectrometer (EDX), Fourier transform infrared spectroscopy (FTIR), proximate analysis, and elemental analysis. The biochar derived from OPT bottom section had the highest intensity peak, measured by XRD, containing 62.05% fixed carbon, 69.21% carbon, 26.28% oxygen, and the lowest ash content of 7.83%. The largest pore size, the highest number of pores, and the highest ash content of 12.34% were found in the biochar top section OPT. This study demonstrates that oil palm trunk biochar produced by drum retort kiln meets The International Biochar Initiative (IBI) and European Biochar Certificate (EBC) standards for use as soil amendment for agricultural applications. The study was continued in the pre-nursery with ultisol soil media in a greenhouse. Oil palm trunk biochar derived from the top, middle, and bottom sections were applied at levels of: 1, 2, 3, and 4% (w/w) for 12 weeks. The results showed that the application of biochar at 2% (w/w) optimally increased the uptake of Nitrogen, Phosfor, Potassium and the growth of oil palm seedlings. Applications up to 2% (w/w) were used in field trials on mature oil palm plants on Ultisol soil. The treatments in this field trial were: B0 (without biochar); B1 (1% biochar application); B2 (2% biochar application). The results showed that the addition of oil palm trunk biochar up to 2% (B2) significantly improved soil chemical properties including pH, organic-C, CEC, Base Saturation, Ca-dd, Mg-dd, K-dd, Boron and P-available. Soil physical properties increased total porosity and available water capacity by 2.8% and 3%, respectively, while decreasing BD by 3–5%. For the biological properties increased total P-solubilizing microbes and soil microbial respiration significantly. As well as significantly increased leaf nutrient content, including N, P, K, Ca, and B, and the weight of one loose fruit bunch.