Pemanfaatan Biochar Asal Cangkang Kelapa Sawit untuk Meningkatkan Serapan Hara dan Sekuestrasi Karbon pada Media Tanah Lithic Hapludults di Pembibitan Kelapa Sawit - Laksmita Prima Santi (Jurnal Tanah dan Iklim (Indonesian Soil and Climate Journal), 2017)
Abstrak: Pemanfaatan biochar asal cangkang kelapa sawit sebagai pembenah tanah memiliki potensi yang baik dalam upaya pengembangan perkebunan kelapa sawit di lahan sub optimal secara berkelanjutan. Kegiatan penelitian ini dilaksanakan untuk mempelajari pengaruh tiga tingkat dosis biochar (50; 100; dan 150 gram) yang dikombinasikan dengan 75% dosis pupuk NPK-Mg per bibit terhadap pertumbuhan bibit kelapa sawit, serapan hara, dan sekuestrasi karbon pada tahap pembibitan utama. Kegiatan lapang dilaksanakan di PT Astra Agro Lestari Tbk, Kalimantan Tengah pada bulan Maret 2015 - April 2016. Penelitian disusun dalam rancangan acak kelompok (RAK) dengan lima perlakuan dan dua puluh ulangan yaitu: (i) 100% dosis standar NPK-Mg per bibit (kontrol); (ii) 75% dosis standar NPK-Mg per bibit; (iii) 75% dosis standar NPK-Mg + 50 g biochar per bibit; (iv) 75% dosis standar NPK-Mg + 100 g biochar per bibit; dan (v) 75% dosis standar NPK-Mg + 150 g biochar per bibit. Pertumbuhan terbaik bibit kelapa sawit yang ditanam dalam media jenis tanah Lithic Hapludults diperoleh dari perlakuan 75% dosis pupuk NPK-Mg yang dikombinasikan dengan 150 gram biochar per bibit. Perlakuan ini berturut-turut meningkatkan tinggi (33,3%); jumlah daun (36,2%); diameter batang (28,9%); panjang dan lebar daun (22,6 dan 33,3%), bobot kering bibit kelapa sawit, khususnya bagian akar (65,2%), kapasitas tukar kation (17,2%), dan C-organik (26,9%). Hasil analisis terhadap perlakuan ini juga menunjukkan serapan hara N daun bibit kelapa sawit yang paling tinggi serta kadar hara P dan K yang tidak berbeda jika dibandingkan dengan perlakuan 100% dosis pupuk NPK-Mg. Atas dasar hasil tersebut maka 75% dosis pupuk NPK-Mg yang dikombinasikan dengan 150 gram biochar per bibit dapat direkomendasikan untuk digunakan pada bibit kelapa sawit.Abstract. The potential of biochar derived from oil palm kernel shell to be used as a soil amendment seems promising for sustaining oil palm plantation in marginal land. This study was conducted to investigate the effects of three biochar dosages (50; 100; and 150 gram) in combination with 75% NPK-Mg dosages per seedling on the growth of oil palm seedling, nutrient uptake and carbon sequestration in the nursery stage. A field experiment was conducted at PT Astra Agro Lestari Tbk, Central Kalimantan in March 2015- April 2016. Experiment was arranged in a completely randomized block design (CRBD) with five treatments and twenty replications i.e: (i) 100% standard dosage NPK-Mg per seed (control); (ii) 75% standard dosage NPK-Mg per seed; (iii) 75% standard dosage NPK-Mg + 50 g biochar per seed; (iv) 75% standard dosage NPK-Mg + 100 g biochar per seed; and (v) 75% standard dosage NPK-Mg + 150 g biochar per seed. The best vegetative growth performance of oil palm seedlings in Lithic Hapludults soil was shown by the application of 75% standard dosage of NPK-Mg fertilizers in combination with 150 gram biochar per seed. This treatment increased height (33.9%); leaf number (36.2%); stem diameter (28.9%); length and width of the leaf (22.6 and 33.3%), dry weight of oil palm seedlings, especially roots (65.2%), CEC (17.2%), and organic C (26.9%). This treatment also showed the highest absorption of N in leaves of oil palm seedlings, but no differences were observed for P and K uptakes compared to the treatment of 100% dosage of NPK-Mg fertilizer. On the basis of these results, the 75% dosage of NPK-Mg combined with 150 g of biochar per seed can be recommended for use on oil palm seedlings.