No abstract

Kebutuhan kedelai hitam nasional masih tergantung pada pasokan dari luar negeri dan terkendala oleh rendahnya produktivitas. Oleh karena itu, pemanfaatan lahan marginal secara optimal perlu didorong untuk budidaya kedelai hitam. Optimalisasi lahan kering masam dihadapkan pada faktor utama pembatas tanah antara lain kemasaman tanah tinggi, air tersedia terbatas, dan efisiensi penggunaan unsur hara rendah. Silika (Si) dalam bentuk yang siap diserap oleh tanaman (asam silikat) mampu meningkatkan toleransi tanaman terhadap cekaman kekeringan dan meningkatkan efisiensi penggunaan hara. Tujuan penelitian ini untuk mengetahui pengaruh aplikasi bio-nano silika di lahan kering yang bereaksi masam terhadap: (i) hasil kedelai hitam, dan (ii) efisiensi penggunaan air. Kegiatan lapang dilaksanakan di Jatitujuh, Majalengka, Jawa Barat, pada bulan Juli-Oktober 2017 dengan menggunakan rancangan acak kelompok (RAK). Pupuk bio-nano silika diberikan dengan dosis 0, 2, 4, dan 6 l ha-1 , sedang pupuk N, P, dan K tunggal diberikan setara dengan 0, 50, 75, dan 100% dosis rekomendasi. Plot kontrol berupa perlakuan standar petani (100% N, P, dan K + 2 t ha-1 pupuk organik). Plot berukuran 100 m 2 dari setiap perlakuan ditanami kedelai hitam varietas Detam-1. Pupuk bio-nano silika diekstraksi dari pasir kuarsa 325 mesh menggunakan larutan asam dan basa. Pupuk bio-nano silika mengandung kadar H4SiO4 > 5% dengan ukuran partikel 18 nm dan dalam aplikasinya diperkaya dengan mikroorganisme pelarut Si, yaitu Aeromonas punctata, Burkholderia cenocepacia, B. vietnamiensis, dan Aspergillus niger. Hasil percobaan menunjukkan bahwa hasil biji kedelai nyata tertinggi diperoleh pada perlakuan 75% NPK + 2 l bio-nano silika per hektar. Aplikasi 4 l ha-1 bio-nano silika dapat menghemat dosis pupuk N, P, dan K sampai dengan 32%. Sementara aplikasi dengan dosis 6 l ha-1 bio-nano silika dapat meningkatkan hasil kedelai hitam var. Detam-1 sampai dengan 36,7% dan menekan kebutuhan air tanaman hingga 65%.

In Indonesia, the development of oil palm plantations has been going on a pervasive way; they covered about 14.03 million hectares in 2017. This massive coverage of land might then generate a tremendous amount of biomass per year, both in the form of both solid and liquid wastes. The processing of fresh fruit bunches (FFB) in palm oil mill (POM) produces wastes that primarily in the form of empty fruit bunches (EFB), which is amounting of up to 25% (w/w) of FFB. It has been being indicated that EFB contains a considerable amount of silica (Si) which attracts the Indonesian Research Institute for Biotechnology and Bioindustry (IRIBB) to investigate the potential use of EFB as a source of bio-available Si, in the form of H4SiO4 (mono silicic acid, BioSilAc). The experiment was carried out at Sungai Mirah Minting Estate, PT Bumitama Gunajaya Agro-Central Kalimantan. The EFB material was obtained from POM and chopped into 2.5-5.0 cm in size. A four-week bio-decomposition process was employed by using bio-decomposers containing Trichoderma pseudokoningii, T. polysporum, and Phanerochaete chrysosporium. Chemical analyses of composted EFB were conducted before and 28-days after decomposer application. The presence of Si in the compost was observed by scanning electron microscopy (SEM).  The effect of Si-containing EFB compost on the immature and mature oil palm was evaluated. Seven treatments, i.e. combination of EFB compost and BioSilAc application with reduced-dosages of NPK fertilisers were arranged in a random block design with three replicates. The results show that large quantities of silica bodies attached to the surface of EFB fibres and amounting to 0.44% soluble Si. The FFB data indicated that the application of 75% NPK + 500 kg composted EFB + 2 L BioSilAc/ha/year on a five-year-old plant resulted in higher yield than that obtained from 100% standard dosage of NPK. The study also revealed that the application of EFB compost reduced 50% of BioSilAc dosage.

<p><strong>Abstrak.</strong> Biochar merupakan material baru yang diteliti secara intensif dalam waktu sepuluh tahun terakhir di berbagai penjuru dunia. Hal ini dipicu oleh fakta bahwa tanah-tanah Terra Preta di wilayah Amazon, Amerika Selatan, dikenal sangat subur karena mengandung arang yang dibentuk dari pembakaran minim oksigen (pirolisis) ribuan tahun yang lalu. Dalam kondisi kemajuan teknologi seperti sekarang ini para peneliti mencoba untuk meniru dalam memperoleh material serupa yang kemudian dikenal secara luas dengan istilah biochar dan menguji manfaatnya terutama untuk perbaikan kondisi tanah agar menghasilkan pertumbuhan dan produksi tanaman yang lebih baik, sekaligus mampu menjadi penghambat lepasnya karbon ke atmosfir (carbon sequestering). Sebagai sebuah topik riset yang baru tentu saja dapat dipahami bahwa hal tersebut menimbulkan pro- dan kontra, khususnya yang menyangkut manfaat positif secara luas. Pihak yang pro mendasarkannya pada banyak bukti tentang manfaat aplikasi biochar terhadap pertumbuhan dan produksi tanaman seperti halnya juga terhadap sifat-sifat tanah. Sebaliknya yang kontra menekankan terbatasnya data yang tersedia sejauh ini dan adanya ketidak-konsistenan hasil yang dilaporkan. Ulasan berikut ini mencoba untuk melihat dari dua sudut tersebut untuk memberikan gambaran yang sebenarnya bagi para calon peminat riset dan/atau pengguna biochar untuk kepentingan perbaikan kesehatan dan produktivitas tanah. Pada akhir diskusi disampaikan perlunya persyaratan mutu biochar untuk memperoleh hasil yang dapat diperbandingkan.</p><p><em><strong>Abstract.</strong> Biochar is a new material researched intensively within the last ten years in various parts of the world. This is fuelled by the fact that the lands of Terra Preta in the Amazon region of South America is known to be very fertile because it contains charcoal that was formed from the minimum oxygen combustion (pyrolysis) at times thousands of years ago. Under the conditions of technological advances like nowadays, researchers tried to replicate it in obtaining similar material which was then widely known by the term biochar and test its usefulness mainly to improved soil conditions in order to generate growth and better crop production and the same time capable of being a barrier to the release of carbon into the atmosphere (carbon sequestering). As a new research topic, it is understandable that it raises pros and cons, especially on its benefits. The pro-side emphasized on the proven beneficial application of biochar to improve growth and yield of crops as well as on soil properties. Others, rised the controversy focused on the limited data reported and somewhat inconsistency on the results. The following review is trying to look at it from the two angles to give the real picture for the prospective applicants of biochar such as researchers and users of biochar for the benefit of improving health and productivity of the soil. At the end of the discussion it is given the necessity for quality standard of biochar to obtain comparable results.</em></p><p> </p>

AbstrakSilika (Si) AbstractSilicon (Si) is the second most abundant in the soil varies from 50 to 400 g Si per kg of soil. Silicon has positive influence on the plant resistance to various abiotic and biotic stressors such as salinity, drought, heavy metal toxicities and diseases. Although Si is abundant in soil, most of its sources are not available for plant uptake due to low solubility of Si compounds in soil. To improve plant-available Si in the soil, silicate solubilizing bacteria (SSB) are potentially important in solubilizing insoluble forms of silicate. The objectives of this study were to determine: (i) silicate solubilizing activity of Burkholderia cenocepacia KTG, Aeromonas punctata RJM3020, and B. vietnamiensis ZEO3 on magnesium trisilicate and quartz, (ii) biochemical characteristics of SSB, and (iii) solubilization of silicate, Ca, and Mg from quarts by SSB activity. A laboratory study was conducted at Microbiology and Environment Laboratory, the Indonesian Research Institute for Biotechnology and Bioindustry, Bogor, in 2016. All SSB were grown on Bunt and Rovira media containing 0.25% magnesium trisilicate or quartz as substrate, respectively. Silica solubilizing activities by SSB were determined by using inductively coupled plasma-atomic emission spectrometry while organic acid concentration in the culture were measured by using highperformance liquid chromatography (HPLC

Accidental spillage or drainage from land of crude oil to the marine environment will potentially cause serious damage to the environment and marine life. Many efforts have been focused on the use of most efficient adsorbent to remove the oil and/or oil-decomposing agent from the water. The current study was aimed at to evaluate the most abundantly-available natural zeolite dominated by clinoptilolite mineral and pronounced molecular sieve characteristics as crude oil spill removal in sea water. Bayah-originated zeolite was characterized by using X-ray diffraction (XRD) analysis, pore distribution and average size, gas sorption capacity, and scanning electron microscopy (SEM). A laboratory experiments were conducted by reacting a 100-mesh zeolite with and without microbial enrichment to crude oil in a 250 mL sea water (3.7% NaCl and pH 6.7) jar at different oil/zeolite ratios, i.e. 50%, 100%, 200%, and 400% (v/w) with three replicates. Observations were made on the stability of zeolite-oil mixture for one week, the weight of zeolite mixed with oil, the oil adsorbed by the zeolite, and free oil after 24-hrs settling. The results indicate that zeolite has highly potential as crude oil adsorbent and the highest oil sorption obtained at zeolite/oil ratio of 1:1 with 86.3% oil adsorbed or 0.87 mL oil per gram zeolite. Enrichment of zeolite with Bacillus subtilis improved the adsorbed oil by the mineral.

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.

SummaryThe availability of high quality and quantity of oil palm seedling needs consistent support of fertilization programs for economic production.  Organo-chemical fertilizer with rock phosphate and urea added was initiated to increased economic value of agriculture and estate crops residues. The prototype of organo-chemical fertilizer has 10% organic C, 11% N, 8% P, 1% K and 4% humic acid respectively. Based on greenhouse experiments, organo-chemical fertilizer treated to oil palm seedlings tends to provide a better vegetative growth of the seedlings.  Dry weights of leave, stem, and root of the seedlings applied with 100 g organo-chemical  fertilizer plus 10 g KCl to each seedling were significantly different compared to the standard dosage conventional fertilizer. This organo-chemical fertilizer could be applied as conventional fertilizer substitute.Ringkasan        Ketersediaan bibit kelapa sawit ber-kualitas dengan kuantitas yang terus meningkat memerlukan dukungan program pemupukan yang konsisten untuk mencapai tingkat produksi yang ekonomis.  Pembuatan pupuk organo-kimia dengan penambahan  batuan fosfat dan N ditujukan untuk meningkatkan nilai ekonomi limbah pertanian dan perkebunan.  Prototipe pupuk organo-kimia ini mengandung 10% C-organik, 11% N, 8% P, 1% K dan 4% asam humik.  Pemberian 100 g pupuk organo-kimia yang ditambah 10 g KCl per bibit menghasilkan berat kering daun, batang, dan akar yang lebih baik dan berbeda nyata apabila dibandingkan dengan peng-gunaan pupuk konvensional dosis standar.  Berdasarkan hasil tersebut, prototipe pupuk organo-kimia ini dapat digunakan sebagai substitusi pupuk konvensional untuk pemupuk-an bibit kelapa sawit.