Ramadhan Kiswara, Iqbal (2017) Laju Dekomposisi Bahan Organik Tanaman Pionir Parasponia andersonii dan Trema Orientalis di Lereng Gunung Kelud. Sarjana thesis, Universitas Brawijaya.
Abstract
Gunung berapi Kelud (Kabupaten Kediri Jawa Timur) mengalami erupsi yang kedua kalinya pada tanggal 14 Februari 2014, mengeluarkan banyak material vulkanik umumnya berupa lava, batuan piroklastik, tepra, dan lahar. Dalam jangka waktu pendek kejadian tersebut merugikan petani di sekitarnya karena menyebabkan pemadatan di permukaan tanah, kekeringan dan miskin unsur hara terutama unsur N dan C. Guna memulihkan kembali kesuburan tanah akibat erupsi gunung Kelud tersebut, petani menambahkan bahan organik (BO) berupa sisa panen, kotoran hewan dan pupuk urea. Salah satu BO yang tersedia daerah erupsi Kelud adalah tanaman pionir yaitu Parasponia andersonii yang masih satu famili dengan tanaman anggrung (Trema orientalis). Parasponia banyak tumbuh di lereng atas yang miskin maupun di aliran lahar. Namun demikian studi laju dekomposisi dari kedua jenis BO tersebut masih belum banyak diketahui. Tujuan penelitian ini adalah untuk mempelajari laju dekomposisi BO dari tanaman pionir Parasponia andersonii dan Trema orientalis di berbagai kelas tutupan lahan yang terkena dampak abu vulkan Gunung Kelud. Penelitian dilakukan di Dusun Kutut, Kecamatan Ngantang, Kabupaten Malang, Jawa Timur pada bulan Mei sampai dengan bulan Juli 2016. Ada 4 macam BO yang di uji: Parasponia andersonii, Trema orientalis, dibanding dengan Kakao (Theobroma cacao) dan Sengon (Paraserianthes falcataria). Kualitas BO dipilih berdasarkan kadar C total, N total, polifenol, dan lignin. Pengamatan di lapang berdasarkan teknik dari TSBF menggunakan litterbag (kantong kasa) berukuran 25x25 cm2. Jumlah BO yang dimasukan kedalam litterbag berdasarkan kadar N masing-masing BO. Litterbag diletakan dalam berbagai tingkat tutupan lahan: (a) Rapat, di lahan hutan produksi; (b) Agak rapat, dilahan semak, (c) Agak terbuka, lahan Agroforestri kopi, (d) Terbuka, dilahan budidaya semusim. Pengukuran BO yang tertinggal dalam litterbag dilakukan pada waktu 1,2,4,8, dan 12 minggu setelah aplikasi (MSA) maka dapat dihitung BO yang hilang. Hasil studi menunjukan bahwa dalam 12 MSA belum ada satupun dari BO yang diuji kehilangan berat mencapai 50%, kecuali BO Parasponia dan Trema di lahan tutupan rapat (hutan), dan BO Parasponia di lahan tutupan agak rapat (semak belukar). Berdasarkan besarnya BO yang hilang selam percobaan, terdapat 2 kelompok: (a) Laju dekomposisi tinggi adalah BO Parasponia dan Trema dengan rata-rata kehilangan berat 159 mg/minggu; (b) Laju dekomposisi rendah dengan rata-rata kehilangan berat 90 mg/minggu. Secara kuantitatif, laju dekomposisi BO ditunjukan dari nilai k atau umur paruh waktunya (1/k). Laju dekomposisi tertinggi terdapat pada tutupan lahan tertutup (Hutan produksi dan semak), kemudian diikuti oleh lahan terbuka di budidaya dan paling lambat di lahan agak terbuka di AF kopi. Laju dekomposisi di lahan hutan sama dengan lahan semak, umur paruh waktu BO parasponia dan Trema rata-rata 20 minggu, ii ii sedangkan BO kakao dan sengon lebih panjang rata-rata 50 minggu. Pada tutupan lahan terbuka dilahan budidaya, umur paruh waktu BO Parasponia dan Trema rata-rata 48 minggu dan 24 minggu; sedangkan BO sengon dan kakao sama dengan di kondisi tutupan tertutup rata-rata 50 minggu. Namun demikian pada kondisi lahan agak tertutup di AF kopi, umur paruh waktu BO Parasponia dan Trema rata-rata 30 minggu dan 34 minggu; sedangkan BO sengon dan kakao rata-rata 77 minggu dan 53 minggu. Perbedaan laju dekomposisi dari berbagai BO dan mungkin akan berpengaruh terhadap mineralisasi N dan ketersediaan N di tanah lapisan atas. Laju dekomposisi BO yang rendah di lereng Gunung Kelud bermanfaat sebagai penutup tanah untuk mengurangi evaporasi berlebihan di musim kemarau dan menekan limpasan permukaan dan erosi di musim penghujan.
English Abstract
The second eruption of Mount. Kelud (Kediri-East Java) occurred on February 14, 2014, releasing a lot of volcanic material generally as rock, tepra, and lavaand pyroclastic. In the short term, it is detrimental to the farmers around it because it causes soil compaction, drought and poor nutrients especially for N and C. In order to restore the soil fertility problem, farmers add organic material (OM) in the form of crop residues, manure and urea. One of the OM source available around the area is from the pioneer plant of Parasponia andersonii which is a family with Trema orientalis. Parasponia grows on the upper slopes of the poor soil as well as in the lava flows. However, the study of decomposition rate of both types of OM is still not widely known. The purpose of this study is to evaluate the decomposition rate of OM from pioneer plants Parasponia and Trema in various types of land cover in the area affected by volcanic as Mount Kelud. The research was conducted in Kutut Hamlet, Ngantang District, Malang Regency, East Java from May to July 2016. There are 4 types of OM tested: Parasponia andersoniii, Trema orientalis, compared to cocoa (Theobroma cacao) and sengon (Paraserianthes falcataria). The quality of OM is selected based on its content of C, N, polyphenol and lignin. Field observations done based on techniques from TSBF using a 25x25 cm2 litter bag. The amount of OM inserted into the litter bag is based on its N content of each OM. Litter bags subsequently are placed in various levels of canopy cover: (a) Close canopy, in production forest land; (b) Rather close, in bushland, (c) Slightly open canopy, in Coffee Agroforestry (AF) and (d) Open canopy, in annual crop land. The measurements of remaining OM in the litterbag were performed at 1, 2, 4, 8, and 12 weeks after application (MSA). The results of the study indicate that within 12 MSA none of the OM tested lost 50% of their weight, except for Parasponia and Trema in closed canopy forest areas, and Parasponia on slightly closed land (bush fallow). Based on the magnitude of lost of OM during the experiment, there are 2 groups: (a) The high decomposition rate is Parasponia and Trema with an average weight loss of 159 mg / week; (b) A low decomposition rate with an average weight loss of 90 mg/week. Quantitatively, the decomposition rate of OM is indicated by the k value or its half life (1/k). The highest decomposition rate is occured in closed canopy land (Production forest and bush), followed by open land in vegetable cultivation and the slowest at open field in AF coffee. The rate of decomposition in forested land is similar to that of bush, Parasponia and Trema's half-life averages 20 weeks, while cocoa and sengon are longer at 50 weeks on average. In open cover on cultivated land, Parasponia and Trema's half-life averages 48 weeks and 24 weeks; Whereas sengon and cocoa are similar to those in closed cover conditions averaging 50 weeks. Nevertheless, on the slightly closed canopy of AF-coffee, Parasponia and Trema's half-life averages 30 weeks and 34 weeks; while sengon and cocoa with an average of 77 weeks and 53 weeks. Differences iv iv in decomposition rates of various types of OM and land canopy cover may affect N mineralization rate and N availability in topsoil. The low decomposition rate of OM on the slopes of Mount Kelud is useful as a ground cover to reduce excessive evaporation in the dry season and suppress surface run off and erosion in the rainy season.
| Item Type: | Thesis (Sarjana) |
|---|---|
| Identification Number: | SKR/FP/2017/329/051706852 |
| Uncontrolled Keywords: | Trema orientalis, Parasponia andersonii, Bahan Organik |
| Subjects: | 600 Technology (Applied sciences) > 631 Specific techniques; apparatus, equipment materials > 631.8 Fertilizers, soil conditioners, growth regulators > 631.86 Organic fertilizers |
| Divisions: | Fakultas Pertanian > Ilmu Tanah |
| Depositing User: | Yusuf Dwi N. |
| Date Deposited: | 01 Nov 2017 01:50 |
| Last Modified: | 22 Jun 2022 08:23 |
| URI: | http://repository.ub.ac.id/id/eprint/4652 |
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