STUDI KESESUAIAN LAHAN TERHADAP JENIS KARET (Hevea brasiliensis Muell) PADA HUTAN TANAMAN INDUSTRI DI PT. KODECO TIMBER PROPINSI KALIMANTAN SELATAN

Bambang Witjaksono Agrarianto, Dr. Ir. Haryono Supriyo

1996 | Tesis | S2 Ilmu Kehutanan

Kecepatan penurunan produktivitas lahan, menurunnya luas hutan alam serta meningkatnya kebutuhan akan kayu perlu diimbangi dengan pembuatan Hutan Tanaman Industri, agar kesinambungan pemasokan bahan baku untuk industri kayu dapat terjamin. Dari sejumlah alternatif tanaman yang disiapkan untuk pembangunan HTI, karet (Hevea brasiliensis Muell) adalah salah satu tanaman yang direkomendasi sesuai dengan Surat Keputusan Direktorat Jenderal Reboisasi dan Rehabilitasi Lahan Nomor 062/Kpts/V/1989 Tanggal 7 Oktober 1989. Tanaman karet dianggap mempunyai beberapa kelebihan, karena teknologi budidayanya sudah dikuasai dengan baik, cukup dikenal oleh masyarakat luas, harga lateksnya cukup baik dan pemasaran hasilnyapun cukup mudah. Pembangunan HTI karet yang diprioritaskan pada areal padang alang-alang, hutan sekunder dan lahan kosong lainnya memberikan dampak positif dalam memacu produkti­vitas lahan, perbaikan lingkungan dan penyerapan tenaga kerja. Keberhasilan HTI perlu ditunjang oleh tingkat kese­suaian lahan setempat. Untuk mengetahui pengaruh faktor lahan terhadap pertumbuhan tanaman dilakukan studi kese­suaian lahan terhadap jenis karet pada HTI milik PT. Kodeco Timber Batulicin Propinsi Kalimantan Selatan. Penelitian ini dilakukan dengan membuat klasifikasi pertumbuhan tanaman karet pada umur 4 tahun, kemudian diadakan uj i peranan faktor lahan terhadap pertumbuhan. Parameter pertumbuhan yang diukur adalah tinggi pohon, diameter batang dan jumlah pohon/ha. Parameter lahan yang diukur adalah kelerengan, pH tanah, kandungan bahan organik, N total, P tersedia, K tersedia, Mn tersedia, Fe oksida bebas, Al-dapat ditukar, kapasitas pertukaran kation (KPK), permeabilitas, tekstur, dan kedalaman efektif akar. Pengambilan data dilakukan dengan systematic line plot sampling. Klasifikasi dilakukan dengan mengana­lisis data pohon dengan metode Minimum Variance Clustering, sedang peranan faktor lahan terhadap pertumbuhan tiap kelompok dilakukan dengan Simple Discriminant Analysis.

The rapid deteriorating rate of land productivity, reduction of natural forest area as well due to the increasing demand of wood should be anticipated by the establishment of Industrial Tree Forest Plantation to secure continuous flow of wood supply. Out of the various available optional plans for the establishment of Industrial Forest Plantation (IFP), rubber. (Hevea brasiliensis Muell) is one of those trees being recommended through the Letter of Directorate General of Afforestation No. 062/Kpts/V /1989, 7 October 1989. Rubber trees are considered to have superior possi­bilities and is widely recognised, how to grow it is well known, and it has high economic value. Establishment of rubber forest plantation which has been developed especially in the alang-alang grass land, secondary forest, and other abandoned land will have a positive effect to improve the land productivity, environ­mental improvement, as well as employment opportunity. The succesful of implementation of the policy depends on the proper choice of wood species suitable to the area affecting land use suitability to rubber, a study on land suitability of rubber plantation was done in IFP area of at PT. Kodeco Timber, Batulicin, South Kalimantan. In this study, the rubber plantations of 4 years old were classified into different groups based on tree growth and then the growth was related to the prevailing condi­tions of the areas. The growth parameters were plant height, stem diameter, and the number of tree/ha. Prevail­ing conditions examined were slope, soil pH, soil organic matter, total N, available P, K, Mn, excangable Al, cation exchange capacity, free Fe oxide, soil permeability, soil texture, and effective root depth. The data were collected using systematic line plot sampling covering through out all sampling units. The classification was done by analy­zing tree growth data using Minimum Variance Clustering method, and the role of prevailing conditions on tree growth in each cluster was analyzed using Simple Discri­minant Analysis. The results indicated that there were differences in land suitability as was shown from the tree growth. With higher tree number per unit area, there was a tendency for the trees were be higher in height and larger average stem diameter. The factors which discrimating land suitability of various clusters were the environmental conditions particularly erodibility, free Fe oxide, followed by soil texture and exchangable Al.

Kata Kunci : Kesesuaian Lahan, Jenis Karet, Hutan Tanaman Industri