EVALUASI RINCI KARAKTERISTIK DAN TINGKAT KESESUAIAN LAHAN TAMBAK DI KECAMATAN BALUSU KABUPATEN BARRU PROVINSI SULAWESI SELATAN

Abstract

Upaya peningkatan produksi tambak yang optimal dan berkelanjutan mutlak didukung oleh informasi karakteristik lahan yang rinci dan mudah diinterpretasi oleh berbagai stakeholder. Ketersediaan informasi spasial tambak di berbagai daerah di Indonesia utamanya masih diperuntukkan bagi kebutuhan umum perencanaan tata ruang wilayah pesisir dan pantai tingkat provinsi dan kabupaten. Dengan demikian data tersebut tentunya belum memuat informasi yang berhubungan langsung dengan upaya pengelolaan dan peningkatan produktivitas lahan tambak. Penelitian ini bertujuan untuk mengetahui karakteristik dan menilai tingkat kesesuaian secara rinci lahan tambak pada salah satu kawasan tambak di Kecamatan Balusu Kabupaten Barru, Sulawesi Selatan melalui analisis spasial. Informasi spasial secara rinci yang meliputi tata letak tambak dan saluran tambak termasuk penggunaan lahan di sekitar tambak diekstrak dari citra satelit resolusi tinggi Quickbird akuisisi tahun 2007. Pengambilan sampel tanah tambak mengikuti metode acak bertingkat (Stratified random sampling) pada wilayah pertambakan. Hasil analisis spasial peubah kimia tanah yang secara rinci dikelompokkan menurut peubah yang mewakili tingkat kemasaman dan kesuburan tanah menunjukkan bahwa hamparan tambak eksisting umumnya memiliki karakteristik tanah yang masam dengan tingkat kesuburan yang rendah. Lebih lanjut diketahui bahwa dari total lahan tambak 548,33 ha yang disurvai; 260,6 ha lahan tersebut berkategori kurang layak; 283,3 ha layak; dan hanya sekitar 4,43 ha yang berkategori sangat layak. Namun demikian 52,47% lahan yang berstatus layak hingga sangat layak tersebut juga masih dapat berubah status menjadi kurang layak dengan adanya batasan aspek hidrologis, utamanya tingkat ketersediaan air yang mengandalkan jaringan saluran tambak.

The current national plan to increase shrimp production to the optimum and sustainable level must be supported by adequate and accurate information on detailed spatial characteristics of coastal areas. The spatial characteristics must also be interpretable or readable to most aquaculture stakeholders. However, the existing available spatial information of land-based aquaculture in most of regions in Indonesia is so far only employed for the global spatial planning of coastal areas (provincial and regency level). In fact, the available information does not have enough detail if it is intended for pond management and engineering applications with respects to upgrading pond productivity. The purpose of this study was to understand the detailed soil characteristics and to assess the level of suitability of the existing brackishwater pond areas in Balusu Sub-district Barru Regency, South Sulawesi with the application of spatial analysis. The detailed spatial information comprising pond layout, canal network and adjacent land use/land cover around the pond unit area was extracted from quickbird satellite imagery acquired in 2007. Soil samples were collected following a stratified random sampling method over shrimp farming areas. Output of spatial analysis of chemical soil variables that were divided into variables representing the level of soil acidity and variables indicating soil fertility showed in general that most of the pond units have high level of soil acidity and can be categorized as marginal land  with low level of soil fertility. Furthermore, the analysis showed that from 548.33 ha area of surveyed fish pond areas, 260.6 ha were categorized as less suitable, 283.3 ha were suitable, and only 4.43 ha were in the category of highly suitable. Although there were 52.47% of the total area classified in the category of suitable to highly suitable, the status might switch to less suitable if there is not enough attention paid onto the existing limiting factors such as the less optimal function of the present canal networks as the main source of tide-water supply for all pond units.