Laju Dekomposisi Bahan Organik dan Pengaruhnya terhadap Sifat Fisik Tanah Lahan Perkebunan Nanas PT Great Giant Pineapple

Abstract

Indonesia sebagai negara beriklim tropis memiliki laju dekomposisi bahan organik yang tinggi, sehingga menyebabkan rendahnya kandungan bahan organik tanah dan berdampak pada sifat fisik tanah. Kondisi tersebut juga terlihat pada lahan perkebunan nanas PT Great Giant Pineapple (GGP), Kabupaten Lampung Tengah. Penelitian ini bertujuan mengidentifikasi laju dekomposisi serasah tanaman nanas dan pengaruhnya terhadap sifat fisik tanah. Metode penelitian melibatkan pengamatan lapangan dan analisis laboratorium dengan pendekatan deskriptif. Serasah tanaman nanas sebanyak ±200 ton/ha, kompos premium 35 ton/ha, dan dolomit 2 ton/ha diaplikasikan pada 18 plot berukuran 1 meter × 1 meter. Pengamatan dilakukan setiap bulan selama 4 bulan, mencakup pengukuran bobot serasah terdekomposisi, C-organik tanah, bobot jenis partikel, bobot isi, porositas, stabilitas agregat, infiltrasi, dan retensi air tanah. Hasil menunjukkan bahwa laju dekomposisi serasah menurun seiring waktu, dengan 41,77% jumlah serasah terdekomposisi setelah 4 bulan. Dekomposisi bahan organik meningkatkan Corganik tanah dan memperbaiki sifat fisik tanah, seperti penurunan bobot isi dan bobot jenis partikel serta peningkatan porositas dan stabilitas agregat. Namun, laju infiltrasi menurun akibat pemadatan tanah dan intensitas hujan. Retensi air tanah cenderung menurun pada bulan-bulan akhir pengamatan akibat kerusakan struktur tanah oleh tetesan air hujan. Penelitian ini menekankan pentingnya pengelolaan bahan organik berkelanjutan untuk mempertahankan produktivitas lahan tropis.

Indonesia, as a tropical country, has a high rate of organic matter decomposition, resulting in low soil organic matter content and affecting soil physical properties. This condition is also observed in the pineapple plantation of PT Great Giant Pineapple (GGP), Central Lampung Regency. This study aimed to identify the decomposition rate of pineapple litter and its effects on soil physical properties. The research employed field observations and laboratory analyses using a descriptive approach. Pineapple litter of approximately ±200 tons/ha, 35 tons/ha of premium compost, and 2 tons/ha of dolomite were applied to 18 plots measuring 1 m × 1 m. Observations were conducted monthly for four months, including measurements of decomposed litter weight, soil organic carbon, particle density, bulk density, porosity, aggregate stability, infiltration, and soil water retention. The results showed that the litter decomposition rate decreased over time, with 41.77% of the litter decomposed after four months. Organic matter decomposition increased soil organic carbon and improved soil physical properties, such as reducing bulk density and particle density while increasing porosity and aggregate stability. However, infiltration rate declined due to soil compaction and rainfall intensity. Soil water retention also tended to decrease in the final months of observation due to soil structure degradation caused by raindrop impact. This study highlights the importance of sustainable organic matter management to maintain the productivity of tropical soils.