KARAKTERISTIK FISIK TANAH AKIBAT PENGOLAHAN TANAH DANGKAL DAN DALAM PADA PERKEBUNAN NANAS

Abstract

Pengolahan tanah yang intensif pada sistem monokultur jangka panjang, seperti di perkebunan nanas PT. Great Giant Pineapple (GGP), berpotensi menyebabkan degradasi kualitas tanah seperti pemadatan tanah, penurunan kandungan bahan organik tanah, dan munculnya krokos atau konkresi besi di permukaan. Awalnya, pengolahan tanah di PT. GGP dilakukan menggunakan bajak dangkal. Namun, penggunaan yang berulang menyebabkan terbentuknya lapisan padat di bawah permukaan (tapak bajak), sehingga sejak 2010 dilakukan pengolahan tanah menggunakan bajak dalam untuk memecah lapisan tersebut. Penelitian ini bertujuan untuk menganalisis dan mengukur pengaruh teknik bajak dangkal (0–20 cm) dan bajak dalam (40–60 cm) terhadap karakteristik fisik tanah. Penelitian dilakukan di lahan R&D PT. GGP dengan rancangan split plot dan enam ulangan untuk tiap perlakuan. Parameter yang diamati terdiri dari bobot isi, stabilitas agregat, kapasitas air tersedia, dan kadar C-organik. Hasil menunjukkan bahwa penggunaan bajak dangkal mempertahankan kadar C-organik yang lebih tinggi di lapisan atas dan menghasilkan bobot isi lebih rendah dibandingkan bajak dalam. Namun, kedua perlakuan belum menunjukkan perbedaan nyata terhadap stabilitas agregat dan kapasitas air tersedia dalam jangka pendek. Indeks stabilitas agregat bulan November tergolong tidak stabil, meningkat menjadi kurang stabil pada Februari, tetapi tetap tidak berbeda nyata antar perlakuan. Hasil ini menunjukkan bahwa dalam jangka pendek, dampak pembajakan terhadap sifat fisik tanah belum sepenuhnya terlihat, namun bajak dangkal berpotensi menjadi strategi konservasi yang lebih berkelanjutan.

Intensive tillage in long-term monoculture systems, such as in the pineapple plantations of PT. Great Giant Pineapple (GGP), has the potential to degrade soil quality, causing soil compaction, a decline in soil organic matter content, and the emergence of krokos or iron concretions at the surface. Initially, land preparation at PT. GGP was carried out using shallow plowing. However, repeated use over time led to the formation of a compacted subsurface layer (plow pan), prompting the adoption of deep plowing in 2010 to break this layer. This study aimed to analyze and evaluate the effects of shallow plowing (0–20 cm) and deep plowing (40–60 cm) on soil physical properties. The research was conducted in the R&D fields of PT. GGP using a split-plot design with six replications for each treatment. Observed parameters included bulk density, aggregate stability, available water capacity, and soil organic carbon content. The results showed that shallow plowing maintained higher soil organic carbon content in the topsoil and produced lower bulk density compared with deep plowing. However, both treatments showed no significant differences in aggregate stability and available water capacity in the short term. Aggregate stability indices in November were classified as unstable, increasing to slightly unstable in February, but still showing no significant differences between treatments. These findings indicate that, in the short term, the effects of plowing depth on soil physical properties are not yet fully apparent. Nevertheless, shallow plowing has the potential to serve as a more sustainable soil management strategy.