Peranan seresah (Litterfall) dalam suplai hara N,P,K di kawasan hutan alam Kaliurang

NURJAMAN, Aji Sukmono Beno, Prof.Dr.Ir. H. Djoko Marsono

2004 | Tesis | S2 Ilmu Kehutanan (Konservasi Sumber Daya Alam dan

Penelitian mengenai peranan seresah dalam suplai hara telah dilakukan di kawasan Hutan Alam Kaliurang selama periode musim kemarau. Penelitian ini bertujuan untuk mengetahui kandungan hara N,P,K dalam seresah di berbagai ketinggian tempat. Penelitian dilakukan dengan cara menentukan ketinggian tempat, yaitu 1500 meter, 1000 meter dan 500 meter. Pada ketinggian tersebut dilakukan analisis vegetasi dengan sistem jalur. Pada setiap jalur berisi 3 Petak Ukur (PU) bertingkat, yaitu 20x20m untuk tingkat pohon, 10x10m untuk tingkat tiang dan 5x5m untuk tumbuhan bawah. Dibuat 3 jalur dengan jarak 200 m sebagai ulangan. Pada setiap PU diletakkan litter trap 1x1m. Selain ketinggian tempat, maka periode pengambilan seresah untuk analisis hara digunakan sebagai perlakuan. Pengambilan seresah untuk analisis hara N,P,K dilakukan setiap 2 bulan sekali dengan asumsi telah terjadi pergeseran musim, yaitu awal musim kemarau, tengah musim kemarau dan akhir musim kemarau. Dengan demikian penelitian ini dilakukan dalam waktu 6 bulan. Analisis statistik menggunakan model faktorial, ketinggian tempat dan waktu pengambilan seresah sebagai faktor. Hasil penelitian menunjukkan bahwa di lokasi penelitian pada ketinggian 1500 m terdapat 8 jenis pohon, 6 jenis tiang dan 10 jenis tumbuhan bawah, dengan produksi seresah rata-rata sebsar 312,16 kg/ha, terdiri dari seresah daun 68,92%, cabang 16,02% dan bahan lain 15,04%, mampu mensuplai hara N sebesar 4,27%/m2, P sebesar 1,08%/m2 dan K sebesar 2,54%/m2. Pada ketinggian 1000 m terdapat 14 jenis pohon, 8 jenis tiang dan 9 jenis tumbuhan bawah, dengan produksi seresah rata-rata sebesar 290,5 kg/ha, terdiri dari seresah daun 69,74%, cabang 19,54% dan bahan lain 10,72%, mampu memasok unsur hara N sebesar 4,3%/m2, P sebesar 3,39%/m2 dan K sebesar 2,51%/m2. Pada ketinggian 500m terdapat 9 jenis pohon, 11 jenis tiang dan 9 jenis tumbuhan bawah, dengan produksi seresah rata-rata sebesar 317,83 kg/ha, terdiri dari seresah daun 74,70%, cabang 19,21% dan bahan lain 6,09%, mampu memasok unsur hara N sebesar 5,02%/m2, P sebesar 3,55%/m2 dan K sebesar 3,71%/m2.

The research concerning the role of litterfall in the supply of N, P and K in the natural forest of Kaliurang was carried out during a dry season period. The research goal was to reveal the content of N, P and K in litterfall at three levels of altitude in the forest. Within the area, 3 (three) nested plots were allocated systematically at the alitude of 500m, 1000m, and 1500m from the sea level, respectively, so that the total plot were 9 (nine) and the horizontal distance between plots was 200m. Each nested plot consisted of a 20 x 20m plot for trees, a 10 x 10m plot for poles, and 5 x 5m plot for ground vegetation. A vegetation analysis was carried in the area. In addition, a litter trap of 1 x 1m was located in the middle of each 20 x 20m plot for 6 months during the dry season. Every 2 months, litter in the traps was taken before being measured the content of N, P and K in the laboratory. The experimental design used was a factorial one with 3 levels of altitude and 3 levels of observation time. The vegetation analysis revealed that the altitude of 1500m, there were 8 tree species, 6 pole species, and 10 species of ground vegetation. At the altitude, the average litter production during the dry season was 312,16 kg/ha consisting of 68,92% leaves, 16,02% branches, and 15,04% othe components whereas the supplies of N, P and K were 4,27%/m2, 1,08%/m2 and 2,54%/m2, respectively. At the altitude of 1000m, there were 14 tree species, 8 pole species, and 9 species of ground vegetation. At the altitude, the average litter production during the dry season was 290 kg/ha consisting of 69,74% leaves, 19,54% branches, and 10,72% other components whereas the supplies of N, P and K were 4,3%/m2, 3,39%/m2, and 2,51%/m2, respectively. Finally, at the altitude of 500m, there were 9 trees species, 11 pole species, and 9 species of ground vegetation. At the altitude, the average litter production during the dry season was 317,83 kg/ha consisting of 74,70% leaves, 19,21% branches, and 6,09% other components whereas the supplies of N, P, and K were 5,02%/m2, 3,55%/m2 and 3,71%/m2, respectively.

Kata Kunci : Hutan Alam,Produksi Seresah,Suplai Hara N,P,K