Runoff and Soil Erosion on Tea Plantation of Gunung Mas PT. Perkebunan Nusantara VIII

Abstract

Most of tea plantations in Indonesia are located on sloping land and mountainous areas with high rainfall. It has the potential to cause runoff and soil erosion. In the land of mature tea plantation, however, erosion almost meaningless because the land is completely covered and some erosion may occured after the process of pruning and removal of the tea plant (Hartemink, 2006). In order to maintain area of picking and improve the productivity of the tea plant, Gunung Mas Tea Plantation Management (PTPN VIII) use to do the periodic pruning and the produces (leaves, twigs, and branches) use to be returned surrounding the plants. This research aims to examine the runoff and soil erosion on tea plantation at some age of pruning. This research had applied three plots measurement of runoff where in the size is 2m x 8m. The plots were randomly located in different plantation blocks with age of pruning: T1 = tea plant first year after pruning (17% of slope), T2 = tea plant third years after pruning (18% of slope), T3 = tea plant fourth years after pruning (16% of slope). The rainfall of study location is equal to 2,627.3 mm. Annual rainfall erosivity of 1,711.1 ton-m ha-1, cm hour-1 with the highest erosivity occured in January of 299.1 ton-m ha-1, cm hour-1 and the lowest occured in August of 2.01 ton-m ha-1, cm hour-1.

Sebagian besar perkebunan teh di Indonesia berada pada lahan miring di daerah pegunungan dengan curah hujan tinggi. Hal tersebut berpotensi menimbulkan aliran permukaan dan erosi tanah. Akan tetapi, pada lahan perkebunan teh dewasa kejadian erosi hampir tidak berarti karena lahan telah tertutup secara sempurna dan beberapa erosi mungkin terjadi setelah proses pemangkasan dan pemindahan tanaman teh (Hartemink, 2006). Untuk menjaga ketinggian bidang petik dan memperbaiki produktifitas tanaman teh, manajemen perkebunan teh Gunung Mas (PTPN VIII) melakukan pemangkasan secara berkala dan hasil pangkasan (daun, ranting, dan cabang) dikembalikan ke sekeliling tanaman teh. Penelitian ini dilakukan untuk mengkaji aliran permukan dan erosi tanah di perkebunan teh pada beberapa umur pemangkasan. Penelitian ini menggunakan 3 petak pengukuran aliran permukaan berukuran 2m x 8m. Plot ditempatkan pada blok kebun berbeda secara acak dengan umur pangkas: T1 = tanaman teh umur tahun ke-1 setelah pemangkasan (lereng 17 %), T2 = tanaman teh umur tahun ke-3 setelah pemangkasan (lereng 18 %), dan T3 = tanaman teh umur tahun ke-4 setelah pemangkasan (lereng 16 %).