Electronic Theses and Dissertation

Kopi robusta merupakan jenis kopi yang paling banyak dibudidayakan di Indonesia karena memiliki kemampuan adaptasi yang baik pada dataran rendah hingga menengah serta produktivitas yang relatif tinggi. Kopi robusta banyak dikembangkan melalui sistem budidaya organik maupun anorganik. Arthropoda permukaan tanah merupakan komponen penting dalam ekosistem kebun kopi robusta karena berperan dalam dekomposisi bahan organik, siklus hara, dan pengendalian organisme lain. Penelitian ini bertujuan untuk mengetahui keanekaragaman jenis arthropoda permukaan tanah pada perkebunan kopi robusta yang dikelola dengan sistem budidaya organik dan anorganik.
Penelitian ini dilaksanakan di dua jenis lahan diperkebunan kopi robusta organik dan anorganik yang berada di Desa Sabet, Kecamatan Jaya, Kabupaten Aceh Jaya dan Laboratarium Pengendalian Hayati, Fakultas Pertanian Universitas Syiah Kuala. Pengambilan sampel dilakukan dengan metode purposive sampling, yaitu penentuan titik pengamatan secara sengaja sesuai dengan tujuan penelitian. Pada setiap lahan ditetapkan lima subplot yang disusun secara diagonal, terdiri atas satu subplot di bagian tengah lahan dan empat subplot pada masing-masing sudut lahan. Peubah yang diamati meliputi komposisi morfospesies arthropoda permukaan tanah, kelimpahan spesies arthropoda permukaan tanah (K), indeks keanekaragaman Shannon wiener (H’), indeks kemerataan arthropoda permukaan tanah, dan indeks dominansi (ID) arthropoda permukaan tanah.
Hasil penelitian menunjukkan bahwa keanekaragaman arthropoda permukaan tanah pada perkebunan kopi robusta berbeda antara lahan organik dan anorganik. Pada lahan organik ditemukan 18 morfospesies dengan total 404 individu, sedangkan pada lahan anorganik ditemukan 15 morfospesies dengan total 251 individu. Kelompok yang mendominasi pada kedua lahan berasal dari ordo Hymenoptera, khususnya famili Formicidae (semut). Pada lahan organik, spesies dengan kelimpahan relatif (KR) tertinggi adalah Acheta domesticus (39,85%), diikuti Odontoponera denticulata (30,20%). Pada lahan anorganik, spesies yang paling dominan adalah Odontoponera denticulata (45,42%), diikuti Tapinoma sessile (15,54%) dan Trachelipus rathkii (13,94%). Kelimpahan Acheta domesticus pada lahan anorganik menurun menjadi 13,15%. Hasil analisis menunjukkan bahwa indeks kelimpahan arthropoda berbeda nyata antara kedua lahan (P=0,031; t=2,596; df=8). Nilai dominansi kelimpahan lebih tinggi pada lahan anorganik (80,8) dibandingkan lahan organik (50,2). Indeks keanekaragaman (H') tidak berbeda nyata (P=0,051; t=2,294; df=8), dengan nilai H' sebesar 1,50 pada lahan organik dan 1,24 pada lahan anorganik yang keduanya termasuk kategori sedang. Indeks kemerataan tidak berbeda nyata (P=0,407; t=0,873; df=8), dengan nilai 0,67 pada lahan organik dan 0,62 pada lahan anorganik, sehingga menunjukkan bahwa kedua lahan memiliki tingkat kemerataan yang relatif sama. Indeks dominansi tidak berbeda nyata (P=0,087; t=-1,943; df=8), meskipun nilai dominansi pada lahan anorganik (0,42) lebih tinggi dibandingkan lahan organik (0,30), yang menunjukkan bahwa pada lahan anorganik terdapat satu atau beberapa spesies yang lebih mendominasi dibandingkan spesies lainnya.

Robusta coffee is the most widely cultivated coffee variety in Indonesia because it adapts well to lowland to midland areas and has relatively high productivity. Robusta coffee is widely cultivated using both organic and inorganic farming systems. Soil-surface arthropods are an important component of the robusta coffee plantation ecosystem because they play a role in the decomposition of organic matter, the nutrient cycle, and the control of other organisms. This study aims to determine the diversity of soil-surface arthropod species in Robusta coffee plantations managed using organic and inorganic farming systems. This study was conducted on two types of land—organic and inorganic Robusta coffee plantations—located in Sabet Village, Jaya Subdistrict, Aceh Jaya Regency, and at the Biological Control Laboratory, Faculty of Agriculture, Syiah Kuala University. Sampling was carried out using the purposive sampling method, in which observation points were deliberately selected in accordance with the research objectives. Five subplots were established on each plot, arranged diagonally, consisting of one subplot in the center of the plot and four subplots at each corner of the plot. The variables observed included the morphospecies composition of soil-surface arthropods, the abundance of soil-surface arthropod species (K), the Shannon-Wiener diversity index (H’), the evenness index of soil-surface arthropods, and the dominance index (DI) of soil-surface arthropods. The results of the study show that the diversity of soil-surface arthropods in Robusta coffee plantations differs between organic and inorganic plots. In the organic plots, 18 morphospecies were found, totaling 404 individuals, while in the inorganic plots, 15 morphospecies were found, totaling 251 individuals. The dominant group in both types of land belonged to the order Hymenoptera, specifically the family Formicidae (ants). On organic land, the species with the highest relative abundance (RA) was Acheta domesticus (39.85%), followed by Odontoponera denticulata (30.20%). On inorganic land, the most dominant species was Odontoponera denticulata (45.42%), followed by Tapinoma sessile (15.54%) and Trachelipus rathkii (13.94%). The abundance of Acheta domesticus on inorganic land decreased to 13.15%. The analysis results showed that the arthropod abundance index differed significantly between the two land types (P=0.031; t=2.596; df=8). The dominance index was higher on inorganic land (80.8) than on organic land (50.2). The diversity index (H') did not differ significantly (P=0.051; t=2.294; df=8), with an H' value of 1.50 in organic plots and 1.24 in inorganic plots, both of which fall into the moderate category. The evenness index did not differ significantly (P = 0.407; t = 0.873; df = 8), with a value of 0.67 on organic land and 0.62 on inorganic land, indicating that both land types have relatively similar levels of evenness. The dominance index did not differ significantly (P=0.087; t=-1.943; df=8), Although the dominance value for inorganic soil (0.42) is higher than that for organic soil (0.30), this indicates that in inorganic soil there is one or more species that are more dominant than the others.