Judul: Radiation Use Efficiency Arabica Variety Gayo 3 Coffee Seed at  Different Shading Intensities
Abstrak: Penelitian ini bertujuan untuk menganalisis pengaruh perbedaan intensitas radiasi matahari terhadap efisiensi pemanfatatan radiasi matahari (EPR) bibit kopi arabika varietas Gayo 3. Bibit kopi arabika varietas Gayo 3 ditanam di dalam pot dan ditempatkan di bawah naungan waring atau paranet – untuk mengurangi transmisivitas (??) radiasi matahari; dan di atasnya diberi plastik – untuk mencegah air hujan masuk dan mengenai pot tanaman. Ada 4 taraf perlakuan intensitas, yaitu N1 (waring+plastik, ?? = 76.1%), N2 (paranet 50%+plastik, ?? = 50.8%), N3 (paranet 75%+plastik, ?? = 25.5%), dan N4 (paranet 90%+plastik, ?? = 14.7%). Selama 74 hari penelitian, total radiasi global 1126.2 MJ/m2 dan yang ditransmisikan ke dalam ruangan dan mencapai tajuk bibit tanaman (MJ/m2) pada N1 adalah 855.8, N2 563.1, N3 269.2, dan N4 193.7. Hasil penelitian menunjukkan pengaruh nyata tingkat intensitas radiasi terhadap EPR bibit tanaman kopi arabika Gayo 3. Nilai EPR (g/MJ) pada perlakuan N1, N2, N3, dan N4 berturut-turut adalah sebesar 0.40, 0.72, 1.00, dan 0.99. Hasil tersebut mengindikasikan bahwa bibit tanaman kopi arabika Gayo 3 membutuhkan naungan untuk dapat tumbuh lebih optimal. Bibit tanaman kopi arabika Gayo 3 yang ditanam pada rata-rata intensitas harian (MJ/m2/hari) 3.5 (N3) dan 2.5 (N4) menunjukkan pertumbuhan lebih optimal dibandingkan dengan yang ditanam pada rata-rata intensitas harian yang lebih tinggi 10.7 (N1) dan 7.2 (N2). Hasil penelitian ini perlu dikaji lebih dalam untuk mendapatkan kisaran optimum intensitas radiasi yang dibutuhkan oleh bibit tanaman kopi arabika Gayo 3., The purpose of this research is to analyze optimum intensity of solar radiation for arabica variety Gayo 3 coffee seed growth which will be expressed by radiation use efficiency (RUE) value and productivity parameters. Arabica coffee seedlings of the Gayo 3 variety were planted in pots and placed under different level of shading by utilizing waring or paranet to reduce the transmissivity (t) of solar radiation; with a layer of plastic to prevent rainwater from entering and hitting the plant pots. There were 4 levels of intensity treatment, namely N1 (netting + plastic, t = 76.1%), N2 (50% paranet + plastic, t = 50.8%), N3 (75% paranet + plastic, t = 25.5%), and N4 (90% paranet + plastic, t = 14.7%). During the 74 days of the study, the total global radiation was 1126.2 MJ/m2, the amount that got transmitted into the greenhouse and reached the canopy of the seedlings (MJ/m2) at N1 was 855.8, N2 563.1, N3 269.2, and N4 193.7. The results showed a significant effect of different level of radiation intensity on the EPR of Gayo 3 Arabica coffee seedlings. The EPR values (g/MJ) in the N1, N2, N3, and N4 treatments were 0.40, 0.72, 1.00, and 0.99, respectively. These results indicate that Gayo 3 Arabica coffee seedlings need shade to grow optimally. The seedlings planted at an average daily intensity (MJ/m2/day) of 3.5 (N3) and 2.5 (N4) showed more optimal growth compared to those planted at a higher average daily intensity of 10.7 (N1) and 7.2 (N2). However, a further study regarding these results is still needed to obtain the optimum range of radiation intensity required by Arabica coffee seedlings of Gayo 3
Keyword: Gayo 3, Growth, Intensity, Seed and Shading