Pengaruh Intensitas Radiasi dan Interval Penyiraman terhadap Karakter Morfologi Daun dan Respon Fisiologis Bibit Kopi LIM 1 Liberika Siap Tanam

Abstract

Persiapan bibit merupakan tahap krusial dalam budidaya kopi, terutama pada kopi liberika yang mulai dikembangkan di lahan marginal. Bibit kopi dipengaruhi oleh faktor lingkungan seperti intensitas radiasi, karena kopi merupakan tanaman C3 yang membutuhkan intensitas radiasi rendah, serta memerlukan interval penyiraman yang tepat untuk menjaga ketersediaan air di media tanam. Penelitian dilaksanakan di Sukabumi menggunakan rancangan petak terpisah (split-plot) dengan perlakuan utama berupa empat tingkat naungan (25%, 50%, 75%, dan 90%) dan anak petak berupa empat interval penyiraman (2, 4, 6, dan 8 hari). Parameter yang diamati meliputi jumlah daun, luas daun, ketebalan daun, kandungan klorofil, laju fotosintesis, konduktivitas stomata, suhu daun, laju transpirasi, efisiensi penggunaan air (WUE), dan kandungan prolin. Hasil penelitian menunjukkan bahwa intensitas naungan berpengaruh sangat nyata terhadap hampir seluruh peubah morfologis dan fisiologis, sedangkan interval penyiraman berpengaruh nyata terhadap jumlah daun, luas daun, buka stomata, laju fotosintesis, efisiensi penggunaan air, suhu daun, dan prolin. Interaksi antara kedua perlakuan hanya berpengaruh nyata terhadap kandungan prolin. Perlakuan rata – rata intensitas radiasi 3,6MJ/m² dan 2,1MJ/m² serta penyiraman setiap 4 hari menghasilkan kondisi pertumbuhan bibit yang terbaik. Temuan ini memberikan dasar ilmiah dalam pengembangan sistem pembibitan kopi liberika yang efisien dan adaptif terhadap kondisi lingkungan terbatas.

Seedling preparation is a crucial stage in coffee cultivation, especially for Liberica coffee, which is beginning to be developed on marginal land. Coffee seedlings are influenced by environmental factors such as intensity radiation, because coffee is a C3 plant that requires low radiation intensity and needs proper watering intervals to maintain water availability in the growing medium. The study was conducted in Sukabumi using a split-plot design with the main treatment consisting of four shading levels (25%, 50%, 75%, and 90%) and subplots consisting of four irrigation intervals (2, 4, 6, and 8 days). The parameters observed included the number of leaves, leaf area, leaf thickness, chlorophyll content, photosynthesis rate, stomatal conductance, leaf temperature, transpiration rate, water use efficiency (WUE), and proline content. The results showed that shading intensity had a significant effect on nearly all morphological and physiological variables, while irrigation intervals had a significant on leaf number, leaf area, stomatal opening, photosynthesis rate, water use efficiency, leaf temperature, and proline content. The interaction between the two treatments only significantly affected proline content. The treatment with an average radiation intensity of 3,6 MJ/m² and 2,1 MJ/m² combined with irrigation every 4 days produced the best seedling growth conditions. These findings provide a scientific basis for developing an efficient liberica coffee nursery system that is adaptive to limited environmental conditions.