RESPON LIMA AKSESI JAHE PUTIH KECIL (Zingiber officinale var. Amarum) TERHADAP PEMUPUKAN

ABSTRAK Penggunaan varietas jahe yang responsif terhadap pemupukan dosis rendah, diharapkan mampu meningkatkan efisiensi pemupukan dan menekan pencemaran lingkungan. Penelitian dengan tujuan untuk mengetahui respon lima aksesi jahe putih kecil terhadap pemupukan dosis rendah telah dilaksanakan di Kebun Percobaan Cimanggu pada bulan Agustus 2009 sampai Mei 2010. Lima aksesi jahe putih kecil dari daerah marginal ditanam dalam polibag dan disusun menggunakan rancangan acak kelompok yang diulang 3 kali. Setiap perlakuan terdiri atas 20 tanaman. Dua perlakuan yang diuji secara faktorial adalah, faktor I adalah 5 aksesi jahe putih kecil, yaitu (1) Ziof 0004, (2) Ziof 0007, (3) Ziof 0008, (4) Ziof 0013, dan (5) Ziof 0014, dan faktor II adalah dosis pupuk, yaitu (a) 50% dosis anjuran (200 kg/ha urea + 150 kg/ha SP-36 + 150 kg/ha KCl), (b) 75% dosis anjuran (300 kg/ha urea + 225 kg/ha SP-36 + 225 kg/ha KCl), dan (c) dosis anjuran (400 kg/ha urea + 300 kg/ha SP-36 + 300 kg/ha KCl). Masing-masing perlakuan diberi pupuk kandang sebagai pupuk dasar dengan dosis 20 t/ha. Pengamatan dilakukan terhadap parameter pertumbuhan (tinggi tanaman, jumlah anakan, diameter batang, dan jumlah daun), hasil dan serapan unsur hara N, P, dan K pada umur 4 BST dan 9 BST. Hasil penelitian menunjukkan bahwa masing-masing aksesi memberikan respon yang berbeda terhadap penurunan dosis pupuk, baik pada fase pertumbuhan maupun produksi tanaman jahe. Pengurangan dosis pupuk sampai 25% tidak mengurangi produksi jahe, tetapi penurunan dosis pupuk sampai 50% dari dosis rekomendasi menyebabkan penurunan produksi jahe secara nyata. Komposisi unsur hara N, P, dan K yang diserap berbeda pada setiap fase pertumbuhan tanaman. Kata kunci : Aksesi, Zingiber officinale, pemupukan, pertumbuhan, produksi ABSTRACT Response of five accessions of small white ginger to fertilizers The use of ginger varieties responsive to low fertilization dosages, is expected to increase fertilizer use efficiency and reduce environmental pollution. Research aimed at observing response of five small white ginger accessions of low-dosage fertilization has been conducted in the Cimanggu Experimental Station in from August 2009 through May 2010. Five small white ginger accessions from marginal areas were planted in polybags. The experiment was and arranged using a randomized block design was repeated with 3 times replications. Each treatment consisted of 20 plants. Two treatments were tested factorially, where factor I : 5 small white ginger accessions, namely (1) Ziof 0004, (2) Ziof 0007, (3) Ziof 0008, (4) Ziof 0013, and (5) Ziof 0014, and factor II : 3 fertilization dosages is dosage of fertilizer, namely (a) 50% recommendation dosage (200 kg urea + 150 kg SP-36 + 150 kg KCl per hectare), (b) 75% recommendation dosage (300 kg urea + 225 kg SP-36 + 225 kg KCl per hectare), and (c) recommendation dosage (400 kg Urea + 300 kg SP-36 + 300 kg KCl per hectare). Each treatment was given 20 t/ha of manure as basal fertilizer. The parameters observed were growth parameters (plant height, number of tillers, stem diameter, and number of leaves), yield and nutrient uptake of N, P, and K at 4 and 9 months after planting (MAP). The results showed that each of the accessions responded differently to the reduction of fertilizer dosages, either in vegetative or generative growth phase of ginger plants. Reduction of fertilizer dosages to 25% did not significantly reduce the yield of ginger, however, fertilizer dosages reduction up to 50% of the recommended dosages led to significant decrease of ginger yield. Compositions of N, P, and K nutrients absorbed by plants were different in every phase of plant growth. Keywords : Accessions, Zingiber officinale, fertilizer, growth, yield