PENGARUH PUPUK K TERHADAP PERTUMBUHAN, HASIL DAN MUTU RIMPANG JAHE MUDA (Zingiber officinale Rocs.) - RAHARDJO, MONO (Jurnal Penelitian Tanaman Industri, 2012)
ABSTRAKKalium merupakan unsur hara yang paling banyak diserap olehtanaman jahe dibandingkan N dan P. Produktivitas tanaman akan menurunapabila kekurangan unsur hara K, karena K mempunyai fungsi pentingpada proses fotosintesis, aktifitas enzim, metabolisme karbohidrat, proteindan sebagai transport ion. Penelitian dilakukan di Kebun PercobaanSukamulya sejak Januari sampai Mei 2010. Tujuan penelitian ini adalahuntuk mengetahui pengaruh pemberian pupuk KCl terhadap pertumbuhan,hasil, serapan hara, dan mutu rimpang jahe muda. Perlakuan disusundalam rancangan acak kelompok dan diulang 4 kali. Perlakuan yangdicoba terdiri atas delapan perlakuan pupuk KCl yaitu; 0, 50, 100, 150,200, 250, 300, dan 350 kg/ha. Jarak tanam yang digunakan adalah 50 x 60cm, dengan populasi 100 tanaman/plot. Contoh tanaman diambil padaumur 4 BST, sebanyak 5 tanaman setiap satuan perlakuan. Peubah yangdiamati adalah, tinggi tanaman, jumlah anakan, bobot segar rimpang,bobot kering rimpang dan tanaman, kadar minyak atsiri, pati, serat, haraN, P dan K. Hasil penelitian menunjukkan bahwa tinggi tanaman, bobotsegar rimpang, bobot kering batang+daun dan bobot kering rimpangmeningkat secara nyata dengan meningkatnya perlakuan pupuk KCl.Tinggi tanaman, bobot segar rimpang, bobot kering batang+daun tertinggidicapai pada perlakuan pupuk KCl dosis 350 kg/ha, masing-masing adalah86,88 cm, 272,51 g/tanaman, dan 27,46 g/tanaman. Peningkatan bobotkering batang+daun dan bobot segar rimpang berkorelasi positif denganmeningkatnya pemupukan KCl sampai dosis 350 kg/ha, membentukpersamaan linier (r = 0,610 tn dan 0,643 tn ) dengan tingkat kepercayaanmasing-masing P = 0,987** dan 0,99**. Kadar serat rimpang meningkatmembentuk persamaan kuadratik (R 2 = 0,792*) dengan peningkatanpemupukan KCl sampai dosis 350 kg/ha, dengan tingkat kepercayaan P =0,997**. Serapan hara N, P dan K berkorelasi positif dengan peningkatanpemupukan KCl sampai dosis 350 kg/ha. Serapan N membentukpersamaan linier (r = 0,541 tn ) dengan tingkat kepercayaan P = 0,977**,serapan P membentuk persamaan kuadratik (R 2 = 0,798*) dengan tingkatkepercayaan P = 0,992**, dan serapan K membentuk persamaan kuadratik(R 2 = 0,643 tn ) dengan tingkat kepercayaan P = 0,947**.Kata kunci : Zingiber officinale Rocs., pupuk KCl, pertumbuhan, mutu,hasil jahe mudaABSTRACTPotassium is the nutrient most absorbed by ginger compared to Nand P nutrients. Crop productivity will decline if it lacks of K nutrient,because K has an important function in the photosynthesis of process,enzyme activity, metabolisms of carbohydrates and proteins, and it alsofunctions as an ion transport. A study, conducted at SukamulyaExperimental Station from January to May 2010, aimed at determining theeffect of KCl fertilizer application on growth, yield, nutrient uptake, andquality of young ginger rhizomes. Treatments were arranged in arandomized block design with four replicates. The treatments consisted ofeight KCl fertilizer dosages, namely: 0, 50, 100, 150, 200, 250, 300, and350 kg/ha. Planting space used was 50 x 60 cm, with plants population of100/plot. Five plants per treatment unit were sampled at the age of 4months after planting. Variables observed were plant height, number oftillers, rhizome fresh weight, dry weights of rhizomes and plants, contentsof essential oil, starch, fiber, and N, P, and K nutrients. The results showedthat plant height, rhizome fresh weight, stems + leaf dry weight, andrhizome dry weight increased significantly in line with the increase in KClfertilizer dosages. The best results of plant height, rhizome fresh weight,and dry weight of stem + leaf were achieved at the highest dosage of KClfertilizer (350 kg/ha). The measures were 86.88 cm, 272.51 g/plant, and27.46 g/plant, respectively. Increase in dry weights of stem + leaf andfresh rhizome were positively correlated with increasing fertilizer dosagesof KCl up to 350 kg/ha, forming a linear equation (r = 0.610 tn and r =0.643 tn ) with P confidence levels of 0.987** and 0.99**, respectively.Increase in fiber content of rhizomes formed a quadratic equation (R 2 =0.792*) by increasing dosages of KCl fertilizer up to 350 kg/ha, with a Pconfidence level of 0.997**. Uptakes of N, P, and K nutrients werepositively correlated with increases in KCl fertilizations up to 350 kg/ha.Uptakes of N nutrient formed a linear equation (r = 0.541 tn ) with a Pconfidence level of 0.977**, P uptakes formed a quadratic equation (R 2 =0.798*) with a P confidence level of 0.992**, and uptakes of K alsoformed a quadratic equation (R 2 = 0.643 tn ) with a P confidence level of0.947**.Key words: Zingiber officinale Rocs., KCl fertilizer, growth, quality,young ginger rizhome