Tujuan penelitian ini adalah : (1) untuk mengetahui pengaruh dosis pupuk KCl terhadap pertumbuhan dan produksi ubi jalar, (2) untuk mengetahui dosis pupuk KCl terbaik terhadap pertumbuhan dan produksi ubi jalar. Penelitian ini menggunakan rancangan dasar Rancangan Acak Kelompok Lengkap yang terdiri dari 5 perlakuan dan 5 ulangan. Data dianalsis menggunakan analisis    ragam dilanjutkan dengan uji Beda Nyata Jujur. Hasil penelitian ini menunjukkan (1) pemberian pupuk KCl  tidak  berpengaruh  terhadap  panjang batang utama, jumlah cabang, dan jumlah daun. (2) pemberian pupuk KCl berpengaruh nyata terhadap berat segar umbi per tanaman, tetapi tidak nyata terhadap diameter umbi per tanaman, jumlah umbi per tanaman, dan panjang umbi per tanaman. (3) Pemberian pupuk KCl berpengaruh terhadap berat umbi sehat per hektar, berat umbi afkir per hektar, berat umbi yang dapat dipasarkan, dan berat segar umbi per hektar. (4) dosis pupuk KCl terbaik adalah 150 kg/ha karena dapat menghasilkan berat segar umbi tertinggi, berat umbi sehat tertinggi, berat umbi afkir terrendah, berat umbi yang dapat dipasarkan yang terberat, dan berat segar umbi tertinggi.

The  purpose of  this research was to study : (1) interaction effect between the dosage of chicken manure with the frequency of  watering, (2) effect  of  chicken  manure  dosage,  and (3)  effect of watering frequency, to the growth of sengon seedlings. This research uses a completely randomized design which was factorially composed, consisting of 2 factors, namely (1) dosage of chicken manure (D), consists of 4 levels, (2) watering frequency (F), consists of 3 levels. From these two factors, were obtained   12 treatment combinations, where each of which was replicated 3 times. Data were analyzed by Analysis of variance, continued by Honestly Significant Diferent Test.  The results of this study is: (1) interaction between dosage of chicken manure and frequency of watering occurs only to seedling height, (2) the dosage of chicken manure significantly effected to stem diameter, number of compound leaves, fresh  weight of seedlings,  and dry  weight  of  seedlings.  While frequency of watering significantly effects only the stem diameter, (3) chicken manure with a dosage of 37.5 g/crop is optimum dosage, while watering with a frequency of 2 times a day is right frequency of watering, for the growth of sengon seedling.