Abstract. The study aimed at finding out the EM4 fermented chicken manure dosage, the concentration of cow biourine, and the interaction between the two which gave the best growth and yield of Japanese spinach were carried out in Candikuning Village, Baturiti District, Tabanan Regency, at altitude of 1,500 m asl. The trial lasted 45 days, starting from Mid April - May 2019, using a Randomized Group Design (RBD), consisting of two factors. The first factor is the chicken manure dose EM-4 fermented (A), with 4 levels, namely: (A0) without chicken manure (control), (A1) chicken manure dose of 10 tons.ha-1 or 480 grams / plot, (A2) chicken manure dose of 20 ton.ha-1 or 960 gram / plot, and (A3) chicken manure dose of 30 ton.ha-1 or 1440 gram / plot. The second factor is the concentration of bovine biourine (B), with 4 levels, namely: (B0) without bovine biourine (control), (B1) concentration of 100 ml.l-1 bovine biourine solution or 10%, (B2) 200 ml bovine biourine concentration. l-1 solution or 20%, (B3) 300 ml.l-1 concentration of beef biourine solution or 30%. The results of the analysis showed that the EM4 fermented chicken manure had a significant effect on almost all variables observed, except plant height per plant aged 17 days and oven dry weight of leaves per plant. The EM4 fermented chicken manure dose of 20 ton.ha-1 gave the highest total wet weight per plant, which was 228.74 g and the highest total oven dry weight per plant, ie 115.37 g. The optimal dose of fermented chicken manure EM-4 is 18.40 ton.ha-1 with a total oven dry weight per plant maximum = 135.21 g. The concentration of 200 ml.l-1 biourine cattle gave the highest total wet weight per plant, which was 238.01 g and the highest total oven dry weight, which was 121.51 g. The optimal concentration of beef biourine is 176.69 ml.l-1 with a total oven dry weight per plant maximum = 135.44 g. The interaction between EM4 fermented chicken manure doses and cattle biourine concentration only significantly affected the number of leaves per plant aged 45 days.Keywords. Chicken manure, Biourine cow, Japanese spinachAbstrak. Penelitian yang betujuan untuk mengetahui dosis pupuk kandang ayam difermentasi EM4, konsentrasi biourine sapi, dan interaksi antara keduanya yang memberikan pertumbuhan dan hasil bayam Jepang terbaik telah dilakukan di Desa Candikuning, Kecamatan Baturiti, Kabupaten Tabanan, pada ketinggian tempat  1.500 m dpl. Percobaan berlangsung selama 45 hari, mulai dari Pertengahan April – Mei 2019, menggunaan Rancangan Acak Kelompok (RAK), terdiri dari dua faktor.  Faktor pertama dosis pupuk kandang kandang ayam difermentasi EM-4 (A), dengan 4 taraf yaitu : (A0) tanpa pupuk kandang ayam (kontrol), (A1) pupuk kandang ayam dosis 10 ton.ha-1 atau 480 gram/petak, (A2) pupuk kandang ayam dosis 20 ton.ha-1 atau 960 gram/petak, dan (A3) pupuk kandang ayam dosis 30 ton.ha-1 atau 1440 gram/petak. Faktor kedua kensentrasi biourine sapi (B), dengan 4 taraf yaitu : (B0) tanpa biourine sapi (kontrol), (B1) konsentrasi biourine sapi 100 ml.l-1larutan atau 10%, (B2) konsentrasi biourine sapi 200 ml.l-1larutan atau 20%, (B3) konsentrasi biourine sapi 300 ml.l-1larutan atau 30%.  Hasil analisis ragam menunjukan dosis pupuk kandang ayam yang difermentasi EM4 berpengaruh nyata sampai sangat nyata terhadap hampir semua variabel yang diamati, kecuali tinggi tanaman per tanaman umur 17 hst dan berat kering oven daun per tanaman. Dosis pupuk kandang ayam yang difermentasi EM4 20 ton.ha-1 memberikan  berat basah total per tanaman tertinggi, yaitu 228,74 g dan berat kering oven total per tanaman tertinggi, yaitu 115,37 g. Dosis optimal pupuk kandang ayam yang difermentasi EM-4 yaitu18,40 ton.ha-1dengan berat kering oven total per tanaman maksimum =  135,21 g. Konsentrasi biourine sapi 200 ml.l-1 larutan memberikan berat basah total per tanaman tertinggi, yaitu 238,01 g   dan berat kering oven total tertinggi, yaitu 121,51 g. Konsentrasi optimal biourine sapi yaitu 176,69 ml.l-1 dengan berat kering oven total per tanaman maksimum = 135,44 g. Interaksi antara dosis pupuk kandang ayam yang difermentasi EM4 dan konsentrasi biourine sapi hanya berpengaruh nyata terhadap jumlah daun per tanaman umur 45 hst.Kata kunci: Pupuk kandang ayam, Biourine sapi, Bayam jepang