ABSTRACT Bazzar Hus. "The Effect of Biological Liquid Fertilizer Concentration and Giving of Biochar on Growth and Yield Plant of Kailan (Brassica Oleraceae)", under the guidance of Dr. Zaitun, SP, M.Si as main supervisor and Taufan Hidayat, S.Si., M.Si as mentors members. This study aimed to determine the effect of liquid bio-fertilizer and biochar on crop growth and yield kailan (Brassica oleraceae), which was held on July 4, 2012 until 1 September 2012 at the University Farm, Station Research 2 Ie Suum, Krueng Raya, Aceh Besar. The experimental design that used in the study was randomized block design (RBD) 3 x 2 factorial with 3 replications. There are two factors that investigated the biological liquid fertilizer concentration factor (0, 1, and 2 liter ha-1), and the factor of biochar (without biochar and with biochar ). The observed variables in the study include plant height and number of leaves at the age of 7, 14, 21, 28, and 35 days after planting, and plant fresh weight, leaf length, leaf width, and dry weight of plant age 35 HST. The results of this research showed that there is an infection between the treatment of liquid bio-fertilizer concentration and giving biochar on crop growth and yield kailan (Brassica oleraceae). The treatment between the concentration of liquid bio-fertilizer 1 liter ha-1 and providing the best treatment is a combination of biochar. The results of this study also showed that the concentration of liquid fertilizer and giving biochar biological effect on the growth and yield of kailan (Brassica oleraceae). The best liquid bio fertilizer treatments contained at a concentration of 1 liter ha-1. Bazzar Hus. “Pengaruh Konsentrasi pupuk Cair Hayati dan Pemberian Biochar Terhadap Pertumbuhan dan Hasil Tanaman Kailan (Brassica oleraceae)”, di bawah bimbingan Ibu Dr. Zaitun, S.P., M.Si sebagai pembimbing utama dan Bapak Taufan Hidayat, S.Si., M.Si sebagai pembimbing anggota. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian pupuk cair hayati dan biochar terhadap pertumbuhan dan hasil tanaman kalian (Brassica oleraceae), yang dilaksanakan pada tanggal 4 Juli 2012 hingga 1 September 2012 di University Farm, Stasiun Riset 2 Ie Suum, Kecamatan Krueng Raya, Kabupaten Aceh Besar. Rancangan percobaan yang digunakan dalam penelitian adalah Rancangan Acak Kelompok (RAK) pola faktorial 3 x 2 dengan 3 ulangan. Ada dua faktor yang diteliti yaitu faktor konsentrasi pupuk cair hayati (0, 1, dan 2 liter ha-1), dan faktor biochar (tanpa biochar dan pemberian biochar). Peubah yang diamati dalam penelitian ini meliputi tinggi tanaman dan jumlah daun pada umur 7, 14, 21, 28, dan 35 HST, serta bobot basah tanaman, panjang daun, lebar daun, dan bobot kering tanaman pada umur 35 HST. Hasil penelitian menunjukkan bahwa terdapat interaksi antara perlakuan konsentrasi pupuk cair hayati dan pemberian biochar terhadap pertumbuhan dan hasil tanaman kailan (Brassica oleraceae). Perlakuan antara konsentrasi pupuk cair hayati 1 liter ha-1 dan pemberian biochar merupakan kombinasi perlakuan terbaik. Hasil penelitian juga menunjukkan bahwa konsentrasi pupuk cair hayati dan pemberian biochar berpengaruh terhadap pertumbuhan dan hasil tanaman kailan (Brassica oleraceae). Perlakuan pupuk cair hayati terbaik terdapat pada konsentrasi 1 liter ha-1.