Sirait et al.: Pengaruh Aplikasi Biochar dan Pemupukan Nitrogen 37 J. Agrotek Tropika. ISSN 2337-4993 Vol. 8, No. 1: 37-46, Januari 2020 PENGARUH APLIKASI BIOCHAR DAN PEMUPUKAN NITROGEN TERHADAP KETERSEDIAAN NPK TANAH PADA PERTANAMAN JAGUNG MANIS (Zea mays L.) THE EFFECT OF BIOCHAR APPLICATION AND NITROGEN FERTILIZING ON THE AVAILABILITY OF SOIL NPK TOWARD SWEET CORN (Zea mays L.) AGRICULTURE Rumse Fitriana Sirait 1) , Sarno 2) , Nur Afni Afrianti 2) dan Ainin Niswati 2) . Jurusan Agroteknologi, Fakultas Pertanian, Universitas Lampung, Jl. Prof. Dr. Sumantri Brojonegoro No. 1, Bandar Lampung 35145 Email: fitrianasirait65@gmail.com ABSTRACT Corn is the second food commodity that has high demand but has low production. Low soil fertility causes inappropriate soil management. Therefore, the efforts to improve soil fertility with the addition of biochar and proper N fertilization should be made. This research aims to study the effect of biochar on soil NPK availability toward sweet corn, to study the effect of N fertilization toward soil NPK availability on sweet corn, and to study the effect of interaction between biochar and N fertilization on soil NPK availability toward sweet corn plants. This research was conducted at the Unila Integrated Field, Bandar Lampung from January to September 2017. The research was designed with a factorial Completely Randomized Design (CRD) with two factors and three replications. The first factor is the biochar dose, namely: 0; 2.5 and 5 t ha -1 . The second factor is the dose of N fertilizer which is 0; 45; 90 and 135 kg N ha -1 . Data homogeneity were tested by using Bartlett Test while data additivity were tested by using Tukey Test. Data were processed by using analysis of variance and continued with Honest Significant Difference test at 1% significance level. The results showed that biochar administration had a very significant effect on the availability of N, P and K nutrients in the soil, very significant effect toward the soil C-organic content and no significant effect on soil pH. N fertilization has a very significant effect on the availability of N, P, K and soil pH and does not significantly affect soil C-organic content. There was a very real interaction between the administration of biochar and N fertilizer toward the availability of N and K nutrients, but did not interact significantly with the P nutrient content in the soil. The optimum dose of biochar administration is 2.5 t ha -1 , while the dose of N fertilizer is 45 and 90 kg N ha -1 . Keywords: biochar, sweet corn, availability of N, P and K nutrients and N fertilization. ABSTRAK Jagung merupakan komoditas pangan kedua yang memiliki permintaan tinggi yang tidak diimbangi dengan produksi yang rendah. Kesuburan tanah yang rendah menyebabkan pengelolaan tanah yang tidak sesuai sehingga perlu dilakukan usaha untuk memperbaiki kesuburan tanah dengan penambahan biochar dan pemupukan N yang tepat. Penelitian ini bertujuan untuk: mempelajari pengaruh biochar terhadap ketersediaan NPK tanah terhadap tanaman jagung manis, mempelajari pengaruh pemupukan N terhadap ketersediaan NPK tanah terhadap tanaman