Bul. Agrohorti 1 (4) : 45 – 50 (2013) Pemanfaatan Alat Deteksi Bunyi untuk Menduga Kadar Air dan Viabilitas Benih Kedelai (Glycine max L. Merrill) The Utilization of Sound Detector to Predict Seed Moisture Content and Viability of Soybean (Glycine max L. Merrill) Nurul Rostami Dewi 1* , M.R Suhartanto 1 , Akhiruddin Maddu 2 1 Departemen Agronomi dan Hortikultura, Fakultas Pertanian, Institut Pertanian Bogor (Bogor Agricultural University), Jl. Meranti, Kampus IPB Darmaga, Bogor 16680, Indonesia Telp.&Faks. 62-251-8629353 e-mail agronipb@indo.net.i 2 Departemen Fisika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Institut Pertanian Bogor, Jl. Lingkar Kampus, Kampus IPB Dramaga, Bogor 16680, Indonesia *email penulis untuk korespondensi: nurulrostami@yahoo.com Disetujui 24 Desember 2013/ Published Online 10 Januari 2014 ABSTRACT Rapid detection of moisture content and seed viability is very important in seed technology. The use of sound that produced by seed if that seed reflected with another material is one method that haven’t yet researched. This research is of use sound detection to determine moisture content and viability of soybean seeds by looking the sound waves frequency produced. This research consisted of two experiment, the first experiment the effect size of seed and moisture content of the sound frequency of sound that produced by reflected seed. The second experiment the effect size of seed and viability of the frequency of the sound that produced by reflected seed. This research was arranged in the randomized completely design was used with two factors is size of seed + moisture content and size of seed + viability. The result showed that in the first experiment there were interaction between size of seed and moisture content. Medium size of seed had a positive correlation between size of seeds and moisture content of the frequency and value of correlation (r) 0.96 approach 1 (≈1), it means the moisture content rise increasingly, the reflected frequencies will be rise increasingly too. The second experiment showed there was not interaction between size of seeds and viability. Medium size of seed had the highest frequency value is 482.36 Hz. Keywords: rapid detection, seed technology, Anjasmoro soybean varieties ABSTRAK Deteksi cepat kadar air dan viabilitas benih sangat penting dalam teknologi benih. Pemanfaatan bunyi yang dihasilkan benih bila dipantulkan dengan benda lain adalah salah satu cara yang belum diteliti. Penelitian ini bertujuan mempelajari pemanfaatan alat deteksi bunyi untuk menduga kadar air dan viabilitas benih kedelai (Glycine max L. Merrill) dengan melihat frekuensi gelombang bunyi yang dihasilkan. Penelitian ini terdiri dari dua percobaan, percobaan pertama mempelajari pengaruh antara ukuran benih dan kadar air terhadap frekuensi bunyi yang dihasilkan dari pantulan benih. Percobaan kedua mempelajari pengaruh antara ukuran benih dan viabilitas terhadap frekuensi bunyi yang dihasilkan dari pantulan benih. Penelitian ini menggunakan rancangan acak lengkap dengan dua faktor yaitu ukuran benih + kadar air dan ukuran benih + viabilitas. Hasil menunjukan bahwa pada percobaan pertama terdapat interaksi antara ukuran benih dan kadar air. Ukuran benih sedang memiliki korelasi yang positif antara kadar air dan ukuran benih terhadap frekuensi dan memiliki nilai korelasi (r) 0.96 yang mendekati 1 (≈1), artinya semakin tinggi kadar air maka frekuensi pantulan bunyi yang dihasilkan semakin tinggi. Percobaan kedua tidak terdapat interaksi antara ukuran benih dan viabilitas. Ukuran benih sedang memiliki nilai frekuensi tertinggi yaitu 482.36 Hz. Kata kunci : deteksi cepat, teknologi benih, kedelai varietas Anjasmoro