ABSTRAKKedelai (Glycine max L) adalah salah satu komoditas tanaman pangan penting di Indonesia. Produksi kedelai yang ada belum dapat mencukupi kebutuhan dalam negeri Indonesia. Berdasarkan data BPS hingga Bulan Desember 2023 produksi kedelai Indonesia berkisar 0.555 ton, sementara kebutuhan dalam negeri mencapai 2.7 juta ton. Salah satu upaya mengoptimalkan pemanfaatan lahan kering masam untuk budidaya tanaman adalah dengan menggunakan mulsa organik. Mulsa organik berasal dari bahan yang mudah terurai sehingga menambah bahan organik dalam tanah. Penelitian ini bertujuan untuk mengetahui pengaruh ketebalan mulsa jerami padi terhadap pertumbuhan dan produksi beberapa varietas kedelai. Penelitian dilaksanakan di Alue Dua, Langsa Baro, Kota Langsa, Provinsi Aceh. Penelitian ini dilakukan pada bulan Agustus-November 2023. Penelitian menggunakan rancangan acak kelompok (RAK) faktorial yang terdiri dari 2 faktor. Faktor pertama adalah ketebalan mulsa jerami padi 4 taraf, yaitu: Mo = Kontrol; Mâ‚ = 5 cm; M2 = 7.5 cm dan M3 = 10 cm. Faktor kedua adalah varietas yang terdiri dari 4 taraf , yaitu: V1 = Demas 1; V2 = Dega 1; V3 = Detap 1 dan V4 = Dena 1. Hasil penelitian menunjukkan bahwa interaksi perlakuan ketebalan mulsa jerami padi dan varietas tidak berpengaruh terhadap semua parameter yang diamati. Perlakuan ketebalan mulsa hanya berpengaruh nyata terhadap tinggi tanaman kedelai pada 14 HST. Perlakuan varietas kedelai berpengaruh nyata terhadap tinggi tanaman umur 14, 28 dan 42 HST, umur berbunga, jumlah cabang produktif dan berat 100 biji. Berat 100 biji paling berat dihasilkan oleh perlakuan V4 (Varietas Dena 1), yaitu 23.00 gram.  ABSTRACTSoybean (Glycine max L) is one of the important food crop commodities in Indonesia. Existing soybean production has not been able to meet Indonesia's domestic needs. Based on BPS data until December 2023, Indonesia's soybean production was around 0.555 tons, while domestic demand reached 2.7 million tons. One effort to optimize the use of acidic dry land for plant cultivation was to use organic mulch. Organic mulch comes from materials that were easily decomposed so that it added organic matter to the soil. This study aimed to determine the effect of rice straw mulch thickness on the growth and production of several soybean varieties. The study was conducted in Alue Dua, Langsa Baro, Langsa City, Aceh Province. This study was conducted in August-November 2023. The study used a factorial randomized block design (RAK) consisting of 2 factors. The first factor was the thickness of 4 levels of rice straw mulch, namely: Mo = Control; Mâ‚ = 5 cm; M2 = 7.5 cm and M3 = 10 cm. The second factor was the variety consisting of 4 levels, namely: V1 = Demas 1; V2 = Dega 1; V3 = Detap 1 and V4 = Dena 1. The results showed that the interaction of the treatment of rice straw mulch thickness and variety did not affect all observed parameters. Mulch thickness treatment only had a significant effect on soybean plant height at 14 HST. Soybean variety treatment had a significant effect on plant height at 14, 28 and 42 HST, flowering age, number of productive branches and weight of 100 seeds. The heaviest weight of 100 seeds was produced by the V4 treatment (Dena 1 Variety), which was 23.00 grams.Â