Tanaman kacang hijau (vigna radiata l.) termasuk suku polong-polongan (fabaceae) memiliki manfaat sebagai sumber bahan pangan berprotein tinggi. salah satu teknik budidaya yang perlu diketahui ialah jarak tanam atau kerapatan tanam yang tepat. tujuan pengaturan kerapatan tanaman atau jarak tanam pada dasarnya adalah memberikan kemungkinan tanaman untuk tumbuh dengan baik tanpa mengalami persaingan dalam hal pengambilan air, unsur hara, cahaya matahari dan memudahkan pemeliharaan tanaman. penggunaan jarak tanam yang kurang tepat dapat merangsang pertumbuhan gulma, sehingga dapat menurunkan hasil. secara umum hasil tanaman per satuan luas tertinggi diperoleh pada kerapatan tanaman tinggi, akan tetapi bobot masing-masing polong secara individu menurun karena terjadinya persaingan antar tanaman, sementara mulsa mempunyai keuntungan menekan fluktuasi suhu tanah dan menjaga kelembapan tanah, selain itu mulsa yang dihamparkan di atas permukaan tanah secara langsung akan menekan laju penguapan secara langsung akan menekan laju penguapan dan secara tidak langsung akan mempertahankan agregasi dan porositas yang akan mempertahankan kapasitas tanah menahan air. mulsa organik yang digunakan dapat berasal dari sisa tanaman alang alang yang mudah didapatkan di sekitar area budidaya. penelitian ini menggunakan rancangan acak kelompok (rak) dengan pola faktorial yang terdiri dari dua faktor yaitu :faktor jarak tanam dengan notasi ( j ) terdiri 3 taraf yaitu :j0 = jarak tanam 20 cm × 20 cm j1 = jarak tanam 25 cm × 20 cm j2 = jarak tanam 30 cm × 20 cm faktor berat mulsa ( m ) terdiri 2 taraf yaitu :m1 = 2 kg mulsa alang-alang m2 = 4 kg mulsa alang-alang berdasarkan rancangan tersebut di peroleh 6 kombinasi perlakuan dengan setiap perlakuan di ulang sebanyak 6 kali masing-masing 4 tanaman sampel sehingga di peroleh 36 satuan percoban setiap bedengan percobaan terdiri dari dari 144 tanaman yang dijadikan sebagai tanaman sempel di setiap ulangan. berdasarkan hasil penelitian yang telah dilakukan dapat disimpulkan bahwa perlakuan pengaruh jarak tanam dan pemberian mulsa alang alang pada pertumbuhan dan produksi tanaman kacang hijau berpengaruh nyata terhadap parameter jumlah polong namun tidak berpengaruh nyata terhadap jumlah daun, lebar daun, dan jumlah 100 biji /plot . pada perlakuan j2m2 (jarak tanam 20 cm x 30 cm + bobot mulsa 4 kg/bedeng) lebih mendominasi di banding parameter lainya. kata kunci: kacang hijau ,jarak tanam, mulsa alang alang

Green bean plant (vigna radiata l.) including leguminous plant (fabaceae) has benefits as a source of high protein food. one of the cultivation techniques that need to be known is the proper planting distance or planting density. the purpose of regulating plant density or planting distance is basically to provide the possibility of plants to grow well without experiencing competition in terms of water intake, nutrients, sunlight and facilitate plant maintenance. the use of less precise planting distance can stimulate the growth of weeds, so it can reduce the yield. the highest plant yield per unit area is typically attained at high plant densities, however due to competition between plants, the weight of each individual pod drops, whereas mulch has the advantage of reducing soil temperature variations and retaining soil moisture. in addition to preventing evaporation directly, mulch applied to the surface of the ground will also prevent evaporation indirectly by preserving soil aggregate and porosity, which will keep the soil's ability to retain water. the organic mulch that is used can come from the remains of reed plants that are easily available around the cultivation area. this research used a randomized group design (rak) with a factorial pattern consisting of two factors, namely planting distance factor with notation (j) consisting of 3 levels, namely: jo-planting distance 20 cm x 20 cm, j1-planting distance 25 cm x 20 cm, 32-planting distance 30 cm 20 cm mulch weight factor (m) consisted of 2 levels, namely: mi 2 kg weed straw, mulch m2-4 kg reed straw mulch. based on the design, 6 treatment combinations were obtained with each treatment repeated as many times, 6 times each with 4 sample plants so that 36 experimental units were obtained in each experimental bed consisting of 144 plants that were used as sample plants in each repetition. based on the results of the research, it was concluded that the planting distance and mulching of reeds on the growth and production of green bean plants had a significant effect on the parameters of the number of pods but had no significant effect on the number of leaves, leaf width, and the number of 100 seeds/plot. the j2m2 treatment (planting distance 20 cm x 30 cm + mulch weight 4 kg/bed) was more dominant than other parameters. keywords: green beans, planting distance, reed mulch