Electronic Theses and Dissertation

Gulma merupakan tumbuhan yang keberadaannya tidak diinginkan dan sangat merugikan bagi tanaman serta dapat menganggu kepentingan manusia dalam budidaya hasil pertanian. Penggunaan herbisida sintetis secara terus menerus telah memunculkan berbagai alternatif untuk mengendalikan gulma, seperti mengeksplor potensi senyawa kimia yang berasal dari tumbuhan yang dapat dimanfaatkan sebagai bioherbisida. Alang-alang merupakan salah satu gulma yang dapat berpotensi sebagai bioherbisida. Tujuan penelitian ini adalah untuk mengetahui bioaktivitas ekstrak metanol alang-alang pada berbagai konsentrasi terhadap pertumbuhan gulma bayam duri. Penelitian ini dilaksanakan di Laboratorium Ilmu Gulma Jurusan Agroteknologi Fakultas Pertanian, Laboratorium Pendidikan Kimia Fakultas Keguruan dan Ilmu Pendidikan, Laboratorium Biologi Fakultas Matematika dan Ilmu Pengetahuan Alam, dan Rumah Kasa Fakultas Pertanian Universitas Syiah Kuala, Darussalam Banda Aceh. Waktu pelaksanaan penelitian dimulai dari bulan Juni sampai dengan September 2021. Penelitian ini menggunakan Rancangan Acak Lengkap pola non faktorial dengan 6 taraf perlakuan yang terdiri dari kontrol positif (2,4-D pada 0,686 kg b.a ha-1), kontrol negatif (aquades), dan ekstrak metanol alang-alang 5%, 10%, 15%, 20%. Setiap perlakuan diulang sebanyak 3 kali dan masing-masing ulangan terdiri dari 2 pot, sehingga diperoleh 36 unit percobaan. Hasil penelitian menunjukkan aplikasi ekstrak metanol alang-alang berpengaruh sangat nyata terhadap tinggi gulma, jumlah daun dan diameter batang gulma bayam duri. Ekstrak metanol alang-alang 20% merupakan konsentrasi terbaik yang mampu memberikan penekanan lebih tinggi terhadap tinggi gulma, jumlah daun, dan diameter batang. Hasil uji fitokimia ekstrak metanol alang-alang mengandung senyawa alkaloid, terpenoid, saponin, flavonoid, dan fenolik.

Kata kunci: Alang-alang, Bioherbisida, dan Fenolik

Weeds are plant whose existence is undesirable and very detrimental to plants and can interfere with human interests in the cultivation of agricultural products. The use of synthetic herbicides continuously has led to various alternatives to control weeds, such as exploring the potential for chemical compounds derived from plants that can be used as bioherbicides. Cogon grass is one of the weeds that has the potential as a bioherbicide. The purpose of this study was to determine the bioactivity of methanol extract cogon grass at various concentrations against the growth of weed spiny amaranth. The research was carried out at the Weed Science Laboratory, Agrotechnology Department, Faculty of Agriculture, Chemistry Education Laboratory, Teaching and Educational Sciences, Biology Laboratory, Faculty of Mathematics and Natural Sciences and the Screen House, Faculty of Agriculture, Syiah Kuala University, Darussalam Banda Aceh. Implementation time starts from June to September 2021. This experiment was arranged based on a completely randomized design (CRD) with a non-factorial pattern with 6 levels of treatment consisting of positive control (2.4-D at 0.686 kg a.i ha-1), negative control (Aquadest), and 5%, 10%, 15%, 20% of methanol extract cogon grass. Each treatment was repeated 3 times and each replication consisted of 2 pots, so that 36 experimental units were obtained. The results showed that the application of methanol extract cogon grass had a very significant effect on weed’s height, number of leaves, and stem diameter of weed spiny amaranth. Concentration 20% of methanol extract cogon grass was the best concentration which was able to give higher suppression of weed’s height, number of leaves and stem diameter. The results of the phytochemical test of methanol extract cogon grass contained alkaloids, terpenoids, saponins, flavonoids, and phenolic compounds. Keywords: Cogon Grass, Bioherbicide, and Phenolics