Potensi Herbisida Ekstrak Etil Asetat Alang-Alang (Imperata cylindrica L.) Terhadap Pertumbuhan Gulma Bayam Duri (Amaranthus spinosus L.)

Abstract

Abstrak. Alang-alang berpotensi untuk dimanfaatkan sebagai bioherbisida karena kemampuanya mengeluarkan senyawa kimia dengan fungsi sebagai penghambat pertumbuhan tanaman lain. Etil asetat adalah salah satu pelarut yang bisa dipakai untuk mengekstraksi alang-alang, dimana sifat pelarut tersebut semi polar mengakibatkannya mampu menarik senyawa polar juga nonpolar. Penelitian ini bertujuan agar diketahuinya pengaruh ekstrak etil asetat alang-alang dengan konsentrasi berbeda terhadap pertumbuhan bayam duri. Penelitian dilakukan di Laboratorium Ilmu Gulma Jurusan Agroteknologi, Laboratorium Pendidikan Kimia Fakultas Keguruan dan Ilmu Pendidikan, Rumah Kasa Kebun Percobaan Fakultas Pertanian, Laboratorium Penelitian Kimia Fakultas Matematika dan Ilmu Pengetahuan Alam, dan Laboratorium Biologi Universitas Syiah Kuala, Banda Aceh. Penelitian dimulai sejak Agustus hingga November 2021. Rancangan yang digunakan yaitu Rancangan Acak Lengkap non faktorial dengan perlakuan 2,4-D 686g b.a ha^-1 (kontrol positif); aquades (kontrol negatif); ekstrak etil asetat alang-alang dengan konsentrasi 5%; 10%; 15%; 20% diulang 3 kali, sehingga ada 18 unit. Tiap unit terdapat 2 unit gulma, jadi totalnya 36 unit. Hasil dari penelitian memperlihatkan aplikasi ekstrak etil asetat alang-alang di beragam konsentrasi memperlihatkan pengaruh nyata terhadap tinggi, diemeter batang dan jumlah daun bayam duri. Konsentrasi terbaik ada pada konsentrasi 15% yang menunjukkan penekanan lebih tinggi dibanding konsentrasi lainnya pada tinggi tanaman umur 21 HSA, jumlah daun 7, 14, dan 21 HSA dan diameter batang umur 21 HSA. Hasil uji fitokimia ekstrak etil asetat alang-alang menunjukkan bahwa senyawa fenolik, tanin, steroid dan alkaloid terkandung di dalamnya.

Kata kunci: Alang-alang, bioherbisida, etil asetat.

Abstract. Cogon grass has the potential to be used as a bioherbicide because of its ability to release chemical compounds with the function of inhibiting the growth of other plants. Ethyl acetate is one of the solvents that can be used to extract cogon grass, where the nature of the solvent is semi-polar which makes it able to attract polar as well as non-polar compounds. This study aims to determine the effect of ethyl acetate extract of cogon grass with different concentrations on the growth of thorn spinach. The research was conducted at the Weed Science Laboratory, Agrotechnology Department, Chemistry Education Laboratory, Teacher Training and Educational Sciences, Experimental Garden Screen House, Faculty of Agriculture, Chemistry Research Laboratory, Faculty of Mathematics and Natural Sciences, and Biology Laboratory, Syiah Kuala University, Banda Aceh. The study started from August to November 2021. The design used was a non-factorial Completely Randomized Design with treatment 2,4-D 686g b.a ha^-1 (positive control); aquades (negative control); cogon grass ethyl acetate extract with a concentration of 5%; 10%; 15%; 20% is repeated 3 times, so there are 18 units. Each unit contains 2 units of weed, so there are 36 units in total. The results of the study showed that the application of Imperata ethyl acetate extract at various concentrations showed a significant effect on the height, stem diameter and number of thorn spinach leaves. The best concentration was at a concentration of 15% which showed higher suppression than other concentrations on plant height at 21 DAP, number of leaves at 7, 14, and 21 DAP and stem diameter at 21 DAP.. The results of the phytochemical test of the ethyl acetate extract of the weeds showed that it contained tannins, phenolic, alkaloids and steroids compounds.

Keywords: Bioherbicide, cogon grass, ethyl acetate.