Electronic Theses and Dissertation

Pengaturan kerapatan tanaman dan aplikasi herbisida pra tumbuh merupakan kombinasi teknik pengendalian gulma yang efektif karena mampu menekan pertumbuhan gulma sejak periode kritis awal tanaman melalui penutupan kanopi yang lebih cepat serta penghambatan perkecambahan gulma secara kimiawi. Penelitian ini bertujuan untuk mengetahui pengaruh kerapatan tanaman dan aplikasi herbisida pra tumbuh, serta interaksi keduanya, terhadap pertumbuhan gulma pada tanaman kedelai. Penelitian telah dilaksanakan di Desa Blang Ketumba, Kecamatan Juli, Kabupaten Bireuen, serta di Laboratorium Pengelolaan Gulma Departemen Agroteknologi Fakultas Pertanian Universitas Syiah Kuala pada bulan Februari sampai Juni 2026, menggunakan Rancangan Acak Kelompok (RAK) faktorial 3 × 3 dengan tiga ulangan sehingga diperoleh 9 kombinasi perlakuan dan 27 unit percobaan. Faktor pertama adalah jarak tanam (15 × 40 cm, 20 × 40 cm, dan 25 × 40 cm), dan faktor kedua adalah jenis herbisida pra tumbuh (kontrol, oksifluorfen 0,75 kg b.a ha⁻¹, dan pendimethalin 0,75 kg b.a ha⁻¹). Hasil penelitian menunjukkan bahwa kerapatan tanaman berpengaruh nyata pada individu gulma 2 dan 8 MST. Aplikasi herbisida pra tumbuh berpengaruh nyata terhadap persentase pengendalian gulma, persentase penutupan gulma, jumlah spesies gulma, jumlah individu gulma, dan bobot kering gulma pada 2, 4 dan 6 MST. Interaksi antara kerapatan tanaman dan jenis herbisida oksifluorfen dan jarak tanam rapat (15 × 40 cm dan 20 × 40 cm) berpengaruh nyata terhadap persentase pengendalian gulma, persentase penutupan gulma dan individu gulma pada 2 MST.

Adjusting plant density and applying pre-emergence herbicides constitute an effective weed control strategy, as they suppress weed growth from the crop's early critical period through accelerated canopy closure and the chemical inhibition of weed germination. This study aimed to determine the effects of plant density and pre-emergence herbicide application—as well as their interaction—on weed growth in soybean crops. The research was conducted in Blang Ketumba Village (Juli District, Bireuen Regency) and at the Weed Management Laboratory of the Agrotechnology Department, Faculty of Agriculture, Syiah Kuala University, from February to June 2026. A 3 × 3 factorial Randomized Block Design (RBD) with three replications was employed, resulting in nine treatment combinations and 27 experimental units. The first factor was planting spacing (15 × 40 cm, 20 × 40 cm, and 25 × 40 cm), and the second factor was the type of pre-emergence herbicide (control, oxyfluorfen at 0.75 kg a.i. ha⁻¹, and pendimethalin at 0.75 kg a.i. ha⁻¹). The results indicated that plant density significantly affected weed counts at 2 and 8 weeks after planting (WAP). Pre-emergence herbicide application significantly influenced weed control percentage, weed cover percentage, number of weed species, number of individual weeds, and weed dry weight at 2, 4, and 6 WAP. The interaction between plant density and herbicide type—specifically oxyfluorfen combined with close spacing (15 × 40 cm and 20 × 40 cm)—had a significant effect on weed control percentage, weed cover percentage, and weed counts at 2 WAP.