[Effect of some methods of weed control on growth and yield of soybean (Glycine max L.)]

English. An experiment to study the effect of some methods of weed control on growth and yield of soybean (Glycine max L.) in the village of Sumbersari, Lowokwaru district, Malang was conducted since April to July 1999. The experiment were arranged in randomized block design with three replications. The experiment consisted of some weed control methods, 1. P1 = conventional tillage (CT) + no weeding, 2. P2 = CT + weeding, once time, 21 days after planting (dap), 3. P3 = CT + weeding once time, 42 dap, 4. P4 = CT + weeding two times, 21 and 42 dap, 5. P5 = CT + oxyfluorfen herbicide, 2 l/ha, no weeding, 6. P6 = CT + oxyfluorfen 2 l/ha, weeding once time, 42 dap, 7. P7 = no tillage (NT) + glyphosate herbicide, 4 l/ha, no weeding, 8. P8 = NT + glyphosate herbicide, 4 l/ha + weeding, once time, 21 dap, 9. P9 = NT + glyphosate herbicide, 4 l/ha, weeding once time, 42 dap, 10. P10 = NT + glyphosate herbicide, 4 l/ha, weeding two times, 21 and 42 dap. The result of experiment showed that the weed of Cyperus rotundus, Cyperus iria, Imperata cylindrica, Eleucine indica, and Mimosa pudica were dominant weed before treatment. After treatment, at 60 days after planting there were weed dominance shifting. The weed of Cyperus rotundus, Amaranthus spinosus, Eclipta alba, Eleucine indica, Ageratum conyzoides, Paspalum conjugatum, Commelina diffusa were dominant weeds at some weed control methods. The dry weight of weed showed that conventional tillage and no tillage + glyphosate herbicide which each weeding two times at 21 and 42 dap or weeding once time at 42 dap were lower than another treatment and would increase if not followed by weeding. Another result showed that plant height, number and leaf area, plant dry weight, pod dry weight, 100 seeds weight, and soybean grain yield were not significantly different between conventional tillage, weeding two times at 21 and 42 dap compared no tillage + glyphosate herbicide 4 l/ha, weeding two times at 21 and 42 dap

Indonesian. Suatu percobaan untuk meneliti pengaruh beberapa metode pengendalian gulma terhadap pertumbuhan dan hasil kedelai telah dilakukan di Desa Sumbersari, Kec. Lowokwaru, Malang pada bulan April sampai Juli 1999. Percobaan disusun berdasarkan Rancangan Acak Kelompok yang terdiri dari sepuluh perlakuan yang diulang sebanyak tiga kali. Perlakuan percobaan terdiri dari: 1. P1 = olah tanah sempurna (OTS) + tidak disiang, 2. P2 = OTS + disiang 1 kali, 21 hst, 3. P3 = OTS + disiang 1 kali, 42 hst, 4. P4 = OTS + disiang 2 kali, 21 dan 42 hst, 5. P5 = OTS + herbisida oksifluorfen 2 l/ha + tidak disiang, 6. P6 = OTS + herbisida oksifluorfen 2 l/ha + disiang 1 kali, 42 hst, 7. P7 = tanpa olah tanah (TOT) + herb. glifosat 4 l/ha, tidak disiang, 8. P8 = TOT + herb. glifosat 4 l/ha + disiang 1 kali, 2 hst, 9. P9 = TOT + herb. glifosat + disiang 1 kali, 42 hst, 10. P10 = TOT + herb. glifosat 4 l/ha + disiang 2 kali, 21 dan 42 hst. Hasil penelitian menunjukkan bahwa gulma Cyperus rotundus, Cyperus iria, Imperata cylindrica, Eleusine indica dan Mimosa pudica merupakan gulma dominan sebelum percobaan. Setelah perlakuan pada pengamatan 60 hst terlihat adanya perbedaan species dan dominasi gulma pada setiap petak perlakuan. Gulma Cyperus rotundus, Amaranthus spinosus, Eclipta alba, Eleusine indica, Ageratum conyzoides, Paspalum conjugatum, Commelina diffusa, merupakan gulma dominan pada berbagai metode pengendalian gulma. Pada pengamatan bobot kering gulma, perlakuan olah tanah sempurna dan perlakuan tanpa olah tanah dengan menggunakan herbisida glifosat yang masing-masing disiang satu kali pada 42 hst atau disiang dua kali pada 21 dan 42 hst nyata berat kering gulmanya rendah. Bobot kering gulma nyata meningkat baik pada perlakuan olah tanah sempurna atau tanpa olah tanah dengan herbisida glifosat jika tidak dilakukan penyiangan. Pengendalian gulma pada olah tanah sempurna maupun tanpa olah tanah dengan herbisida glifosat yang masing-masing diikuti penyiangan dua kali pada 21 dan 42 hst nyata meningkatkan pertumbuhan tinggi tanaman, jumlah dan luas daun serta berat kering tanaman, demikian juga terhadap berat kering polong, berat 100 biji dan hasil biji panen