Weed control and selectivity of different pre-emergence active ingredients in a soybean crop

• Published in: Agronomía colombiana Vol. 39; no. 3; pp. 392 - 404
• Main Authors: Silva, Marcelo de Sousa da, Furtado, José Augusto Lima, Castro, Janine Quadros, Santos, Iasmim Leite dos, Almeida, Edmilson Igor Bernardo, Oliveira, Leonardo Bernardes Taverny de, Sousa, Washington da Silva, Araújo, Rodolfo César de Albuquerque
• Format: Journal Article
• Language: English
• Published: Universidad Nacional de Colombia, Facultad de Agronomía 01-09-2021; Centro Editorial of Facultad de Ciencias Agrarias, Universidad Nacional de Colombia
• Subjects: AGRONOMY; diclosulam; Glycine max (L.) Merrill; phytosociology; pre-emergence herbicides; weed competition; Glycine max (L.) Merrill; weed competition; pre-emergence herbicides; competencia de malezas; diclosulam; fitosociología; herbicidas de preemergencia; phytosociology
• ISSN: 0120-9965; 2357-3732
• DOI: 10.15446/agron.colomb.v39n3.96334

This study aimed to analyze the efficacy of different pre-emergence active ingredients on the suppression of the weed seed bank and the growth of soybeans. The experiments were carried out on a commercial farm located in Brejo (MA, Brazil), during the 2019/2020 harvest. The experiment was designed in randomized blocks with nine treatments and four replicates. The treatments consisted of control (without pre-emergence application), s-metolachlor, flumioxazin + imazethapyr, flumioxazin, imazethapyr, trifluralin, diclosulam, diclosulam + imazethapyr, and clomazone + carfentrazone-ethyl. Phytosociological surveys were carried out in pre- and post-planting (10 and 36 d after application - DAA) to control weed competition. Nineteen species of weeds were identified, distributed in 17 genera and 13 botanical families. The species Scoparia dulcis, Richardia scabra, and Cyperus iria exhibited the highest phytosociological indices (123.77, 28.62, and 28.29, respectively), estimated at 36 DAA. Flumioxazin and diclosulam were the most efficient in suppressing weed competition, with only 15.63 and 16.13 plants m-2. The highest phytotoxicity scores (3.0) were found at 10 DAA with the application of s-metolachlor, flumioxazin + imazethapyr, trifluralin, and diclosulam + imazethapyr. The pre-emergent control using flumioxazin and diclosulam is recommended for the edaphoclimatic conditions in the Eastern mesoregion of the state of Maranhão, Brazil.