No abstract

The survey of weed species in crops allows the identification, quantification of weed flora, its evolution in the area and helps in decision making for control of species. In this sense, the objective of this work was to survey weeds in pivot-irrigated rice fields in Cachoeira do Sul, Capané district, in the experimental area of the Rio Grandense do Arroz Institute (IRGA). Evaluations were performed by applying the 0.25 m2 square method, randomly launched sixty-eight times. Weeds in the sampled areas were removed from the soil, species identified and quantified. The evaluations were performed after the application of Gamit (preemerging), Ricer and Clincher and Imazethapyr (postemerging). Even after herbicide applications, 13 species were identified, representing the families Asteraceae, Poaceae, Malvaceae and Rubiaceae. Knowledge of the weeds present in the crop allows planning to improve control, avoiding unnecessary expense with herbicides or even using other methods to control these species.

PRODUTIVIDADE DA SOJA EM FUNÇÃO DA ÉPOCA DA SEMEADURA E DA IRRIGAÇÃO SUPLEMENTAR NA REGIÃO CENTRAL DO RS     ZANANDRA BOFF DE OLIVEIRA1, ALBERTO EDUARDO KNIES2, LARRISSA RIBEIRO RODRIGUES1, DIOGO ANDRÉ SCHMIDT1, ALEXANDRE GONÇALVES KURY1   1 Universidade Federal de Santa Maria Campus Cachoeira do Sul, Curso de Engenharia Agrícola, Rodovia Taufik Germano, 3013, Passo D'Areia, CEP. 96503-205, Cachoeira do Sul/RS, Brasil, zanandra.oliveira@ufsm.br; larrissarodriguesmtm@gmail.com; diogoschmidt443@gmail.com; alexandregkury96@gmail.com. 2 Universidade Estadual do Rio grande do Sul, Unidade de Cachoeira o Sul, Rua Sete de Setembro, 1040, Centro, CEP. 96508-010, Cachoeira do Sul/RS, Brasil, albertoek@gmail.com.     1 RESUMO   O presente estudo tem como objetivo avaliar a produtividade da soja em função da época de semeadura e da irrigação suplementar para as condições edafoclimáticas da região central do RS. O experimento de campo foi instalado na Estação Agronômica da Uergs em Cachoeira do Sul-RS. O delineamento experimental foi o de blocos ao acaso com parcelas subdivididas, no esquema fatorial (4x2). O fator “A” constituiu de quatro épocas de semeadura da soja: 23/10/19 (Época 1), 19/11/19 (Época 2), 19 /12/ 19 (Época 3), 16/1/20 (Época 4). O fator “D” constitui de dois regimes hídricos: irrigado e não irrigado (sequeiro). A cultivar utilizada foi a BMX Garra. A produtividade da soja irrigada foi superior a 4200 kg ha-1 para épocas de semeadura entre outubro e dezembro, com produtividade máxima de 4563,83 kg ha-1 para a semeadura em novembro, apresentando redução de 60% na semeadura em janeiro. A soja de sequeiro foi mais influenciada pela época de semeadura, apresentando produtividade máxima de 3587,28 kg ha-1 para semeadura em outubro com uma redução de aproximadamente 30 kg ha-1dia-1 com o atraso da semeadura, chegando a 67% de redução na produtividade com semeadura de safrinha (janeiro).   Palavras-chave: déficit hídrico, rendimento de grãos, Glycine max.     OLIVEIRA, Z.B.; KNIES, A.E.; RODRIGUES, L.R.; SCHMIDT, D.A.;KURY, A.E SOYBEAN PRODUCTION DURING THE SEEDING TIME AND SUPPLEMENTARY IRRIGATION IN THE CENTRAL REGION OF RS   2 ABSTRACT   This study aims to evaluate soybean productivity as a function of sowing time and supplementary irrigation under edaphoclimatic conditions in the central region of the RS. The field experiment was conducted at the Uergs Agronomic Station in Cachoeira do Sul-RS. The experimental design was a randomized block with subdivided plots, in the factorial scheme (4x2). The “A” factor constituted the four soybean sowing seasons: 23/10/19 (Season 1), 19/11/19 (Season 2), 19/12/19 (Season 3), 1/16/20 (Season 4). The “D” factor consists of two water regimes: irrigated and non-irrigated (rainfed). A cultivar used for BMX Garra. The productivity of irrigated soybeans was greater than 4200 kg ha-1 for sowing times between October and December, with a maximum productivity of 4563.83 kg ha-1 for sowing in November, a reduction of 60% in sowing in January. The rainfed soybean was more influenced by the sowing time, the maximum productivity increased from 3587.28 kg ha-1 for sowing in October with a reduction of approximately 30 kg ha-1day-1 with the sowing delay, reaching 67% reduction in productivity with safrinha sowing (January).   Keywords: water déficit, grain yield, Glycine max.

The presence of weed species in soybean crops is a concern for farmers. Knowing these species is of great importance, as they cause serious damage to crops due to competition for nutrients, water, light and physical space with soy. This work aimed to survey weeds in pivot irrigated soybean crops in Cachoeira do Sul municipality, Capané district, in the experimental area of the Rio Grandense do Arroz Institute (IRGA). The evaluations were performed by applying the 0.25 m2 square method, launched at random sixty times. Weeds in the sampled areas were removed from the soil, species identified and quantified. Evaluations were performed after three applications of glyphosate herbicide. Even after glyphosate applications, seven species were identified, representing the families Asteraceae, Poaceae, Malvaceae, Euphorbiaceae and Rubiaceae. This survey enables the planning of preventive strategies for the sustainable control of weeds in the field, reducing production costs and the impact on the environment.