Effect of weed interference on soybean cultivars at two sowing times

Abstract

-This study aimed to evaluate the effects of weed interference on soybean cultivars at two sowing times in Urutaí, GO. The treatments were arranged in split-plots, and the sowing times (November 16 and December 16, 2009) were allocated in the plots; the soybean cultivars [BRSGO Amaralina, P98C81 (semi-late cycle) BRSGO Raissa, BRSGO Indiara, P98Y11 (median cycle) and BRSGO 7560, BRSGO Caiapônia, Emgopa 302RR (early cycle)] were allocated in the split-plots; and the coexistence or non coexistence of soybean cultivars with weeds, throughout their cycle, was allocated in the split-plots. Non coexistence was established by manual weeding. The experiment was arranged in randomized blocks with four replications. It was verified that the optimal time for sowing soybeans was the month of November, and that under these conditions, the cultivars had higher competitive ability against weeds. Late sowing affected the cycle, development, and yield of the soybean cultivars; this effect was greater under the influence of the weed community.Keywords: Glycine max, competition, crop yield.RESUMO -Objetivou-se avaliar os efeitos da interferência de plantas daninhas sobre cultivares de soja, em duas épocas de semeadura em Urutaí, GO. Os tratamentos foram arranjados em parcelas subsubdivididas, sendo nas parcelas alocadas as épocas de semeadura (16 de novembro e 16 de dezembro de 2009); nas subparcelas, os cultivares de soja [BRSGO Amaralina, P98C81 (ciclo semitardio), BRSGO Indiara, BRSGO Raíssa, P98Y11 (ciclo médio) e BRSGO 7560, BRSGO Caiapônia, Emgopa 302RR (precoce)]; e nas subsubparcelas, a convivência ou não de os cultivares de soja com plantas daninhas, por todo o ciclo destas. A não convivência entre eles foi estabelecida por capinas manuais. O ensaio foi montado em blocos ao acaso com quatro repetições. Foi observado que a época indicada para semeadura dos cultivares de soja foi o mês de novembro e que, nessa condição, os cultivares apresentaram maior capacidade competitiva com as plantas daninhas. O atraso na semeadura dos cultivares de soja afetou o ciclo, o desenvolvimento e a produtividade da soja, sendo esse efeito maximizado quando houve a interferência da comunidade infestante.Palavras-chave: Glycine max, competição, rendimento de grãos.

Effect of tillage system on yield and weed populations of soybean ( Glycin Max L.)

“…In other words, soybean seed yield was reduced by 22% in un-weeded treatment compared with the WCH+WCHW treatment. Marangoni et al (2013) reported that soybean seed yield was reduced by 30% due to weed competition. SEYED Z. HOSSEINI, SAEED FIROUZI, HASHEM AMINPANAH and HAMID R. SADEGHNEJHAD…”

The effect of nitrogen application and various means of weed control on grain yield, protein and lipid content in soybean cultivation

“…However, results for weedy canopy did not significantly differ from of the mechanically weeded. According to research done by Marangoni et al (2013), weed management had a significant effect of on grain yield of soybeans. The yield of soybean in the absence of coexistence with weeds (weeded) was higher compared to the yield of soybean in coexistence (unweeded) with weeds.…”

“…If weeds are not controlled, it will not only interfere with the growth and crop yield, but will also increase the production cost due to the increase in labour costs, agricultural inputs or machinery. According to the study by Marangoni et al (2013), weed management (weeded, unweeded) greatly influenced soybeans yield. The effect of weed management on different soybean varieties was studied and positive and negative effects on yields were found depending on varieties.…”

Do Weeds From Seeds or Regrowth in Coexistence Periods Alter Biochemical and Yield Characteristics of Soybeans?

“…For example, the weeds of the species Galinsoga parviflora, Digitaria horizontalis, Brachiaria decumbens, Amaranthus retroflexus, Bidens pilosa, Euphorbia heterophylla and others, in competition with soybeans throughout the crop cycle, reduced the grain yield by 30% (Marangoni et al, 2013). Soybean in competition with maize that emerged ten days earlier than or on the same day produced an average of 382% and 241% less than when maize emerged ten days after the crop (Piasecki, 2015).…”