Corn growth and yield in competition with weeds

Abstract

-Although labor is intensive, evaluating the growth of crops may allow a better understanding of crop performance, including the reasons why certain cultivars can compete better with weeds. This study aims at evaluating growth, green ear yield, and grain yield in corn when in competition with weeds. Cultivars AG 1051 and BRS 106 were grown with (two hoeings, at 20 and 40 days after sowing) or without weed control. In order to evaluate crop growth, six collections of the above-ground part and the root system of corn were performed, every 15 days, with the first collection made 30 days after sowing. A randomized complete block design was adopted, with split-split plots (weed control in plots, cultivars in subplots, and collections in sub-subplots) and ten replicates. Eighteen weed species were found in the experiment area. Increased values of corn leaf area, above-ground part and root system, due to plant age function, were smaller in non-hoed plots than in hoed plots and were dependent upon cultivar. The lack of weed control increased dry matter of weeds aboveground part and decreased green ear yield and grain yield. Cultivar AG 1051 had higher increases in leaf area, above-ground part of the plant and root system, due to plant age function, and controlled weeds better than cultivar BRS 106. In addition, cultivar AG 1051 was superior to other cultivars with respect to most traits used for green corn yield and grain yield assessment.Keywords: Zea mays, green corn, grain yield, dry matter.RESUMO -A avaliação do crescimento das culturas, embora trabalhosa, pode possibilitar o melhor entendimento do desempenho das culturas, inclusive das razões pelas quais determinadas cultivares são capazes de competir melhor com as plantas daninhas. O trabalho teve como objetivo avaliar o crescimento e os rendimentos de espigas verdes e de grãos do milho, em competição com plantas daninhas. As cultivares AG 1051 e BRS 106 foram cultivadas com duas capinas (aos 20 e 40 dias após a semeadura) e sem controle de plantas daninhas. Para avaliação do crescimento da cultura, foram realizadas seis coletas da parte aérea e do sistema radicular do milho, de 15 em 15 dias, a primeira sendo efetuada 30 dias após a semeadura. Utilizou-se o delineamento de blocos completos casualizados, com parcelas sub-subdivididas (controle de plantas daninhas nas parcelas, cultivares nas subparcelas e coletas nas sub-subparcelas) e dez repetições. Dezoito espécies de plantas daninhas ocorreram na área experimental. Os aumentos da área foliar, da parte aérea e do sistema radicular do milho, em função da idade, foram menores em parcelas não capinadas do que nas parcelas capinadas e dependeram das cultivares. A falta de controle das plantas daninhas aumentou a matéria seca da parte aérea das plantas daninhas e reduziu os rendimentos de espigas verdes e de grãos. A cultivar AG 1051 apresentou maiores aumentos da área foliar, da parte aérea da planta e do sistema radicular, em função da idade da planta, e controlou melhor as plantas daninhas, que a cultiva...

Competitive interaction and economic injury level of Urochloa plantaginea in corn hybrids

“…In the same comparison, we found greater competitiveness in the corn hybrids Syngenta Status VIP3, Pioneer P1630H, Pioneer 30F53 YH, and Dow 135021, which presented smaller losses of grain productivity in contrast to the other hybrids. Some studies have evidenced differences in the competitive ability of corn hybrids in the presence of weeds, a fact assigned to several factors, mainly the competition that occurs among the species involved, be it intra-or interspecific (BRITO et al, 2011;SILVA et al, 2011;FARIA et al, 2014).…”

“…Therefore, this study showed that less productive materials presented higher competitive ability with U. plantaginea, considering the parameter i, quite possibly due to a smaller need for allocating resources in other organs of the plant rather than the ear. Leaf architecture and plant arrangement are factors that influence the absorption of solar radiation and the performance of photosynthesis, elements that have a direct relationship with the development of ears and grains (BRITO et al, 2011;SILVA et al, 2011;FARIA et al, 2014).…”

“…In Brazil, corn is an important cereal since approximately 95 million tons of grains are produced in an area of about 17.7 million hectares (USDA, 2019). This level of production is only possible because of enhanced culture management, associated with the use of hybrids with high productive potential due to genetic improvement (BRITO et al, 2011;SILVA et al, 2011).…”

“…We highlight the chemical method using herbicides to control the weeds infesting a culture for its efficiency, practicality, and low-cost when compared with other control methods (GALON et al, 2018), as it can be used pre-and post-emergence, preferentially during the critical period of competition (GALON et al, 2008;SILVA et al, 2011). However, nowadays, the aim is to have more sustainable production models due to the need for exploring the economic injury level (EIL) to cultures to reduce environmental impacts.…”

The Problems of Corn Growers Regarding Weeds and Their Control in Sakarya Province, Turkey

“…Üretim alanlarında sorun olan yabancı ot türleri, mısır üretiminde % 37'lik bir ürün kaybına neden olabilmektedirler [6]. Mısırda, yabancı otlarla mücadele dönemi iki aylık süreci kapsamaktadır [7]. Bu süreçte verim kayıplarının önüne geçilmesi için mücadelenin doğru yönetilmesi ve etkin bir şekilde yapılması gerekmektedir.…”