Application of herbicides as growth regulators of emerald Zoysia grass fertilized with nitrogen

Abstract

Nitrogen (N) is essential for nutrition and for the maintenance of the intense green color of lawns. However, this element affects shoot growth and, therefore, mowing frequency, which is a key factor of lawn-maintenance costs. Accordingly, this study aimed to evaluate the use of nitrogen fertilization in combination with the use of potential herbicides as growth regulators to promote the maintenance of the high visual (intense green) and nutritional quality of lawns of emerald Zoysia (Zoysia japonica Steud.) grown in Ultisol soil while reducing their leaf growth. The experiment was conducted at the Teaching, Research and Extension Education Farm (Fazenda de Ensino, Pesquisa e Extensão) of São Paulo State University (Universidade Estadual Paulista Júlio de Mesquita Filho, UNESP), Ilha Solteira Campus/ São Paulo (SP), from June/2012 to June/2013. The experimental design consisted of randomized blocks with 20 treatments established in a 5 x 4 factorial arrangement with four replicates, including four herbicides (glyphosate, imazaquin, imazethapyr, and metsulfuron-methyl, applied at doses of 200, 420, 80, and 140 g ha -1 active ingredient (a.i.), respectively) and a control (without herbicide), and four N doses (0, 5, 10, and 20 g m -2 ), split into five applications delivered throughout the year. The following items were evaluated: length, LCI (leaf chlorophyll index), leaf dry matter production and leaf N concentration and the percentage of phytotoxicity on lawn grass shoots. Doses from 10 to 20 g m -2 N provided sufficient N concentrations to maintain the emerald Zoysia. The herbicides metsulfuron-methyl and glyphosate were superior in the control of lawn leaf growth. While the former was phytotoxic, the latter had no effect on the aesthetic quality of the lawn, standing out as an herbicide that may be used at a dose of 200 g ha -1 to regulate the growth of emerald Zoysia. fator do custo de manutenção em gramados. Neste contexto, objetivou-se avaliar a adubação nitrogenada e o uso potencial de herbicidas como reguladores de crescimento em grama esmeralda (Zoysia japonica Steud.), em Argissolo Vermelho, visando manter o gramado com boa qualidade visual (verde intenso) e nutricional bem como reduzir o seu crescimento foliar. O experimento foi conduzido na Fazenda de Ensino, Pesquisa e Extensão da UNESP, Campus de Ilha Solteira/SP, de junho/2012 a junho/2013. Utilizou-se o delineamento em blocos casualizados com 20 tratamentos dispostos num fatorial 5 x 4 com quatro repetições, sendo quatro herbicidas: glyphosate, imazaquin, imazethapyr e metsulfuronmethyl aplicados na dose de, respectivamente, 200, 420, 80 e 140 g ha -1 do ingrediente ativo (i.a.) e a testemunha -sem herbicida; e quatro doses de N: 0, 5, 10 e 20 g m -2 , parceladas em cinco aplicações durante o ano. Avaliaram-se: o comprimento, o índice ICF (índice de clorofila foliar) e a produção de matéria seca das folhas, determinaram-se também a concentração foliar de N e a porcentagem de fitointoxicação da parte aérea do gramado. Doses de 10 a 20 g m ...

Crescimento e teor de pigmentos de Paspalum notatum em resposta a aplicação de herbicidas

“…It is worth highlighting that these amino acids are precursor of most aromatic compounds in plants, that glyphosate reduces the synthesis of phytoalexins and that there is an increase in the concentration, at toxic levels, of nitrate, ethylene, cinnamic acid and other compounds that accelerate the death of plants, due to the herbicide effect over the aforementioned route (HRAC, 2017). This is different from what was observed by Dinalli at al. (2015) who, when applying 200 g a.e.…”

“…However, there are some difficulties in inhibiting the grass growth without affecting the green color of the species. Plant growth regulators are becoming important in grass management programs, since they suppress plant growth without damaging its visual quality and without causing leaf phytointoxication, discoloring or thinning (Costa et al, 2009;Maciel et al, 2013;Dinalli, et al, 2015).…”

Desempenho fitométrico do milho sob efeito de doses de trinexapac-ethyl e clomazone

“…Costa et al (2009) ao trabalhar com quatro espécies de gramas e o redutor de crescimento trinexapac-ethyl, obtiveram resposta diferente da encontrada no presente trabalho, em que houve redução da massa fresca das plantas conforme incrementou-se a dose do redutor. Dinalli et al (2015) e Marchi et al (2013) ao testarem os reguladores trinexapac-ethyl, prohexadione-calcium, bispyribac-sodium e os herbicidas glyphosate, imazaquin, imazethapyr, e metsulfuron-methyl como redutores de crescimento Figura 1. Características fitométricas do milho em resposta a doses de trinexapac-ethyl e clomazone.…”

Paclobutrazol and phenoxaprope-P-ethyl potential as growth regulator in Carpet grass Plus®

“…However, according to Kreuser (2015), mowing may be difficult due to the embankment slope, and also, resulting in higher expenses (Santos and Castilho, 2018). Thus, an alternative to this management would be the use of plant growth regulators (Dinalli et al, 2015;Marchi et al, 2017;Dias et al, 2019;Gazola et al, 2019). It has the function slower the plant growth, without causing visible damage, such as necrotic spots of phytotoxicity, discoloration or thinning, but allowing the maintenance of its aesthetics and characteristic green colour (Gazola et al, 2016;Dias et al, 2019).…”