scholarly journals Preemergence herbicides on weed control in elephant grass pasture

2017 ◽  
Vol 41 (1) ◽  
pp. 52-59
Author(s):  
Alexandre Magno Brighenti ◽  
Leonardo Henrique Ferreira Calsavara ◽  
Yago Vieira Guerra Varotto

ABSTRACT Elephant grass (Pennisetum purpureum Schum.) is an important forage crop that has been proposed as a potential feedstock for bioenergy production. However, weed interference is a major factor limiting elephant grass production. Field experiments were conducted in 2014 and 2015 to evaluate preemergence herbicides for selective weed control in an elephant grass pasture. Herbicide treatments included atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, diuron + hexazinone, sulfentrazone, imazethapyr, and atrazine at label use rates. Weedy and weed-free treatments were included. Atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine did not cause phytotoxicity on elephantgrass 35 days after treatment (DAT). However, diuron + hexazinone and imazethapyr were the most phytotoxic on elephantgrass, resulting in 81 and 70% phytotoxicity in 2014, and 7 and 6% phytotoxicity in 2015 respectively 35 DAT. All treatments provided effective weed control (>81%) with the exception of ethoxysulfuron (0 and 11% in 2014 and 2015, respectively), and atrazine (59% in 2014). These results show that atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine were selectives when applied in preemergence in elephant grass pasture.

Author(s):  
Mayara de Oliveira Lessa ◽  
Guilherme Quintela Calixto ◽  
Bruna Maria Emerenciano das Chagas ◽  
Emerson Moreira Aguiar ◽  
Marcus Antônio de Freitas Melo ◽  
...  

2021 ◽  
Vol 244 ◽  
pp. 126651
Author(s):  
Carlos M. Dos-Santos ◽  
Wiglison B.A. Nascimento ◽  
Bruna P. do Nascimento ◽  
Stefan Schwab ◽  
José I. Baldani ◽  
...  

2017 ◽  
Vol 16 (25) ◽  
pp. 1428-1433 ◽  
Author(s):  
Kesia Faria Vidal Ana ◽  
da Costa Barbe Tatiane ◽  
Figueiredo Daher Rogerio ◽  
Eustáquio Almeida Filho Janeo ◽  
Samara Nunes de Lima Roberta ◽  
...  

2018 ◽  
Vol 32 (4) ◽  
pp. 364-370 ◽  
Author(s):  
Zachary D. Lancaster ◽  
Jason K. Norsworthy ◽  
Robert C. Scott

AbstractField experiments were conducted in 2014 and 2015 in Fayetteville, Arkansas, to evaluate the residual activity of acetyl-CoA carboxylase (ACCase)–inhibiting herbicides for monocot crop injury and weed control. Conventional rice, quizalofop-resistant rice, grain sorghum, and corn crops were evaluated for tolerance to soil applications of six herbicides (quizalofop at 80 and 160 g ai ha–1, clethodim at 68 and 136 g ai ha–1, fenoxaprop at 122 g ai ha–1, cyhalofop at 313 g ai ha–1, fluazifop at 210 and 420 g ai ha–1, and sethoxydim at 140 and 280 g ai ha–1). Overhead sprinkler irrigation of 1.3 cm was applied immediately after treatment to half of the plots, and the crops planted into the treated plots at 0, 7, and 14 d after herbicide treatment. In 2014, injury from herbicide treatments increased with activation for all crops evaluated, except for quizalofop-resistant rice. At 14 d after treatment (DAT) in 2014, corn and grain sorghum were injured 19% and 20%, respectively, from the higher rate of sethoxydim with irrigation activation averaged over plant-back dates. Conventional rice was injured 13% by the higher rate of fluazifop in 2014. Quizalofop-resistant rice was injured no more than 4% by any of the graminicides evaluated in either year. In 2015, a rainfall event occurred within 24 h of initiating the experiment; thus, there were no differences between activation via irrigation or by rainfall. However, as in 2014, grain sorghum and corn were injured 16% and 13%, respectively, by the higher rate of sethoxydim, averaged over plant-back dates. All herbicides provided little residual control of grass weeds, mainly broadleaf signalgrass and barnyardgrass. These findings indicate the need to continue allowing a plant-back interval to rice following a graminicide application, unless quizalofop-resistant rice is to be planted. The plant-back interval will vary by graminicide and the amount of moisture received following the application.


2020 ◽  
Vol 23 (4) ◽  
Author(s):  
Sabrina Mara de Macedo Vieira ◽  
Marcelo de Castro Knop ◽  
Patrícia da Luz Mesquita ◽  
Eduardo Prado Baston ◽  
Fabiano Luiz Naves ◽  
...  

2017 ◽  
Vol 9 (11) ◽  
pp. 234
Author(s):  
Alexandre M. Brighenti ◽  
Juarez C. Machado ◽  
Francisco J. S. Ledo ◽  
Leonardo H. F. Calsavara ◽  
Yago V. Guerra Varotto

The interference imposed by weeds is one of the most important factors limiting elephant grass forage yield. Two experiments were carried out in 2015/2016 and 2017 to evaluate the selectivity and weed control of 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides applied alone or in combination with atrazine in elephant grass. The treatments applied in the experiment conducted in Valença, Rio de Janeiro State, Brazil, were as follows: two rates of mesotrione (0.072 and 0.144 kg ha-1 + 0.5% v/v mineral oil - Assist®), two rates of tembotrione (0.075 and 0.100 kg ha-1 + 0.5% v/v mineral oil - Aureo®), atrazine + mesotrione (1.25 + 0.072 kg ha-1 + 0.5% v/v mineral oil - Assist®), atrazine + tembotrione (1.25 + 0.100 kg ha-1 + 0.5% v/v mineral oil - Aureo®), atrazine + mesotrione (1.25 + 0.072 kg ha-1), atrazine + tembotrione (1.25 + 0.100 kg ha-1) and two checks (weed-free check and weedy check). The same herbicide treatments and a check without application were applied in an experiment conducted in Coronel Pacheco, Minas Gerais State, Brazil. Two application rates of mesotrione with the addition of mineral oil or the tank mixture of atrazine plus mesotrione, with or without the addition of mineral oil, did not provide injuries capable to reduce elephant grass forage yield. Tembotrione was phytotoxic to elephant grass when applied with mineral oil. Atrazine plus tembotrione in a tank-mix, with or without mineral oil, were also phytotoxic to elephant grass. All treatments provided satisfactory weed control.


2015 ◽  
Vol 43 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Dogan ISIK ◽  
Adem AKCA ◽  
Emine KAYA ALTOP ◽  
Nihat TURSUN ◽  
Husrev MENNAN

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.


2018 ◽  
Vol 39 (1) ◽  
pp. 275
Author(s):  
Ana Paula da Silva Carvalho ◽  
Roney Mendes de Arruda ◽  
Joadil Gonçalves de Abreu ◽  
Alexandre Lima de Souza ◽  
Rosane Cláudia Rodrigues ◽  
...  

This study aimed to evaluate how different irrigation water depths influence the agronomical features of elephant grass (Pennisetum purpureum Schum) cv. Roxo. Grass was cultivated in a pasture belonging to the Bovine Sector of the National Agrotechnical School of Caceres – MT. The experiment was a block design with five treatments and four repetitions. Treatments consisted of five water depths: 0 = 0% of available water (AW), 1 = 21% of AW, 2 = 34% of AW, 3 = 74% of AW, and 5 = 100% of AW. Evaluated features were production (dry matter ha-1), plant height, leaf/steam ratio, and stem diameter. Dry matter production of cuts from May and July increased linearly with increasing water depth (P < 0.05). Plant height increased linearly as water depth increased in the cuts of May and September, while the height of July cuts was 71.76 cm under an irrigation depth of 390.77 mm. In May, July, and September cuts, leaf percentage decreased linearly as water depth increased (P < 0.05). An increase of 1 mm in water depth reduced leaf percentage by 0.0936% (May), 0.0295% (July), and 0.0122% (September). Our results indicate that to improve dry matter production, May, July, and September cuts should be irrigated with water depths of 56.03 mm, 601.78 mm, and 577.65 mm, respectively.


2020 ◽  
Vol 42 ◽  
pp. e48272
Author(s):  
Maikon Figueredo Lemos ◽  
Alexandro Pereira Andrade ◽  
Pedro Henrique Ferreira da Silva ◽  
Camila Oliveira Santos ◽  
Caio Felipe Barros Souza ◽  
...  

The aim of this study was to evaluate nutritional value, fermentation losses, and aerobic stability of elephant grass silage (Pennisetum purpureum Schum.) treated with exogenous fibrolytic enzymes. The experiment was conducted in a completely randomized design with four replicates (experimental silos) and five levels of fibrolytic enzymes (0, 1.5, 3.0, 4.5 and 6.0%). For this, the elephant grass was ensiled at 70 days of age in plastic buckets with 20L capacity. Silos were opened 60 days after sealing. Analyses were made for chemical composition, in vitro dry matter digestibility (IVDMD), effluent losses (EL), gas losses (GL) and dry matter recovery (DMR), as well as the aerobic stability of the silage. Data were analyzed with PROC REG of SAS® University, at 5% probability. There was an increase in IVDMD content (p < 0.0001) and reduction in NDF and ADF contents (p < 0.0001) according to enzyme levels. These results were related to the increase in the degradation of fiber fractions. There were higher EL (p = 0.0062) as a function of enzyme levels and aerobic deterioration after silo opening, at all levels tested. Thus, it can be concluded that the exogenous fibrolytic enzymes change the chemical composition of elephant grass silage, and increase its digestibility and nutritional value. Moreover, when used alone as an additive, fibrolytic enzymes are not able to recover all dry matter of this silage (with effluent and gas losses), and are not able to maintain aerobic stability in the first hours after opening the silos.


2019 ◽  
Vol 33 (03) ◽  
pp. 431-440
Author(s):  
Thomas J. Peters ◽  
Andrew B. Lueck ◽  
Aaron L. Carlson

AbstractSugarbeet growers only recently have combined ethofumesate, S-metolachlor, and dimethenamid-P in a weed control system for waterhemp control. Sugarbeet plant density, visible stature reduction, root yield, percent sucrose content, and recoverable sucrose were measured in field experiments at five environments between 2014 and 2016. Sugarbeet stand density and stature reduction occurred in some but not all environments. Stand density was reduced with PRE application of S-metolachlor at 1.60 kg ai ha–1 and S-metolachlor at 0.80 kg ha–1 + ethofumesate at 1.68 kg ai ha–1 alone or followed by POST applications of dimethenamid-P at 0.95 kg ai ha–1. Sugarbeet visible stature was reduced when dimethenamid-P followed PRE treatments. Stature reduction was greatest with ethofumesate at 1.68 or 4.37 kg ha–1 PRE and S-metolachlor at 0.80 kg ha–1 + ethofumesate at 1.68 kg ha–1 PRE followed by dimethenamid-P at 0.95 kg ha–1 POST. Stature reduction ranged from 0 to 32% 10 d after treatment (DAT), but sugarbeet recovered quickly and visible injury was negligible 23 DAT. Although root yield and recoverable sucrose were similar across herbicide treatments and environments, we caution against the use of S-metolachlor at 0.80 kg ha–1 + ethofumesate at 1.68 kg ai ha–1 PRE followed by dimethenamid-P at 0.95 kg ha–1 in sugarbeet.


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