scholarly journals HERBICIDE SELECTIVITY TO SIGNAL GRASS AND CONGO GRASS

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
A.H.C. ANÉSIO ◽  
M.V. SANTOS ◽  
R.R. SILVEIRA ◽  
E.A. FERREIRA ◽  
T.G.S. BRAZ ◽  
...  

ABSTRACT This study was conducted in order to evaluate the selectivity of signal grass and congo grass, submitted to post-emergence herbicide application. The experiment was conducted under greenhouse conditions, in Diamantina, Minas Gerais state, and it was arranged in a randomized block design, with five replications. Treatments were set in factor scheme (8 x 2) + 2. Eight herbicides (nicosulfuron; clomazone; glyphosate; fluazifop-p-butyl + fomesafen; lactofen; fomesafen; fluazifop-p-butyl and mesotrione) were applied in doses recommended by the manufacturer on two fodder species: Brachiaria decumbens cv. Basilisk (signal grass) and Brachiaria ruziziensis (congo grass); in addition, there were two control samples without herbicide application, for a total of 18 treatments. The evaluated herbicides showed less intoxication on signal grass when compared to congo grass. Nicosulfuron and glyphosate promoted higher intoxication on both species when compared to the other herbicides. Glyphosate, fluazifop-p-butyl + fomesafen, fluazifop-p-butyl, mesotrione and nicosulfuron affected the ratio variable / maximum fluorescence (Fv/Fm) in both species, indicating an effect provided by these herbicides on the electron transport chain. Results demonstrated that signal grass and congo grass have higher susceptibility to glyphosate, fluazifop-p-butyl + fomesafen, fluazifop-p-butyl, mesotrione and nicosulfuron. congo grass shows higher susceptibility to the studied herbicides when compared to signal grass.

2011 ◽  
Vol 40 (6) ◽  
pp. 1195-1203 ◽  
Author(s):  
Cristiane Prezotto Silveira ◽  
Daniela Alves de Oliveira ◽  
Edna Maria Bonfim-Silva ◽  
Francisco Antonio Monteiro

The objective of this research was to evaluate the effect of combinations of nitrogen and sulfur rates in degraded signal grass (Brachiaria decumbens) pasture on their productive, morphological and nutritional attributes in the root system at four soil depths. The pasture used in the experiment was established over eight years ago in Entisol. Five nitrogen rates (0; 150; 300; 450 and 600 kg/ha/year) and five sulfur rates (0; 15; 30; 45 and 60 kg/ha/year) were combined in a fractionated factorial in a randomized block design, with three replications. Nitrogen was supplied as ammonium nitrate and sulfur as gypsum, and the rates were split into three times in the rainy season. The evaluations occurred at intervals of 35 days during the rainy season and 56 days in the dry season, in two consecutive years. Roots were collected with a 4-cm diameter auger at 0-10; 10-20; 20-30 and 30-40 cm soil depths. It was determined root dry matter, length and surface of the root system and nitrogen and sulfur concentrations in roots. Nitrogen rates applied in two consecutive years in the pasture affected dry mass, length, surface and nitrogen concentration in signal grass root system. Rates of sulfur by themselves or combined with nitrogen rates do not affect attributes of root system.


2017 ◽  
Vol 38 (6) ◽  
pp. 3695 ◽  
Author(s):  
Renan Coelho Dias ◽  
Márcia Vitória Santos ◽  
Fabiana Lopes Ramos de Oliveira ◽  
Evander Alves Ferreira ◽  
José Barbosa dos Santos ◽  
...  

The use of herbicides to control grass in Medicago sativa (alfalfa) pastures is still incipient. Therefore, the objective of this study was to evaluate the efficiency of fluazifop-p-butyl in the control of Brachiaria decumbens (signalgrass) in alfalfa. Thus, randomized block design was used, with seven doses of fluazifop-p-butyl (0, 25, 50, 100, 200, 300, 400 g ha-1), and four replications. Herbicide application was performed when the plants had about 20 cm height. Chlorophyll fluorescence, control of signalgrass and alfalfa toxicity were evaluated at 7, 15 e 30 days after application (DAA) and, at 45 DAA and 45 days after cut (DAC), both species were cut and tiller density, as well as branches and dry matter of forage species, were determined. Fluazifop-p-butyl does not affect the integrity of the photosynthetic apparatus of alfalfa plants, due to high tolerance to this mechanism of action presented by dicotyledonous species. However, signalgrass had physiological variables negatively affected by the herbicide, indicating the presence of physiological stress, even at the lowest doses of the product. The dose of 50 g ha-1 of fluazifop-p-butyl is effective in controlling signalgrass, without causing physiological and growth damage in alfalfa plants.


2012 ◽  
Vol 30 (4) ◽  
pp. 861-870 ◽  
Author(s):  
N.M. Correia ◽  
F.J. Perussi ◽  
L.J.P. Gomes

The aim of this study was to assess the efficacy of S-metolachlor applied in pre-emergence conditions for the control of Brachiaria decumbens, Digitaria horizontalis, and Panicum maximum in sugar cane mechanically harvested without previous burning of the crop (green harvest) with the crop residue either left or not on the soil surface. The experiments were established in the field according to a randomized complete block design with four repetitions in a 7 x 2 split-plot scheme. In the plots, five herbicide treatments were studied (S-metolachlor at 1.44, 1.92, and 2.40 kg ha-1, clomazone at 1.20 kg ha-1, and isoxaflutole at 0.188 kg ha-1), and two control treatments with no herbicide application. In the subplots, the presence or absence of sugar cane crop residue on the soil surface was evaluated. S-metolachlor efficacy was not hampered by either 14 or 20 t ha-1 of sugar cane crop residue on the soil surface. When sugar cane crop residue was covering the soil surface, S-metolachlor at a rate of 1.44 kg ha-1 resulted in weed control similar at their larger rates, where as without the presence of crop residue, S-metolachlor controlled B. decumbens, D. horizontalis, and P. maximum at the rates of 1.92, 1.44, and 1.92 kg ha-1, respectively. The herbicides clomazone and isoxaflutole were effective for the studied species, independently of the crop residue covering the soil surface. S-metolachlor caused no visible injury symptoms to the sugar cane plant. Clomazone and isoxaflutole caused visible injuries to the sugar cane plant. None of the herbicides negatively affected the number of viable culms m² or the culm height and diameter.


Revista CERES ◽  
2011 ◽  
Vol 58 (4) ◽  
pp. 413-418 ◽  
Author(s):  
Karen Rodrigues de Toledo Alvim ◽  
Césio Humberto de Brito ◽  
Afonso Maria Brandão ◽  
Luiz Savelli Gomes ◽  
Maria Teresa Gomes Lopes

Reduction in leaf area in corn plants during reproduction changes physiological metabolism and consequently the accumulation of dry matter in grains. The aim of this work was to study changes in agronomic characteristics caused by defoliation in corn during the reproduction phase. The experiment was carried out in Uberlândia, Minas Gerais state, in the agricultural year 2007/2008. The experiment was arranged in a randomized block design, consisting of seven treatments: control without defoliation, removal of two apical leaves, removal of four apical leaves, removal of all leaves above spike, removal of four intermediate leaves, removal of all leaves below spike, and removal of all plant leaves, with five repetitions. The genotype used for the evaluations was hybrid NB 7376. Defoliation was carried out when plants were at the growth stage R2. The variables assessed were: yield, density of spikes and corncobs, root resistance and stem integrity. When all leaves above the spike were removed, grain yield was reduced by 20%. Corncob density, stem integrity and root resistance to uprooting were also affected. Spike density was only affected when all plant leaves were removed. The leaf area remaining physiologically active above the spike was found to be most efficient in terms of grain yield.


2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Elaine Cristina Batista ◽  
José Luiz De Andrade Rezende Pereira ◽  
Adriano Teodoro Bruzi ◽  
Everton Vinucius Zambiazzi ◽  
Karina Barroso Silva

Cultivar evaluation is one of the basic steps recommended for a given region, since the best adapted cultivars have higher yields, and success in this parameter is based on the genotype of the material and its interaction with the environmental variables. The aim of this study was to evaluate thebehavior of 23 soy cultivars in the soil-climatic conditions of the south region of Minas Gerais State (MG), Brazil, in the municipality of Inconfidentes. The evaluated traits were grain yield, plant height, height of insertion of the first legume and lodging. The experiments were conducted on the 2013/2014 and 2014/2015 harvests, adopting a randomized block design with three replicates and 23 treatments, which were constituted by the following cultivars: FAVORITA RR, BRS MG 760SRR, NA 5909 RG, NA 7200 RR, CD 2630, CD 250, NA 7620 RR, CD 2737, TMG 123, V-MAX RR, P 98Y11 RR, NS 7100 RR, BMX Potencia, Anta 82 RR, CD 237, V-TOP, TMG 1176 RR, TMG 1174 RR, TMG 1179 RR, TMG 1181 RR, BMX Força, Monsoy 7211 RR and BRS MG 780 RR. Of the studied cultivars, those that most stood out for the traits evaluated in the conditions of Inconfidentes (MG) were TMG 1179 RR (48.6 bags of 60 kg ha-1), NA 7200 RR (45.6 bags), CD 2737 (41.1 bags), CD 237 (41 bags) and BRS MG 760 SRR (40.6 bags), all of which displayed satisfactory conditions for mechanical harvesting, demonstrating the good performance of the crop in the south region of Minas Gerais State.


2019 ◽  
Vol 11 (9) ◽  
pp. 21
Author(s):  
Guilherme V. Pimentel ◽  
Silvino G. Moreira ◽  
Mateus O. T. de Avila ◽  
Antonio Henrique F. de Carvalho ◽  
Alessandro A. P. da Silva ◽  
...  

Maize hybrids have different levels of tolerance to the herbicide nicosulfuron, depending on the dose, the environment, the phenological stage of the plant and the timing of nitrogen fertilization, and phytotoxic effects can occur without proper management. There is also limited information on the selectivity of current genetically modified hybrids for other recommended herbicides, such as tembotrione. Thus, the objective of this study was to evaluate the effects of herbicides (tembotrione and nicosulfuron) and the timing of nitrogen fertilization on the yield of maize hybrids. The experimental design was a randomized block design, in a 4 × 2 factorial arrangement, with 4 replicates. The treatments consisted of four treatments [weeding; nicosulfuron + atrazine (20 and 32 + 1250 g ha-1 ai) and tembotrione + atrazine (75.6 + 1250 g ha-1 ai)] and two nitrogen fertilization times (0 and 7 days after application). Maize hybrids P30F53 Leptra, DKB 230PRO3 and KWS 9004PRO2 were assessed in two growing seasons (1st and 2nd harvest) during the 2016/2017 growing season. The percentages of weed control; phytotoxicity at 7, 14 and 21 days after application (DAA); plant height; number of rows per ear; and yield at harvest were evaluated. All herbicides were more effective in controlling weeds at the 1st harvest because of favourable climatic conditions. Nitrogen fertilization can be carried out on the same day as the application of the herbicides nicosulfuron and tembotrione with no reduction in yield for the hybrids P30F53 Leptra, DKB 230PRO3 and KWS 9004PRO2.


Author(s):  
S. Selvakumar ◽  
R. Ajaykumar ◽  
A. Ammaiyappan

Background: Time of pre-emergence herbicide application is an important factor that decides the efficiency of herbicide. If the pre-emergence herbicide is not applied at appropriate time, it may cause ineffective weed control or toxicity to crops. With this background, a field experiment was conducted at TNAU, Madurai to optimize the time of pre-emergence herbicides namely pendimethalin and oxyfluorfen application for effective weed management in irrigated blackgram. Methods: The experiment was laid out in randomized block design with three replication. Treatments were application of pendimethalin at 0.75 kg ha-1 and oxyfluorfen at 0.2 kg ha-1 on 1, 2, 3, 4 days after sowing, weed free check and unweeded check. Result: Results of the study revealed that oxyfluorfen gave maximum weed control efficiency as compared to pendimethalin, but toxicity to the crop was observed when oxyfluorfen was sprayed after 2 days of sowing. Yield and economics were achieved higher with application of 0.75 kg ha-1 of pendimethalin at 2 DAS, which was on par with application of 0.2 kg ha-1 of oxyfluorfen at 1 DAS due to lesser toxicity. Application of 0.75 kg ha-1 of pendimethalin and 0.2 kg ha-1 of oxyfluorfen didn’t leave any herbicide residue after harvest. Hence, application of 0.75 kg ha-1 of pendimethalin at 2 DAS and 0.2 kg ha-1 of oxyfluorfen at 1 DAS can be recommended for effective weed management in irrigated balckgram.


2018 ◽  
Vol 39 (6) ◽  
pp. 2517
Author(s):  
Armindo Neivo Kichel ◽  
Luis Carlos Ferreira de Souza ◽  
Roberto Giolo de Almeida ◽  
José Alexandre Agiova da Costa

This study aimed to assess productivity and nutritional value of the tropical grasses Brachiaria brizantha cv. Piatã, Xaraés, and Marandu, Panicum maximum cv. Mombaça, and B. ruziziensis cv. Kennedy in the interseason of an integrated crop-livestock (ICL) system since alternatives are needed for forage production for animal grazing in Autumn and Winter. The experimental design was a randomized block design in a split-split plot scheme with four replications. The treatments of plots consisted of five grasses, subplots consisted of three cropping systems (monoculture, intercropping with corn and unsuppressed grass, and intercropped with corn and suppressed grass), and sub-subplots consisted of four cutting intervals of grasses (50, 90, 125, and 195 days after emergence - DAE). The experiment was carried out from February to September 2014. Dry matter (DM) productivity, obtained at 195 DAE for the three cropping systems (monoculture grass, unsuppressed and suppressed grass in intercropping), were 18.45, 7.15, and 3.05 t ha?1, respectively, and average crude protein contents of leaf blades of grasses decreased linearly between the cutting intervals of 50 to 195 DAE from 19.95 to 9.70%, respectively. Under integrated systems, the studied grasses showed better yields and nutritional quality when compared to traditional grazing systems. Panicum maximum cv. Mombaça and Brachiaria brizantha cv. Xaraés and Piatã had the highest leaf and crude protein yields when compared to Brachiaria ruziziensis cv. Kennedy and Brachiaria brizantha cv. Marandu. In terms of nutritional value, Brachiaria ruziziensis cv. Kennedy was superior to Mombaça and Xaraés grasses but had lower total dry matter yield. Finally, Xaraés, Piatã and Mombaça grasses are recommended choices ICL systems when fodder grass production is the goal.


2017 ◽  
Vol 57 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Sylwia Kaczmarek

AbstractField experiments to evaluate the split application of mesotrione + s-metolachlor, mesotrione + terbuthylazine, dicamba + prosulfuron, terbuthylazine + mesotrione + s-metolachlor, and sulcotrione in the cultivation of sorghum var. Rona 1 were carried out in 2012 and 2013. The field tests were conducted at the field experimental station in Winna Góra, Poznań, Poland. Treatments with the herbicides were performed directly after sowing (PE) and at leaf stage 1–2 (AE1) or at leaf stage 3–4 (AE2) of sorghum. The treatments were carried out in a laid randomized block design with 4 replications. The results showed that the tested herbicides applied at split doses were effective in weed control. After the herbicide application weed density and weed biomass were significantly reduced compared to the infested control. The best results were achieved after the application of mesotrione tank mixture with s-metolachlor and terbuthylazine. Application of split doses of herbicides was also correlated with the density, biomass, and height of sorghum.


2019 ◽  
Vol 7 (1) ◽  
pp. 09-17
Author(s):  
Ann I. Hoka ◽  
Michael Gicheru ◽  
Syprine Otieno ◽  
Hezekiah Korir

Appropriate methods of mutation induction are of high importance in pastures for increased genetic variability and improved performance. The objective of this research was to improve the agronomic and nutritive performance of mutant lines (M7) through induced mutagenesis to seeds of a local landrace Brachiaria ruziziensis. The seeds were irradiated with 0, 10, 20, 30 and 40Gy doses of gamma radiation from Cobalt 60 (60Co).  Treatments were; KE 0Gy, KE 10Gy, KE 20Gy, KE 30Gy and KE 40Gy resulting into M1 seeds. The M1 seeds were planted in the greenhouse in germination pots for one month and the seedlings transplanted to the field. Seeds of M6 plants (M7 seeds) were used to establish field experiment in a completely randomized block design, with three replications. Parameters measured included; tillering, leaf-stem ratio, dry matter weight, and seed weight. Data collected was analyzed using the SAS package. Mutant lines exhibited better agronomic performance compared to the wild type. Performance increased with increased gamma-ray exposure with 40Gy treatment outperforming all other treatments whereas the control performed dismally. There was a significant difference (P0.05) in the dry matter with 40Gy treatment having the highest values of dry matter yields, whereas control had the lowest values. Application of nuclear technology to other grasses would lead to increased biomass and improved nutrition for increased animal productivity leading to food and nutrition security.


Sign in / Sign up

Export Citation Format

Share Document