scholarly journals SOURGRASS INTERFERENCE ON SOYBEAN GROWN IN BRAZILIAN CERRADO

2021 ◽  
Vol 34 (2) ◽  
pp. 350-358
Author(s):  
GUILHERME BRAGA PEREIRA BRAZ ◽  
ALINE GUIMARÃES CRUVINEL ◽  
ALAN BRUNO CANEPPELE ◽  
HUDSON KAGUEYAMA TAKANO ◽  
ALESSANDRO GUERRA DA SILVA ◽  
...  

ABSTRACT Sourgrass (Digitaria insularis) is one of the main species causing significant losses in Brazilian soybean production systems. Thus, this paper aimed to evaluate sourgrass interference on soybeans grown under Cerrado conditions. Three field experiments were conducted, of which the first two (E1 and E2) simulated sourgrass after pre-sowing burndown, using plants already emerged by the time soybeans were sown; whereas the third (E3) simulated both sourgrass and soybeans emerged simultaneously. Both E1 and E2 were conducted in a randomized complete block design (RCBD) with five treatments based on sourgrass infestation densities (0, 2, 4, 6, and 8 plants m-2) and four replications. In turn, E3 was also carried out in an RCBD but with treatments arranged in a 2 x 5 factorial and four replications. The first factor comprised two soybean cultivars, while the second was sourgrass density levels, just as in E1 and E2. The results showed that increasing sourgrass densities reduced soybean yield regardless of the plant growth stage when the crop was sown. Yield losses were higher when sourgrass plants were already established by the time soybean was sown. Soybean yield losses reached up to 80% under higher sourgrass infestation levels.

Revista CERES ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 314-320
Author(s):  
Núbia Maria Correia ◽  
Agnaldo Donizete Ferreira de Carvalho

ABSTRACT When selecting a weed chemical treatment (herbicide, product mixtures, dose, or application timing), an important issue to consider is its selectivity to the crop of commercial interest. The objective of this study was to evaluate the selectivity of the herbicide metribuzin to carrot plants as a function of genotype, dose, and plant growth stage at the time of application. Two experiments were carried out, one in a greenhouse and another in the field. The greenhouse experiment was arranged in a completely randomized, 5 x 2 x 3 factorial design, with four replications. Metribuzin doses (0, 72, 96, 144, and 192 g ha-1) were sprayed on plants with 2-3 and 4-5 true leaves of the cultivars Maestro, BRS Planalto, and Verano. Cultivar Maestro was cultivated in the field in a 2 x 5 factorial experiment in randomized complete block design, with four replications. Carrot plants, at two stages of development (2 and 5 true leaves), were sprayed with the same doses of metribuzin applied in the greenhouse experiment. Metribuzin, regardless of application time and dose tested, was selective for cultivars BRS Planalto and Verano (greenhouse) and Maestro (both greenhouse and field), without reduction in quality and yield of roots.


2018 ◽  
Vol 32 (5) ◽  
pp. 570-578
Author(s):  
Blake R. Barlow ◽  
Lovreet S. Shergill ◽  
Mandy D. Bish ◽  
Kevin W. Bradley

AbstractField experiments were performed in 2016 and 2017 in Missouri to determine whether interactions exist between PRE herbicides and seed treatments in soybean. The experiments consisted of a randomized complete block design with factorial arrangements of varieties, seed treatments, and herbicides. We selected two genetically similar varieties of soybean, one with known tolerance to PPO-inhibiting herbicides and one with known sensitivity. Each variety of seed received three separate seed treatment mixtures (STMs): (1) STM1, imidacloprid plus prothioconazol+penflufen+metalaxyl plus metalaxyl plusBacillus subtilis+B. pumilis, (2) STM2,Pasteuria nishizawaeplus thiamethoxam plus prothioconazol+penflufen+metalaxyl plus metalaxyl plusB. subtilis+B. pumilis, and (3) STM3, fluopyram plus imidacloprid plus prothioconazol+penflufen+metalaxyl plus metalaxyl plusB. subtilis+B. pumilis. Chlorimuron-ethyl+flumioxazin+pyroxasulfone, chlorimuron-ethyl+flumioxazin+metribuzin, and chlorimuron-ethyl+sulfentrazone were applied PRE to each variety and seed treatment combination at 1× and 2× the labeled use rate. Chlorimuron-ethyl+sulfentrazone treatment at the 2× rate resulted in greater injury of 8% and 14% to the sensitive variety than the tolerant in 2016 and 2017, respectively; this was the highest injury observed from any herbicide treatment in either year. In 2017, chlorimuron-ethyl+sulfentrazone resulted in the greatest height reductions in both varieties, but this reduction was more evident in the sensitive (19%) than in the tolerant (6%) variety. Overall, yield differences between the two varieties were not consistent between years, and for both varieties, the sulfentrazone-containing treatments resulted in the highest yield losses. The results of this research indicate that there is a larger interaction between herbicides and varieties than there is between herbicides and seed treatments, or seed treatments and varieties.


2020 ◽  
Vol 51 (2) ◽  
pp. 592-599
Author(s):  
Mahmood & et al.

The field trial was conducted at Qwshtapa district , Grdmala village, which is 30 km far from center of  Erbil city to compare between nine genotypes of cotton (Gossipum hirsutum L) during the growing season 2016, the genotypes were (Coker 310, Lachata ‘Iraqi genotypes ’ Cafko, Dunn 1047, Montana, Stone Ville ‘ USA genotypes ‘, Bakhtegon, Khdorda , Vanamin   Iranian genotypes )  using randomized complete block design  (RCBD)with three replicates. any fertilizers were not added to the field during the research and Irrigation was done using Statistical analysis of the traits shown significant differences among genotypes , Coker 310 obtained  the highest value for  number of fruiting brunches, number of Bolls plant-1،Boll weight )g(, seed yield plant-1,  ginning% and oil% with values of (8.93  ,29.27,4.23, ,77.67, 39.87 and 28.33 ) respectively. Lashata genotype recorded highest value of protein and linoleic acid % which were (34.82 and 63.68) % respectively. Depending on growth stage, agronomic characteristics and their quality the genotypes were discerning to three main clusters, the first one included (Lachata and Stone Ville) genotypes, while the second clusters indicated only Cafko genotype and the third cluster included (Coker 310, Dunn 1047and, Montana, Bakhtegon , Khdorda and Vanamin) genotypes.  


2004 ◽  
Vol 18 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Diego J. Bentivegna ◽  
Osvaldo A. Fernández ◽  
María A. Burgos

Chemical weed control with acrolein has been shown to be a lower cost method for reducing submerged plant biomass of sago pondweed in the irrigation district of the Lower Valley of Rio Colorado, Argentina (39°10′S–62°05′W). However, no experimental data exist on the effects of the herbicide on plant growth and its survival structures. Field experiments were conducted during 3 yr to evaluate the effect of acrolein on growth and biomass of sago pondweed and on the source of underground propagules (i.e., rhizomes, tubers, and seeds). Plant biomass samples were collected in irrigation channels before and after several herbicide treatments. The underground propagule bank was evaluated at the end of the third year. Within each treatment, plant biomass was significantly reduced by 40 to 60% in all three study years. Rapid new plant growth occurred after each application; however, it was less vigorous after repeated treatments. At the end of the third year at 3,000 m downstream from the application point, plant biomass at both channels ranged from 34 to 3% of control values. Individual plant weight and height were affected by acrolein treatments, flowering was poor, and seeds did not reach maturity. After 3 yr, acrolein did not reduce the number of tubers. However, they were significantly smaller and lighter. Rhizomes fresh weight decreased by 92%, and seed numbers decreased by 79%. After 3 yr of applications, operational functioning of the channels could be maintained with fewer treatments and lower concentrations of acrolein.


2021 ◽  
Vol 11 (01) ◽  
pp. 736-748
Author(s):  
M. M. Hossain ◽  
◽  
S. Yesmin ◽  
M. Z. Islam ◽  
M. A. Hossain ◽  
...  

An experiment was conducted at the Sher-e-Bangla Agricultural University farm from April to June 2017 in Kharif season to evaluate the performance of two mungbean varieties under different NPK fertilizers doses in field conditions. The experiment was laid out in Randomized Complete Block Design (RCBD), comprising six treatments with three replications. In the experiment, varieties used were BARI mung-6 and BARI mung-5 and the combination of the treatment were T0 = (control), T1 (10-40-25 NPK kg ha-1), T2 (10-60-45 NPK kg ha-1), T3 (20-50-35 NPK kg ha-1), T4 (30-40-25 NPK kg ha-1) and T5 (30-40-45 NPK kg ha-1), respectively. Mungbean cultivars responded noticeably to the supplementary NPK fertilizers as the crop characters were significantly influenced by different levels of NPK fertilizers. Data were recorded on plant height, leaves plant-1, branches plant-1, pods plant-1, seeds pod-1, 1000-seed weight, seed, and straw yield at different days after sowing. Of the two varieties, BARI mung-6 gave the highest seed yield (1.72 t ha-1) next to the higher plant growth and straw yield On the contrary, BARI mung-5 cultivar produced the lowest seed yield (1.57t ha-1), plant growth, and straw yield. The results showed that T3 (20-50-35 NPK kg ha-1) treatment was the best treatment as regards plant growth and yield parameters. The highest seed yield was produced by treated plot T3 (20-50-35 NPK kg ha-1) over the untreated control plot, T1, T2, T4, and T5, respectively. As for the combined effect, V1T3 (BARI mung-6 and T3 = 20kg N + 50kg P + 35kg K ha-1) performed the best results in all growth and development characters. Therefore, the combined application of 20-50-35 kg NPK ha-1 might be considered to be found optimal to get a considerable seed yield of mungbean variety BARI mung-6.


2016 ◽  
Vol 51 (8) ◽  
pp. 942-949 ◽  
Author(s):  
Gilberto Nava ◽  
Karine Louise dos Santos ◽  
Murilo Dalla Costa ◽  
Marlise Nara Ciotta

Abstract: The objective of this work was to investigate the effect of liming and phosphorus fertilization on the growth, mineral composition of the leaves, fruit yield, and mycorrhizal colonization of young feijoa (Acca sellowiana) plants. Treatments consisted of four liming levels - 0, 25, 50, and 100% of the dose required to raise the soil pH to 6.5 - and of five levels of P - 0, 60, 120, 180, and 240 kg ha-1 P2O5 -, placed in a randomized complete block design, in a split-plot arrangement, with three replicates. The orchard was established in 2010 with the Helena cultivar. In 2012, 2013, and 2014, plant growth was evaluated by measuring trunk perimeter, plant height, and tree canopy width. Mineral composition of the leaves, regarding P, N, K, Ca, and Mg contents, was assessed annually. Mycorrhizal colonization was evaluated in 2012, and fruit yield was determined in 2014. No interaction was observed between the studied factors. P contents had no effect on the evaluated variables. Liming, however, increases plant growth, mycorrhizal colonization, fruit yield, and Ca and Mg leaf contents, besides reducing K leaf contents.


2015 ◽  
Vol 33 (3) ◽  
pp. 491-497
Author(s):  
A. T. FARIA ◽  
E. A. FERREIRA ◽  
P. R. R. ROCHA ◽  
D. V. SILVA ◽  
A. A. SILVA ◽  
...  

ABSTRACT Growth regulators can be used to further retard or inhibit vegetative growth. In this sense, the objective of this study was to determine the effects of age and number of trinexapac-ethyl applications on the growth and yield of sugarcane. The experiment was in a randomized complete block design with four replications. The treatments were in a 3 x 2 + 2 factorial arrangement, where factor A corresponded to the application times of the plant growth regulator (120, 200 and 240 days after bud burst (DAB) of sugarcane) and factor B to the number of applications (one or two applications). In addition, two controls (one with three applications and another application without the regulator) were added. The application of trinexapac-ethyl decreased the number and the distance between buds, height, root volume and sugarcane yield. The sequential application (2 or 3 times) induced an increase in stem diameter and three applications of the product increased the number of plant tillers. The use of growth regulators applied at 240 DAB has reduced plant height, however without changing the number of buds. It can be concluded that trinexapac-ethyl changes sugarcane growth and yield, regardless of season and number of applications.


2016 ◽  
Vol 41 (4) ◽  
pp. 713-723
Author(s):  
S Akther ◽  
F Ahmed ◽  
MR Islam ◽  
MA Hossen ◽  
AHMM Rahman Talukder

Field experiments were carried out in the Agronomy field of BARI, Joydebpur, RARS, Jamalpur and RARS, Ishurdi during two consecutive kharif seasons of 2012 and 2013 to determine the suitable plant spacing and optimum fertilizer dose for higher yield of mukhikachu. Three levels of spacing viz., 60 cm x 60 cm, 60 cm x 45 cm and 60 cm x 30 cm and three levels of fertilizer dose viz., recommended dose (3000-96-27-81-18 kg ha-1 of CD-N-P-K-S), 25% less than the recommended dose and 25% higher than the recommended dose were used as treatment variables. The experiments were laid out in factorial randomized complete block design with three replications. Results revealed that the closer spacing (60 cm x 30 cm) in combination with 25% higher than the recommended fertilizer dose gave the maximum edible yield of mukhikachu (two years average) at all locations (20.04 t ha-1, 20.75 t ha-1 and 16.63 t ha-1 at Joydebpur, Jamalpur and Ishurdi, respectively). The wider spacing (60 cm x 60 cm) coupled with 25% less than the recommended fertilizer dose produced the lowest yield (two years average). The maximum benefit- cost ratio (two years average) was obtained from the combination of the recommended fertilizer dose and 60 cm x 30 cm spacing, that were 2.93 at Joydebpur and 3.42 at Ishurdi, while at Jamalpur the maximum benefit-cost ratio (two years average) was found maximum from 60 cm x 30 cm spacing with 25% higher than the recommended fertilizer dose (3.12).Bangladesh J. Agril. Res. 41(4): 713-723, December 2016


2018 ◽  
Vol 36 (0) ◽  
Author(s):  
C. PIASECKI ◽  
M.A. RIZZARDI

ABSTRACT: Volunteer corn is extremely competitive with soybean and the degree of interference varies with the corn density, time of emergence and origin. The objectives of this work were to determine the economic threshold (ET) of volunteer corn GR® F2 in soybean as a function of the time of emergence (same day and nine days after soybean) and origin (individual plants or clumps). Each clump was manually adjusted to have seven corn plants. Four field experiments were conducted in randomized blocks design with four replicates in Passo Fundo, RS, Brazil. The soybean yield losses (%) were calculated and adjusted to the model of the rectangular hyperbola and generated the parameters for the determination of the ET, that was calculated based on the volunteer corn control costs (US$ ha-1), efficiency of control (%), price paid for soybean (US$ kg-1) and soybean yield (kg ha-1). The ET mean was 0.3 and 0.48 for individual corn plants m-2 emerged together and nine days after soybean, and 0.08 and 0.03 m-2 for individual plants and clumps, respectively. Increases in grain yield and price paid for soybean, greater control efficiency of corn and lower control cost promote reduction in the ET of volunteer corn in soybean. The control of volunteer corn is justified in a density less than 0.5 individual plant m-2 and is close to zero when corn originates from clumps. Volunteer corn is one of the most competitive weed in soybean crops.


2018 ◽  
Vol 45 (3) ◽  
pp. 278 ◽  
Author(s):  
Firmansyah Aznur ◽  
Suwarto , ◽  
Dan Heni Purnamawati

Light use efficiency (LUE) determines biomass production based on interception energy during photosynthesis. The product of photosynthesis is allocated to the plants organs based on the partitioning of carbohydrates. The LUE and carbohydrate partitioning are two important parameters in crop modelling. The research was conducted at Cikabayan experimental station of IPB, Bogor from July to November 2015. The experiment was designed according to a randomize block design with five replications. The fertilizer treatments rate were 0%, 50%, 100%, 150%, and 200% of reference N fertilization of 120 kg ha-1.  The  value  of  light use efficiency and the partition coefficient of sorghum were not affected by N fertilization. The value of light use efficiency is 1.41 g MJ-1. The carbohydrates partitioning was developed based on plant growth stage. The partition from the planting to the emergence stage (0 ≤ s ≤ 0.25) was 0.81 x s/0.25 root, 0 stem, 0.19 x s/0.25 leaves, and 0 panicle. The partition from the emergence to the maximum vegetative stage (0.25 &lt; s ≤ 0.5) was 0.81-(0.59 x s/0.5) root, 0.14 x s/0.5  stem, 0.19 + (0.45 x s/0.5) leaves, and 0 panicle. The partition from the maximum vegetative stage to the flowering stage (0.5 &lt; s ≤ 0.75) was 0.22 - (0.09 x s/0.75) root, 0.14 + (0.39 x s/0.75) stem, 0.64 - (0.46 x s/0.75) leaves, and 0.16 x s/0.75 panicle. The partition from flowering to the harvest stage (0.75 &lt; s ≤ 1) was 0.13 - (0.13 x s) root, 0.53 - (0.52 x s) stem, 0.18-(0.18 x s) leaves, and 0.16 + (0.84 x s) panicle.<br /><br />Keywords: crop modelling, light use efficiency, N fertilizer, partitioning carbohydrates<br /><br />


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