scholarly journals Evaluation of Alternative Pre-emergence Herbicides to Atrazine for Weed Control on Maize (Zea maysL.) plot in Ogbomoso, Southwest Nigeria

2021 ◽  
Vol 4 (4) ◽  
pp. 40-45
Author(s):  
Olabode O.S. ◽  
Oladapo O.S. ◽  
Ogunsola A. ◽  
Sangodele A.O.
Keyword(s):  
Field Experiments ◽  
Growth Parameters ◽  
Weed Density ◽  
University Of Technology ◽  
Standard Procedures ◽  
Southwest Nigeria ◽  
Knapsack Sprayer ◽  
Density And Biomass ◽  
And Control ◽  
Block Experiment

Field experiments were carried out at the Teaching and Research Farm of the LadokeAkintola University of Technology, (LAUTECH), Ogbomoso to evaluate the effectiveness and determine the optimum rate of applying alternative herbicides to atrazine on maize plots in view of the current criticism against the herbicide. Five herbicides, namely; 3-maize force, Xtra force, Pre-maize Guard force (solution and pellet) at two rates (100% and 50% recommended rates) were compared with atrazine at full dose and 3 hoe-weeding in a Randomized complete Block Experiment with 3 replications. Maize, Variety OBA Super, maturing in 75 days, was planted at two plants per stand at a spacing of 75 x 50cm in two-year trials and maintained following the standard procedures. The herbicides were applied using a knapsack sprayer calibrated to deliver at 200liters/ha. Results showed that there were no significant differences (p=0.05) among the treatment and between the treatments and control with respect to seed germination, plant survival and other growth parameters. The highest grain yield (6757.3kg/ha) obtained with atrazine was not significantly different from those of other treatments and control. The effectiveness of the herbicides, measured using weed density and biomass, showed comparable effectiveness across the herbicides and atrazine. Furthermore, at a dosage of 50%, the herbicide’s effectiveness was highly comparable to those of atrazine at 100%. The implications of these findings were discussed.

The Effect of Trifluralin Applied Preplant on Grass Weed Control and Establishment and Yield of Barley (Hordeum vulgare)

1997 ◽  
Vol 11 (3) ◽  
pp. 515-519 ◽  
Author(s):  
Julio A. Scursoni ◽  
Emilio H. Satorre
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Herbicide Application ◽  
Planting Pattern ◽  
Weed Density ◽  
Time Of Application ◽  
Density And Biomass ◽  
And Control ◽  
Crop Planting ◽  
Grass Weed

The objective of this paper was to evaluate the effect of preplant applications of trifluralin on barley stand and yield, and control of grass weeds in field experiments during 1992 and 1993. Factors examined were: (1) crop planting patterns (conventional drill with rows 15 cm apart and deep-seeder drill with rows 25 cm apart), (2) herbicide application times (22 d before sowing and immediately before sowing), and (3) herbicide application. During 1993, hand-weeded plots also were established. Trifluralin applied preplant at 528 g ai/ha reduced weed density and biomass. Weed control was higher under conventional planting than under the deep planting pattern, and there was no effect of the time of application on herbicide efficacy. There was no herbicide injury to the crop, and grain yield was higher in treated than in untreated plots due to successful weed control.

Green Foxtail (Setaria viridis) and Pale Smartweed (Polygonum lapathifolium) Interference in Field Crops

1994 ◽  
Vol 8 (2) ◽  
pp. 311-316 ◽  
Author(s):  
John T. O'Donovan
Keyword(s):  
Crop Yield ◽  
Field Experiments ◽  
Dry Weight ◽  
Limiting Factor ◽  
Yield Losses ◽  
Weed Density ◽  
Green Foxtail ◽  
Polygonum Lapathifolium ◽  
And Control ◽  
The Relationship

Field experiments were conducted at Vegreville, Alberta in 1984, 1985, 1986, and 1988 to determine the effects of green foxtail and pale smartweed on yield of wheat, barley, and canola. There was considerable variation among years in the response of crop yield to both weeds and in the relationship between weed dry weight and weed density. Mostly relationships between crop yield and either weed density or dry weight were poor, suggesting that the weeds competed weakly with the crops. Thus density or dry weight may be poor predictors of crop yield losses due to green foxtail or pale smartweed. Where the crops emerged ahead of these weeds, and where soil moisture was not a limiting factor, crop yield losses were minimal and control with herbicides probably uneconomical. In some instances, growth and development of the weeds was suppressed by the crops to the extent that little or no weed dry matter was present at crop maturity. This was most evident with barley, and where the crops emerged ahead of the weeds.

scholarly journals Weed Spectrum in Durum Wheat under Different Soil Tillage and Fertilizer Application in Mediterranean Environment

2021 ◽  
Vol 13 (13) ◽  
pp. 7307
Author(s):  
Verdiana Petroselli ◽  
Emanuele Radicetti ◽  
Alireza Safahani Langeroodi ◽  
Mohamed Allam ◽  
Roberto Mancinelli
Keyword(s):  
Durum Wheat ◽  
Field Experiments ◽  
Block Design ◽  
Mineral Soil ◽  
Mineral Fertilizer ◽  
Fertilizer Application ◽  
Soil Tillage ◽  
Weed Density ◽  
Density And Biomass ◽  
The Impact

Agricultural intensification may cause significant changes in weed density due to high weed competitiveness. Therefore, sustainable practices are to be designed to get maximum benefits of plant biodiversity in the agro-ecosystems. Field experiments were conducted in 2013/2014 and 2014/2015 to evaluate the impact of fertilizer source and soil tillage on weed spectrum in durum wheat (Triticum durum Desf.). Treatments in this study were: (i) two fertilizer sources (mineral fertilizer (MIN) and municipal organic waste (MOW)), and (ii) three tillage regimes (plowing (Plo), subsoiling (Sub) and spading (SM)). A randomized complete block design with three replications was adopted. Data on weed density and biomass were collected at the wheat tillering stage. Weed density was higher in MOW than MIN (53.8 vs. 44.0 plants·m−2), especially in 2014/2015, while S was the highest among tillage regimes (58.2 plants·m−2). Annual and monocots species were always the highest in subsoiling (43.5 and 10.1 plants·m−2). The density of perennial and dicots species was higher in MOW compared with MIN plots, regardless of soil tillage management. Weed community, in terms of weed species composition, varied between the two fertilizer sources, while among soil tillage regimes, it only differed between plowing and subsoiling. Based on the analysis of weed community composition, annual dicot species were mainly associated with plowing, while monocots tended to be associated with MIN fertilizer. Spading tillage may be a useful strategy for managing weed diversity under organic fertilization, where mineral soil nitrogen availability was limited. Conversely, the spading machine produced lower grain yields than plowing with mineral fertilizer application.

Tank Mixing Saflufenacil, Glufosinate, and Indaziflam Improved Burndown and Residual Weed Control

2013 ◽  
Vol 27 (2) ◽  
pp. 422-429 ◽  
Author(s):  
Amit J. Jhala ◽  
Analiza H. M. Ramirez ◽  
Megh Singh
Keyword(s):  
Weed Control ◽  
Broad Spectrum ◽  
Field Experiments ◽  
Additive Effect ◽  
Control Efficacy ◽  
Weed Density ◽  
Florida Citrus ◽  
Density And Biomass ◽  
Grass Weed

Saflufenacil and indaziflam, POST and PRE herbicides, respectively, have been registered recently for weed control in Florida citrus. Glufosinate is under evaluation and may be registered in the future for POST weed control in citrus. Citrus growers often want to have a tank mixture of herbicides that provide broad-spectrum weed control. Saflufenacil is a broadleaf herbicide and needs to be tank mixed with other herbicide(s) to increase weed control spectrum. Information is not available on interaction of saflufenacil, glufosinate, and indaziflam applied in tank mixtures on weed control efficacy. Greenhouse and field experiments were conducted at two locations (Polk and Orange County, FL) to evaluate the efficacy and potential antagonism or synergy of saflufenacil and glufosinate applied in tank mixes, and various three-way mixes with indaziflam. The results suggested that tank mixing saflufenacil with glufosinate had no effect on grass weed control, but had additive effect on broadleaf weed control. Indaziflam tank mixed at the recommended label rate (0.073 kg ha−1) provided better residual weed control compared with the lower rate (0.05 kg ha−1). Tank mixing indaziflam with saflufenacil and glufosinate improved broadleaf and grass weed control, reduced weed density, and biomass compared with tank mixing saflufenacil and glufosinate. Tank mixing indaziflam at 0.073 kg ha−1with saflufenacil and glufosinate provided ≥ 88% control of broadleaf and grass weeds at 30 d after treatment (DAT), and it was comparable with tank mixing saflufenacil, glyphosate and pendimethalin. This treatment combination recorded the lowest weed density (≤ 7 plants m−2) and biomass (< 80 g m−2) at 60 DAT. Glyphosate applied alone was less effective than tank mixing with saflufenacil and glufosinate for broadleaf and grass weed control. This indicates additive effect of tank mixture on glyphosate efficacy. It is concluded that saflufenacil can be tank mixed with glufosinate for control of broadleaf and grass weeds; however, addition of indaziflam in tank mixture provided long-term, broad-spectrum weed control in Florida citrus compared with other treatments.

Interference of Three Annual Grasses with Grain Sorghum (Sorghum bicolor)

1990 ◽  
Vol 4 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Brenda S. Smith ◽  
Don S. Murray ◽  
J. D. Green ◽  
Wan M. Wanyahaya ◽  
David L. Weeks
Keyword(s):  
Linear Regression ◽  
Grain Yield ◽  
Field Experiments ◽  
Grain Sorghum ◽  
Grass Species ◽  
Row Spacing ◽  
Yield Data ◽  
Weed Density ◽  
Annual Grasses ◽  
Wide Row Spacing

Barnyardgrass, large crabgrass, and Texas panicum were evaluated in field experiments over 3 yr to measure their duration of interference and density on grain sorghum yield. When grain yield data were converted to a percentage of the weed-free control, linear regression predicted a 3.6% yield loss for each week of weed interference regardless of year or grass species. Grain sorghum grown in a narrow (61-cm) row spacing was affected little by full-season interference; however, in wide (91-cm) rows, interference increased as grass density increased. Data from the wide-row spacing were described by linear regression following conversion of grain yield to percentages and weed density to log10. A separate nonlinear model also was derived which could predict the effect of weed density on grain sorghum yield.

LAMB’S-QUARTERS INTERFERENCE WITH DIRECT SEEDED BROCCOLI

1990 ◽  
Vol 70 (4) ◽  
pp. 1215-1221 ◽  
Author(s):  
IRIS BITTERLICH ◽  
MAHESH K. UPADHYAYA
Keyword(s):  
Brassica Oleracea ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Total Yield ◽  
Growth And Yield ◽  
Marketable Yield ◽  
Weed Density ◽  
Weed Interference ◽  
Lamb’S Quarters ◽  
Cole Crop

Field experiments were conducted in 1987 and 1988 to study the effect of lamb’s-quarters (Chenopodium album L.) interference on broccoli (Brassica oleracea L. var. botrytis ’Emperor’) growth and yield. Broccoli growth was initially affected by weed interference at 28–36 d after seeding. Generally, the negative effect of weed interference on broccoli growth increased with increasing weed density and time after seeding. Interference by 15 lamb’s-quarters plants m−2 reduced the biomass of broccoli plants by 71–73% compared to the weed-free control at 57–58 d after seeding. Weed density-crop yield relationship curves showed that one lamb’s-quarters plant m−2 decreased total yield by 18–20% and marketable yield by 22–37%. Lamb’s-quarters reduced the total yield per plot by decreasing the average head weight of broccoli. The number of heads per plot was not affected. Weed interference also reduced the weight of heads classified as marketable (> 10 cm across). However, in 1987 more heads failed to reach a marketable size which resulted in a much smaller marketable yield than in 1988.Key words: Brassica oleracea var. botrytis, broccoli, Chenopodium album L., weed density, weed interference, cole crop

scholarly journals Metalearners for estimating heterogeneous treatment effects using machine learning

2019 ◽  
Vol 116 (10) ◽  
pp. 4156-4165 ◽  
Author(s):  
Sören R. Künzel ◽  
Jasjeet S. Sekhon ◽  
Peter J. Bickel ◽  
Bin Yu
Keyword(s):  
Machine Learning ◽  
Treatment Effects ◽  
Field Experiments ◽  
Average Treatment Effect ◽  
Regularity Conditions ◽  
Heterogeneous Treatment Effects ◽  
Lipschitz Continuous ◽  
Additive Regression ◽  
Underlying Mechanisms ◽  
And Control

There is growing interest in estimating and analyzing heterogeneous treatment effects in experimental and observational studies. We describe a number of metaalgorithms that can take advantage of any supervised learning or regression method in machine learning and statistics to estimate the conditional average treatment effect (CATE) function. Metaalgorithms build on base algorithms—such as random forests (RFs), Bayesian additive regression trees (BARTs), or neural networks—to estimate the CATE, a function that the base algorithms are not designed to estimate directly. We introduce a metaalgorithm, the X-learner, that is provably efficient when the number of units in one treatment group is much larger than in the other and can exploit structural properties of the CATE function. For example, if the CATE function is linear and the response functions in treatment and control are Lipschitz-continuous, the X-learner can still achieve the parametric rate under regularity conditions. We then introduce versions of the X-learner that use RF and BART as base learners. In extensive simulation studies, the X-learner performs favorably, although none of the metalearners is uniformly the best. In two persuasion field experiments from political science, we demonstrate how our X-learner can be used to target treatment regimes and to shed light on underlying mechanisms. A software package is provided that implements our methods.

scholarly journals Effect of Irrigation System and Soil Conditioners on Growth and Essential Oil of Rosmarinus officinalis L. Cultivated in Egypt

2020 ◽  
Author(s):  
Elsayed Omer ◽  
Saber Hendawy ◽  
Abdel Nasser ElGendy ◽  
Alberto Mannu ◽  
Giacomo L. Petretto ◽  
...  
Keyword(s):  
Essential Oil ◽  
Field Experiments ◽  
Agricultural Research ◽  
Growth Parameters ◽  
Irrigation System ◽  
Water Saving ◽  
Rosmarinus Officinalis ◽  
Research Station ◽  
Soil Conditioners ◽  
Rosmarinus Officinalis L

A relevant improvement of the cultivar conditions of Rosmarinus officinalis L. in desert areas was achieved by a specific combination between irrigation system and soil conditioner. A drastic reduction of water employment was obtained without affect the quality of the plants, determined by monitoring growth parameters and essential oil characteristics. In particular, the effect of surface and subsurface drip irrigation systems and different soil conditioners on growth parameters, yield, and essential oil constituents of rosemary plant was assessed. Field experiments at the Agricultural Research Station (Al-Adlya farm), SEKEM group Company, El-Sharkiya Governorate, Egypt, conducted over the two seasons revealed the effectiveness of the subsurface irrigation system in obtaining better performances, especially in terms of water saving. The combination of subsurface irrigation and the conditioner Hundz soil with bentonite showed the maximum mean values of growth characters compared with other soil amendments during both seasons. The possibility to employ a water-saving irrigation system as the subsurface one without any drawback in the resulting plants was also explored in terms of molecular composition. GC-MS analysis of the essential oil extracted from plants growth under different irrigation conditions revealed a comparable composition in both cases. The goodness of the most performing system was also confirmed by the comparable yield of the essential oil.

Contamination of hay and haylage with enteric bacteria and selected antibiotic resistance genes following fertilization with dairy manure or biosolids.

2022 ◽  
Author(s):  
Andrew Scott ◽  
Roger Murray ◽  
Yuan-Ching Tien ◽  
Edward Topp
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Field Experiments ◽  
Antibiotic Resistance Genes ◽  
Enteric Bacteria ◽  
Dairy Manure ◽  
Plate Count ◽  
Growing Seasons ◽  
Route Of Exposure ◽  
And Control

The present study evaluated if enteric bacteria or antibiotic resistance genes carried in fecal amendments contaminate the hay at harvest, representing a potential route of exposure to ruminants that consume the hay. In field experiments, dairy manure was applied to a hay field for three successive growing seasons, and biosolids applied to a hay field for one growing season. Various enteric bacteria in the amendments were enumerated by viable plate count, and selected gene targets were quantified by qPCR. Key findings include the following: At harvest, hay receiving dairy manure or biosolids did not carry more viable enteric bacteria than did hay from unamended control plots. Fermentation of hay did not result in a detectable increase in viable enteric bacteria. The application of dairy manure or biosolids did result in a few gene targets being more abundant on hay at the first harvest. Fermentation of hay did result in an increase in the abundance of gene targets, but this occurred both with hay from amended and control plots. Overall, application of fecal amendments will result in an increase in the abundance of some gene targets associated with antibiotic resistance on first cut hay.

Circumstantial evidence of effect of trout farming on length-weight relations of native fish species: Barbus oligolepis (Battalgil, 1941) and Squalius cii (Richardson, 1857)

2020 ◽  
Vol 9 (3) ◽  
pp. 87-90
Author(s):  
elin Ertürk Gürkan
Keyword(s):  
Fish Species ◽  
Growth Parameters ◽  
B Value ◽  
Native Fish ◽  
Growth Type ◽  
Positive Allometry ◽  
Fish Samples ◽  
Extra Food ◽  
One Year ◽  
And Control

This study was carried out to reveal how the aquaculture activities, located near the stream bed, effect the length-weight relations of native freshwater fish. Fish samples were collected on monthly for one year on the Kocabaş Stream (Çanakkale), a trout farm constructed next to stream. Fish specimens were collected from up and down sections of the trout farm and control station selected from another branch of the stream by electrofishing between August 2015-July 2016. The growth type sign; b value in length-weight relationship indicates that both species are in positive allometry at the down station and isometric growth at the upper station. Fish farm might affect the growth type of both species positively due to contribution of extra food resources originated from the farm via discharge of waste water of trout farm at the down section. However, this hypothesis should be tested by proper growth parameters of the fish species.

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