Spatial Pattern of Weeds Based on Multispecies Infestation Maps Created by Imagery

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 474-485 ◽  
Author(s):  
Louis Longchamps ◽  
Bernard Panneton ◽  
Robin Reich ◽  
Marie-Josée Simard ◽  
Gilles D. Leroux
Keyword(s):  
Spatial Distribution ◽  
Image Segmentation ◽  
Spatial Pattern ◽  
Weed Management ◽  
Herbicide Application ◽  
Weed Species ◽  
Site Specific ◽  
Weed Cover ◽  
Weed Infestation ◽  
Level Of Aggregation

Weeds are often spatially aggregated in maize fields, and the level of aggregation varies across and within fields. Several annual weed species are present in maize fields before postemergence herbicide application, and herbicides applied will control several species at a time. The goal of this study was to assess the spatial distribution of multispecies weed infestation in maize fields. Ground-based imagery was used to map weed infestations in rain-fed maize fields. Image segmentation was used to extract weed cover information from geocoded images, and an expert-based threshold of 0.102% weed cover was used to generate maps of weed presence/absence. From 19 site-years, 13 (68%) demonstrated a random spatial distribution, whereas six site-years demonstrated an aggregated spatial pattern of either monocotyledons, dicotyledons, or both groups. The results of this study indicated that monocotyledonous and dicotyledonous weed groups were not spatially segregated, but discriminating these weed groups slightly increased the chances of detecting an aggregated pattern. It was concluded that weeds were not always spatially aggregated in maize fields. These findings emphasize the need for techniques allowing the assessment of weed aggregation prior to conducting site-specific weed management.

scholarly journals Effect of site-specific weed management in winter crops on yield and weed populations

2014 ◽  
Vol 60 (No. 1) ◽  
pp. 27-35 ◽  
Author(s):  
P. Hamouz ◽  
K. Hamouzová ◽  
L. Tyšer ◽  
J. Holec
Keyword(s):  
Weed Management ◽  
Standard Treatment ◽  
Species Abundance ◽  
Herbicide Application ◽  
Weed Species ◽  
Site Specific ◽  
Weed Population Dynamics ◽  
Herbicide Treatments ◽  
Weed Infestation ◽  
Winter Crops

Site-specific weed management (SSWM) methods allow spatially variable treatment of weed populations according to actual weed abundance, thus offering the opportunity for herbicide savings. However, SSWM&rsquo;s effect on weed population dynamics is not sufficiently understood. In this study, SSWM was conducted based on various application thresholds to analyse the effects on crop yield and weed infestation in the succeeding crop. SSWM was used on a 3.07 ha experimental field in winter wheat (2011) and winter oilseed rape (2012). The whole area was split into application cells of 6 &times; 10 m and abundance of all weed species was evaluated manually in each cell. Four different herbicide treatments were tested. Standard whole-field herbicide application (blanket spraying) was treatment 1.<br /> Treatments 2, 3 and 4 comprised SSWM using different thresholds for post-emergent herbicide application. SSWM resulted in savings of post-emergent herbicides ranging from 71.9% to 100%, depending on the application threshold. Differences in winter rape yield among treatments were generally small and statistically insignificant<br /> (P = 0.989). Although some minor changes in weed abundances were observable, the experiment showed that none of the site-specific herbicide treatments caused a significant (&alpha; = 0.05) increase of weed species abundance compared to the standard treatment.

scholarly journals Impact of site-specific weed management on herbicide savings and winter wheat yield  

2013 ◽  
Vol 59 (No. 3) ◽  
pp. 101-107 ◽  
Author(s):  
P. Hamouz ◽  
K. Hamouzová ◽  
J. Holec ◽  
L. Tyšer
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Wheat Yield ◽  
The Other ◽  
Herbicide Application ◽  
Site Specific ◽  
Treatment Thresholds ◽  
Patch Spraying ◽  
Winter Wheat Yield ◽  
Weed Infestation

An aggregated distribution pattern of weed populations provides opportunity to reduce the herbicide application if site-specific weed management is adopted. This work is focused on the practical testing of site-specific weed management in a winter wheat and the optimisation of the control thresholds. Patch spraying was applied to an experimental field in Central Bohemia. Total numbers of 512 application cells were arranged into 16 blocks, which allowed the randomisation of four treatments in four replications. Treatment 1 represented blanket spraying and the other treatments differed by the herbicide application thresholds. The weed infestation was estimated immediately before the post-emergence herbicide application. Treatment maps for every weed group were created based on the weed abundance data and relevant treatment thresholds. The herbicides were applied using a sprayer equipped with boom section control. The herbicide savings were calculated for every treatment and the differences in the grain yield between the treatments were tested using the analysis of variance. The site-specific applications provided herbicide savings ranging from 15.6% to 100% according to the herbicide and application threshold used. The differences in yield between the treatments were not statistically significant (P = 0.81). Thus, the yield was not lowered by site-specific weed management.

Weed Decision Threshold as a Key Factor for Herbicide Reductions in Site-Specific Weed Management

2016 ◽  
Vol 30 (4) ◽  
pp. 888-897 ◽  
Author(s):  
Carolina San Martín ◽  
Dionisio Andújar ◽  
Judit Barroso ◽  
Cesar Fernández-Quintanilla ◽  
José Dorado
Keyword(s):  
Spatial Distribution ◽  
Weed Management ◽  
Crop Yields ◽  
Decision Threshold ◽  
Weed Species ◽  
Site Specific ◽  
Patch Spraying ◽  
Key Factor ◽  
Sampling Procedures ◽  
Herbicide Use

The objective of this research was to explore the influence that weed decision threshold (DT; expressed as plants m−2), weed spatial distribution patterns, and spatial resolution of sampling have on potential reduction in herbicide use under site-specific weed management. As a case study, a small plot located in a typical corn field in central Spain was used, constructing very precise distribution maps of the major weeds present. These initial maps were used to generate herbicide prescription maps for each weed species based on different DTs and sampling resolutions. The simulation of herbicide prescription maps consisted of on/off spraying decisions based on information from two different approaches for weed detection: ground-based vs. aerial sensors. In general, simulations based on ground sensors resulted in higher herbicide savings than those based on aerial sensors. The extent of herbicide reductions derived from patch spraying was directly related to the density and the spatial distribution of each weed species. Herbicide savings were potentially high (up to 66%) with relatively sparse patchy weed species (e.g., johnsongrass) but were only moderate (10 to 20%) with abundant and regularly distributed weed species (e.g., velvetleaf). However, DT has proven to be a key factor, with higher DTs resulting in reductions in herbicide use for all the weed species and all sampling procedures and resolutions. Moreover, increasing DT from 6 to 12 plants m−2resulted in additional herbicide savings of up to 50% in the simulations for johnsongrass and up to 28% savings in the simulations for common cocklebur. Nonetheless, since DT determines the accuracy of patch spraying, the consequences of using higher DTs could be leaving areas unsprayed, which could adversely affect crop yields and future weed infestations, including herbicide-resistant weeds. Considering that the relationship between DT and accuracy of herbicide application depends on weed spatial pattern, this work has demonstrated the possibility of using higher DT values in weeds with a clear patchy distribution compared with weeds distributed regularly.

scholarly journals Weeds and Their Effect on the Performance of Maize and Finger Millet in Mid-Hills of Nepal

2014 ◽  
Vol 2 (3) ◽  
pp. 275-278 ◽  
Author(s):  
Tika Bahadur Karki ◽  
Shrawan K. Sah ◽  
Resam B. Thapa ◽  
Andrew J. McDonald ◽  
Adam S. Davis ◽  
...  
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Finger Millet ◽  
Crop Yields ◽  
Management Strategies ◽  
Cropping System ◽  
Weed Species ◽  
Ageratum Conyzoides ◽  
Alternative Crop ◽  
Weed Infestation

Relay cropping of maize with fingermillet (maize/fingermillet) is the predominant cropping system for sustaining food security situation in the hilly regions of Nepal. In this region weed pressure severely reduces crop yields. Basic information on weed species composition, biomass production and their effect on crop yields and economics are lacking for this region. This information will be necessary to develop effective weed management strategies for the future. In light of this an empirical study was carried out in two representatives mid hill districts of Parbat and Baglung during summer season of 2010/2011 in Nepal. A total of 10 major weed species with densities of 172 in Parbat and 311 per 0.25m2 area in Baglung were observed. The highest percentage of both relative and absolute densities were recorded for Ageratum conyzoides in Parbat and Polygonum chinensis in Baglung. Weed infestation under farmers practice of crop management reduced the grain yield of maize by 1.985 Mt ha-1 (117%) in Baglung and 1.760 Mt ha-1 (108%) in Parbat. Similarly, in finger millet it was 0.489 Mt ha-1 (63%) in Baglung and 0.403 Mt ha-1 in Parbat. Similarly, the combined yield of both the crops was also significantly reduced by 79.3% and 61.7% in Baglung and Parbat respectively. Hence, weeds are directly affecting the crop performance in the region. Therefore, there is an urgent need to develop an alternative crop production system in the hills. DOI: http://dx.doi.org/10.3126/ijasbt.v2i3.10790Int J Appl Sci Biotechnol, Vol. 2(3): 275-278  

scholarly journals Spatial and Temporal Distribution of Ecballium elaterium in Almond Orchards

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 751 ◽  
Author(s):  
Lior Blank ◽  
Nitzan Birger ◽  
Hanan Eizenberg
Keyword(s):  
Spatial Pattern ◽  
Weed Management ◽  
Nearest Neighbor ◽  
Temporal Distribution ◽  
Nearest Neighbors ◽  
Chemical Application ◽  
Site Specific ◽  
Herbicide Treatments ◽  
Suitable Target ◽  
Almond Orchards

The concept of site-specific weed management is based on the assumption that weeds are aggregated in patches. In this study, we surveyed four plots in four commercial almond orchards for three years and mapped the locations of Ecballium elaterium, a troublesome weed in Israeli agriculture, specifically in almond orchards. We analyzed the spatial pattern of the plants’ locations using nearest neighbor analysis and Ripley’s L function. The number of E. elaterium plants increased by more than 70% in the four plots from 2015 to 2016. In addition, the observed mean distance between nearest neighbors increased by more than 10% from 2016 and 2017. We found in all four plots that the spatial pattern of E. elaterium was clustered and that these weed patch locations were consistent over the years although the density within the patches increased. The extent of these clusters ranged between 40 to 70 m and remained similar in size throughout the study. These features make E. elaterium a suitable target for site-specific weed management and for pre-emergence patch spraying. Knowledge of the spatial and temporal pattern of weeds could aid in understanding their ecology and could help target herbicide treatments to specific locations of the field and, thus, reducing the chemical application.

Weeds and yields of spring cereals as influenced by stubble-cultivation and reduced doses of herbicides in five long-term trials

2000 ◽  
Vol 134 (3) ◽  
pp. 237-244 ◽  
Author(s):  
U. BOSTRÖM ◽  
M. HANSSON ◽  
H. FOGELFORS
Keyword(s):  
Weed Management ◽  
Plant Density ◽  
Crop Yields ◽  
Field Trials ◽  
Herbicide Application ◽  
Weed Species ◽  
Full Dose ◽  
Spring Cereals ◽  
One Year

The influence of herbicides at reduced rates and repeated stubble-cultivation on weeds and crop yields was estimated in five field trials with spring-sown cereals situated in the south of Sweden during the autumn of 1989 until the spring of 1997. Stubble-cultivation was accomplished during 1989–1996, while herbicides were applied at 0, 1/8, 1/4 or 1/2 of full dose during 1990–1996.In the spring of 1997, i.e. after 7 years without herbicide application, seedling densities 3 weeks after weed emergence were 68–340/m2 at three sites and 535–610/m2 at two sites when averaged over tillage treatments.Averaged over herbicide doses, stubble-cultivation reduced the plant density of annual broad- leaved weeds by 6–32% at three sites and increased the density by 25% at one site. At the remaining site, the density was not significantly influenced. Stubble-cultivation reduced the populations of two perennial and seven annual weed species, while one species was stimulated and nine species showed null, or inconsistent, responses. In the spring of 1997, i.e. one year after the last herbicide application, the densities of weed seedlings in 1/8, 1/4 and 1/2-doses were 34, 46 and 56% lower, respectively, than in the untreated controls.Stubble-cultivation increased crop yields at four sites by 200 kg/ha as a mean over herbicide doses. At these four sites, averaged over 1993–1995, herbicides increased yields in plots that were not stubble-cultivated by 7, 8 and 10% in the 1/8, 1/4 and 1/2 of a full dose, respectively, relative to the untreated control. In 1996, herbicides increased yields at only two sites.It is concluded that a fruitful way for weed management with a low input of agrochemicals is to combine the use of herbicides at reduced rates with repeated stubble-cultivation.

The effects of weed density and different weed control applications on yield and yield components of chickpea cultivars

2019 ◽  
Author(s):  
Melih Yilar Omer Sozen ◽  
Ufuk Karadavut
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Yield Components ◽  
Control Method ◽  
Herbicide Application ◽  
Weed Species ◽  
Control Applications ◽  
Weed Density ◽  
Yield And Yield Components ◽  
Plot Design

This study was conducted to determine the effects of weed density and different weed control treatments on chickpea yield and yield components. The experiment was carried out in split plot design with 3 replications in experimental fields of Kirsehir Ahi Evran University during 2016 and 2017 crop seasons. Total nine treatments (no weed control, permanent weed control, one-time hoeing, two-time hoeing, three-time hoeing, herbicide application after emergence, one-time hoeing with herbicide application, two-time hoeing with herbicide application and three-time hoeing with herbicide application) were compared to know the most effective weed control method. Vaccaria pyramidata Medik., Sinapis arvensis L., Acroptilon repens L. weed species were found to be the most intense in the experimental area. All weed control applications had significant effect on chickpea yield and yield components compared to weedy plots. Three-time hoeing with herbicide application increased the yield by 361.55-478.50% compared to weedy plots. Likewise, three-time hoeing application even increased the yield by 348.50-357.09% compared to weedy plots. The results revealed that three-time hoeing with herbicide and three-time hoeing applications stood out in weed management to obtain a good yield in chickpea cultivation at Kirsehir province.

scholarly journals The impact of different weed management strategies on weed flora of wheat-based cropping systems

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247137
Author(s):  
Muhammad Shahzad ◽  
Khawar Jabran ◽  
Mubshar Hussain ◽  
Muhammad Aown Sammar Raza ◽  
Leonard Wijaya ◽  
...  
Keyword(s):  
Weed Management ◽  
Cropping Systems ◽  
Management Strategies ◽  
Cropping System ◽  
Herbicide Application ◽  
Water Extracts ◽  
The World ◽  
Weed Flora ◽  
Weed Infestation ◽  
The Impact

The world population will rise in future, which would demand more wheat production to fulfil dietary needs of wheat-dependent population of the world. Food security in wheat-dependent regions will greatly rely on wheat productivity. Weed infestation is a major constraint reducing wheat productivity globally. Nonetheless, cropping systems and weed management strategies strongly influence weed infestation in modern agriculture. Herbicides are the key weed management tool in conventional agriculture. However, frequent use of herbicides have resulted in the evolution of herbicide-resistance weeds, which made weed management a challenging task. Sustainable and eco-friendly weed management strategies shift weed-crop competition in the favour of crop plants. Limited studies have evaluated the interactive effect of cropping systems and weed management strategies on weed flora of wheat-based cropping systems (WBCSs). This two-year study evaluated the impact of different weed management strategies (WMSs) on weed flora of WBCSs, i.e., fallow-wheat (FW), rice-wheat (RW), cotton-wheat (CW), mungbean-wheat (MW) and sorghum-wheat (SW). The WMSs included in the study were, false seedbed, allelopathic water extracts and herbicide application, while weed-free and weedy-check were maintained as control treatments. Data relating to diversity and density of individual and total broadleaved and narrow-leaved weeds were recorded. The WBCSs, WMSs and their interaction significantly altered diversity and density of individual, total, broadleaved and narrow-leaved weeds. Weed-free and weedy-check treatments recorded the lowest and the highest values of diversity and density of individual, total, broadleaved and narrow-leaved weeds. Herbicide application effectively reduced density and diversity of weeds. Allelopathic water extracts and false seedbed proved less effective than herbicides. On the other hand, SW cropping system not only reduced weed density but also limited the weed flora. It is concluded that false seedbed and SW cropping system can be efficiently used to manage weeds in WBCSs. However, long-term studies are needed to infer the impact of SW cropping system and false seedbed on soil properties, soil microbes and productivity of wheat crop.

Influence of application timing and herbicide rate on the efficacy of tolpyralate plus atrazine

2019 ◽  
Vol 33 (03) ◽  
pp. 448-458 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Integrated Weed Management ◽  
Herbicide Application ◽  
Weed Species ◽  
Common Ragweed ◽  
Application Timing ◽  
Common Lambsquarters ◽  
Green Foxtail ◽  
Equivalent Control

AbstractEffective POST herbicides and herbicide mixtures are key components of integrated weed management in corn; however, herbicides vary in their efficacy based on application timing. Six field experiments were conducted over 2 yr (2017–2018) in southwestern Ontario, Canada, to determine the effects of herbicide application timing and rate on the efficacy of tolpyralate, a new 4-hydroxyphenyl pyruvate dioxygenase inhibitor. Tolpyralate at 15, 30, or 40 g ai ha−1 in combination with atrazine at 500 or 1,000 g ai ha−1 was applied PRE, early POST, mid-POST, or late POST. Tolpyralate + atrazine at rates ≥30 + 1,000 g ha−1 provided equivalent control of common lambsquarters and Powell amaranth applied PRE or POST, whereas no rate applied PRE controlled common ragweed, velvetleaf, barnyardgrass, or green foxtail. Common ragweed, common lambsquarters, velvetleaf, and Powell amaranth were controlled equally regardless of POST timing. In contrast, control of barnyardgrass and green foxtail declined when herbicide application was delayed to the late-POST timing, irrespective of herbicide rate. Similarly, corn grain yield declined within each tolpyralate + atrazine rate when herbicide applications were delayed to late-POST timing. Overall, the results of this study indicate that several monocot and dicot weed species can be controlled with tolpyralate + atrazine with an early to mid-POST herbicide application timing, before weeds reach 30 cm in height, and Powell amaranth and common lambsquarters can also be controlled PRE. Additionally, this study provides further evidence highlighting the importance of effective, early-season weed control in corn.

Predicted Corn Yield Loss Due to Weed Competition Prior to Postemergence Herbicide Application on Wisconsin Farms

2013 ◽  
Vol 27 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Nathanael D. Fickett ◽  
Chris M. Boerboom ◽  
David E. Stoltenberg
Keyword(s):  
Weed Management ◽  
Yield Loss ◽  
Economic Loss ◽  
The United States ◽  
Yield Potential ◽  
Weed Competition ◽  
Corn Yield ◽  
Herbicide Application ◽  
Weed Species ◽  
Early Season

Approximately 50% of the genetically modified herbicide-resistant corn hectares in the United States are treated only with POST-applied herbicides for weed management. Although a high degree of efficacy can be obtained with POST-applied herbicides, delayed timing of application may result in substantial corn yield loss. Our goal was to characterize on-farm corn–weed communities prior to POST herbicide application and estimate potential corn-yield loss associated with early-season corn–weed competition. In 2008 and 2009, field surveys were conducted across 95 site-years in southern Wisconsin and recorded weed species, density, and height in addition to crop height, growth stage, and row spacing. WeedSOFT® was used to predict corn yield loss. Common lambsquarters, velvetleaf, dandelion, common ragweed, andAmaranthusspecies were the five most abundant broadleaf weed species across site-years, present in 92, 86, 59, 45, and 44% of all fields, respectively, at mean densities of 19, 3, 3, 4, and 3 plants m−2, respectively. Mean plant heights among these species were 17 cm or less. Grass and sedge species occurred in 96% of fields at a mean density of 25 plants m−2and height of 7 cm. The mean and median of total weed density across site-years were 96 and 52 plants m−2, with heights of 14 and 13 cm, respectively. Mean predicted corn yield loss was 4.5% with a mean economic loss of $62 ha−1. However, predicted yield loss was greater than 5% on one-third of the site-years, with a maximum of 26%. These results indicate that delayed application of POST herbicides has led to corn yield loss due to early-season weed-crop competition on a substantial number of fields across southern Wisconsin, and suggest that management tactics need to be improved to protect corn yield potential fully.

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