scholarly journals Spatial and Temporal Stability of Weed Patches in Cereal Fields under Direct Drilling and Harrow Tillage

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 452 ◽  
Author(s):  
Jordi Izquierdo ◽  
Alice E. Milne ◽  
Jordi Recasens ◽  
Aritz Royo-Esnal ◽  
Joel Torra ◽  
...  
Keyword(s):  
Temporal Stability ◽  
Soil Management ◽  
Conservation Agriculture ◽  
Weed Species ◽  
Site Specific ◽  
Bromus Diandrus ◽  
North Eastern ◽  
Weed Cover ◽  
Direct Drilling ◽  
Cereal Fields

The adoption of conservation agriculture (CA) techniques by farmers is changing the dynamics of weed communities in cereal fields and so potentially their spatial distribution. These changes can challenge the use of site-specific weed control, which is based on the accurate location of weed patches for spraying. We studied the effect of two types of CA (direct drilling and harrow-tilled to 20 cm) on weed patches in a three-year survey in four direct-drilled and three harrow-tilled commercial fields in Catalonia (North-eastern Spain). The area of the ground covered by weeds (hereafter called “weed cover”) was estimated at 96 to 122 points measured in each year in each field, in 50 cm × 50 cm quadrats placed in a 10 m × 10 m grid in spring. Bromus diandrus, Lolium rigidum, and Papaver rhoeas were the main weed species. The weed cover and degree of aggregation for all species varied both between and within fields, regardless of the kind of tillage. Under both forms of soil management all three were aggregated in elongated patterns in the direction of traffic. Bromus was generally more aggregated than Lolium, and both were more aggregated than Papaver. Patches were stable over time for only two harrow-tilled fields with Lolium and one direct-drilled field with Bromus, but not in the other fields. Spatial stability of the weeds was more pronounced in the direction of traffic. Herbicide applications, crop rotation, and traffic seem to affect weed populations strongly within fields, regardless of the soil management. We conclude that site-specific herbicides can be applied to control these species because they are aggregated, although the patches would have to be identified afresh in each season.

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 Effects of Some Cover Crops on Light Extinction and Weed Coverage in Sunflower Field

2014 ◽  
Vol 47 (2) ◽  
pp. 29-40 ◽  
Author(s):  
S. Hassannejad ◽  
A.R. Mobli
Keyword(s):  
Extinction Coefficient ◽  
Cover Crops ◽  
Cover Crop ◽  
Agricultural Research ◽  
Block Design ◽  
Light Extinction ◽  
Research Station ◽  
Hairy Vetch ◽  
Weed Species ◽  
Weed Cover

Abstract In order to evaluate the effects of some cover crops on extinction coefficient and weed cover percentage in sunflower, a field experiment was conducted based on a randomized complete block design with nine treatments and three replicates at the Agricultural Research Station, Tabriz University of Iran, during growing season 2012-2013. Treatments were triticale, hairy vetch, rapeseed, triticale + hairy vetch, triticale + rapeseed, hairy vetch + rapeseed, application of trifluralin herbicide, and controls (weed infested and weed free without planting cover crop). Result indicated than once established, living mulches can rapidly occupy the open space between the rows of the main crop and use the light that would otherwise be available to weeds. In the all cover crops treatments, the light extinction coefficient was increased and weed cover percentage was reduced. Highest reduction in total weed species was observed in hairy vetch + rapeseed and triticale + rapeseed cover crop 61.92% and 61.43 %, respectively, compared to weed infested, so this treatment was better than trifluralin application. It concluded that cover crops could be considered as integrated strategies for weed sustainable management.

scholarly journals Seed germination ecology of Conyza stricta Willd. and implications for management

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244059
Author(s):  
Safdar Ali ◽  
Fakhar Din Khan ◽  
Rehmat Ullah ◽  
Rahmat Ullah Shah ◽  
Saud Alamri ◽  
...  
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Cropping Systems ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Conservation Agriculture ◽  
Weed Species ◽  
Seed Burial ◽  
Germination Ecology ◽  
Tillage Practices

Numerous cropping systems of the world are experiencing the emergence of new weed species in response to conservation agriculture. Conyza stricta Willd. is being a newly emerging weed of barley-based cropping systems in response to conservational tillage practices. Seed germination ecology of four populations (irrigated, rainfed, abandoned and ruderal habitats) was studied in laboratory and greenhouse experiments. The presence/absence of seed dormancy was inferred first, which indicated seeds were non-dormant. Seed germination was then recorded under various photoperiods, constant and alternating day/night temperatures, and pH, salinity and osmotic potential levels. Seedling emergence was observed from various seed burial depths. Seeds of all populations proved photoblastic and required 12-hour light/dark period for germination. Seeds of all populations germinated under 5–30°C constant temperature; however, peak germination was recorded under 17.22–18.11°C. Nonetheless, the highest germination was noted under 20/15°C alternating day/night temperature. Ruderal and irrigated populations better tolerated salinity and germinated under 0–500 mM salinity. Similarly, rainfed population proved more tolerant to osmotic potential than other populations. Seeds of all populations required neutral pH for the highest germination, whereas decline was noted in germination under basic and alkaline pH. Seedling emergence was retarded for seeds buried >2 cm depth and no emergence was recorded from >4 cm depth. These results add valuable information towards our understanding of seed germination ecology of C. stricta. Seed germination ability of different populations under diverse environmental conditions suspects that the species can present severe challenges in future if not managed. Deep seed burial along with effective management of the emerging seedlings seems a pragmatic option to manage the species in cultivated fields. However, immediate management strategies are needed for rest of the habitats.

Conservation Agriculture in the North Eastern Himalayan Eco-Region of India

2021 ◽  
pp. 223-237
Author(s):  
G. S. Yadav ◽  
Subhash Babu ◽  
Jayanta Layek ◽  
R. Singh ◽  
Ripan Das ◽  
...  
Keyword(s):  
Conservation Agriculture ◽  
The North ◽  
North Eastern

A Method for Assessing Herbicide Performance in Small Plot Experiments

Weed Science ◽  
1977 ◽  
Vol 25 (5) ◽  
pp. 386-389 ◽  
Author(s):  
A.S. Hamill ◽  
P.B. Marriage ◽  
G. Friesen
Keyword(s):  
Individual Species ◽  
Weed Species ◽  
Rating Systems ◽  
Small Areas ◽  
Retrieval Systems ◽  
Weed Cover ◽  
Weed Plants ◽  
Plot Area ◽  
Small Plot ◽  
Grass Weed

A method is described that provides an accurate and useful assessment of herbicide performance in small plot experiments. This method is an extension of previous rating systems and provides an assessment of the control of individual species through an estimation of the percentage that each contributes to the total broadleaf or grass weed cover on the whole plot area. It permits data collection on individual weed species but is less time-consuming than counting individual plants and it takes into account the size and vigor of individual weed plants as well as their relative abundance. Further, the system allows tabulation of data from across the entire plot rather than from small areas within the plot. The data can be readily entered into various computerized retrieval systems.

Weed infestation during the transition phase from conventional to conservation agriculture

2020 ◽  
Author(s):  
Felice Sartori ◽  
Donato Loddo ◽  
Ilaria Piccoli ◽  
Antonio Berti
Keyword(s):  
Species Richness ◽  
Seed Bank ◽  
Conservation Agriculture ◽  
Soil Disturbance ◽  
Transition Phase ◽  
Effective Control ◽  
Silty Clay ◽  
Weed Species ◽  
Number Of Species ◽  
Weed Species Richness

<p>Despite conservation agriculture and, overall, the reduction of soil disturbance are considered soil improving cropping systems, these practices could conflict with weed control. Indeed, reduced tillage is usually linked to increased weed species richness and abundance and, thus, it could increase the dependence on chemical treatments. Weed management is one of the reasons behind the distrust of European farmers in the conservation agriculture, that is still not widespread, despites European subsidies. In fact, conservation agriculture is implemented only in the 2.8% of European cropland.</p><p>The aim of this study is to evaluate the effect of different tillage intensities on spring-summer weeds richness and abundance in a maize monoculture, during the transition phase from conventional to conservation agriculture.</p><p>The weed survey was conducted in June 2019 on an experiment comparing three levels of tillage management: conventional agriculture (CT), which represents the most common choice in Veneto region, involving deep ploughing and harrowing in spring; minimum tillage (MT), consisting only in harrowing at 20 cm; and no tillage (NT), namely sod seeding. The experiment started in 2018, at Padova University experimental farm, in a sub-humid area, with a silty clay loam soil. The survey was conducted with a set of random throws of a 30×30 cm square frame in each plot (ca. 3300 m<sup>2</sup>).  Weed plants found within the frame were classified and counted. Subsequently, data analysis assessed which botanical families were promoted by each treatment.</p><p>The NT resulted the treatment with the highest weed density (915 plant/m<sup>2</sup>): 6% higher than MT (823 plant/m<sup>2</sup>) and four-fold more than CT (209 plant/m<sup>2</sup>). The latter showed to be the treatment with higher diversity, according to both Shannon and Simpson indices. The survey evidenced higher weed species richness in MT, where both annual and perennial species were identified, while the lowest number of species were detected in NT. Plantago major and Chenopodium album were the species with the highest density in CT (>32 plant/m<sup>2</sup>) while they are negligible in NT and MT (7 plant/m<sup>2</sup>, on average). Digitaria sanguinalis was instead the dominant species in MT and NT (>600 plant/m<sup>2</sup>) while a lower density was observed in CT (11 plant/m<sup>2</sup>). Low levels of Asteraceae weeds were measured in all treatments. These results shows that the actual flora rapidly changes depending on tillage intensity, with an increase of both dominance and number of species in MT. Differently, only a limited number of adapted species germinated in NT, despite higher infestations if compared with the other treatments.</p><p>It should be expected that other species more adapted to conservation agriculture (namely Asteraceae), still marginally present in the seed bank, will spread in the next years. This stresses the importance of a continuous monitoring and effective control of weeds to avoid uncontrolled evolutions of the weed flora and increase of seed bank in the transition phase from conventional to conservation agriculture.</p>

Interaction of Rice Residue and PRE Herbicides on Emergence and Biomass of Four Weed Species

2012 ◽  
Vol 26 (4) ◽  
pp. 627-632 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Seth B. Abugho
Keyword(s):  
Weed Control ◽  
Seedling Emergence ◽  
Conservation Agriculture ◽  
Bare Soil ◽  
Weed Species ◽  
Herbicide Treatments ◽  
Agriculture Systems

Studies were conducted in a screenhouse to determine the interaction of rice residue as mulch (0, 3, and 6 t ha−1) and herbicides (nontreated, oxadiazon at 0.5 and 1.0 kg ai ha−1, and pendimethalin at 1.0 and 2.0 kg ai ha−1) on seedling emergence and biomass of barnyardgrass, crowfootgrass, junglerice, and rice flatsedge. Regardless of the residue amount, crowfootgrass and junglerice were effectively controlled by all herbicide treatments. No seedlings of these weed species escaped the herbicides when applied in the presence of residue cover. There was no survival of barnyardgrass seedlings when both herbicides were applied on bare soil (without residue cover); however, some seedlings survived oxadiazon and pendimethalin when applied in the presence of residue cover. For rice flatsedge, the herbicide applications in the presence of residue cover resulted in lower weed control than in the absence of residue. These results suggest that some weed species can escape the application of PRE herbicides in conservation agriculture systems in which residue can bind soil-applied herbicides and result in lower efficacy.

Effect of Herbicides on Field Violet (Viola arvensis) in Direct-Seeded Spring Wheat

2005 ◽  
Vol 19 (2) ◽  
pp. 359-371 ◽  
Author(s):  
Rory F. Degenhardt ◽  
Dean Spaner ◽  
K. Neil Harker ◽  
William R. Mcgregor ◽  
Linda M. Hall
Keyword(s):  
Spring Wheat ◽  
Crop Production ◽  
Field Experiments ◽  
Plant Density ◽  
Dry Weight ◽  
Effective Control ◽  
Weed Species ◽  
Weed Growth ◽  
Direct Seeded ◽  
Cereal Fields

The agrestal field violet, a pervasive weed in Europe, has been identified in reduced-tillage cereal fields in Alberta. The efficacy of herbicides in direct-seeded spring wheat was assessed on natural field violet infestations in Alberta in 2002 and 2003. Only fluroxypyr + 2,4-D, applied postemergence, provided control of field violet in 2002 when rainfall was limiting. Over both years, this herbicide combination reduced biomass by 59 to 69% and plant density by 83 to 91%, relative to nontreated plots. The herbicides metsulfuron, sulfosulfuron, and thifensulfuron + tribenuron only suppressed weed growth under drought conditions in 2002 but controlled the weed in 2003 when rainfall was greater, reducing plant density by 82 to 92% and rendering remaining plants sterile. Suppression was also observed with MCPA + mecoprop + dicamba in 2002 and 2003 and with metribuzin only in 2003. Effective control of field violet was conferred by a pre–crop emergence application of glyphosate at 445 g ae/ha in 2003, the only year that this treatment was evaluated. Activity of herbicides on three- to four-leaf seedlings was also evaluated in a greenhouse dose– response assay. All herbicides had greater efficacy in the greenhouse, and those that provided control in situ reduced field violet dry weight by 85% at less than the recommended rate used in field experiments. Management of field violet is possible with herbicides registered for use on spring wheat in Alberta. However, the weed does not appear to cause significant crop production losses; hence, herbicide selection should be based on knowledge of all weed species present within the field.

scholarly journals New challenges in soil management

2018 ◽  
pp. 91-92
Author(s):  
Márta Birkás
Keyword(s):  
Sustainable Agriculture ◽  
Soil Conservation ◽  
Crop Production ◽  
Production Systems ◽  
Soil Management ◽  
Soil Protection ◽  
Site Specific ◽  
The Future ◽  
Induced Stresses ◽  
New Challenges

Soil management represents two important tasks that are harmonization of the soil protection with demands of the crop to be grown on the given land under prevailing farming condition. Further goals are to preserve and/or develop the soil physical, biological and chemical condition and to avoid the unfavourable changes of the soil biological activity and the soil structure. Classical authors emphasised the importance of creating proper seedbed for plants. In the physical approach, tillage was believed to play an important role in controlling soil processes. Consequently, the period of several centuries dominated by this approach is referred to as the era of crop-oriented tillage (Birkás et al., 2017). The overestimation of the importance of crop requirements resulted in damaging the soils, which inevitably led to turn to the soil-focused tillage. Since the first years of climate change, as the new trends have raised concern, tillage must be turned into a climate-focused effort with the aim of reducing climate-induced stresses through improving soil quality. The development of soil management has always been determined by the economical background. At the same time, deteriorating site conditions have contributed to the conception of new tillage trends by forcing producers to find new solutions (e.g. dry farming theory in the past or adaptable tillage theory nowadays). Győrffy (2009) recited the most important keywords were listed in 2001 and that seemed to be important in the future of crop production. These keywords (endeavours) were as follows: − Biofarming, organic farming, alternative farming, biodynamic farming, low input sustainable agriculture; − Mid-tech farming, sustainable agriculture, soil conservation farming, no till farming, environmentally sound, environmentally friendly, diversity farming; − Crop production system, integrated pest management, integrated farming, high-tech farming; − Site specific production, site-specific technology, spatial variable technology, satellite farming; − Precision farming. Győrffy’s prognosis proved to be realistic and the efforts mentioned above have mostly been implemented. New challenges have also appeared in soil management in relation to the last decades. The most important endeavours for the future are: 1) Preserving climate-induced stresses endangering soils. 2) Turn to use climate mitigation soil tillage and crop production systems. 3) Applying soil management methods are adaptable to the different soil moisture content (over dried or wet may be quite common). 4) Use effectual water conservation tillage. 5) Use soil condition specific tillage depth and method. 6) Adapting the water and soil conservation methods in irrigation. 7) Preserving and improving soil organic matter content by tillage and crop production systems. 8) Considering that stubble residues are matter for soil protection, humus source and earthworm’ feed. 9) Site-specific adoption of green manure and cover crops. 10) Applying site-adopted (precision) fertilization and crop protection. Considering the development in agriculture, new endeavours will occur before long.

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