scholarly journals Influence of edaphoclimatic conditions on stem production and stem morphological characteristics of 10 European hemp (Cannabis sativa L.) varieties

2020 ◽  
Vol 115 (2) ◽  
pp. 399
Author(s):  
Marko FLAJŠMAN ◽  
Darja KOCJAN AČKO
Keyword(s):  
Correlation Analysis ◽  
Plant Growth ◽  
Weed Management ◽  
Cannabis Sativa ◽  
Morphological Characteristics ◽  
Weather Conditions ◽  
Row Spacing ◽  
Weed Biomass ◽  
Viable Seeds ◽  
Stem Production

<p> </p><p>Six dioecious (Antal, KC Dóra, Kompolti hibrid TC, Monoica, Tiborszallasi and Tisza) and four monoecious (Fedora 17, Futura 75, Santhica 27 and USO 31) European hemp varieties were sown at a density of 300 viable seeds per m<sup>2</sup> and a row spacing of 12.5 cm in a three-year field trial (2017-2019) to evaluate the yield of the stems (fresh and dry) and some other biometric characteristics of the stems. No pesticides were used during plant growth to suppress weeds, diseases and pests. The highest yield of fresh and dry stems was achieved by the variety Antal with 12.3 t ha<sup>-1</sup> and 5.3 t ha<sup>-1</sup>, respectively, followed by the varieties Futura 75 and Tiborszallasi. The lowest yields of fresh and dry stems were recorded for the monecious variety USO 31 (6.0 and 2.6 t ha<sup>-1</sup>). In general, dioecious varieties had higher and thicker stems than monoecious varieties. The year of production had a highly significant impact on all variables, in particular on the proportion of weed biomass, which was the highest in 2019 (77.2 %), when weather conditions were most unfavourable for hemp cultivation. The correlation analysis between fresh/dry stem yields and weed biomass was highly negative (-0.85 and -0.83) and strongly statistically significant (<em>p </em>&lt; 0.001), indicating the issue related to weed management.</p><p><span style="font-family: Times New Roman;"><br /></span></p>

Effect of cultivar, row spacing, and weed management on weed biomass, potato yield, and net crop value

2001 ◽  
Vol 78 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Shawn P. Conley ◽  
Larry K. Binning ◽  
Timothy R. Connell
Keyword(s):  
Weed Management ◽  
Potato Yield ◽  
Row Spacing ◽  
Weed Biomass

Weed Management in a Legume-Cereal Cover Crop with the Rotary Hoe

2006 ◽  
Vol 20 (3) ◽  
pp. 733-737 ◽  
Author(s):  
Nathan S. Boyd ◽  
Eric B. Brennan
Keyword(s):  
Weed Management ◽  
Cover Crop ◽  
Weather Conditions ◽  
Weed Species ◽  
Common Vetch ◽  
Weed Biomass ◽  
Weed Density ◽  
Crop Density ◽  
Before And After ◽  
Density And Biomass

Substantial weed growth often occurs in legume-cereal cover-crop mixes commonly grown on organic vegetable farms. A 2-yr study at the USDA-ARS in Salinas, CA, was conducted to test the effect of zero, one, and two passes with a rotary hoe on weed control in a mixed cover crop of 10% rye, 15% common vetch, 15% purple vetch, 25% peas, and 35% bell bean. Rotary hoeing occurred 14–15 days after planting (DAP) in the one-pass treatment, and 14 and 28 DAP in the two-pass treatment. Rotary hoeing did not affect total cover-crop density or biomass in either year, but reduced rye density and biomass in year 2. One pass reduced total weed density by 69% in year 1 and 49% in year 2. A second pass did not affect weed density in year 1 but reduced weed density an additional 33% in year 2. One pass decreased weed biomass in year 1, whereas two passes were required to reduce weed biomass in year 2. Rotary hoeing reduced seed shed by chickweed and shepherd's-purse seeds, the two predominant weed species, by 80 to 95% in both years. Rotary hoe efficacy depended on weather conditions directly before and after cultivation. The decision to repeat rotary hoeing should be based upon field scouting and weather conditions following the initial pass with the rotary hoe.

scholarly journals Cultural Practices and Mechanical Weed Control for the Management of a Low-Diversity Weed Community in Spinach

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 616
Author(s):  
Ioannis Gazoulis ◽  
Panagiotis Kanatas ◽  
Nikolaos Antonopoulos
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Cultural Practices ◽  
Spinacia Oleracea ◽  
Row Spacing ◽  
Weed Biomass ◽  
Weed Communities ◽  
Spinacia Oleracea L ◽  
Low Diversity ◽  
Mechanical Weed Control

Low-diversity weed communities are dominated by few species that are highly competitive to crops. The management of such weed communities should rely upon sustainable cultural and non-chemical practices, especially in crops such as spinach (Spinacia oleracea L.), where very few herbicides are available. A two-year field trial (2020 and 2021) was conducted to evaluate different fertilization practices (broadcast and banded), intra-row spacings (15 cm, 11 cm, 7 cm), and mechanical weed control treatments (untreated, one treatment, two treatments) for the management of a low-diversity weed community in spinach. Weed competition severely affected spinach commercial biomass (R2 = 0.845). Compared to broadcast fertilization, banded fertilization reduced weed biomass and improved spinach yield and nitrogen use efficiency. Narrow intra-row spacing (7-cm) reduced weed biomass by 28 and 45% compared to intra-row spacings of 11-cm and 15-cm, respectively. Two mechanical weed control treatments resulted in 49% lower weed biomass compared to a single treatment. Commercial biomass increased with decreasing intra-row spacing (R2 = 0.881) and increasing the number of mechanical treatments (R2 = 0.911). More cultural and non-chemical practices should be evaluated for weed management in spinach, especially at sites infested with low-diversity weed communities.

scholarly journals Spring-planted cover crops for weed control in soybean

2021 ◽  
pp. 1-8
Author(s):  
Katja Koehler-Cole ◽  
Christopher A. Proctor ◽  
Roger W. Elmore ◽  
David A. Wedin
Keyword(s):  
Weed Control ◽  
Biomass Production ◽  
Cover Crops ◽  
Weed Management ◽  
Block Design ◽  
Weed Suppression ◽  
Crop Species ◽  
Cold Temperatures ◽  
Weed Biomass ◽  
Small Grains

Abstract Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%. Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.

Can hemp hurd or paper mulch and biochar application improve weed management in matted-row strawberry production systems?

2021 ◽  
pp. 1-11
Author(s):  
Greta G. Gramig ◽  
Samantha K. Hogstad ◽  
Patrick M. Carr
Keyword(s):  
Weed Management ◽  
Production Systems ◽  
Weed Suppression ◽  
Plastic Mulch ◽  
Yield Data ◽  
Weed Biomass ◽  
Soil Temperatures ◽  
The Impact ◽  
Hemp Hurd ◽  
Amended Soil

Abstract During 2015 and 2016, studies were conducted at Absaraka and Dickinson, North Dakota to evaluate the impacts of hemp (applied at 1156 m3 ha−1) and commercial paper mulch, as well as soil-applied biochar (applied at 11.25 m3 ha−1), on weed suppression and strawberry growth during the establishment year, and on weed suppression and strawberry yield during the production year, in a matted row production (MRP) system. During 2015, biochar influenced dry weed biomass only within the hemp mulch, with slightly more weed biomass associated with biochar application compared to zero biochar (3.1 vs 0.4 g m−2), suggesting that biochar may have increased weed germination and/or emergence from beneath hemp mulch. Biochar application also slightly increased soil pH, from 6.9 in non-amended soil to 7.0 in amended soil. Strawberry runner number during 2015 was greater in association with hemp or paper mulch compared to zero mulch (4.5 and 4.9 vs 2.4 runners plant −1, respectively). This result mirrored a similar differential in per berry mass across sites (7.6 and 7.4 vs 6.2 g berry −1 for hemp mulch, paper mulch and zero mulch, respectively). These results may be related to hemp and paper mulch reducing maximum soil temperatures during summer 2015. During the establishment year, both hemp and paper mulch suppressed weeds well compared to zero mulch, although at Absaraka hemp mulch provided slightly better weed suppression than paper mulch. During the production year, both mulches continued to suppress weeds compared to zero mulch at Dickinson. However, at Absaraka, only hemp mulch provided weed suppression compared to zero mulch, possibly because of faster paper degradation caused by greater numbers of large precipitation events and greater relative humidity at Absaraka compared to Dickinson. Weeds were removed from plots during 2015 to allow separation of weed suppression from other possible mulch impacts; therefore, yield data do not reveal striking differences among mulch treatments. Because previous research has demonstrated the impact of weed management during the establishment of strawberries in a matted row system, we concluded that hemp mulch may provide more durable weed suppression compared to paper mulch, which would increase strawberry yield protection in an MRP system. Material cost may be an issue for implementing hemp mulch, as hemp hurd cost was 25 times paper mulch at the application rates used in this study. However, hemp mulch could still be a beneficial option, especially for organic strawberry growers desiring a renewable and environmentally sound replacement for plastic mulch who are able to find affordable local sources of this material.

scholarly journals Grain yield and competitive ability against weeds in modern and heritage common wheat cultivars are differently influenced by sowing density

2017 ◽  
Vol 11 ◽  
Author(s):  
Mariateresa Lazzaro ◽  
Ambrogio Costanzo ◽  
Dalia Hosam Farag ◽  
Paolo Bàrberi
Keyword(s):  
Grain Yield ◽  
Common Wheat ◽  
Weed Suppression ◽  
Strong Impact ◽  
Wheat Cultivars ◽  
Modern Cultivar ◽  
Weed Biomass ◽  
Growing Seasons ◽  
Viable Seeds ◽  
Crop Stand

Sowing density can have a strong impact on crop stand development during wheat growing cycle. In organic and low-input agriculture, and therefore with minimum or nil use of chemical herbicides, increased sowing density is expected to affect not only grain yield but also weed suppression. In this study we tested, under Mediterranean conditions, six common wheat cultivars (three modern and three heritage) and two three-component mixtures (arranged by combining the three modern or the three heritage cultivars). The different crop stands were tested at sowing densities of 250 (low) and 400 (high, similar to standard sowing density used by local farmers) viable seeds m-2 for two growing seasons. We did not detect a significant effect of crop stand diversity (single cultivars vs mixtures) on grain yield and weed suppression. Differences were ascribed to type of cultivars used (heritage vs modern). Compared to high sowing density, in modern cultivars grain yield did not decrease significantly with low sowing density whereas in heritage cultivars it increased by 15.6%, possibly also because of 21.5% lower plant lodging. Weed biomass increased with low sowing density both in heritage and modern cultivar crop stand types. However, heritage crop stands had, on average, a lower weed biomass (56%) than modern crop stands. Moreover, weed biomass in heritage crop stands at low density (6.82 ± 1.50 g m-2) was lower than that of modern cultivars at the same sowing density (15.54 ± 3.35 g m-2), confirming the higher suppressive potential of the former. We can conclude that lower sowing density can be advisable when using heritage crop stands as it keeps productivity while decreasing plant lodging and maintaining weeds under control.

scholarly journals Hormesis with glyphosate depends on coffee growth stage

2013 ◽  
Vol 85 (2) ◽  
pp. 813-822 ◽  
Author(s):  
LEONARDO B. DE CARVALHO ◽  
PEDRO L.C.A. ALVES ◽  
STEPHEN O. DUKE
Keyword(s):  
Plant Growth ◽  
Weed Management ◽  
Growth Stage ◽  
Growth Stages ◽  
Coffee Plant ◽  
Herbicide Application ◽  
Coffee Plantations ◽  
Plant Growth Stages ◽  
Coffee Plants ◽  
Almost All

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants was reduced at higher glyphosate doses, low doses caused no effects on growth characteristics of young plants and stimulated growth of older plants. Therefore, hormesis with glyphosate is dependent on coffee plant growth stage at the time of herbicide application.

Urban Finescale Forecasting Reveals Weather Conditions with Unprecedented Detail

2017 ◽  
Vol 98 (12) ◽  
pp. 2675-2688 ◽  
Author(s):  
R. J. Ronda ◽  
G. J. Steeneveld ◽  
B. G. Heusinkveld ◽  
J. J. Attema ◽  
A. A. M. Holtslag
Keyword(s):  
Local Governments ◽  
Weather Forecasting ◽  
Weather Prediction ◽  
Morphological Characteristics ◽  
Weather Conditions ◽  
Human Thermal Comfort ◽  
Forecasting System ◽  
The Impact ◽  
Urban Weather ◽  
Neighborhood Level

Abstract Urban landscapes impact the lives of urban dwellers by influencing local weather conditions. However, weather forecasting down to the street and neighborhood scale has been beyond the capabilities of numerical weather prediction (NWP) despite the fact that observational systems are now able to monitor urban climate at these scales. In this study, weather forecasts at intra-urban scales were achieved by exploiting recent advances in topographic element mapping and aerial photography as well as looking at detailed mappings of soil characteristics and urban morphological properties, which were subsequently incorporated into a specifically adapted Weather Research and Forecasting (WRF) Model. The urban weather forecasting system (UFS) was applied to the Amsterdam, Netherlands, metropolitan area during the summer of 2015, where it produced forecasts for the city down to the neighborhood level (a few hundred meters). Comparing these forecasts to the dense network of urban weather station observations within the Amsterdam metropolitan region showed that the forecasting system successfully determined the impact of urban morphological characteristics and urban spatial structure on local temperatures, including the cooling effect of large water bodies on local urban temperatures. The forecasting system has important practical applications for end users such as public health agencies, local governments, and energy companies. It appears that the forecasting system enables forecasts of events on a neighborhood level where human thermal comfort indices exceeded risk thresholds during warm weather episodes. These results prove that worldwide urban weather forecasting is within reach of NWP, provided that appropriate data and computing resources become available to ensure timely and efficient forecasts.

scholarly journals Trinexapac-Ethyl and Sulfometuron-Methyl Selectivity to Young Eucalyptus Plants

2015 ◽  
Vol 33 (2) ◽  
pp. 259-266 ◽  
Author(s):  
N.M. Correia ◽  
G.B. Villela
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Weather Conditions ◽  
Sulfometuron Methyl ◽  
Crown Diameter ◽  
Apical Bud ◽  
Assessment Period ◽  
Commercial Yield ◽  
Higher Doses

Trinexapac-ethyl and sulfometuron-methyl are the most widely used ripeners in sugarcane. The application is performed by airborne spraying. Thus, if weather conditions are unfavorable, spray drift to neighboring areas may occur. The objective of this study was to assess the selectivity of the plant growth regulators trinexapac-ethyl and sulfometuron-methyl, used as sugarcane ripeners, to eucalyptus (Eucalyptus urograndis) young plants. The experiment was installed in an eucalyptus commercial yield area, in the municipality of Tambaú, state of São Paulo, Brazil, and arranged in a 2 x 8 factorial design in randomized blocks with four replications. The treatments studied were trinexapac-ethyl and sulfometuron-methyl, sprayed in eight doses, 0; 1.0; 2.5; 5.0; 10; 25; 50 and 100% of the dose used in sugarcane as ripeners (200 g ha-1 of trinexapac-ethyl and 15 g ha-1 of sulfometuron-methyl). Chemical ripeners were applied on eucalyptus plants with 48 cm in height on average; 10.1 branches; 4.5 mm of stem diameter and 44.3 cm of crown diameter, at 46 days after seeding. Trinexapac-ethyl was selective to eucalyptus and stimulated crown diameter growth. At higher doses, sulfometuron-methyl promoted severe noticeable injuries in eucalyptus plants, such as apical bud death. However, during the assessment period the plants recovered and the visual symptoms of phytotoxicity and growth alterations were not observed at 60 days after application. The plant growth regulators trinexapac-ethyl and sulfometuron-methyl were selective to eucalyptus young plants.

scholarly journals Exploiting Beneficial Pseudomonas spp. for Cannabis Production

2022 ◽  
Vol 12 ◽  
Author(s):  
Carole Balthazar ◽  
David L. Joly ◽  
Martin Filion
Keyword(s):  
Plant Growth ◽  
Environmental Sustainability ◽  
Cannabis Sativa ◽  
Production Systems ◽  
Growth Promotion ◽  
Production Costs ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Naturally Occurring ◽  
The Many

Among the oldest domesticated crops, cannabis plants (Cannabis sativa L., marijuana and hemp) have been used to produce food, fiber, and drugs for thousands of years. With the ongoing legalization of cannabis in several jurisdictions worldwide, a new high-value market is emerging for the supply of marijuana and hemp products. This creates unprecedented challenges to achieve better yields and environmental sustainability, while lowering production costs. In this review, we discuss the opportunities and challenges pertaining to the use of beneficial Pseudomonas spp. bacteria as crop inoculants to improve productivity. The prevalence and diversity of naturally occurring Pseudomonas strains within the cannabis microbiome is overviewed, followed by their potential mechanisms involved in plant growth promotion and tolerance to abiotic and biotic stresses. Emphasis is placed on specific aspects relevant for hemp and marijuana crops in various production systems. Finally, factors likely to influence inoculant efficacy are provided, along with strategies to identify promising strains, overcome commercialization bottlenecks, and design adapted formulations. This work aims at supporting the development of the cannabis industry in a sustainable way, by exploiting the many beneficial attributes of Pseudomonas spp.

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