Seed burial by tillage promotes field recruitment of false cleavers (Galium spurium) and catchweed bedstraw (Galium aparine)

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 578-585 ◽  
Author(s):  
Danielle J. Reid ◽  
Rene C. Van Acker
Keyword(s):  
Soil Moisture ◽  
Bulk Density ◽  
Great Plains ◽  
Field Experiments ◽  
Soil Depth ◽  
Soil Surface ◽  
Northern Great Plains ◽  
Galium Aparine ◽  
Tillage Operation ◽  
Galium Spurium

False cleavers and catchweed bedstraw are problematic weeds of field crops in high-latitude regions of the northern Great Plains of North America. The abundance of these species has been increasing in areas of greater tillage intensity and frequency. Field experiments were established over 4 site-yr in Manitoba, Canada, and results indicated that the recruitment of false cleavers and catchweed bedstraw was strongly promoted by a single shallow tillage operation with a sweep cultivator in the spring. Percent recruitment levels in 2001 (pooled over sites) were 17 and 46% for the untilled and tilled treatments, respectively. In 2002, the percent recruitment levels for the untilled and tilled treatments, respectively, were 28 and 38% for the Komarno site and 13 and 28% for the Petersfield site. Only a few and minor differences in microsite conditions (soil temperature, soil moisture, and bulk density) resulted from the single spring tillage pass. The single tillage pass caused a significant relocation of simulated seeds (plastic beads) to below the soil surface and deeper into the soil profile (2–4 cm). Mean bulk density and volumetric soil moisture increased significantly with soil depth. The results of this study suggest that the positive effect of tillage on cleavers recruitment was not due to the effect of tillage on microsite conditions per se. Rather, the vertical redistribution of seed by tillage moved these seeds to a place in which the microsite conditions differed from those on the surface and were more favorable for recruitment. False cleavers and catchweed bedstraw recruitment is clearly promoted by tillage (even minor tillage) under field conditions, and farmers might be able to limit recruitment by limiting spring tillage.

Stable Isotope Ratios of Carbon in Phytoliths as a Quantitative Method of Monitoring Vegetation and Climate Change

1991 ◽  
Vol 35 (2) ◽  
pp. 222-233 ◽  
Author(s):  
Eugene F. Kelly ◽  
Ronald G. Amundson ◽  
Bruno D. Marino ◽  
Michael J. Deniro
Keyword(s):  
Great Plains ◽  
Soil Depth ◽  
Carbon Isotopic Composition ◽  
Soil Surface ◽  
Northern Great Plains ◽  
Surface Layers ◽  
Carbon Isotopic ◽  
Occluded Carbon ◽  
Vegetation And Climate ◽  
Isotopic Effects

AbstractThe 13C/12C ratios of occluded carbon within opal phytoliths from the northern Great Plains show potential as a basis for paleoclimatic reconstruction. A significant correlation exists between the carbon isotopic composition of a host plant and that of the organic matter in its phytoliths. The 13C/12C ratios for phytoliths from surface layers of soils along climatic gradients reflect the current proportions of C3 and C4 plants. Variations in the δ13C values of phytoliths with soil depth are caused by a variety of processes: burial of soil surface by dust, bioturbation, and possible illuviation by percolating water. Also, contributions of phytoliths by dust and roots have unknown isotopic effects. The δ13C values of phytoliths from soils increase with decreasing 14C age, suggesting that the proportion of C4 plants in this region has increased during the Holocene. Phytoliths of apparent mid-Holocene age suggest exclusive dominance by C4 plants which agrees with paleoclimatic interpretations of an arid middle Holocene climate.

Seasonal cycles in germination and seedling emergence of summer and winter populations of catchweed bedstraw (Galium aparine) and wild mustard (Brassica kaber)

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Husrev Mennan ◽  
Mathieu Ngouajio
Keyword(s):  
Soil Depth ◽  
Cropping Systems ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Soil Surface ◽  
Burial Depth ◽  
Galium Aparine ◽  
Wild Mustard ◽  
Seed Population ◽  
Brassica Kaber

Catchweed bedstraw and wild mustard each produce two populations per year: a winter population (WP) in June, and a summer population (SP) in September. Experiments were conducted to determine whether the WP and SP differ in seed mass and seasonal germination. Seeds of both weeds were buried at 0, 5, 10, and 20 cm in cultivated fields, and retrieved at monthly intervals for 24 mo for germination tests in the laboratory. Additionally, seedling emergence from seeds buried at 0, 5, and 10 cm in the field was evaluated for 1 yr. Seeds from the WP were heavier than those from the SP for both species. Germination of exhumed seeds was affected by burial depth and by seed population. It was highest for seeds that remained on the soil surface and declined with increasing depth of burial. The WP of catchweed bedstraw produced two germination peaks per year, whereas the SP and all populations of wild mustard had only one peak. The WP of both weeds germinated earlier than the SP. Seedling emergence for both species in the field was greater for the WP than for the SP. Increasing soil depth reduced seedling emergence of both the WP and SP of wild mustard and affected only the WP of catchweed bedstraw. We conclude that the WP and SP of catchweed bedstraw and wild mustard seeds used in this study differed in seed mass, seasonal germination, and seedling emergence. The ability of a WP to produce large seeds that germinate early and have two germination peaks per year could make these populations a serious problem in cropping systems.

Evaluation of fungicide efficacy on sunflower rust (Puccinia helianthi) on oilseed and confection sunflower

2021 ◽  
Author(s):  
Brandt Berghuis ◽  
Andrew Friskop ◽  
Michelle Gilley ◽  
Jessica Halvorson ◽  
Bryan Hansen ◽  
...  
Keyword(s):  
Great Plains ◽  
Field Experiments ◽  
Field Trials ◽  
Northern Great Plains ◽  
Puccinia Helianthi ◽  
Action Threshold ◽  
The Us ◽  
Fungicide Efficacy ◽  
Rust Severity ◽  
Important Disease

Sunflower rust, caused by Puccinia helianthi, is an economically and globally important disease of sunflower. Two types of sunflowers are produced in the US Northern Great Plains; the oilseed type and the confection type. Although approximately 80% of the acreage in this region is planted as the oilseed type sunflower, fungicide efficacy and timing studies have been conducted primarily on the more rust-susceptible confection type. A total of ten sunflower rust efficacy field experiments were conducted on oilseed type and confectionary type hybrid trials from 2016-2018. Eleven fungicides from three FRAC groups were evaluated for efficacy and protection of yield. Severity differences among fungicide treatments were identified in both confection and oilseed type sunflower trials. A combined analysis of all confection field trials (five) indicated that rust severity was lower in all fungicide treatments as compared to the non-treated control. Despite rust severity levels below the fungicide action threshold for confection sunflower, seven of the eleven fungicide treatments had yield higher than the non-treated control. In oilseed trials, rust severity was lower in all fungicide treatments as compared to the non-treated control, similar to the findings of the confection type. Rust severity was too low to detect yield differences in oilseed trials. Additional work is needed to elucidate yield-loss potential on oilseed type sunflower and refine the fungicide action threshold on confection type sunflower.

scholarly journals The Soil Moisture during Dry Spells Model and Its Verification

Resources ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 85
Author(s):  
Małgorzata Biniak-Pieróg ◽  
Mieczysław Chalfen ◽  
Andrzej Żyromski ◽  
Andrzej Doroszewski ◽  
Tomasz Jóźwicki
Keyword(s):  
Soil Moisture ◽  
Least Squares Method ◽  
Soil Depth ◽  
Soil Layer ◽  
Atmospheric Precipitation ◽  
Soil Surface ◽  
Model Verification ◽  
Individual Measurement ◽  
Dry Spells ◽  
Dry Spell

The objective of this study was the development and verification of a model of soil moisture decrease during dry spells—SMDS. The analyses were based on diurnal information of the occurrence of atmospheric precipitation and diurnal values of soil moisture under a bare soil surface, covering the period of 2003–2019, from May until October. A decreasing exponential trend was used for the description of the rate of moisture decrease in six layers of the soil profile during dry spells. The least squares method was used to determine, for each dry spell and soil depth, the value of exponent α , which described the rate of soil moisture decrease. Data from the years 2003–2015 were used for the identification of parameter α of the model for each of the layers separately, while data from 2016–2019 were used for model verification. The mean relative error between moisture values measured in 2016–2019 and the calculated values was 3.8%, and accepted as sufficiently accurate. It was found that the error of model fitting decreased with soil layer depth, from 8.1% for the surface layer to 1.0% for the deepest layer, while increasing with the duration of the dry spell at the rate of 0.5%/day. The universality of the model was also confirmed by verification made with the use of the results of soil moisture measurements conducted in the years 2009–2019 at two other independent locations. However, it should be emphasized that in the case of the surface horizon of soil, for which the process of soil drying is a function of factors occurring in the atmosphere, the developed model may have limited application and the obtained results may be affected by greater errors. The adoption of calculated values of coefficient α as characteristic for the individual measurement depths allowed calculation of the predicted values of moisture as a function of the duration of a dry spell, relative to the initial moisture level adopted as 100%. The exponential form of the trend of soil moisture changes in time adopted for the analysis also allowed calculation of the duration of a hypothetical dry spell t, after which soil moisture at a given depth drops from the known initial moisture θ0 to the predicted moisture θ. This is an important finding from the perspective of land use.

Investigating the Relationship between the Evaporative Stress Index and Land Surface Conditions in the Contiguous United States

2020 ◽  
Vol 21 (7) ◽  
pp. 1469-1484
Author(s):  
Yafang Zhong ◽  
Jason A. Otkin ◽  
Martha C. Anderson ◽  
Christopher Hain
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Great Plains ◽  
Land Surface ◽  
The United States ◽  
Stress Index ◽  
Northern Great Plains ◽  
Reference Network ◽  
North Central ◽  
Central United States

AbstractDespite the key importance of soil moisture–evapotranspiration (ET) coupling in the climate system, limited availability of soil moisture and ET observations poses a major impediment for investigation of this coupling regarding spatiotemporal characteristics and potential modifications under climate change. To better understand and quantify soil moisture–ET coupling and relevant processes, this study takes advantage of in situ soil moisture observations from the U.S. Climate Reference Network (USCRN) for the time period of 2010–17 and a satellite-derived version of the evapotranspiration stress index (ESI), which represents anomalies in a normalized ratio of actual to reference ET. The analyses reveal strong seasonality and regional characteristics of the ESI–land surface interactions across the United States, with the strongest control of soil moisture on the ESI found in the southern Great Plains during spring, and in the north-central United States, the northern Great Plains, and the Pacific Northwest during summer. In drier climate regions such as the northern Great Plains and north-central United States, soil moisture control on the ESI is confined to surface soil layers, with subsurface soil moisture passively responding to changes in the ESI. The soil moisture–ESI interaction is more uniform between surface and subsurface soils in wetter regions with higher vegetation cover. These results provide a benchmark for simulation of soil moisture–ET coupling and are useful for projection of associated climate processes in the future.

Factors affecting seed germination of annual sowthistle (Sonchus oleraceus) in southern Australia

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 854-860 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Gurjeet Gill ◽  
Christopher Preston
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Field Experiments ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Factors Affecting ◽  
Control Programs ◽  
Buried Seed ◽  
Ph Range

Annual sowthistle has become more abundant under no-till systems in southern Australia. Increased knowledge of germination biology of annual sowthistle would facilitate development of effective weed control programs. The effects of environmental factors on germination and emergence of annual sowthistle seeds were examined in laboratory and field experiments. Seeds of annual sowthistle were able to germinate over a broad range of temperatures (25/15, 20/12, and 15/9 C day/night temperatures). Seed germination was favored by light; however, some germination occurred in the dark as well. Greater than 90% of seeds germinated at a low level of salinity (40 mM NaCl), and some seeds germinated even at 160 mM NaCl (7.5%). Germination decreased from 95% to 11% as osmotic potential increased from 0 to −0.6 MPa and was completely inhibited at osmotic potential greater than −0.6 MPa. Seed germination was greater than 90% over a pH range of 5 to 8, but declined to 77% at pH 10. Seedling emergence was the greatest (77%) for seeds present on the soil surface but declined with depth, and no seedlings emerged from a soil depth of 5 cm. In another experiment in which seeds were after-ripened at different depths in a field, seed decay was greater on the soil surface than at 2 or 5 cm depth. At the end of the growing season, there was a much greater persistence of buried seed (32 to 42%) than seeds present on the soil surface (8%). Greater persistence of buried seed could be due to dormancy enforced by dark in this species.

scholarly journals Soil Quality and Water Redistribution Influences on Plant Production over Low Hillslopes on Reclaimed Mined Land

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Stephen D. Merrill ◽  
Mark A. Liebig ◽  
John D. Hendrickson ◽  
Abbey F. Wick
Keyword(s):  
Soil Quality ◽  
Great Plains ◽  
Spring Wheat ◽  
Soil Depth ◽  
Surface Mining ◽  
Plant Production ◽  
Northern Great Plains ◽  
Cool Season ◽  
Water Redistribution ◽  
Highly Correlated

Coal surface mining in northern Great Plains USA led to reclamation experiments with soil respreading. Respread soil depth (RSD) and runoff of water redistribution (WR) effects interacted in original North Dakota studies, complicating interpretations. We determined WR and soil depth/soil quality (SQ) effects on hillslope production patterns for sites with soil wedges (2%–5% slope, 50-m length) over sodic mine spoils. At Zap, cool-season forages crested wheatgrass (CWG: Agropyron cristatum) and Russian wildrye (Psathyrostachys juncea) generally decreased as RSD increased upslope. At Stanton, alfalfa (Medicago sativa), native grasses (Bouteloua spp.), and CWG responded to RSD, increasing 70% to midslope and decreasing further. A SQ index (SQI) based on six indicator properties was highly correlated (r > 0.7) with RSD. Yield regressions with RSD or SQI were generally significant for Stanton forages and for spring wheat (Triticum aestivum) at both sites. Yield regressions with WR index (catchment area-based) indicated dominance of WR effects at Zap. Cool-season forages at Zap evidently responded to springtime runoff, while Stanton forages and spring wheat at both sites used water later in the season and responded to soil depth/SQ effects. Results suggest models for interaction of SQ and landform WR affecting productivity should include plant community composition and water-use information.

Effect of Kochia (Kochia scoparia) Interference on Sunflower (Helianthus annuus) Yield

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 158-165 ◽  
Author(s):  
Derek W. Lewis ◽  
Robert H. Gulden
Keyword(s):  
Great Plains ◽  
Growth And Development ◽  
Seed Quality ◽  
Seedling Recruitment ◽  
Soil Surface ◽  
Northern Great Plains ◽  
Limited Information ◽  
Leaf Stage ◽  
Action Threshold ◽  
Sunflower Crop

Kochia is a weed found in many sunflower fields across the Northern Great Plains. There is limited information about the ability of sunflower plants to compete with kochia, specifically when the weed grows both in the crop row and in the inter-row space, as in zero tillage systems that rely solely on herbicides to manage weeds. An experiment was conducted over seven site–yr, from 2009 to 2011, to determine the effect of kochia density and relative time of kochia seedling recruitment on sunflower growth and development, yield and seed quality. Kochia seed was broadcast on the soil surface at six densities, into sunflowers planted in 75-cm rows, either at the same time as the sunflower crop was planted (early weed seedling recruitment), or when the sunflowers were at the four-leaf stage (late weed seedling recruitment). When kochia plants emerged at the same time as the sunflowers, yield was reduced by up to 76% and sunflower head diam was reduced in four site–yr, stem diam was reduced in three site–yr, height was reduced in two site–yr and the number of leaves per sunflower plant was reduced in two site–yr The 5% action threshold for early emerging kochia was four kochia plants m−2in the combined site–yr analysis. Additionally, early recruiting kochia seedlings reduced sunflower seed size and seed weight at two and three site–yr, respectively. Kochia plants that emerged after the four-leaf stage of the sunflower crop did not affect sunflower growth and development, yield, or seed quality. To reduce the potential for yield and seed quality losses, sunflower growers should be proactive with respect to managing kochia in sunflowers, particularly when the kochia plants emerge at about the same time as the sunflowers.

scholarly journals Effect of green manure crops, termination method, stubble crops, and fallow on soil water, available N, and exchangeable P

2016 ◽  
Vol 96 (5) ◽  
pp. 867-886 ◽  
Author(s):  
S.P. Mooleki ◽  
Y. Gan ◽  
R.L. Lemke ◽  
R.P. Zentner ◽  
C. Hamel
Keyword(s):  
Great Plains ◽  
Green Manure ◽  
Field Experiments ◽  
Northern Great Plains ◽  
Available N ◽  
Sustainable Agricultural Systems ◽  
Lathyrus Sativus L ◽  
Nitrogen Phosphorus ◽  
Green Manure Crops ◽  
Exchangeable P

Green manure crops may have a role to play in the development of sustainable agricultural systems in the semiarid northern Great Plains of North America. This study determined the benefits of different green manure crops, seeding dates, and termination methods on soil nitrogen, phosphorus, and moisture, as well as the performance of durum wheat following green manures the following year. Field experiments were conducted at Swift Current, Saskatchewan, from 2006 to 2009. Three green manure crops [forage pea (Pisum sativum L.), chickling vetch (Lathyrus sativus L.), and black lentil (Lens culinaris Medik.)] were seeded in May, June, and July, and terminated at full bloom using glyphosate, rototilling or by frost. Other treatments included summerfallow and stubble of selected crops harvested for grain or silage. Different green manure crops, seeding dates or termination methods had similar effects on soil moisture, available N, and exchangeable P at termination or the following spring. These effects of green manure management on soil residual characteristics were comparable to those observed under summerfallow, but higher than those on grain or silage stubble. Therefore, green manure is a viable alternative to summerfallowing and could be seeded any time during the growing season. If seeded late, green manure could be terminated by frost, thus saving on costs.

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