Seedling Emergence Patterns of Six Restoration Species in Soils from Two Big Sagebrush Plant Communities

Winter annual weeds protect the soil from erosion and retain nutrients during the winter; however, they can also act as a host for crop pests and pathogens and impede planting. Increased knowledge of the reproductive biology and the seed fate of winter annuals would be useful to improve management and crop productivity. The objectives of this research were to determine the recruitment biology of shepherd's-purse, henbit, common chickweed, and field pennycress, including seed production, dispersal, dormancy, and seedling emergence, based on growing degree days (GDD). Henbit was the least prolific of the four weeds studied, producing 800 to 40,000 seeds m−2at naturally occurring densities; shepherd's-purse was the most prolific, producing 11,000 to 400,000 seeds m−2with 40 to 230 plants m−2. Fifty percent seed rain occurred for henbit, common chickweed, shepherd's-purse, and field pennycress at 620, 790, 880, and 1300 GDDBase,0C, respectively. Overall, seeds were dormant for all species at the time of dispersal. In 2 of 3 yr, dormancy of later-dispersed common chickweed decreased after 6 mo of storage at natural, fluctuating temperatures in the absence of water. The emergence patterns of the four species followed the Gompertz equation and were indicative of facultative winter annuals. The emergence patterns by rate were similar between henbit and common chickweed and between shepherd's-purse and field pennycress. Seed production, dispersal, dormancy, and seedling emergence were influenced by moisture; therefore, including a precipitation or soil moisture component into a GDD model (such as the use of hydrothermal time) would improve the accuracy of predicting winter annual reproduction, seed fate, and emergence.

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Factors affecting Cyperus difformis seed germination and seedling emergence

Planta Daninha ◽

10.1590/s0100-83582013000400008 ◽

2013 ◽

Vol 31 (4) ◽

pp. 823-832 ◽

Cited By ~ 7

Author(s):

A. Derakhshan ◽

J. Gherekhloo

Keyword(s):

Seed Germination ◽

Integrated Management ◽

Germination Rate ◽

Seedling Emergence ◽

Management Strategies ◽

Soil Surface ◽

Weed Species ◽

Factors Affecting ◽

Cyperus Difformis ◽

Emergence Patterns

Specific knowledge about the dormancy, germination, and emergence patterns of weed species aids the development of integrated management strategies. Laboratory studies were conducted to determine the effect of several environmental factors on seed germination and seedling emergence of Cyperus difformis. Germination of freshly harvested seeds was inhibited by darkness; however, when seeds were subsequently transferred to complete light they germinated readily. Our results showed that 2 wk of cold stratification overcome the light requirement for germination. Seeds of C. difformis were able to germinate over a broad range of temperatures (25/15, 30/20, 35/25, and 40/30 ºC day/night). The response of germination rate to temperature was described as a non-linear function. Based on model outputs, the base, the optimum and the ceiling temperatures were estimated as 14.81, 37.72 and 45 ºC, respectively. A temperature of 120 ºC for a 5 min was required to inhibit 50% of maximum germination. The osmotic potential and salinity required for 50% inhibition of maximum germination were -0.47 MPa and 135.57 mM, respectively. High percentage of seed germination (89%) was observed at pH=6 and decreased to 12% at alkaline medium (pH 9) pH. Seeds sown on the soil surface gave the greatest percentage of seedling emergence, and no seedlings emerged from seeds buried in soil at depths of 1 cm.

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Potential Invasiveness for Eucalyptus Species in Florida

Invasive Plant Science and Management ◽

10.1614/ipsm-d-14-00030.1 ◽

2015 ◽

Vol 8 (1) ◽

pp. 90-97 ◽

Cited By ~ 11

Author(s):

Kimberly A. Lorentz ◽

Patrick J. Minogue

Keyword(s):

Plant Communities ◽

Seedling Recruitment ◽

Seedling Emergence ◽

Bare Soil ◽

Bioenergy Crops ◽

Eucalyptus Species ◽

Buffer Zones ◽

Forest Road ◽

Central Florida ◽

Perennial Plant

AbstractTo assess the potential invasiveness of common eucalyptus species planted for pulpwood, mulch wood or bioenergy crops, field surveys of eucalyptus seedling recruitment were conducted in north and central Florida locations within seed bearing eucalyptus stands and in the proximate plant communities where seed dispersal may occur. Plant communities included non-grazed pasture, intensively site-prepared forestland, abandoned forest road and upland mixed pine- hardwood forest. No eucalyptus seedlings were found in any of the 310 1-m2 survey plots across the two locations. Second, seed addition studies were conducted to determine the relative potential for seedling emergence and survival among Eucalyptus amplifolia, E. camaldulensis and E. grandis added into plots at two seed densities, under disturbed and nondisturbed conditions, in the understory of the eucalyptus stands and in each of the aforementioned proximate plant communities. Overall, the probability of emergence of added seed was very low (P = 0.0 to 0.0032), and seed density effects were not significant. Emergence was significantly greater in disturbed conditions compared to nondisturbed conditions for seedlings originating from natural seed rain from the eucalyptus canopy in central Florida. The amount of time that seedlings survived was greater for E. camaldulensis compared to the other species but no seedlings survived more than 13 wk. These data indicate that under specific favorable conditions, eucalyptus seedlings may establish within or proximate to planted stands, but the overall level of invasiveness demonstrated by E. amplifolia and E. grandis is low for north or central Florida. The demonstrated role of disturbance in facilitating eucalyptus seedling recruitment suggests that a stable perennial plant community (native grasses) should be established instead of bare soil buffer zones to mitigate spread.

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An Emergence Model for Wild Oat (Avena fatua)

Weed Science ◽

10.1614/ws-07-059.1 ◽

2007 ◽

Vol 55 (6) ◽

pp. 584-591 ◽

Cited By ~ 32

Author(s):

Krishona Martinson ◽

Beverly Durgan ◽

Frank Forcella ◽

Jochum Wiersma ◽

Kurt Spokas ◽

...

Keyword(s):

Seedling Emergence ◽

Soil Water Potential ◽

The United States ◽

Weibull Function ◽

Wild Oat ◽

Degree Days ◽

Weekly Basis ◽

Emergence Patterns ◽

Base Soil ◽

Permanent Quadrats

Wild oat is an economically important annual weed throughout small grain producing regions of the United States and Canada. Timely and more accurate control of wild oat may be developed if there is a better understanding of its emergence patterns. The objectives of this research were to evaluate the emergence pattern of wild oat and determine if emergence could be predicted using soil growing degree days (GDD) and/or hydrothermal time (HTT). Research plots were established at Crookston, MN, and Fargo, ND, in 2002 and 2003. On a weekly basis, naturally emerging seedlings were counted and removed from six 0.37-m2permanent quadrats randomly distributed in a wild oat–infested area. This process was repeated until no additional emergence was observed. Wild oat emergence began between May 1 and May 15 at both locations and in both years and continued for 4 to 6 wk. Base soil temperature and soil water potential associated with wild oat emergence were determined to be 1 C and −0.6 MPa, respectively. Seedling emergence was correlated with GDD and HTT but not calendar days (P = 0.15). A Weibull function was fitted to cumulative wild oat emergence and GDD and HTT. The models for GDD (n= 22,r2= 0.93, root mean square error [RMSE] = 10.7) and HTT (n= 22,r2= 0.92, RMSE = 11.2) closely fit observed emergence patterns. The latter model is the first to use HTT to predict wild oat emergence under field conditions. Both models can aid in the future study of wild oat emergence and assist growers and agricultural professionals with planning timely and more accurate wild oat control.

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Saving the sagebrush sea: An ecosystem conservation plan for big sagebrush plant communities

Biological Conservation ◽

10.1016/j.biocon.2011.07.016 ◽

2011 ◽

Vol 144 (11) ◽

pp. 2573-2584 ◽

Cited By ~ 257

Author(s):

Kirk W. Davies ◽

Chad S. Boyd ◽

Jeffrey L. Beck ◽

Jon D. Bates ◽

Tony J. Svejcar ◽

...

Keyword(s):

Plant Communities ◽

Big Sagebrush ◽

Ecosystem Conservation ◽

Conservation Plan

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Short communication: Evaluation of a model for predicting Avena fatua and Descurainia sophia seed emergence in winter rapeseed

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2017152-10572 ◽

2017 ◽

Vol 15 (2) ◽

pp. e03SC01 ◽

Cited By ~ 1

Author(s):

Mohammad A. Aboutalebian ◽

Shahram Nazari ◽

Jose L. Gonzalez-Andujar

Keyword(s):

Seedling Emergence ◽

Weibull Model ◽

Avena Fatua ◽

Coefficient Of Determination ◽

Semiarid Region ◽

Brassica Napus L ◽

Data Set ◽

Descurainia Sophia ◽

Emergence Patterns ◽

Winter Rapeseed

Avena fatua and Descurainia sophia are two important annual weeds throughout winter rapeseed (Brassica napus L.) production systems in the semiarid region of Iran. Timely and more accurate control of both species may be developed if there is a better understanding of its emergence patterns. Non-linear regression techniques are usually unable to accurately predict field emergence under such environmental conditions. The objectives of this research were to evaluate the emergence patterns of A. fatua and D. sophia and determine if emergence could be predicted using cumulative soil thermal time in degree days (CTT). In the present work, cumulative seedling emergence from a winter rapeseed field during 3 year data set was fitted to cumulative soil CTT using Weibull and Gompertz functions. The Weibull model provided a better fit, based on coefficient of determination (R2sqr), root mean square of error (RMSE) and Akaike index (AICd), compared to the Gompertz model between 2013 and 2016 seasons for both species. Maximum emergence of A. fatua occured 70-119 days after sowing or after equals 329-426 °Cd, while in D. sophia it occurred 119-134 days after sowing rapeseed equals 373-470 °Cd. Both models can aid in the future study of A. fatua and D. sophia emergence and assist growers and agricultural professionals with planning timely and more accurate A. fatua and D. sophia control.

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Allometric Modeling of Bunchgrasses in Big Sagebrush Plant Communities

Rangeland Ecology & Management ◽

10.1016/j.rama.2021.07.009 ◽

2021 ◽

Vol 79 ◽

pp. 77-86

Author(s):

Alexandra J. Smith ◽

Daniel R. Schlaepfer ◽

Kyle A. Palmquist ◽

Ingrid C. Burke ◽

William K. Lauenroth

Keyword(s):

Plant Communities ◽

Big Sagebrush

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Spatial Distribution Patterns of Seedling Emergence of Stipagrostis pennata in Gurbantonggut Desert

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.2101 ◽

2012 ◽

Vol 524-527 ◽

pp. 2101-2108

Author(s):

Xia Zhang ◽

Wen Ling Wang ◽

Huan Ge ◽

Li Hong Long ◽

Shao Ming Wang

Keyword(s):

Spatial Distribution ◽

Population Distribution ◽

Seedling Emergence ◽

Distribution Patterns ◽

Leeward Side ◽

Seedling Density ◽

Spatial Distribution Patterns ◽

Emergence Patterns ◽

Distribution Rule ◽

Significant Difference

The aim of this study was to investigate the spatial distribution patterns and the amounts of seedling density of S. pennata in different sample dunes in Gurbantonggut Desert. Results indicate that spatial patterns of seedling emergence of S. pennata were of general similar with the distribution patterns of its associated standing vegetations, and was greatly associated with spatial distribution of the threshold wind (≥6m.s-1) frequency from the various directions. There existed a significant difference in its seedling emergence patterns among the different parts of the dunes and the different directions around its parent vegetation beds. The highest seedling density was found to be on the top parts of sampling dunes and at the underlayer of standing vegetation beds of S. pennata, and higher seedling densities usually took place in the leeward side of the vegetation beds. These results had revealed the ecological characteristics of the population distribution rule and the recruitments mechanism of S. pennata.

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Invasion of Medusahead into the Great Basin

Weed Science ◽

10.1017/s0043174500077419 ◽

1970 ◽

Vol 18 (1) ◽

pp. 89-97 ◽

Cited By ~ 19

Author(s):

James A. Young ◽

Raymond A. Evans

Keyword(s):

Great Basin ◽

Plant Communities ◽

Coniferous Forest ◽

Clay Soils ◽

Native Plant ◽

Big Sagebrush ◽

Forest Sites ◽

Environmental Unit ◽

Woodland Communities ◽

High Elevations

We characterized soil and vegetation assemblages, many of which are infested with medusahead (Taeniatherum asperum(Sim.) Nevski), on the margin of the Great Basin. Interpretations of these assemblages provide an index of the validity of the basic environmental unit of this ecosystem which can be manipulated through weed control and revegetation techniques. Vertisol (churning clay soils) sites with sparse native plant communities are more susceptible to medusahead invasion than more complex low sagebrush (Artemisia arbusculaNutt.) or low sagebrush-woodland communities on related clay soils. If the more complex communities are degraded to a low seral state, medusahead can invade and occupy the site. Wet meadows and burned coniferous forest sites at high elevations were the only sites where medusahead occurred on soils with textures other than clay. Big sagebrush (Artemisia tridentataNutt.) communities on medium to coarse textured soils were very resistant to medusahead invasion. The restriction of medusahead to certain sites controls the mechanism of invasion and interacts with the breeding system of the species to influence its evolution.

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