No-tillage altered weed species dynamics in a long-term (36-year) grain sorghum experiment in southeast Texas

Weed Science ◽  
2020 ◽  
Vol 68 (5) ◽  
pp. 476-484
Author(s):  
Prabhu Govindasamy ◽  
Debalin Sarangi ◽  
Tony Provin ◽  
Frank Hons ◽  
Muthukumar Bagavathiannan
Keyword(s):  
Management Practices ◽  
Grain Sorghum ◽  
Base Temperature ◽  
Weed Species ◽  
Perennial Weed ◽  
Species Dominance ◽  
Species Dynamics ◽  
Ct System ◽  
The Impact

AbstractTillage regimes can influence weed population dynamics and, consequently, the choice of appropriate weed management practices. Studies were conducted in 2016 and 2017 in a long-term (36-yr) grain sorghum [Sorghum bicolor (L.) Moench ssp. bicolor] experiment at Texas A&M University, College Station, to determine the impact of long-term no-till (NT) and conventional till (CT) systems on weed species dynamics. Higher densities of johnsongrass [Sorghum halepense (L.) Pers.], prostrate spurge [Chamaesyce humistrata (Engelm. ex A. Gray) Small], waterhemp [Amaranthus tuberculatus (Moq.) Sauer], and henbit (Lamium amplexicaule L.) were recorded in the NT system compared with the CT system. Further, the NT system showed greater weed diversity (Shannon-Wiener index, H = 0.8) and species richness (S = 6.2), compared with the CT system (H = 0.6, S = 4.2). Seedling emergence of some dominant weed species was also delayed in the NT system. In the CT system, 50% emergence of S. halepense (8.5 C base temperature) and waterhemp (10 C base temperature) occurred at 59 and 63 growing degree days (GDD), respectively, whereas 68 and 75 GDD, respectively, were required in the NT system. Further, a greater proportion (61%) of the viable seedbank was present at the top 5 cm of the soil in the NT system compared with the CT system (46%). Overall, findings from this 36-yr-long tillage experiment have revealed that the NT system had greater weed densities (especially of the perennial weed S. halepense) and a high proportion of weed seeds (particularly small-seeded annuals) on the topsoil layer, corroborating some earlier reports that were based on short-term investigations. Findings indicate that growers transitioning to NT systems should be mindful of potential shifts in weed species dominance and develop appropriate management tactics.

Temporal changes in an alligator snapping turtle (Macrochelys temminckii) population

2013 ◽  
Vol 40 (1) ◽  
pp. 77 ◽  
Author(s):  
Mitchell B. East ◽  
J. Daren Riedle ◽  
Day B. Ligon
Keyword(s):  
Management Practices ◽  
Unknown Origin ◽  
Current Status ◽  
Macrochelys Temminckii ◽  
The Status ◽  
Management Recommendations ◽  
The Impact ◽  
Term Monitoring ◽  
Term Data

Context Monitoring populations of long-lived species requires continuous long-term efforts. This is especially applicable for species that have experienced declines range-wide. Aims Our study assessed the current status of a population of wild Macrochelys temminckii and compared the present results to those from a survey conducted nearly a decade ago. Methods Trapping in 2010–2011 was conducted on two creeks within the refuge, during the months of May–July. Capture data were compared with data collected by similar methods in 1997–2001. Key results The population structure of M. temminckii was dominated by juveniles, with few large adults or small juveniles detected and a missing size class was evident. Retrospective analysis of 1997–2001 data revealed that the population was likely to be in decline even then, despite high capture rates. Conclusions The M. temminckii population showed significant declines that indicated that the population had experienced stressors of unknown origin. The status of M. temminckii at the refuge is concerning, given the protection afforded this remnant population. Implications Short-term data from 1997–2001 indicated a healthy M. temminckii population, whereas longer-term data showed that the population has declined, resulting in significant demographic changes. Continued monitoring will be necessary to develop management recommendations and track the impact of implemented management practices. Longer-term monitoring of long-lived vertebrates is required to identify population trends.

scholarly journals The impact of stubble crop on spring barley weed infestation

2016 ◽  
Vol 69 (3) ◽  
Author(s):  
Eleonora Wrzesińska ◽  
Anna Komorowska ◽  
Grażyna Nurkiewicz
Keyword(s):  
Cover Crop ◽  
Spring Barley ◽  
Block Design ◽  
Control Treatment ◽  
White Mustard ◽  
Weed Species ◽  
Fresh Matter ◽  
Species Dominance ◽  
Weed Infestation ◽  
The Impact

The condition and degree of weed infestation were determined in a spring barely crop grown in a short-term monoculture after mulching the soil with plants grown as a stubble crop (the control treatment without cover crop – lacy phacelia, white mustard, sunflower). The field experiment was carried out in 2010–2013 on good rye soil complex using a split-block design in four replications. The obtained results (the mean from all years of the experiment) showed that the stubble crop, especially sunflower, reduced the diversity of weed species without causing at the same time changes in weed species dominance. In all the control treatments of the experiment, <em>Chenopodium album</em> and <em>Fallopia convolvulus</em> were the dominant species. The degree of spring barley weed infestation depended on the species grown in the cover crop. White mustard and lacy phacelia slightly increased the number of weeds but their fresh matter significantly increased. However, the sunflower cover crop significantly increased the number of weeds without any substantial differentiation of their fresh mass.

scholarly journals Tallgrass Prairie Responses to Management Practices and Disturbances: A Review

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 300 ◽  
Author(s):  
Pradeep Wagle ◽  
Prasanna Gowda
Keyword(s):  
Species Richness ◽  
Soil Quality ◽  
Plant Species ◽  
Tallgrass Prairie ◽  
Management Practices ◽  
The United States ◽  
N Fertilization ◽  
Native Plant ◽  
The Impact

Adoption of better management practices is crucial to lessen the impact of anthropogenic disturbances on tallgrass prairie systems that contribute heavily for livestock production in several states of the United States. This article reviews the impacts of different common management practices and disturbances (e.g., fertilization, grazing, burning) and tallgrass prairie restoration on plant growth and development, plant species composition, water and nutrient cycles, and microbial activities in tallgrass prairie. Although nitrogen (N) fertilization increases aboveground productivity of prairie systems, several factors greatly influence the range of stimulation across sites. For example, response to N fertilization was more evident on frequently or annually burnt sites (N limiting) than infrequently burnt and unburnt sites (light limiting). Frequent burning increased density of C4 grasses and decreased plant species richness and diversity, while plant diversity was maximized under infrequent burning and grazing. Grazing increased diversity and richness of native plant species by reducing aboveground biomass of dominant grasses and increasing light availability for other species. Restored prairies showed lower levels of species richness and soil quality compared to native remnants. Infrequent burning, regular grazing, and additional inputs can promote species richness and soil quality in restored prairies. However, this literature review indicated that all prairie systems might not show similar responses to treatments as the response might be influenced by another treatment, timing of treatments, and duration of treatments (i.e., short-term vs. long-term). Thus, it is necessary to examine the long-term responses of tallgrass prairie systems to main and interacting effects of combination of management practices under diverse plant community and climatic conditions for a holistic assessment.

The impact of livestock grazing on the persistence of a perennial forb in a temperate Australian grassland

2003 ◽  
Vol 9 (4) ◽  
pp. 302 ◽  
Author(s):  
Josh Dorrough ◽  
Julian Ash
Keyword(s):  
Plant Species ◽  
Management Practices ◽  
Livestock Grazing ◽  
Grazing Management ◽  
Population Growth Rates ◽  
Perennial Plant ◽  
South Wales ◽  
Recent Occurrence ◽  
The Impact

The presence of perennial plant species in grazed habitats may be an imperfect predictor of their long-term ability to persist under grazing by livestock. This is particularly the case in landscapes where grazing by livestock is a relatively recent occurrence or where management practices are leading to intensification of grazing. This paper investigates the impacts of grazing on the native perennial inter-tussock forb Leptorhynchos elongatus (Asteraceae) in grasslands on the Monaro Tablelands of New South Wales. Although the species persists in grazed habitats, exclosures indicate that current grazing management can lead to severe depletion of seed, largely due to selective removal of flowers and seed heads by livestock. A population model suggests that under current grazing management, population growth rates may be negative. Removal of livestock during flowering and seed set may assist long-term persistence of this species in grazed habitats. Despite almost 200 years of livestock grazing on the Monaro Tablelands, recent intensification of grazing management could result in the future loss of some plant species in grazed habitats.

RELATIONSHIP BETWEEN LAND TENURE AND SOIL PRODUCTIVITY

1986 ◽  
Vol 66 (2) ◽  
pp. 357-366 ◽  
Author(s):  
W. VAN VUUREN ◽  
P. YSSELSTEIN
Keyword(s):  
Land Tenure ◽  
Soil Conservation ◽  
Management Practices ◽  
Agricultural Land ◽  
Soil Productivity ◽  
Corn Yield ◽  
Contractual Obligations ◽  
The Impact

Renting of agricultural land is gaining in importance in Canada. The impact of rental on soil conservation and on long-term soil productivity was examined in central southwestern Ontario. Prevailing leasing contracts were short-term, with a minimum of contractual obligations on both parties. A difference in soil management practices was found between owner-operated land and rented land. Both recurrent and nonrecurrent practices upgrading the soil were carried out to a lesser extent on rented than on owner-operated land, while the quality of the rented land was in fact lower and in greater need of ameliorative practices. This resulted in a difference in grain corn yield; the lower yield being obtained from rented land. Key words: Land tenure, tenancy, rental contract, soil conservation, soil productivity, soil quality

Long-Term Measurements to Quantify the Impact of Arable Management Practices on Deep Seepage and Nitrate Leaching

2010 ◽  
pp. 243-252 ◽  
Author(s):  
Uwe Schindler ◽  
Lothar Müller ◽  
Ralf Dannowski ◽  
Dietmar Barkusky ◽  
Glyn Francis
Keyword(s):  
Nitrate Leaching ◽  
Management Practices ◽  
The Impact

scholarly journals Venous thromboembolism in the elderly

2008 ◽  
Vol 100 (05) ◽  
pp. 780-788 ◽  
Author(s):  
Joel M. Gore ◽  
Darleen Lessard ◽  
Cathy Emery ◽  
Luigi Pacifico ◽  
George Reed ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Major Bleeding ◽  
Clinical Characteristics ◽  
Management Practices ◽  
The Elderly ◽  
Population Based ◽  
Long Term Outcomes ◽  
Recurrent Vte ◽  
The Impact

SummaryWhile the magnitude of venous thromboembolism (VTE) increases dramatically with advancing age,relatively little is known about the contemporary management of VTE in the elderly and the impact of age on associated short- and long-term outcomes. The objectives of this population-based study were to compare the clinical characteristics,treatment practices,and outcomes of subjects ≥65 years with VTE to those of younger patients.The medical records of residents of the Worcester (MA, USA) metropolitan area with ICD-9 codes consistent with VTE during 1999, 2001, and 2003 were independently validated and reviewed by trained data abstractors. Information about patients’ demographic and clinical characteristics, hospital management practices, and hospital and long-term outcomes was collected. There were a total of 1,897 validated events of VTE – 1,048 (55%) occurred in patients ≥65 years of age. Patients ≥65 years were less likely to have “unprovoked” VTE than younger patients.They were less likely to receive parenteral anticoagulation or warfarin as acute treatment. Rates of recurrent VTE did not differ significantly between patients 65 years of age or older compared to younger patients but the adjusted rates of major bleeding were increased approximately two-fold in older patients. In conclusion, advancing age is not a predictor of recurrent VTE but is associated with a significant increase in major bleeding episodes. Physicians treating elderly patients with VTE should continue to base their decisions on clinical characteristics previously shown to impact the risk of recurrent VTE. These decisions must be tempered by our observation that major bleeding occurs frequently in these patients.

The impact of strategic planning on the competitiveness, performance and effectiveness of bank branches: a neural network analysis

2002 ◽  
Vol 20 (3) ◽  
pp. 102-110 ◽  
Author(s):  
L. Moutinho ◽  
P.A. Phillips
Keyword(s):  
Neural Network ◽  
Strategic Planning ◽  
Distribution System ◽  
Management Practices ◽  
Bank Branch ◽  
Marketing Effectiveness ◽  
Overall Performance ◽  
And Control ◽  
The Impact

The banking distribution system is going through a rapid process of change. This research study focuses on the analysis of the perceptions, of 58 bank branch managers selected from 14 branches belonging to two major Scottish banks, of the impact of a variety of planning practices on competitiveness, overall performance, strategic planning effectiveness and marketing effectiveness. The gathered data were then subjected to a number of learning iterations as part of a specifically designed neural network topology. Major findings derived from the study revealed that: bank branch effectiveness is affected by effective management practices; the overall performance of the branch depends highly on both long term thinking and innovation; long‐term thinking seems to have also a high degree of impact on strategic planning effectiveness; and finally, the degree of precision attached to planning, programming, budgeting and control seems to trigger high levels of marketing effectiveness.

scholarly journals Long-term experiments on chernozem soil in the University of Debrecen

2018 ◽  
pp. 357-369
Author(s):  
Péter Pepó
Keyword(s):  
Winter Wheat ◽  
Crop Rotation ◽  
Management Practices ◽  
Crop Protection ◽  
Chernozem Soil ◽  
Wheat Varieties ◽  
Maize Production ◽  
Long Term Experiments ◽  
The Impact

The impact of agrotechnical management practices (nutrient and water supply, crop rotation, crop protection, genotype) on the yields of winter wheat and maize and on the soil water and nutrient cycles was studied in long-term experiments set up in 1983 in Eastern Hungary on chernozem soil. The long-term experiments have shown that nitrogen fertilizer rates exceeding the N-optimum of winter wheat resulted in the accumulation of NO3-N in the soil. Winter wheat varieties can be classified into four groups based on their natural nutrient utilization and their fertilizer response. The fertilizer responses of wheat varieties depended on crop year (6.5–8.9 t ha-1 maximum yields in 2011–2015 years) and the genotypes (in 2012 the difference was ~3 t ha-1 among varieties). The optimum N(+PK) doses varied between 30–150 kg ha-1 in different crop years. In maize production fertilization, irrigation and crop rotation have decision role on the yields. The efficiency of fertilization modified by cropyear (in dry 891–1315 kg ha-1, in average 1927–4042 kg ha-1, in rainy cropyear 2051–4473 kg ha-1 yield surpluses of maize, respectively) and crop rotation (in monoculture 1315–4473 kg ha-1, in biculture 924–2727 kg ha-1 and triculture 891–2291 kg ha-1 yield surpluses of maize, respectively). The optimum fertilization could improve the water use efficiency in maize production. Our long-term experiments gave important ecological and agronomic information to guide regional development of sustainable cropping systems.

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