A Comparison of Threshold Strategies in Tomatoes and Soybean

2008 ◽  
Vol 22 (4) ◽  
pp. 729-735 ◽  
Author(s):  
Carlos D. Mayén ◽  
Kevin D. Gibson ◽  
Stephen C. Weller
Keyword(s):  
Weed Control ◽  
Seed Bank ◽  
Crop Yields ◽  
Control Strategies ◽  
Seed Banks ◽  
Weed Seed ◽  
Tomato Seed ◽  
Giant Foxtail ◽  
The Difference

Weed control strategies based on conserving crop yields rather than preventing weed seed production may result in increased weed densities and management costs over the long-term, particularly in less competitive crops such as tomatoes. The effect of crop, tillage, and duration of weed control on weed seed bank size and composition was examined from spring 2001 to spring 2003 near Lafayette, IN. Main plots in 2001 and 2002 contained soybean or tomato planted in rotation (soybean-tomato, tomato-soybean). Subplots were managed with either conventional or no-till practices. Sub-subplots contrasted threshold strategies in which weeds were either controlled for four to six weeks (period threshold, PT) or throughout the growing season (no-seed-threshold, NST). Seed banks were sampled annually in the spring. Emergent weeds were counted` at four and twelve weeks after planting (WAP) in 2001 and 2002. Weed seed banks did not significantly change in the NST plots in any year. However, seed bank densities increased substantially following tomatoes in PT plots. In contrast, weed seed bank densities decreased following soybeans in PT plots. The difference in seed banks and emergent weeds between soybean and tomatoes could be attributed primarily to greater suppression of giant foxtail by the soybean canopy. Giant foxtail control was greater in PT soybeans than in PT tomatoes in both years and giant foxtail comprised most of the PT tomato seed bank in 2002 and 2003. Tillage did not affect weed seed banks in any year. This study highlights the need to control later emerging weeds in tomatoes to prevent large increases in the weed seed bank.

Weed Seed Banks in Established Strawberry Fields

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 459f-460
Author(s):  
Faye Propsom ◽  
Emily Hoover
Keyword(s):  
Organic Matter ◽  
Weed Control ◽  
Seed Bank ◽  
Cultural Practices ◽  
Seed Banks ◽  
Soil Samples ◽  
Soil Types ◽  
Twin Cities ◽  
Weed Seed ◽  
Metro Area

Weed control in strawberries, either in a new planting or one that is established, is a major source of problems for growers in Minnesota. To control weeds, growers need to know which weeds are a problem, which weeds are deleterious, and which weeds have the potential to become a problem. Weeds present, soil type, and weed seed bank information are needed in order to predict potential weed problems. With different weed control practices applied between and within the rows, we assumed weed seed bank populations would vary. In addition, we were interested in seeing if the seed banks differed between soil types and individual farmer's cultural practices. Soil samples were collected from 13 commercial strawberry fields located around the Twin Cities metro area. In 1996, samples were taken after renovation and before mulch was applied. In 1997, they were taken after mulch was removed and prior to renovation. The soil samples for each date, treatment, and farm were dried, and organic matter was separated from inorganic. The weed seeds were removed from the remaining organic matter, identified and counted. Soil types and cultural practices were used to compare the differences among the farms.

Management Filters and Species Traits: Weed Community Assembly in Long-Term Organic and Conventional Systems

Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 265-277 ◽  
Author(s):  
Matthew R. Ryan ◽  
Richard G. Smith ◽  
Steven B. Mirsky ◽  
David A. Mortensen ◽  
Rita Seidel
Keyword(s):  
Weed Control ◽  
Seed Bank ◽  
Community Assembly ◽  
Species Traits ◽  
Seed Banks ◽  
Management Systems ◽  
Conventional System ◽  
Weed Seed ◽  
Organic Systems ◽  
Weed Communities

Community assembly theory provides a useful framework to assess the response of weed communities to agricultural management systems and to improve the predictive power of weed science. Under this framework, weed community assembly is constrained by abiotic and biotic “filters” that act on species traits to determine community composition. We used an assembly approach to investigate the response of weed seed banks to 25 yr of management-related filtering in three different row-crop management systems in southeastern Pennsylvania: organic manure-based, organic legume-based, and conventional. Weed seed banks were sampled in April of 2005 and 2006 and quantified by direct germination in a greenhouse. We also assessed the filtering effects of weed management practices and relationships between assembled seed bank and emergent weed communities by allowing or excluding weed control practices within each management system and measuring emergent weed community response. Germinable weed seed bank densities and species richness in the final year of the study were over 40% and 15% higher, respectively, in the organic systems relative to the conventional system. Seed bank community structure in the organic systems was different from the conventional system, and the relationships between assembled seed banks and the emergent flora varied. Primary tillage, weed control, timing of planting, and fertility management appeared to be the main filters that differentiated weed seed banks in the three systems. Weed life history, emergence periodicity, seed size, and responsiveness to soil fertility and hydrology appeared to be the most important functional traits determining how weed species responded to management-related filters. Our results suggest that management systems can exert strong filtering effects that can persist over relatively long (greater than one growing season) time scales. Legacy effects of community-level filtering might be more important than previously assumed, and should be incorporated into predictive models of weed community assembly.

Weed population responses to weed control practices. I. Seed bank, weed populations, and crop yields

Weed Science ◽  
1999 ◽  
Vol 47 (4) ◽  
pp. 416-422 ◽  
Author(s):  
Douglas D. Buhler
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Crop Yields ◽  
Initial Density ◽  
Control Treatment ◽  
Weed Seed ◽  
Weather Factors ◽  
Giant Foxtail ◽  
Broadleaf Species ◽  
Yield Responses

Weed control practices affected the weed seed content of the soil, weed seedling populations, and corn and soybean yields in two 4-yr field experiments. When the initial weed seed density was high, giant foxtail seed numbers in soil declined rapidly under weed-free conditions. Changes in seed densities when initial densities were low varied over years. Mechanical and chemical control treatments had variable effects on weed seed numbers over the course of the experiment. Weed seed numbers and weed densities were sometimes greater if herbicides were banded, but crop yields were similar to full-rate herbicides in both experiments in all years. When the initial density was low, giant foxtail seed numbers in soil increased over the course of the experiment regardless of the weed control treatment. Seed densities of broadleaf species decreased under the same conditions. Also, when initial weed densities were low, weed control and crop yields were less sensitive to weed control practices than at high weed densities. Weather factors that influenced treatment efficacy had a major affect on weed populations and crop yield responses to the weed control treatments over years. The interactions of weed control practices, weed populations, and crop yields were complex. Initial weed density and species composition interacted with weed control treatments and weather patterns to generate the results observed.

Weed Control with Reduced Rates of Chlorimuron Plus Metribuzin and Imazethapyr in No-Till Narrow-Row Soybean (Glycine max)

1998 ◽  
Vol 12 (1) ◽  
pp. 32-36 ◽  
Author(s):  
William G. Johnson ◽  
Jeffrey S. Dilbeck ◽  
Michael S. Defelice ◽  
J. Andrew Kendig
Keyword(s):  
Glycine Max ◽  
Weed Control ◽  
Field Studies ◽  
Weed Suppression ◽  
Crop Response ◽  
Soybean Production ◽  
No Till ◽  
Giant Foxtail ◽  
The Difference ◽  
Narrow Row

Field studies were conducted at three locations in 1993 and 1994 to evaluate weed control and crop response to combinations of glyphosate, metolachlor, 0.5 X and 1 X label rates of chlorimuron plus metribuzin applied prior to planting (PP), and 0.5 X and 1 X label rates of imazethapyr applied early postemergence (EPOST) or postemergence (POST) in no-till narrow-row soybean production. Giant foxtail densities were reduced with sequential PP followed by (fb) EPOST or POST treatments. Large crabgrass was reduced equivalently with all herbicide combinations involving chlorimuron plus metribuzin PP fb imazethapyr. Common cocklebur control was variable but was usually greater with treatments that included imazethapyr. Ivyleaf morningglory densities were not reduced with any herbicide combinations. Sequential PP fb EPOST or POST treatments tended to provide slightly better weed suppression than PP-only treatments, but the difference was rarely significant. Soybean yields with treatments utilizing 0.5 X rates were usually equal to 1 X rates.

scholarly journals Responses of weed community, soil nutrients, and microbes to different weed management practices in a fallow field in Northern China

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7650 ◽  
Author(s):  
Xian Gu ◽  
Yu Cen ◽  
Liyue Guo ◽  
Caihong Li ◽  
Han Yuan ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Soil Nutrients ◽  
Seed Bank ◽  
Weed Management ◽  
Seed Banks ◽  
Total Biomass ◽  
Weed Seed ◽  
Soil Biodiversity ◽  
Deep Tillage ◽  
Positive Effects

The long-term use of herbicides to remove weeds in fallow croplands can impair soil biodiversity, affect the quality of agricultural products, and threaten human health. Consequently, the identification of methods that can effectively limit the weed seed bank and maintain fallow soil fertility without causing soil pollution for the next planting is a critical task. In this study, four weeding treatments were established based on different degrees of disturbance to the topsoil: natural fallow (N), physical clearance (C), deep tillage (D), and sprayed herbicide (H). The changes in the soil weed seed banks, soil nutrients, and soil microbial biomass were carefully investigated. During the fallow period, the C treatment decreased the annual and biennial weed seed bank by 34% against pretreatment, whereas the H treatment did not effectively reduce the weed seed bank. The D treatment had positive effects on the soil fertility, increasing the available nitrogen 108% over that found in the N soil. In addition, a pre-winter deep tillage interfered with the rhizome propagation of perennial weeds. The total biomass of soil bacterial, fungal, and actinomycete in H treatment was the lowest among the four treatments. The biomass of arbuscular mycorrhizal fungi in the N treatment was respectively 42%, 35%, and 91%, higher than that in the C, D, and H treatments. An ecological weeding strategy was proposed based on our findings, which called for exhausting seed banks, blocking seed transmission, and taking advantage of natural opportunities to prevent weed growth for fallow lands. This study could provide a theoretical basis for weed management in fallow fields and organic farming systems.

scholarly journals Weed seed-bank responses to long-term fertilization in a rice-wheat rotation system

2014 ◽  
Vol 60 (No. 8) ◽  
pp. 344-350 ◽  
Author(s):  
M. Jiang ◽  
Shen XP ◽  
W. Gao ◽  
Shen MX ◽  
Dai QG
Keyword(s):  
Seed Bank ◽  
Surface Soil ◽  
Soil Nutrient ◽  
Organic Fertilizers ◽  
Weed Seed ◽  
Factors Affecting ◽  
Fertilization Experiment ◽  
Rotation System ◽  
Major Nutrients

We studied the heterogeneity of soil weed seed-bank in a rice-wheat rotation system after long-term application of different organic or non-organic fertilizers, and the effects of major nutrients on the characteristics of the weed seed-bank. The soil was sampled in the Taihu area after a 31-year long-term fertilization experiment. Weed seeds were identified and counted in the surface soil of 12 differentially treated areas using microscopic examination, and analyzed by the Simpson, Shannon, Margalef, and Pielou indexes. The long-term application of organic fertilizers could significantly reduce the density of soil weed seed-bank; non-organic fertilizers and a combination of non-organic and organic fertilizers had a significant influence on the number of species and diversity of weeds. The application of organic fertilizers improved the Simpson, Shannon and Pielou indexes of soil weed seed-bank community and stabilized the community structure. In terms of the soil nutrient system itself, the soil organic materials and total nitrogen content are the main environmental factors affecting the distribution of soil weed seed-bank.

Modeling Population Dynamics of Kochia (Bassia scoparia) in Response to Diverse Weed Control Options

Weed Science ◽  
2019 ◽  
Vol 67 (1) ◽  
pp. 57-67 ◽  
Author(s):  
O. Adewale Osipitan ◽  
J. Anita Dille ◽  
Muthukumar V. Bagavathiannan ◽  
Stevan Z. Knezevic
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Weed Control ◽  
Seed Production ◽  
Seedling Recruitment ◽  
Control Strategies ◽  
Effective Control ◽  
Parameter Estimates ◽  
Herbicide Resistant

AbstractKochia [Bassia scoparia(L.) A. J. Scott] is a problematic weed species across the Great Plains, as it is spreading fast and has developed herbicide-resistant biotypes. It is imperative to understand key life-history stages that promote population expansion ofB. scopariaand control strategies that would provide effective control of these key stages, thereby reducing population growth. Diversifying weed control strategies has been widely recommended for the management of herbicide-resistant weeds. Therefore, the objectives of this study were to develop a simulation model to assess the population dynamics ofB. scopariaand to evaluate the effectiveness of diverse weed control strategies on long-term growth rates ofB. scopariapopulations. The model assumed the existence of a glyphosate-resistant (GR) biotype in theB. scopariapopulation, but at a very low proportion in a crop rotation that included glyphosate-tolerant corn (Zea maysL.) and soybean [Glycine max(L.) Merr.]. The parameter estimates used in the model were obtained from various ecological and management studies onB. scoparia. Model simulations indicated that seedling recruitment and survival to seed production were more important than seedbank persistence forB. scopariapopulation growth rate. Results showed that a diversified management program, including glyphosate, could provide excellent control ofB. scopariapopulations and potentially eliminate already evolved GRB. scopariabiotypes within a given location. The most successful scenario was a diverse control strategy that included one or two preplant tillage operations followed by preplant or PRE application of herbicides with residual activities and POST application of glyphosate; this strategy reduced seedling recruitment, survival, and seed production during the growing season, with tremendous negative impacts on long-term population growth and resistance risk inB. scoparia.

Long-term perennial weed control strategies: Economic analyses and yield effect in hazelnut (Corylus avellana)

2016 ◽  
Vol 80 ◽  
pp. 7-14 ◽  
Author(s):  
Emine Kaya-Altop ◽  
Kianoosh Haghnama ◽  
Dogan Sarıaslan ◽  
Colin J. Phillippo ◽  
Husrev Mennan ◽  
...  
Keyword(s):  
Weed Control ◽  
Control Strategies ◽  
Corylus Avellana ◽  
Perennial Weed ◽  
Economic Analyses

scholarly journals Evolution with a seed bank: the population genetic consequences of microbial dormancy

2017 ◽  
Author(s):  
WR Shoemaker ◽  
JT Lennon
Keyword(s):  
Seed Bank ◽  
Population Genetic ◽  
Evolutionary Dynamics ◽  
Phenotypic Diversity ◽  
Seed Banks ◽  
Hedging Strategy ◽  
Term Survival ◽  
Evolutionary Forces ◽  
Growth And Reproduction

ABSTRACTDormancy is a bet-hedging strategy that allows organisms to persist through conditions that are sub-optimal for growth and reproduction by entering a reversible state of reduced metabolic activity. Dormancy allows a population to maintain a reservoir of genetic and phenotypic diversity (i.e., a seed bank) that can contribute to the long-term survival of a population. This strategy can be potentially adaptive and has long been of interest to ecologists and evolutionary biologists. However, comparatively little is known about how dormancy influences the fundamental evolutionary forces of genetic drift, mutation, selection, recombination, and gene flow. Here, we investigate how seed banks affect the processes underpinning evolution by reviewing existing theory, implementing novel simulations, and determining how and when dormancy can influence evolution as a population genetic process. We extend our analysis to examine how seed banks can alter macroevolutionary processes, including rates of speciation and extinction. Through the lens of population genetic theory, we can understand the extent that seed banks influence microbial evolutionary dynamics.

scholarly journals A Review of Research Directions and Research Methods of Farmland Weeds

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Shujuan Li ◽  
Guoqin Huang
Keyword(s):  
Research Methods ◽  
Weed Control ◽  
High Efficiency ◽  
Research Work ◽  
Reference Value ◽  
Seed Banks ◽  
High Yield ◽  
Weed Seed ◽  
Research Directions ◽  
Weed Communities

Farmland weeds are an important part of farmland ecosystems. Research on farmland weeds is one of the major research fields in agricultural ecology. It is of great significance for achieving high yield, high quality and high efficiency in agriculture. In recent years, research on farmland weeds has focused on investigation of weed communities, research on weed seed banks, and research on weed control. These three research directions complement each other. Among them, the investigation work of weed communities and the research of weed seed banks are helpful for us to grasp the occurrence of farmland weeds more accurately and provide references for the control of farmland weeds. This article summarizes the research directions of farmland weeds in recent years (weed community investigation, weed seed bank, weed control) and the research methods used, provide reference value for the follow-up research work of farmland weeds, and provide theoretical support for promoting the development of rural ecological industry and building beautiful villages.

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