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

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.

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A Review of Research Directions and Research Methods of Farmland Weeds

NASS Journal of Agricultural Sciences ◽

10.36956/njas.v3i2.430 ◽

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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Weed Seed Banks in Established Strawberry Fields

HortScience ◽

10.21273/hortsci.33.3.459f ◽

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.

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Integrated Weed Management Systems for Irrigated Corn (Zea mays) Production in Colorado—A Case Study

Weed Science ◽

10.1017/s0043174500094121 ◽

1996 ◽

Vol 44 (2) ◽

pp. 423-428 ◽

Cited By ~ 5

Author(s):

Mark J. Vangessel ◽

Edward E. Schweizer ◽

Donald W. Lybecker ◽

Philip Westra

Keyword(s):

Weed Control ◽

Seed Bank ◽

Weed Management ◽

Management Systems ◽

Integrated Weed Management ◽

Management Research ◽

Weed Seed ◽

Cooperative Research ◽

Gross Margin ◽

Management Tactics

Cooperative research was initiated by a multidisciplinary team of weed scientists and agricultural economists in 1975 that laid the foundation for integrated weed management research in Colorado. Colorado's integrated weed management research has four phases: weed seed bank decline, systems approach to weed management, bioeconomic modeling, and multiple weed management tactics. Each phase considered weed seed bank, weed control efficacy, weed control costs, crop yield, and gross margin. All four phases emphasize the need for a weed management system that minimizes seed production in situations where a high soil weed seed bank exists. However, once the weed seed bank is reduced, a weed management program with less than 100% weed control can be employed without increasing the seed bank. Intensive weed management systems are seldom justified when economics, weed control, and weed seed bank are considered. Integrated weed management approaches require integrating crop and weed biology with management tactics. Integrated weed management requires advanced managerial skills and often more time than traditional approaches.

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A Comparison of Threshold Strategies in Tomatoes and Soybean

Weed Technology ◽

10.1614/wt-07-155.1 ◽

2008 ◽

Vol 22 (4) ◽

pp. 729-735 ◽

Cited By ~ 2

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.

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

PeerJ ◽

10.7717/peerj.7650 ◽

2019 ◽

Vol 7 ◽

pp. e7650 ◽

Cited By ~ 1

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.

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VIABILITY OF WEED SEED BANK UNDER DIFFERENT EFFECTS OF WEED CONTROL IN LENTIL

Mesopotamia Journal of Agriculture ◽

10.33899/magrj.2010.34318 ◽

2010 ◽

Vol 38 (0) ◽

pp. 237-243

Author(s):

A. M. Sultan

Keyword(s):

Weed Control ◽

Seed Bank ◽

Weed Seed

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Effect of a Living Mulch on Weed Seed Banks in Tomato

Weed Technology ◽

10.1614/wt-d-10-00101.1 ◽

2011 ◽

Vol 25 (2) ◽

pp. 245-251 ◽

Cited By ~ 11

Author(s):

Kevin D. Gibson ◽

John Mcmillan ◽

Stephen G. Hallett ◽

Thomas Jordan ◽

Stephen C. Weller

Keyword(s):

Seed Production ◽

Seed Bank ◽

Critical Period ◽

Field Studies ◽

Seed Banks ◽

Weed Suppression ◽

Weed Seed ◽

Fresh Market ◽

Living Mulch ◽

Seed Rate

Weeds that emerge between rows in fresh market tomatoes after the critical period of competition are not suppressed by the crop and can produce large quantities of seed. A living mulch planted between rows might limit weed seed production. Buckwheat was seeded between tomato rows after the critical period in 2007 and 2008 in field studies near Lafayette, IN. Weeds were allowed to emerge after the critical period (CP), controlled throughout the growing season (no seed threshold [NST]), or mowed to limit seed production (MOW). Buckwheat and MOW plots were mowed twice after the critical period in 2007 and once in 2008. Seed banks were sampled after the critical period and in the following spring. Tomato yields were not reduced by growing buckwheat between rows. Seed bank densities for common purslane and carpetweed, which escaped mowing due to their prostrate habits, increased in all treatments. Germinable seed bank densities were 306 seeds m−2or less in the NST and buckwheat treatments but 755 seeds m−2or more in the CP treatments for species with erect habits in both years. Seed bank densities were lower in the MOW treatment than in the CP treatments in 2007 but not in 2008. In a parallel experiment conducted in adjacent plots, buckwheat was seeded at five rates (0, 56, 112, 168, and 224 kg seed ha−1). Plots were mowed and emergent weeds sampled as described for the intercrop experiment. Weed densities before mowing decreased linearly with buckwheat seed rate. After mowing, no relationship was detected between seed rate and weed densities. This study supports the hypothesis that a living mulch planted after the critical period can be used to limit seed bank growth without reducing tomato yields, but additional research is needed to better understand the effect of mowing on living mulch growth and weed suppression.

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Weed Seed Banks Are More Dynamic in a Sod-Based, Than in a Conventional, Peanut–Cotton Rotation

Weed Science ◽

10.1614/ws-d-15-00003.1 ◽

2015 ◽

Vol 63 (4) ◽

pp. 877-887 ◽

Cited By ~ 6

Author(s):

Ramon G. Leon ◽

David L. Wright ◽

James J. Marois

Keyword(s):

Crop Rotation ◽

Seed Bank ◽

Seed Banks ◽

Community Diversity ◽

Weed Seed ◽

Weed Species ◽

Perennial Crop ◽

Seed Bank Dynamics ◽

Weed Seeds ◽

Grass Weed

Crop rotation promotes productivity, nutrient cycling, and effective pest management. However, in row-crop systems, rotation is frequently limited to two crops. Adding a third crop, especially a perennial crop, might increase crop-rotation benefits, but concerns about disruption of agricultural and ecological processes preclude grower adoption of a three-crop rotation. The objective of the present research was to determine whether weed seed banks differ between a sod-based rotation (bahiagrass–bahiagrass–peanut–cotton) and a conventional peanut–cotton rotation (peanut–cotton–cotton) and the importance of crop phase in weed seed-bank dynamics in a long-term experiment initiated in 1999 in Florida. Extractable (ESB) and germinable (GSB) seed banks were evaluated at the end of each crop phase in 2012 and 2013, and total weed seed or seedling number, Shannon-Weiner's diversity (H′), richness, and evenness were determined. ESB increased in H′ (36%), richness (29%), and total number of weed seeds (40%) for sod-based compared with conventional rotation, whereas GSB increased 32% in H′, 27% in richness, and 177% in total number of weed seedlings. Crop phase was a determinant factor in the differences between crop rotations. The first year of bahiagrass (B1) exhibited increases in weed seed and seedling number, H′, and richness and had the highest values observed in the sod-based rotation. These increases were transient, and in the second year of bahiagrass (B2), weed numbers and H′ decreased and reached levels equivalent to those in the conventional peanut–cotton rotation. The B1 phase increased the germinable fraction of the seed bank, compared with the other crop phases, but not the total number of weed seeds as determined by ESB. The increases in H′ and richness in bahiagrass phases were mainly due to grass weed species. However, these grass weed species were not associated with peanut and cotton phases of the sod-based rotation. The results of the present study demonstrated that including bahiagrass as a third crop in a peanut–cotton rotation could increase weed community diversity, mainly by favoring increases in richness and diversity, but the structure and characteristics of the rotation would prevent continuous increases in the weed seed bank that could affect the peanut and cotton phases.

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