Promotion of weed species diversity and reduction of weed seedbanks with conservation tillage and crop rotation

In a 6-yr study on four farms (36 fields) in Ontario, Canada, we tested the effects of tillage (moldboard, chisel plow, no tillage) and crop rotations (continuous corn, corn-soybean, corn-soybean-winter wheat) on emerged and seedbank weed species diversity and density. Aside from the imposed experimental treatments, all other management was generally consistent among farms. Tillage had the largest effect on weed diversity and density. No tillage promoted the highest weed species diversity, chisel plow was intermediate, and moldboard plow resulted in the lowest species diversity. These results are consistent with ecological succession theory. The increase in weed species diversity resulted from 20 species being associated with no tillage systems, 15 of which were winter annuals, biennials, or perennials. Emerged weed density was affected only by tillage. Over 6 yr, seedbank declined in no-tillage systems from 41,000 to 8,000 seeds m−3. Crop yields were not affected by tillage or crop rotation. In practical terms, reduced tillage in combination with a good crop rotation may reduce weed density and expenditures on weed management.

Download Full-text

Alternative weed management strategies in conservation tillage systems for white beans (Phaseolus vulgaris L.)

Canadian Journal of Plant Science ◽

10.4141/p97-055 ◽

1998 ◽

Vol 78 (2) ◽

pp. 363-370 ◽

Cited By ~ 1

Author(s):

David C. Hooker ◽

Tony J. Vyn ◽

Clarence J. Swanton

Keyword(s):

Phaseolus Vulgaris ◽

Weed Management ◽

Conservation Tillage ◽

Management Strategies ◽

First Year ◽

Tillage Systems ◽

No Till ◽

White Bean ◽

Chisel Plow ◽

Moldboard Plow

White bean producers often perceive that increased herbicide inputs are required with the adoption of conservation tillage. Acceptance of conservation tillage systems for this crop would increase if effective weed management practices were assured. In 1991 and 1992, various weed management strategies were evaluated in white bean (Phaseolus vulgaris L.) grown with three tillage systems at two sites in southern Ontario. Experiments were newly established each year following corn harvested for grain. Primary tillage treatments were fall moldboard plowing, fall chisel plowing, and first-year no-till. Combinations of mechanical weeding, metobromuron [3–(4–bromophenyl)–1–methoxy–1–methylurea] herbicide broadcasted at two rates, and a band application of the herbicide were investigated in each tillage system. Timely rotary hoeing reduced weed numbers in moldboard plow and chisel plow treatments, but was not effective in no-till. Weeds were adequately controlled in all tillage systems with mechanical treatments following a herbicide either broadcasted at a reduced rate or banded over the crop row. Metobromuron broadcasted at the full recommended rate alone controlled weeds in no-till; in contrast, the degree of weed control was poor without mechanical cultivation in both moldboard and chisel plow systems. Integrating mechanical and chemical control methods was more beneficial in tilled systems. Overall weed populations were lower in first-year no-till than moldboard plow or chisel plow tillage systems. White bean producers who adopt conservation tillage under conditions similar to those investigated can be assured of effective weed management alternatives as well as bean yields equivalent to conventional tillage. Key words: Conservation tillage, weed management, rotary hoe, inter-row cultivation, Phaseolus vulgaris

Download Full-text

Weed Infestation and Health of the Soybean Crop Depending on Cropping System and Tillage System

Agriculture ◽

10.3390/agriculture10060208 ◽

2020 ◽

Vol 10 (6) ◽

pp. 208 ◽

Cited By ~ 1

Author(s):

Dorota Gawęda ◽

Małgorzata Haliniarz ◽

Urszula Bronowicka-Mielniczuk ◽

Justyna Łukasz

Keyword(s):

Crop Rotation ◽

Amaranthus Retroflexus ◽

Fungal Diseases ◽

Lower Percentage ◽

No Tillage ◽

Weed Species ◽

Tillage Systems ◽

Soybean Crop ◽

Study Results ◽

Weed Infestation

This study evaluated weed infestation and health of the soybean crop grown in crop rotation (CR) and monoculture (CM) under conventional tillage (CT) and no-tillage (NT) conditions. The research proved that growing soybean in monoculture and under no-tillage conditions increases weed infestation and infection of soybean with fungal diseases. In these treatments, increased numbers of most of the dominant species were also found. A significantly higher percentage of monocotyledonous species and a much lower percentage of dicotyledonous ones in total weed dry weight were shown in the CR treatment relative to CM and in the NT system compared to CT. The biodiversity of the weed community was similar in monoculture and crop rotation, and slightly greater in the NT system in comparison with CT conditions. In both tillage systems, Amaranthus retroflexus was the weed species that most infested the soybean crop. In soybean grown after itself, Amaranthus retroflexus was the weed that occurred in the greatest numbers, while, in crop rotation, this was Echinochloa crus-galli. In all years of the study, soybean was infected with Septoria glycines to the highest degree, which was followed by Cercospora sojina, whereas infection with Ascochyta sp. was the lowest. Weather conditions in individual years of the study were proven to affect weed infestation and infection of soybean with fungal diseases. The study results prove that cropping systems and tillage systems significantly affect weed infestation and health of the soybean crop.

Download Full-text

The Selective Memory of Weed Seedbanks after 18 Years of Conservation Tillage

Weed Science ◽

10.1614/ws-d-10-00092.1 ◽

2011 ◽

Vol 59 (1) ◽

pp. 98-106 ◽

Cited By ~ 28

Author(s):

Anne Légère ◽

F. Craig Stevenson ◽

Diane L. Benoit

Keyword(s):

Crop Rotation ◽

Weed Management ◽

Conservation Tillage ◽

Red Clover ◽

Seed Rain ◽

Crop Rotations ◽

Residual Effects ◽

Weed Species ◽

Emergence Patterns ◽

Herbicide Use

A conservation tillage study provided the opportunity to test whether tillage effects on the germinable weed seedbank would be consistent across different crop rotations and to investigate the potential residual effects of herbicide treatments terminated 12 yr earlier. Our objective was to measure the effects of tillage (moldboard plow [MP] vs. chisel plow [CP] vs. no-till [NT]), crop rotation (2-yr barley–red clover followed by 4-yr barley–canola–wheat–soybean rotation, compared to a cereal monoculture), and of a prior weed management factor (three intensity levels of herbicide use) on the density, diversity, and community structure of weed seedbanks. Species richness, evenness (Shannon'sE), and diversity (Shannon'sH′) of spring seedbanks varied little across treatments and over time. Total seedbank density generally increased as tillage was reduced, with some variations due to weed management in 1993 and crop rotation in 2006. Crop rotations generally had smaller seedbanks with fewer species than the monoculture. In 1993, seedbanks with minimum weed management were twice as dense as those with intensive or moderate weed management (approximately 6,000 vs. 3,000 seed m−2). By 2006, seed density averaged 6,838 seed m−2across intensive and moderate weed management regardless of tillage, but was nearly twice as large in NT (12,188 seed m−2) compared to MP (4,770 seed m−2) and CP (7,117 seed m−2) with minimum weed management (LSD0.005= 4488). Species with abundant seedbanks responded differently to treatments. Barnyardgrass and green foxtail had larger seedbanks in the monoculture than in the rotation. Common lambsquarters and pigweed species had large seedbanks in tilled treatments in the rotation, whereas yellow foxtail and field pennycress contributed to the large seedbanks observed in NT treatments. The latter two species were also associated with residual effects of weed management treatments (terminated 12 yr earlier) in NT. The differential seedbank response of weed species, attributed in part to contrasting weed emergence patterns and agronomic practice effects on seed rain, explained some of the weak treatment effects observed for total seedbank density and diversity. The large weed seedbanks observed in NT plots after 18 yr confirms the importance of seed rain and seedbank management for the sustainability of NT systems.

Download Full-text

Effects of crop rotation and field management methods on weed density and species composition in the southeastern part of Latvia

Environment Technology Resources Proceedings of the International Scientific and Practical Conference ◽

10.17770/etr2015vol2.275 ◽

2015 ◽

Vol 2 ◽

pp. 235

Author(s):

Jevgenija Ņečajeva ◽

Zane Mintāle ◽

Ieva Dudele ◽

Anda Isoda-Krasovska ◽

Jolanta Čūrišķe ◽

...

Keyword(s):

Species Composition ◽

Weed Control ◽

Crop Rotation ◽

Weed Management ◽

Management Practices ◽

Integrated Weed Management ◽

Weed Species ◽

Southeastern Part ◽

Weed Density ◽

Field Management

Integrated weed management (IWM) is a complex approach to weed control that is based on use of several different methods complementing each other, instead of relying on one single method, like chemical weed control. Weed control methods that can be used as parts of IWM strategy include mechanical weed control, application of herbicides, low tillage, changes in the rate and application time of fertilizers, use of undersown crops and crop rotation. Weed surveys were carried out in 2013 and 2014 in the southeastern part of Latvia. The aim of this study was to assess the effect of crop rotation and other field management practices on weed density and weed species composition using the data collected in the surveys. Survey was carried out in the arable fields of conventional farms within four different size categories. One of the significant factors that explained the variation of weed composition within a field was a proportion of cereals in crop rotation within a four year period. Further surveys are required to estimate the effects of climatic variables. Density-dependence can also be important for practical management decisions for particular weed species and should be investigated.

Download Full-text

Integrated weed management and weed species diversity

Phytoprotection ◽

10.7202/706048ar ◽

2005 ◽

Vol 75 (1) ◽

pp. 1-18 ◽

Cited By ~ 86

Author(s):

D.R. Clements ◽

S.F. Weise ◽

C.J. Swanton

Keyword(s):

Species Diversity ◽

Weed Management ◽

Community Dynamics ◽

Crop Yields ◽

Integrated Weed Management ◽

Weed Species ◽

Community Interactions ◽

Natural Systems ◽

Weed Diversity ◽

Alternative Practices

Alternative practices for weed management, such as integrated weed management (IWM) may allow the persistence of weed populations below a given economic threshold. Increased species diversity of weeds also may result. If diversity increases, and the number of ecological interactions also increases, weed species should be viewed as an interactive community, rather than an unrelated set of targets for control. In this review we summarize how diversity is evaluated in unmanaged Systems, examine how IWM techniques may alter the diversity of weed species and suggest how strategies can be developed for managing weed diversity under IWM. Methods used to evaluate diversity in natural Systems may be used to evaluate weed diversity in alternative Systems of weed management. We made preliminary calculations of diversity for reduced tillage, modified herbicide use, crop rotation, critical period of weed control, techniques to improve crop competitiveness, and alternative control methods. Many of these IWM techniques potentially may result in changes in weed species diversity. We examined potential effects of these changes in weed diversity within six primary elements of community ecology: colonization, disturbance, the physical environment, interactions with other communities, community interactions and community dynamics. Opportunities to develop strategies of community management exist within each of these elements. If diversity could be managed while maintaining acceptable crop yields, some previously unrealized benefits of the presence of weeds could be seen, as predicted by relationships among plants of unmanaged communities. Moreover, the goal of producing a more sustainable System that incorporates the diversity of the weed community would be complemented by trends in policy towards encouraging biodiversity in agroecosystems.

Download Full-text

Nitrogen distribution in soil density fractions and its relation to nitrogen mineralisation under different tillage systems

Soil Research ◽

10.1071/s97027 ◽

1998 ◽

Vol 36 (2) ◽

pp. 247 ◽

Cited By ~ 15

Author(s):

R. Alvarez ◽

C. R. Alvarez ◽

P. E. Daniel ◽

V. Richter ◽

L. Blotta

Keyword(s):

Crop Yields ◽

Conservation Tillage ◽

No Tillage ◽

Soil Density ◽

Nitrogen Mineralisation ◽

Tillage Systems ◽

Nitrogen Distribution ◽

Soil Medium ◽

Density Fractions

Cropping leads to a depletion of soil organic matter which is associated with a decrease in crop yields. In order to reduce land degradation, conservation tillage systems have been developed over the last few decades. We evaluated the effects of 12 years of no-tillage, chisel tillage, and plough tillage, in a Typic Argiudoll from the Argentine Pampa, on nitrogen distribution in the light (<1·6 g/mL), medium (1·6–2·0 g/mL), and heavy (>2·0 g/mL) soil density fractions and its mineralisation potential. Under no-tillage, nitrogen in light and heavy fractions, and mineralised nitrogen of the whole soil, diminished markedly with depth. Meanwhile, in ploughed soil these variables remained constant up to 20 cm depth. Under chisel tillage, an intermediate condition was observed. In the first 20 cm, no-tillage accumulated more nitrogen in light and medium fractions. A higher and positive correlation was observed between the percentage of organic nitrogen mineralised and the nitrogen in the soil medium fraction, as a percentage of the total nitrogen. Cumulative nitrogen production fitted significantly to the exponential (R2 > 0·931), hyperbolic (R2 > 0·932), and logistic (R2 > 0·930) models, while the Gompertz equation described the data best, obtaining the highest determination coefficient (R2 > 0·989). In vitro nitrogen mineralisation was highest under no-tillage. These results could be attributed to the accumulation of labile organic components associated with a lower mineralisation intensity in the field, a consequence of lower temperatures. This increase under no-tillage in fertility can represent a nitrogen reserve for future crops.

Download Full-text

Weed infestation of soybean (Glycine max L. Merr.) under different tillage systems

Acta Agrobotanica ◽

10.5586/aa.2015.005 ◽

2015 ◽

Vol 68 (1) ◽

pp. 53-58 ◽

Cited By ~ 1

Author(s):

Dorota Gawęda ◽

Rafał Cierpiała ◽

Elżbieta Harasim ◽

Marian Wesołowski ◽

Karol Bujak

Keyword(s):

Crop Yields ◽

Chenopodium Album ◽

Dry Weight ◽

No Tillage ◽

Weed Species ◽

Tillage Systems ◽

Sowing Time ◽

Soybean Cultivars ◽

Weed Infestation ◽

Direct Drilling

Direct drilling is one of the methods to reduce tillage costs. Low labor intensity of this system also makes it possible to grow crops in locations where it is a problem to maintain optimal sowing time. However, the use of no-tillage can cause increased weed infestation of crop plants and as a consequence a decline in crop yields. The present study investigated the effect of two tillage systems, plough tillage and direct drilling, on the species composition, density and air-dry weight of weeds in crops of two soybean cultivars (‘Aldana’ and ‘Augusta’). A three-year field experiment was set up on loess-derived gray-brown podzolic soil. The study showed that the use of direct drilling for soybean cropping resulted in a significant increase in the density and dry weight of weeds relative to plough tillage. The study also found richer floristic composition of weeds and an increase in the numbers of dominant species under no-tillage conditions. Elymus repens, Echinochloa crus-galli and Chenopodium album were dominant weed species in all experimental treatments. Chenopodium album and Galinsoga parviflora were characterized by the highest constancy (constancy classes V and IV) in crops of both soybean cultivars, whereas Echinochloa crus-galli showed the highest constancy value in the ‘Aldana’ crop. Under direct drilling, most weed species were found to exhibit higher constancy compared to plough tillage.

Download Full-text

The Effect of Different Soil Tillage Systems and Crop Residues on the Composition of Weed Communities

Agronomy ◽

10.3390/agronomy11071276 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1276

Author(s):

Vaida Steponavičienė ◽

Aušra Marcinkevičienė ◽

Lina Marija Butkevičienė ◽

Lina Skinulienė ◽

Vaclovas Bogužas

Keyword(s):

Soil Ph ◽

Crop Residues ◽

Soil Tillage ◽

Reduced Tillage ◽

Plant Residues ◽

No Tillage ◽

Agricultural Crops ◽

Weed Species ◽

Tillage Systems ◽

Weed Communities

The composition of weed communities in agricultural crops is dependent on soil properties and the applied agronomic practices. The current study determined the effect of different tillage systems and crop residue on the soil weed community composition. The research programme encompassed 2013–2015 in a long-term field experiment located in the Experimental Station of Vytautas Magnus University in Lithuania. The soil type in the experimental field was qualified as Endocalcaric Stagnosol (Aric, Drainic, Ruptic, Amphisiltic). Weeds were categorised into communities according to soil pH, nitrogen and moisture indicators. The results of investigations were grouped using cluster analysis. Agricultural crops were dominated by different weed species depending on the soil pH and moisture. Weed species were relatively more frequent indicating nitrogen-rich and very nitrogen-rich soils. In the reduced tillage and no-tillage systems, an increase in the abundance of weed species indicating moderate acidity and low acidity, moderately wet and wet, nitrogen-rich and very nitrogen-rich soils was observed. The application of plant residues decreased the weed species abundance. In the reduced tillage and no-tillage systems, the quantitative distribution of weed was often uneven. By evaluating the association of weed communities with groups of different tillage systems with or without plant residues, their control can be optimised.

Download Full-text

Influence of crop rotation, tillage, and management inputs on weed seed production

Weed Science ◽

10.1017/s0043174500091591 ◽

1999 ◽

Vol 47 (2) ◽

pp. 175-183 ◽

Cited By ~ 44

Author(s):

George O. Kegode ◽

Frank Forcella ◽

Sharon Clay

Keyword(s):

Seed Production ◽

Crop Rotation ◽

Crop Production ◽

Conservation Tillage ◽

Farming Systems ◽

Crop Rotations ◽

Weed Seed ◽

Weed Species ◽

Weed Seeds ◽

Ridge Tillage

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to 1994, average grass weed seed productions were 7.3 by 103, 3.7 by 1036.1 by 103and 5.7 by 103seeds m−-2, whereas average broad-leaved weed seed productions were 0.4 by 103, 0.4 by 103, 1.4 by 103, and 0.4 by 103seeds m−-2in crop rotations using conventional tillage (moldboard plow), conservation tillage, no tillage, and ridge tillage, respectively. Crop rotations using conventional or ridge tillage consistently produced more grass and broad-leaved weed seeds, especially in low-input plots. There was little difference in weed seed production among input levels for crop rotations using conservation tillage. Comparing rotations that began and ended with a corn crop revealed that by increasing crop diversity within a rotation while simultaneously reducing the amount of tillage, significantly fewer grass and broad-leaved weed seeds were produced. Among the rotations, grass and broad-leaved weed fecundity were highly variable, but fecundity declined from 1990 to 1994 within each rotation, with a concomitant increase in grass and broad-leaved weed density over the same period. Crop rotation in combination with reduced tillage is an effective way of limiting grass and broad-leaved weed seed production, regardless of the level of management input applied.

Download Full-text

Influence of Weed Management Practices and Crop Rotation on Glyphosate-Resistant Horseweed (Conyza canadensis) Population Dynamics and Crop Yield-Years III and IV

Weed Science ◽

10.1614/ws-09-006.1 ◽

2009 ◽

Vol 57 (4) ◽

pp. 417-426 ◽

Cited By ~ 40

Author(s):

Vince M. Davis ◽

Kevin D. Gibson ◽

Thomas T. Bauman ◽

Stephen C. Weller ◽

William G. Johnson

Keyword(s):

Population Dynamics ◽

Crop Rotation ◽

Crop Yield ◽

Cover Crops ◽

Weed Management ◽

Management Practices ◽

Plant Density ◽

Crop Yields ◽

Management Systems ◽

No Till

Horseweed is an increasingly common and problematic weed in no-till soybean production in the eastern cornbelt due to the frequent occurrence of biotypes resistant to glyphosate. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual non-glyphosate herbicides, and preplant application timing on the population dynamics of glyphosate-resistant (GR) horseweed and crop yield. A field study was conducted from 2003 to 2007 in a no-till field located at a site that contained a moderate infestation of GR horseweed (approximately 1 plant m−2). The experiment was a split-plot design with crop rotation (soybean–corn or soybean–soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying in-field horseweed plant density, seedbank density, and crop yield. Horseweed densities were collected at the time of postemergence applications, 1 mo after postemergence (MAP) applications, and at the time of crop harvest or 4 MAP. Viable seedbank densities were also evaluated from soil samples collected in the fall following seed rain. Soybean–corn crop rotation reduced in-field and seedbank horseweed densities vs. continuous soybean in the third and fourth yr of this experiment. Preplant herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season-long in-field horseweed densities and protecting crop yields since the growth habit of horseweed in this region is primarily as a summer annual. Management systems also influenced the GR and glyphosate-susceptible (GS) biotype population structure after 4 yr of management. The most dramatic shift was from the initial GR : GS ratio of 3 : 1 to a ratio of 1 : 6 after 4 yr of residual preplant herbicide use followed by non-glyphosate postemergence herbicides.

Download Full-text