Weed seedbank community composition in a 35-yr-old tillage and rotation experiment

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 263-273 ◽  
Author(s):  
Lynn M. Sosnoskie ◽  
Catherine P. Herms ◽  
John Cardina

Knowledge about how the type, timing, and arrangement of cultural practices influence weed species composition is important for understanding the ecological results of control strategies and designing alternative crop management systems. We evaluated weed seed density, diversity, and community composition from 1997 to 1999 in a 35-yr-old study comparing cropping sequences (continuous corn, corn–soybean, corn–oat–hay) and tillage systems (conventional, minimum, and no-tillage) in Wooster, OH. Weed seedbank diversity, as measured by species richness (S), evenness (J), and the Shannon–Weiner index (H′), was influenced by crop diversity; mean values for each of the indices were generally higher for all combinations of the three-crop sequence than for the corn monoculture or the corn–soybean rotation. Except for 1998, mean seed density (to a depth of 10 cm) was higher in continuous cornthan in corn and soybean rotationsSpecies richness and seed density were also affected by tillage. Mean values forand mean germinable seedswere greatest in the no-tillage system, where the soil was disturbed only by the coulter units of the planter. Differences in weed seedbank community composition among tillage and rotation treatments were examined using two multivariate analyses. Using a multiresponse permutation procedure and canonical discriminant analysis, results suggest that the weed seed community in a corn–oat–hay rotational system differs in structure and composition from communities associated with continuous corn and corn–soybean systems. Additionally, germinable weed seed communities in no-tillage differed in composition from those in conventional and minimum tillage. Crop sequence and tillage system influenced weed species density and diversity and therefore community structure. Manipulation of these factors could help reduce the negative impact of weeds on crop production.

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Lynn M. Sosnoskie ◽  
Catherine P. Herms ◽  
John Cardina ◽  
Theodore M. Webster

The compositions of the germinable weed seedbank and aboveground weed communities in a long-term tillage and rotation study were characterized 4, 5, and 6 yr (2002 to 2004) after the adoption of glyphosate-tolerant corn and soybean. Averaged across rotation, mean germinable weed seed density and diversity were greatest in the no-tillage treatment as compared to the minimum- and conventional-tillage treatments. Averaged over tillage, density and diversity were greater in the corn–oat–hay (ryegrass + alfalfa) system as compared to the continuous corn and corn–soybean rotations. Similar trends in density and diversity were observed for the aboveground weed communities. Differences in community composition among treatments were quantified with the use of a multiresponse permutation procedure. Results indicated that the weed seedbank community in a corn–oat–hay rotational system differed from the communities associated with the continuous corn and corn–soybean rotational systems. Weed seedbank communities developing under a no-tillage operation differed from those in minimum- and conventional-tillage scenarios. Compositional differences among the aboveground weed communities were less pronounced in response to tillage and rotation. Indicator species analyses indicated that the number of significant indicator weed species was generally higher for no tillage than minimum or conventional tillage for both the seedbank and the aboveground weed communities. The number of significant indicator species for the seedbank and weed communities was generally greater in the three-crop rotation as compared to the continuous corn and corn–soybean rotations. The trends observed in density, diversity, and community composition after the adoption of glyphosate-tolerant corn and soybeans, and a glyphosate-dominated weed management program, were also observed when soil-applied herbicides were included in the study. We suggest that the switch to a POST-glyphosate protocol did not significantly alter weed communities in the short term in this study.


2014 ◽  
Vol 38 (4) ◽  
pp. 1281-1292 ◽  
Author(s):  
Luis Alberto Lozano ◽  
Carlos Germán Soracco ◽  
Vicente S. Buda ◽  
Guillermo O. Sarli ◽  
Roberto Raúl Filgueira

The area under the no-tillage system (NT) has been increasing over the last few years. Some authors indicate that stabilization of soil physical properties is reached after some years under NT while other authors debate this. The objective of this study was to determine the effect of the last crop in the rotation sequence (1st year: maize, 2nd year: soybean, 3rd year: wheat/soybean) on soil pore configuration and hydraulic properties in two different soils (site 1: loam, site 2: sandy loam) from the Argentinean Pampas region under long-term NT treatments in order to determine if stabilization of soil physical properties is reached apart from a specific time in the crop sequence. In addition, we compared two procedures for evaluating water-conducting macroporosities, and evaluated the efficiency of the pedotransfer function ROSETTA in estimating the parameters of the van Genuchten-Mualem (VGM) model in these soils. Soil pore configuration and hydraulic properties were not stable and changed according to the crop sequence and the last crop grown in both sites. For both sites, saturated hydraulic conductivity, K0, water-conducting macroporosity, εma, and flow-weighted mean pore radius, R0ma, increased from the 1st to the 2nd year of the crop sequence, and this was attributed to the creation of water-conducting macropores by the maize roots. The VGM model adequately described the water retention curve (WRC) for these soils, but not the hydraulic conductivity (K) vs tension (h) curve. The ROSETTA function failed in the estimation of these parameters. In summary, mean values of K0 ranged from 0.74 to 3.88 cm h-1. In studies on NT effects on soil physical properties, the crop effect must be considered.


2001 ◽  
Vol 36 (12) ◽  
pp. 1539-1545 ◽  
Author(s):  
Maria Alexandra Reis Valpassos ◽  
Eloiza Gomes Silva Cavalcante ◽  
Ana Maria Rodrigues Cassiolato ◽  
Marlene Cristina Alves

The objective of this experiment was to study the effects of soil management systems on the bulk density, chemical soil properties, and on the soil microbial activity on a Latossolo Vermelho distrófico (Oxisol). Soil samples were collected from plots under the following management conditions: a) natural dense "cerrado" vegetation (savanna); b) degraded Brachiaria decumbens pasture, 20 years old; c) no-tillage treatment with annual crop sequence (bean, corn, soybean and dark-oat in continuous rotation), 8 years old; d) conventional tillage treatment with crop residues added to the soil, and annual crop sequence, 10 years old. The continuous use of no-tillage system resulted in an increase in microbial biomass and decrease in soil basal respiration, therefore displaying evident long-term effects on the increase of soil C content. The no-tillage system also provided an improvement in bulk density and chemical properties of the soil. Hence, the no-tillage management system could be an alternative for the conservation and maintenance of physical and chemical conditions and the productive potential of "cerrado" soils.


2018 ◽  
Vol 71 (3) ◽  
Author(s):  
Dorota Gawęda ◽  
Andrzej Woźniak ◽  
Elżbieta Harasim

In-crop weed infestation is affected by both habitat conditions and agronomic practices, including the forecrop and tillage treatments used. This study evaluated the effect of the forecrop and the tillage system on species composition, number and dry weight of weeds in a winter wheat ‘Astoria’. A field study was carried out over the period 2014–2017 at the Uhrusk Experimental Farm (SE Poland), on a mixed rendzina soil with a grain-size distribution of sandy loam. Wheat was grown in a four-course crop rotation: soybean – winter wheat – rapeseed – winter wheat. The experimental factors were as follows: a forecrop of winter wheat (soybean and winter rapeseed) and a tillage system (ploughing and no-tillage). <em>Avena fatua</em> was the most frequently occurring weed in the wheat crop sown after soybean, whereas after winter rapeseed it was <em>Viola arvensis</em>. <em>Viola arvensis</em> was the dominant weed under both tillage systems. In all experimental treatments, the species <em>Viola arvensis</em> and <em>Cirsium arvense</em> were characterized by the highest constancy (Constancy Class V and IV), and also <em>Veronica arvensis</em> after the previous winter rapeseed crop. In the wheat crop sown after winter rapeseed, the number of weeds was found to be higher by 62.1% and the weed dry weight higher by 27.3% compared to these parameters after the previous soybean crop. A richer floristic composition of weeds was also observed in the stand after winter rapeseed. Under conventional tillage conditions, compared to no-tillage, the number of weeds was found to be lower by 39.7% and their dry weight by 50.0%. An increase in the numbers of the dominant weed species was also noted in the untilled plots.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 845C-845 ◽  
Author(s):  
Lynn Marie Sosnoskie* ◽  
John Cardina ◽  
Catherine Papp Herms ◽  
Matthew Kleinhenz

Community composition of the soil seedbank were characterized 35 years after the implementation of a long-term study involving cropping sequences (continuous corn, corn-soybean, corn-oat-hay) and tillage systems (conventional-, minimum- and no-tillage). Germinable seeds within the top 10 cm of soil in early spring were identified and enumerated in 1997, 1998 and 1999. Species diversity, which was characterized by richness (S), evenness (E) and the Shannon-Weiner index (H'), was significantly influenced by crop rotation rather than tillage. Generally, diversity measures were greatest in the corn-oat-hay sequences as compared to the corn-soybean rotations and the corn monoculture. Species richness and H' typically declined with increasing soil disturbance (no-tillage > minimum-tillage > conventional-tillage), whereas E increased with more intense tillage. A synthetic importance value (RI), incorporating both density and frequency measures, was generated for each species in each plot. Multiresponse permutation procedures (MRPP) were used to examine differences in weed community composition with respect to management system for all three years. Results suggest that the weed seed community in a corn-oat-hay rotational system differs substantially, in structure and composition, from communities associated with continuous corn and corn-soybean systems. No tillage systems were significantly different in composition as compared to conventional tillage and minimum tillage treatments. Crop sequence and tillage system are important cultural methods of shifting weed species number and diversity, and therefore, community structure. Manipulation of these factors could help to reduce the negative impact of weeds on crop production.


Weed Science ◽  
1994 ◽  
Vol 42 (2) ◽  
pp. 205-209 ◽  
Author(s):  
Douglas D. Buhler ◽  
David E. Stoltenberg ◽  
Roger L. Becker ◽  
Jeffery L. Gunsolus

Management of perennial weeds is a major concern in reduced-tillage cropping systems. Field research was conducted at Nashua, IA, from 1977 through 1990 to evaluate the long-term impacts of tillage and cropping patterns on perennial weed populations in corn and soybean production. Continuous corn and a corn/soybean rotation were conducted utilizing moldboard plow, chisel plow, ridge tillage, and no-tillage systems. The research area was free of established perennial weed species at the initiation of the experiment in 1977. Hemp dogbane was observed by 1980, with the greatest densities in no-tillage. By 1990, continuous corn had greater hemp dogbane densities with no-tillage than other tillage system by crop rotation treatments. American germander densities were not affected by tillage systems in 1980 and 1981, but by 1990, corn/soybean rotations had greater densities in moldboard plow than other tillage systems. Field bindweed developed primarily in the corn/soybean rotations with the greatest densities occurring in no-tillage. Greater and more diverse populations of perennial weeds developed in reduced-tillage systems than in the moldboard plow system. However, practices used to control annual weeds and environmental factors interacted with tillage to regulate perennial weed populations.


Weed Science ◽  
2018 ◽  
Vol 66 (5) ◽  
pp. 651-661
Author(s):  
Nathaniel M. Drewitz ◽  
David E. Stoltenberg

AbstractPrevious research has shown that strip-tillage (ST) systems conserve soil, reduce production costs, and save time for growers compared with intensive-tillage systems. In contrast to these well-documented benefits, we have limited information on weed community dynamics and management risks in ST corn (Zea maysL.) production systems in the northern Corn Belt. Therefore, we conducted research in 2015 and 2016 to characterize weed community composition, emergence patterns, and aboveground productivity in an ST corn/no-tillage (NT) soybean [Glycine max(L.) Merr.] rotation that was established in 2007 compared with a long-term intensive-tillage chisel-plow (CP) continuous-corn system. Fifteen or more weed species were identified in nontreated quadrats in each cropping system in each year. Common lambsquarters (Chenopodium albumL.) was the most abundant weed species across systems and years.Chenopodium albumdensities were similar between CP and ST corn phases and were approximately 2-fold greater compared with the NT soybean phase. Other abundant weed species occurred at much lower densities thanC. album. In each year, cumulative emergence of nontreated weed communities was described best by a logistic function in each cropping system. Maximum weed community emergence was greater in CP corn than ST corn phases in 2015, but did not differ in 2016. In the ST corn phase, most (about 75%) weed community emergence occurred in the in-row (tilled) zone compared with the between-row (nondisturbed) zone. Total late-season weed shoot biomass did not differ between nontreated CP and ST corn phases in either year, withC. albumaccounting for >85% of total weed biomass in these phases. These results suggest that weed community composition, total emergence, and productivity were similar between CP and ST corn phases after 10 yr. Our findings, coupled with previous research that showed favorable agronomic performance and greater soil conservation associated with the long-term ST corn/NT soybean system, suggest that production risks are no greater than a CP corn system, while processes that underpin ecosystem services are enhanced. These results provide strong evidence to support grower adoption of ST practices as an alternative to intensive tillage.


1974 ◽  
Vol 17 (3) ◽  
pp. 0414-0416 ◽  
Author(s):  
L. L. Harrold ◽  
W. M. Edwards

Weed Science ◽  
1988 ◽  
Vol 36 (4) ◽  
pp. 500-503 ◽  
Author(s):  
Frank Forcella ◽  
Michael J. Lindstrom

Weed seed and seedling populations, and weed competition were compared in plots of continuous corn and corn/soybean rotation under ridge and conventional tillage. After 7 to 8 yr of standard chemical and mechanical weed control, from 1500 to 3000 weed seeds/m2(to a 10-cm depth) were found in continuous corn with ridge tillage whereas about two-thirds fewer seeds were found in conventionally tilled corn. Soil from a corn/soybean rotation had from 200 to 700 seeds/m2in both tillage systems. Annual loss of weed seeds from the soil through germination was from 3 to 12% in ridge tillage and 11 to 43% in conventional tillage. Additions to the seed pool were supplied by small weeds whose germination was stimulated by “layby” cultivation, with up to 10 times more emergence and 140 times more seed production in ridge than in conventional tillage. Withholding herbicides for 1 yr reduced yields of continuous corn by 10 to 27% in ridge tillage, only 2 to 4% in conventional tillage, and negligibly in corn/soybean rotations regardless of tillage. Reducing seed production of small layby weeds in ridge tillage may aid in solving the weed problem in this conservation tillage system.


1988 ◽  
Vol 3 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Gerald E. Brust ◽  
Garfield J. House

AbstractWeed seed consumption experiments involving comparison of rates of seed loss by seed feeders were conducted over a five-week period in low-input (no insecticide, low herbicide usage) conventional- and no-tillage soybean agroecosystems. Seeds of four broadleaf weed species (ragweed[Ambrosia artemisiifoliaL.], pigweed[Amaranthus retroflexusL.], sicklepod[Cassia obtusifoliaL.], and jimsonweed[Datura stramoniumL.]) and one grain crop species (wheat[Triticum aestivumL.]) were provided in a free choice design at densities of 10, 25, and 50 seeds/24 cm3. Approximately 2.3 times more seeds overall, and 1.4 times more large seeds as a group were consumed in notillage systems than in conventional-tillage systems. In our experimental low-input, notillage treatments, large ground beetles (Carabidae: Coleoptera) (15–25 mm) and mice preferentially fed on the larger seed species, while small carabids (< 15 mm), ants and crickets, fed almost exclusively on the smaller seed species. Carabid beetles were responsible for more than half of all seeds consumed. Laboratory and field studies indicated that ground beetles selectively consumed specific seed species. In conventional-tillage, ants were one of the dominant consumers of seeds, suggesting different patterns of resource partitioning in each tillage system. We suggest that selective feeding by arthropod seed feeders, in combination with their high number, could affect the species composition and possibly the abundance of weeds in low-input, no-tillage agroecosystems.


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