Understanding the Long-Term Weed Community Dynamics in Organic and Conventional Crop Rotations Using the Principal Response Curve Method

Weed Science ◽  
2019 ◽  
Vol 67 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Dilshan Benaragama ◽  
Julia L. Leeson ◽  
Steve J. Shirtliffe
Keyword(s):  
Community Composition ◽  
Community Dynamics ◽  
Cropping Systems ◽  
High Input ◽  
Organic Systems ◽  
No Till ◽  
Principal Response Curve ◽  
Predominant Factor ◽  
Conventional Systems

AbstractWeeds have acquired evolutionary adaptations to the diverse crop and weed management strategies used in cropping systems. Therefore, changes in crop production practices such as conventional to organic systems, tillage-based to no-till systems, and diversity in crop rotations can result in differences in weed community composition that have management implications. A study was carried out to understand the weed community dynamics in a long-term alternative cropping systems study at Scott, SK, Canada. Long-term (18-yr) weed community composition data in wheat (Triticum aestivumL.) in ORG (organic), RED (reduced-input, no-till), and HIGH (high-input, conventional tillage) systems with three levels of crop rotation diversity, LOW (low diversity), DAG (diversified annual grains), and DAP (diversified annuals and perennials), were used to study the effect of different cropping systems and the effect of environment (random temporal effects) on residual weed community composition using the principal response curve (PRC) technique. The interaction between cropping systems and year-to-year random environmental changes was found to be the predominant factor causing fluctuations in weed community composition. Furthermore, the single most predominant factor influencing the weed composition was year-to-year random changes. Organic systems clearly differed from the two conventional systems in most years and had more diverse weed communities compared with the two conventional systems. The two conventional systems exhibited similar weed composition in most years. In this study, the use of the PRC method allowed capture of the real temporal dynamics reflected in the cropping systems by time interaction. This study further concludes that moving from a tillage-based, high-input conventional system to a no-till, reduced-input system did not cause significant changes in the weed community composition throughout the time period, but diversity in organic systems was high, probably due to increased occurrence of some difficult to control species.

scholarly journals Soil fertility and crop yields in long-term organic and conventional cropping systems in Eastern Nebraska

2011 ◽  
Vol 27 (3) ◽  
pp. 200-216 ◽  
Author(s):  
Sam E. Wortman ◽  
Tomie D. Galusha ◽  
Stephen C. Mason ◽  
Charles A. Francis
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Cropping Systems ◽  
Animal Manure ◽  
Conventional System ◽  
Organic System ◽  
Organic Systems ◽  
Long Term Study ◽  
Conventional Systems

AbstractOrganic agriculture aims to build soil quality and provide long-term benefits to people and the environment; however, organic practices may reduce crop yields. This long-term study near Mead, NE was conducted to determine differences in soil fertility and crop yields among conventional and organic cropping systems between 1996 and 2007. The conventional system (CR) consisted of corn (Zea maysL.) or sorghum (Sorghum bicolor(L.) Moench)–soybean (Glycine max(L.) Merr.)–sorghum or corn–soybean, whereas the diversified conventional system (DIR) consisted of corn or sorghum–sorghum or corn–soybean–winter wheat (wheat,Triticum aestivumL.). The animal manure-based organic system (OAM) consisted of soybean–corn or sorghum–soybean–wheat, while the forage-based organic system (OFG) consisted of alfalfa (Medicago sativaL.)–alfalfa–corn or sorghum–wheat. Averaged across sampling years, soil organic matter content (OMC), P, pH, Ca, K, Mg and Zn in the top 15 cm of soil were greatest in the OAM system. However, by 2008 OMC was not different between the two organic systems despite almost two times greater carbon inputs in the OAM system. Corn, sorghum and soybean average annual yields were greatest in either of the two conventional systems (7.65, 6.36 and 2.60 Mg ha−1, respectively), whereas wheat yields were greatest in the OAM system (3.07 Mg ha−1). Relative to the mean of the conventional systems, corn yields were reduced by 13 and 33% in the OAM and OFG systems, respectively. Similarly, sorghum yields in the OAM and OFG systems were reduced by 16 and 27%, respectively. Soybean yields were 20% greater in the conventional systems compared with the OAM system. However, wheat yields were 10% greater in the OAM system compared with the conventional DIR system and 23% greater than yield in the OFG system. Alfalfa in the OFG system yielded an average of 7.41 Mg ha−1annually. Competitive yields of organic wheat and alfalfa along with the soil fertility benefits associated with animal manure and perennial forage suggest that aspects of the two organic systems be combined to maximize the productivity and sustainability of organic cropping systems.

scholarly journals Progress of soybean charcoal rot under tillage and no-tillage systems in Brazil

2003 ◽  
Vol 28 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Álvaro M. R. Almeida ◽  
Lilian Amorim ◽  
Armando Bergamin Filho ◽  
Eleno Torres ◽  
José R. B. Farias ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Disease Incidence ◽  
Cropping System ◽  
Macrophomina Phaseolina ◽  
Conventional System ◽  
Survival Times ◽  
Charcoal Rot ◽  
No Till ◽  
Four Seasons ◽  
Conventional Systems

The increase in incidence of charcoal rot caused by Macrophomina phaseolina on soybeans (Glycine max) was followed four seasons in conventional and no-till cropping systems. In the 1997/98 and 2000/01 seasons, total precipitation between sowing and harvest reached 876.3 and 846.9 mm, respectively. For these seasons, disease incidence did not differ significantly between the no-till and conventional systems. In 1998/99 and 1999/00 precipitation totaled 689.9 and 478.3 mm, respectively. In 1998/99, in the no-till system, the disease incidence was 43.7% and 53.1% in the conventional system. In 1999/00 the final incidence was 68.7% and 81.2% for the no-till and conventional systems, respectively. For these two seasons, precipitation was lower than that required for soybean crops (840 mm), and the averages of disease incidence were significantly higher in the conventional system. The concentration of microsclerotia in soil samples was higher in samples collected in conventional system at 0 - 10 cm depth. However, analysis of microsclerotia in roots showed that in years with adequate rain no difference was detected. In dry years, however, roots from plants developed under the conventional system had significantly more microsclerotia. Because of the wide host range of M. phaseolina and the long survival times of the microsclerotia, crop rotation would probably have little benefit in reducing charcoal rot. Under these study conditions it may be a better alternative to suppress charcoal rot by using the no-till cropping system to conserve soil moisture and reduce disease progress.

Long-term organic and conventional farming effects on nutrient density of oats

2021 ◽  
pp. 1-15
Author(s):  
Emmanuel Chiwo Omondi ◽  
Marisa Wagner ◽  
Atanu Mukherjee ◽  
Kristine Nichols
Keyword(s):  
Amino Acids ◽  
Cropping Systems ◽  
Vitamin B1 ◽  
Essential Amino Acids ◽  
Total Carbon ◽  
Nutrient Concentrations ◽  
Amino Acid Synthesis ◽  
Organic Systems ◽  
Nutrient Density

Abstract Declining nutrient densities of crops in the past 50–70 years have been attributed to unsound agricultural practices and plant breeding focus on yield rather than quality. Few studies have quantified the soil and nutritional quality of grains in organic and conventional farms and reported results are scarce and inconsistent. The Rodale Institute's Farming Systems Trial (FST) was established in 1981 to quantify the effects of long-term organic and conventional grain cropping systems and tillage practices. A 2014 study to quantify effects on the nutrient density of oat grains was integrated into three systems within the long-term trial: organic manure-based (MNR), organic legume-based (LEG), and conventional synthetic input-based (CNV), split between tilled (T) and no-till (NT) practices. Oat grains with hulls removed were analyzed for minerals (n = 24), vitamins (n = 24), amino acids (n = 24) and proteins (n = 24), while soil samples to a depth of 10 cm were analyzed for elemental minerals, and total carbon (C), nitrogen (N) and sulfur (S). Organic systems increased six out ten soil minerals whose concentrations were influenced by cropping systems: aluminum (Al), iron (Fe), chromium (Cr), calcium (Ca), barium (B) and strontium (Sr). All essential amino acids were greater in oat grains under LEG systems compared with other systems except lysine, histidine and methionine. Both LEG systems also increased 12 out of 13 non-essential amino acids in oat grains. Total oat N, C and S required for amino acid synthesis tended to be greater in organic systems. Soil N, C and S were highly correlated with total oat amino acids under organic systems compared to CNV. Organic LEG had significantly greater vitamin B1 than MNR and CNV. These results suggest that nutrient concentrations of oat grains were greater in organic systems compared to CNV systems, and the increase could be partially explained by the long-term soil management differences between the systems.

scholarly journals Natural Suppression of Rhizoctonia Bare Patch in a Long-Term No-Till Cropping Systems Experiment

Plant Disease ◽  
2014 ◽  
Vol 98 (3) ◽  
pp. 389-394 ◽  
Author(s):  
W. F. Schillinger ◽  
T. C. Paulitz
Keyword(s):  
Pacific Northwest ◽  
Cropping Systems ◽  
Spring Barley ◽  
The United States ◽  
Carthamus Tinctorius ◽  
Bare Patch ◽  
Yellow Mustard ◽  
No Till ◽  
Mapping Software

The soilborne fungus Rhizoctonia solani AG-8 is a major concern for farmers who practice no-till in the inland Pacific Northwest of the United States. Bare patches caused by Rhizoctonia spp. first appeared in 1999 during year 3 of a 15-year no-till cropping systems experiment near Ritzville, WA (269 mm of annual precipitation). The extent and pattern of patches were mapped each year from 1999 to 2012 at the 8-ha study site with a backpack-mounted global positioning system equipped with mapping software. Bare patches appeared in winter and spring wheat (SW; Triticum aestivum), spring barley (SB; Hordeum vulgare), yellow mustard (Brassica hirta), and safflower (Carthamus tinctorius). At its peak in years 5 to 7, bare patches occupied as much as 18% of total plot area in continuous annual monoculture SW. The area of bare patches began to decline in year 8 and reached near zero levels by year 11. No measurable patches were present in years 12 to 15. Patch area was significantly greater in continuous SW compared with SW grown in a 2-year rotation with SB. Additionally, the 15-year average grain yield for SW in rotation with SB was significantly greater than for continuous SW. Russian thistle (Salsola tragus), a troublesome broadleaf weed with a fast-growing tap root, was the only plant that grew within patches. This article reports the first direct evidence of natural suppression of Rhizoctonia bare patch with long-term no-till in North America. This suppression also developed in a rotation that contained broadleaf crops (yellow mustard and safflower) in all but 5 years of the study, and the suppression was maintained when safflower was added back to the rotation.

scholarly journals Impacts of Repeated Glyphosate Use on Wheat-Associated Bacteria Are Small and Depend on Glyphosate Use History

2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Daniel C. Schlatter ◽  
Chuntao Yin ◽  
Scot Hulbert ◽  
Ian Burke ◽  
Timothy Paulitz
Keyword(s):  
Pacific Northwest ◽  
Bacterial Communities ◽  
Cropping Systems ◽  
Soil Microbial Communities ◽  
Cropping System ◽  
Environmental Benefits ◽  
No Till ◽  
History Of ◽  
History Of Use

ABSTRACT Glyphosate is the most widely used herbicide worldwide and a critical tool for weed control in no-till cropping systems. However, there are concerns about the nontarget impacts of long-term glyphosate use on soil microbial communities. We investigated the impacts of repeated glyphosate treatments on bacterial communities in the soil and rhizosphere of wheat in soils with and without long-term history of glyphosate use. We cycled wheat in the greenhouse using soils from 4 paired fields under no-till (20+-year history of glyphosate) or no history of use. At each cycle, we terminated plants with glyphosate (2× the field rate) or by removing the crowns, and soil and rhizosphere bacterial communities were characterized. Location, cropping history, year, and proximity to the roots had much stronger effects on bacterial communities than did glyphosate, which only explained 2 to 5% of the variation. Less than 1% of all taxa were impacted by glyphosate, more in soils with a long history of use, and more increased than decreased in relative abundance. Glyphosate had minimal impacts on soil and rhizosphere bacteria of wheat, although dying roots after glyphosate application may provide a “greenbridge” favoring some copiotrophic taxa. IMPORTANCE Glyphosate (Roundup) is the most widely used herbicide in the world and the foundation of Roundup Ready soybeans, corn, and the no-till cropping system. However, there have been recent concerns about nontarget impacts of glyphosate on soil microbes. Using next-generation sequencing methods and glyphosate treatments of wheat plants, we described the bacterial communities in the soil and rhizosphere of wheat grown in Pacific Northwest soils across multiple years, different locations, and soils with different histories of glyphosate use. The effects of glyphosate were subtle and much less than those of drivers such as location and cropping systems. Only a small percentage of the bacterial groups were influenced by glyphosate, and most of those were stimulated, probably because of the dying roots. This study provides important information for the future of this important tool for no-till systems and the environmental benefits of reducing soil erosion and fossil fuel inputs.

scholarly journals Methane emission from soil under long-term no-till cropping systems

2012 ◽  
Vol 124 ◽  
pp. 1-7 ◽  
Author(s):  
Cimélio Bayer ◽  
Juliana Gomes ◽  
Frederico Costa Beber Vieira ◽  
Josiléia Accordi Zanatta ◽  
Marisa de Cássia Piccolo ◽  
...  
Keyword(s):  
Methane Emission ◽  
Cropping Systems ◽  
No Till

scholarly journals Long-term cropping system studies support intensive and responsive cropping systems in the low-rainfall Australian Mallee

2015 ◽  
Vol 66 (6) ◽  
pp. 553 ◽  
Author(s):  
A. M. Whitbread ◽  
C. W. Davoren ◽  
V. V. S. R. Gupta ◽  
R. Llewellyn ◽  
the late D. Roget
Keyword(s):  
Crop Residue ◽  
Field Experiments ◽  
Cropping Systems ◽  
Cropping System ◽  
Continuous Cropping ◽  
Gross Margin ◽  
No Till ◽  
Residue Retention ◽  
Term Field

Continuous-cropping systems based on no-till and crop residue retention have been widely adopted across the low-rainfall cereal belt in southern Australia in the last decade to manage climate risk and wind erosion. This paper reports on two long-term field experiments that were established in the late 1990s on texturally different soil types at a time of uncertainty about the profitability of continuous-cropping rotations in low-rainfall environments. Continuous-cereal systems significantly outyielded the traditional pasture–wheat systems in five of the 11 seasons at Waikerie (light-textured soil), resulting in a cumulative gross margin of AU$1600 ha–1 after the initial eight seasons, almost double that of the other treatments. All rotation systems at Kerribee (loam-textured soil) performed poorly, with only the 2003 season producing yields close to 3 t ha–1 and no profit achieved in the years 2004–08. For low-rainfall environments, the success of a higher input cropping system largely depends on the ability to offset the losses in poor seasons by capturing greater benefits from good seasons; therefore, strategies to manage climatic risk are paramount. Fallow efficiency, or the efficiency with which rainfall was stored during the period between crops, averaged 17% at Kerribee and 30% at Waikerie, also indicating that soil texture strongly influences soil evaporation. A ‘responsive’ strategy of continuous cereal with the occasional, high-value ‘break crop’ when seasonal conditions are optimal is considered superior to fixed or pasture–fallow rotations for controlling grass, disease or nutritional issues.

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