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 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 Bacterial Communities on Wheat Grown Under Long-Term Conventional Tillage and No-Till in the Pacific Northwest of the United States

2017 ◽  
Vol 1 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Chuntao Yin ◽  
Nicholas Mueth ◽  
Scot Hulbert ◽  
Daniel Schlatter ◽  
Timothy C. Paulitz ◽  
...  
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
Bacterial Communities ◽  
Rhizosphere Soil ◽  
The United States ◽  
Conventional Tillage ◽  
Bulk Soil ◽  
Tillage Practices ◽  
No Till

Cultural practices, such as tillage, often have widespread impacts on phytobiomes. No-till has been increasingly adopted by wheat growers in the dryland cropping areas of the inland Pacific Northwest in the United States to reduce soil erosion and decrease fuel and labor inputs, yet there are limited data on how conversion to no-till impacts plant-associated bacteria in this highly productive system. To address this knowledge gap, we evaluated bacterial communities in bulk and rhizosphere soil of wheat in two locations (Idaho and Washington) for 2 years, comparing long-term no-till plots and adjacent plots under conventional tillage. In this study, members of phylum Proteobacteria were relatively more abundant in rhizosphere soil, while Acidobacteria and Gemmatimonadetes were more abundant in bulk soil than in the rhizosphere. Bacteroidetes were more frequent under conventional than conservation tillage. In general, bacterial families were more affected by the position of the sample (rhizosphere versus bulk soil) than by tillage practices. Families generally regarded as copiotrophic (Oxalobacteriaceae, Pseudomonadaceae, and Cytophagaceae) were more abundant in rhizosphere soil than bulk in both years. On the contrary, oligotrophic families such as Gaiellaceae and those within Gemmatimonadetes were more abundant in bulk soil than in the rhizosphere. Families affected by tillage varied between the 2 years. These results suggest that bacterial communities in soil were more influenced by plant proximity (rhizosphere versus bulk soil) than by tillage practices, but that specific differences were not consistent and may vary among locations and years.

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.

Liming demand and plant growth improvements for an Oxisol under long-term no-till cropping

2017 ◽  
Vol 155 (7) ◽  
pp. 1093-1112 ◽  
Author(s):  
A. C. A. CARMEIS FILHO ◽  
C. A. C. CRUSCIOL ◽  
A. M. CASTILHOS
Keyword(s):  
Root Length Density ◽  
Cropping Systems ◽  
Cropping System ◽  
No Tillage ◽  
Tropical Regions ◽  
No Till ◽  
Rotation Scheme ◽  
Tropical Conditions ◽  
Tillage System

SUMMARYThe adequate management of soil acidity has long been a challenge in no-till (NT) cropping systems. Some studies conducted in sub-tropical conditions have demonstrated the feasibility of surface liming. However, for tropical regions with dry winters, little long-term information about adequate rates and frequencies of application is available. A 12-year field trial was performed under a tropical no-tillage system with an annual crop rotation scheme. The treatments were composed of four lime rates (0, 1000, 2000 and 4000 kg/ha), estimated via the base saturation (BS) method. Surface application of lime was found to be an effective method for improving the soil fertility profile under this long-term NT cropping system. All three acidity components (pH, hydrogen + aluminium (H + Al), exchangeable Al) and some fertility attributes (phosphorus, exchangeable calcium and magnesium, and BS) were adjusted to a linear function, and better soil chemical conditions were obtained in the 4000 kg/ha treatment, even 4 years after the final application. Due to soil chemical changes, the root length density of wheat and common bean was greater at depths <0·20 m, which led to a higher grain yield, even under unfavourable weather conditions. The results indicate that the application of lime at higher rates can be an acceptable criterion for a tropical Oxisol under a no-tillage system, reducing the frequency of lime application.

Nitrate Leaching to a Shallow Mid-Atlantic Coastal Plain Aquifer as Influenced by Conventional No-Till and Low-Input Sustainable Grain Production Systems

1993 ◽  
Vol 28 (3-5) ◽  
pp. 691-700 ◽  
Author(s):  
J. P. Craig ◽  
R. R. Weil
Keyword(s):  
Management Practices ◽  
Production Systems ◽  
Cropping Systems ◽  
Cropping System ◽  
Atlantic Coastal Plain ◽  
Grain Production ◽  
Nitrogen And Phosphorus ◽  
Mineral N ◽  
Low Input ◽  
No Till

In December, 1987, the states in the Chesapeake Bay region, along with the federal government, signed an agreement which called for a 40% reduction in nitrogen and phosphorus loadings to the Bay by the year 2000. To accomplish this goal, major reductions in nutrient loadings associated with agricultural management practices were deemed necessary. The objective of this study was to determine if reducing fertilizer inputs to the NT system would result in a reduction in nitrogen contamination of groundwater. In this study, groundwater, soil, and percolate samples were collected from two cropping systems. The first system was a conventional no-till (NT) grain production system with a two-year rotation of corn/winter wheat/double crop soybean. The second system, denoted low-input sustainable agriculture (LISA), produced the same crops using a winter legume and relay-cropped soybeans into standing wheat to reduce nitrogen and herbicide inputs. Nitrate-nitrogen concentrations in groundwater were significantly lower under the LISA system. Over 80% of the NT groundwater samples had NO3-N concentrations greater than 10 mgl-1, compared to only 4% for the LISA cropping system. Significantly lower soil mineral N to a depth of 180 cm was also observed. The NT soil had nearly twice as much mineral N present in the 90-180 cm portion than the LISA cropping system.

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.

scholarly journals Effect of Nitrogen and Seeding Rate on β-Glucan, Protein, and Grain Yield of Naked Food Barley in No-Till Cropping Systems in the Palouse Region of the Pacific Northwest

2021 ◽  
Vol 5 ◽  
Author(s):  
Cedric Habiyaremye ◽  
Kurtis L. Schroeder ◽  
John P. Reganold ◽  
David White ◽  
Daniel Packer ◽  
...  
Keyword(s):  
Grain Yield ◽  
Pacific Northwest ◽  
Animal Feed ◽  
Cropping Systems ◽  
N Fertilization ◽  
Test Weight ◽  
Seeding Rate ◽  
No Till ◽  
The Pacific ◽  
Days To Heading

Barley (Hordeum vulgare L.) has a storied history as a food crop, and it has long been a dietary staple of peoples in temperate climates. Contemporary research studies have focused mostly on hulled barley for malt and animal feed. As such, nitrogen (N) and seeding rate agronomic data for naked food barley are lacking. In this study, we evaluated the effects of N on ß-glucan and protein content, and N and seeding rate on phenotypic characteristics of naked food barley, including grain yield, emergence, plant height, days to heading, days to maturity, test weight, percent plump kernels, and percent thin kernels. Experiments were conducted at two no-till farms, located in Almota, WA, and Genesee, ID, in the Palouse region of the Pacific Northwest from 2016 to 2018. The experiment comprised two varieties (“Havener” and “Julie”), employed N rates of 0, 62, 95, 129, and 162 kg N ha−1, and seeding rates of 250, 310, and 375 seeds/m−2. Increased N fertilization rate was shown to significantly increase all response variables, except β-glucan content of the variety Julie, days to heading, test weight, and percent plump and thin kernels. Increased N fertilization resulted in higher mean grain yield of Havener and Julie in both Almota and Genesee up to 95 kg N ha−1. Havener had higher yields (3,908 kg N ha−1) than Julie (3,099 kg N ha−1) across locations and years. Julie had higher β-glucan (8.2%) and protein (12.6%) content compared to Havener (β-glucan = 6.6%; protein = 9.1%). Our results indicate that β-glucan content is associated with genotype, environmental, and agronomic factors in dryland cropping systems of the Palouse.

Response of sunflowers (Helianthus annuus L.) to varying seeding rates and nitrogen fertilizer rates in a no-till cropping system in Saskatchewan

2018 ◽  
Vol 98 (6) ◽  
pp. 1331-1341 ◽  
Author(s):  
W.E. May ◽  
M.P. Dawson ◽  
C.L. Lyons
Keyword(s):  
Plant Density ◽  
Cropping Systems ◽  
Cropping System ◽  
Seeding Rate ◽  
Yield Increase ◽  
No Till ◽  
Rate Study ◽  
Optimum N Rate ◽  
Precision Planting ◽  
N Rates

In the past, most sunflower research was conducted in tilled cropping systems and was based on wide row configurations established using precision planters. Little agronomic information is available for the no-till systems predominant in Saskatchewan, where crops are typically seeded in narrow rows using an air drill. Two studies were conducted in Saskatchewan to determine the optimum seeding and nitrogen (N) rates for short-season sunflowers in a no-till cropping system. The N rate study used 5 N rates (10, 30, 50, 70, and 90 kg N ha−1) with the hybrid 63A21. The seeding rate study used 7 seeding rates (37 000, 49 000, 61 000, 74 000, 86 000, 98 000, and 111 000 seeds ha−1) with two cultivars, AC Sierra (open pollinated) and 63A21 (hybrid). There was a linear yield increase as the N rate increased from 10 to 90 kg N ha−1. Based on the N rates tested in this study and current N fertilizer costs below $1 kg−1, sunflower yields and gross returns were most favorable at 90 kg N ha−1. Future N response research with a wider range of N rates is warranted to best determine the optimum N rate. The optimum seeding rate was between 98 000 and 111 000 seeds ha−1 for AC Sierra and between 74 000 and 86 000 seeds ha−1 for 63A21. The optimum plant density, approximately 70 000 to 75 000 plants ha−1, was similar for both cultivars. These results are higher than the current recommended seeding rates for wide-row precision planting systems in areas with a longer growing season.

scholarly journals Long-Term Green Manure Rotations Improve Soil Biochemical Properties, Yield Sustainability and Nutrient Balances in Acidic Paddy Soil under a Rice-Based Cropping System

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 780
Author(s):  
Muhammad Qaswar ◽  
Jing Huang ◽  
Waqas Ahmed ◽  
Dongchu Li ◽  
Shujun Liu ◽  
...  
Keyword(s):  
Grain Yield ◽  
Green Manure ◽  
Cropping Systems ◽  
Cropping System ◽  
Biochemical Properties ◽  
Control Treatment ◽  
Yield Sustainability ◽  
Double Rice ◽  
Winter Fallow

Cultivation of green manure (GM) crops in intensive cropping systems is important for enhancing crop productivity through soil quality improvement. We investigated yield sustainability, nutrient stocks, nutrient balances and enzyme activities affected by different long-term (1982–2016) green manure rotations in acidic paddy soil in a double-rice cropping system. We selected four treatments from a long-term experiment, including (1) rice-rice-winter fallow as a control treatment (R-R-F), (2) rice-rice-milkvetch (R-R-M), (3) rice-rice-rapeseed (R-R-R), and (4) rice-rice-ryegrass (R-R-G). The results showed that different GM rotations increased grain yield and the sustainable yield index compared with those of the R-R-F treatment. Compared with those of R-R-F, the average grain yield of early rice in R-R-M, R-R-R, and R-R-G increased by 45%, 29%, and 27%, respectively and that of late rice increased by 46%, 28%, and 26%, respectively. Over the years, grain yield increased in all treatments except R-R-F. Green manure also improved the soil chemical properties (SOM and total and available N and P), except soil pH, compared to those of the control treatment. During the 1983–1990 cultivation period, the soil pH of the R-R-M treatment was lower than that of the R-R-F treatment. The addition of green manure did not mitigate the soil acidification caused by the use of inorganic fertilizers. The soil organic matter (SOM), total nitrogen (TN) and total phosphorus (TP) contents and stocks of C, N and P increased over the years. Furthermore, GM significantly increased phosphatase and urease activities and decreased the apparent N and P balances compared with those in the winter fallow treatment. Variance partitioning analysis revealed that soil properties, cropping systems, and climatic factors significantly influenced annual grain yield. Aggregated boosted tree (ABT) analysis quantified the relative influences of the different soil properties on annual grain yield and showed that the relative influences of TN content, SOM, pH, and TP content on annual crop yield were 27.8%, 25.7%, 22.9%, and 20.7%, respectively. In conclusion, GM rotation is beneficial for sustaining high crop yields by improving soil biochemical properties and reducing N and P balances in acidic soil under double- rice cropping systems.

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.

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