Crop damage caused by residual acetolactate synthase herbicides in the soils of south-eastern Australia

2006 ◽  
Vol 46 (10) ◽  
pp. 1323 ◽  
Author(s):  
K. L. Hollaway ◽  
R. S. Kookana ◽  
D. M. Noy ◽  
J. G. Smith ◽  
N. Wilhelm
Keyword(s):  
Acetolactate Synthase ◽  
Clay Soils ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Metsulfuron Methyl ◽  
Herbicide Residues ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Grain growers in south-eastern Australia have reported unexpected crop failures with theoretically safe recropping periods for acetolactate synthase herbicides in alkaline soils. This experience has led to the concern that these herbicides may degrade very slowly in alkaline soils, and herbicide residues have at times been blamed for unexplained crop losses. To address this issue, we established 5 recropping trials across Victoria and South Australia with 5 acetolactate synthase herbicides (chlorsulfuron, triasulfuron, metsulfuron-methyl, imazethapyr, and flumetsulam). The herbicides were applied to separate plots in years 1, 2 or 3, and sensitive crop species were sown in year 4 to measure the impact of herbicide residues. We observed that the persistence of the sulfonylureas (chlorsulfuron, triasulfuron, metsulfuron-methyl) varied between herbicides, but all persisted longer in alkaline soils than in acid soils, and were, therefore, more likely to damage crops in alkaline soil. Imazethapyr persisted longer in clay soils than in sandy soils and was, therefore, more likely to damage crops in clay soils. All herbicides persisted longer when rainfall was below average. Canola was more sensitive to imazethapyr than either pea, lentil or medic, but was less sensitive to the sulfonylureas. In contrast, lentil and medic were the most sensitive to sulfonylureas. Despite some damage, we found that safe recropping periods could be predicted from the product labels in all but one situation. The sole exception was that metsulfuron-methyl reduced dry matter and yield of lentil and medic sown 10 months after application in a soil with pH 8.5. We hypothesise that the real cause of crop failure in many situations is not unusual herbicide persistence, but failure to take full account of soil type (pH and clay content including variation in the paddock) and rainfall when deciding to recrop after using acetolactate synthase herbicides.

Persistence and leaching of sulfonylurea herbicides over a 4-year period in the highly alkaline soils of south-eastern Australia

2006 ◽  
Vol 46 (8) ◽  
pp. 1069 ◽  
Author(s):  
K. L. Hollaway ◽  
R. S. Kookana ◽  
D. M. Noy ◽  
J. G. Smith ◽  
N. Wilhelm
Keyword(s):  
Crop Damage ◽  
Sulfonylurea Herbicides ◽  
Alkaline Soils ◽  
Metsulfuron Methyl ◽  
South Eastern ◽  
Eastern Australia ◽  
Current Product ◽  
Potential Damage ◽  
Ph Range ◽  
South Eastern Australia

The sulfonylurea herbicides are commonly used in the cereal belt of south-eastern Australia and there is concern that their persistence in alkaline soils is long enough to damage subsequent rotational crops such as legumes and oilseeds. In this study, we investigated leaching and persistence of 3 commonly used herbicides (chlorsulfuron, triasulfuron and metsulfuron-methyl) in alkaline soils of south-eastern Australia (pH range 7.4–8.6) for at least 4 years after treatment. In general, chlorsulfuron was predicted to persist for 3–5 years [time to degrade to 1% (DT99) of 33–63 months after treatment depending on the field site], triasulfuron for 1–3 years (DT99 of 13–37 months after treatment), and metsulfuron-methyl for less than 1 year (although data were insufficient for degradation estimates) after its application. However, this varied between sites and years of application. Although, the majority of residues remained in the top 20 cm of the soil profile throughout the study, leaching of a small fraction of the residue to deeper layers of the profiles (up to 1 m) was observed. Despite their slow rate of degradation, the herbicides did eventually dissipate, even in soils with very high pH (8.5). In most cases, the current product labels provide an adequate safety period to protect sensitive rotational crops from potential damage due to excessive persistence. However, in particular years at 3 of the 5 field sites, metsulfuron-methyl and triasulfuron persisted beyond the recommended recropping period (9 months for metsulfuron-methyl and 22 months for triasulfuron in soils up to pH 7.5 or 24 months in soils pH 7.6 and above). An accurate measurement of soil pH and its variability within the paddock is essential to minimise any subsequent crop damage by these herbicides.

Persistence and leaching of imazethapyr and flumetsulam herbicides over a 4-year period in the highly alkaline soils of south-eastern Australia

2006 ◽  
Vol 46 (5) ◽  
pp. 669 ◽  
Author(s):  
K. L. Hollaway ◽  
R. S. Kookana ◽  
D. M. Noy ◽  
J. G. Smith ◽  
N. Wilhelm
Keyword(s):  
Clay Soil ◽  
Soil Depth ◽  
Sandy Soils ◽  
Clay Content ◽  
Acetolactate Synthase ◽  
Alkaline Soils ◽  
South Eastern ◽  
Adequate Information ◽  
Eastern Australia ◽  
South Eastern Australia

Imazethapyr and flumetsulam are acetolactate synthase herbicides commonly used in the cereal belt of south-eastern Australia. As their labels recommend recropping periods of up to 34 months for imazethapyr and 24 months for flumetsulam, there are concerns that in some cases their persistence may damage subsequent rotation crops. This is the first major study in south-eastern Australia to investigate their leaching and persistence for up to 4 years after treatment. Imazethapyr persisted for more than 3 years at 2 sites and flumetsulam for more than 2 years at 3 sites. For imazethapyr, soil type (clay content) rather than soil pH seemed to be most important in determining persistence, with residues of 10% of applied imazethapyr predicted to persist for 24 months after treatment in clay soil and 5 months after treatment in sandy soil. The potential for leaching below our studied soil depth of 40 cm is of concern for imazethapyr but not for flumetsulam. The current labels appear to provide adequate information for safe recropping periods, but may be conservative for imazethapyr in sandy soils.

Subsoil constraints to crop production on neutral and alkaline soils in south-eastern Australia: a review of current knowledge and management strategies

2007 ◽  
Vol 47 (11) ◽  
pp. 1245 ◽  
Author(s):  
D. Adcock ◽  
A. M. McNeill ◽  
G. K. McDonald ◽  
R. D. Armstrong
Keyword(s):  
Crop Production ◽  
Rooting Depth ◽  
Nutrient Deficiencies ◽  
Alkaline Soils ◽  
Management Options ◽  
Deep Placement ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Crop yield variability and productivity below potential yield on neutral and alkaline soils in the semiarid Mediterranean-type environments of south-eastern Australia have been attributed, in part, to variable rooting depth and incomplete soil water extraction caused by physical and chemical characteristics of soil horizons below the surface. In this review these characteristics are referred to as subsoil constraints. This document reviews current information concerning subsoil constraints typical of neutral and alkaline soils in south-eastern Australia, principally salinity, sodicity, dense soils with high penetration resistance, waterlogging, nutrient deficiencies and ion toxicities. The review focuses on information from Australia (published and unpublished), using overseas data only where no suitable Australian data is available. An assessment of the effectiveness of current management options to address subsoil constraints is provided. These options are broadly grouped into three categories: (i) amelioration strategies, such as deep ripping, gypsum application or the use of polyacrylamides to reduce sodicity and/or bulk density, deep placement of nutrients or organic matter to overcome subsoil nutrient deficiencies or the growing of ‘primer’ crops to naturally ameliorate the soil; (ii) breeding initiatives for increased crop tolerance to toxicities such as salt and boron; and (iii) avoidance through appropriate agronomic or agro-engineering solutions. The review highlights difficulties associated with identifying the impact of any single subsoil constraint to crop production on neutral and alkaline soils in south-eastern Australia, given that multiple constraints may be present. Difficulty in clearly ranking the relative effect of particular subsoil constraints on crop production (either between constraints or in relation to other edaphic and biological factors) limits current ability to develop targeted solutions designed to overcome these constraints. Furthermore, it is recognised that the task is complicated by spatial and temporal variability of soil physicochemical properties and nutrient availability, as well as other factors such as disease and drought stress. Nevertheless, knowledge of the relative importance of particular subsoil constraints to crop production, and an assessment of impact on crop productivity, are deemed critical to the development of potential management solutions for these neutral to alkaline soils.

Mobility and persistence of three sulfonylurea herbicides in alkaline cropping soils of south-eastern Australia

1999 ◽  
Vol 39 (4) ◽  
pp. 465 ◽  
Author(s):  
I. D. Black ◽  
R. N. Pederson ◽  
A. Flynn ◽  
M. Moerkerk ◽  
C. B. Dyson ◽  
...  
Keyword(s):  
Field Trials ◽  
Biologically Active ◽  
Alkaline Soil ◽  
Sampling Depth ◽  
Metsulfuron Methyl ◽  
South Eastern ◽  
Eastern Australia ◽  
Sampling Zone ◽  
Low Levels ◽  
South Eastern Australia

Biologically active residues of the herbicides metsulfuron-methyl, chlorsulfuron and triasulfuron were estimated with field pea bioassays in soil samples to 80 cm depth from 4 field trials in south-eastern Australia situated on neutral to highly alkaline soil. Residues were both mobile and persistent at low levels. Leaching occurred beyond the lowest sampling depth during the winter–spring growing season. Metsulfuron-methyl was the most mobile of the 3 herbicides. Plant-back experiments involving susceptible crop and pasture species on 2 of the sites showed that the rates of decline of these residues in the sampling zone were slower than might be inferred from label plant-back recommendations in 1 of 2 seasons.

The impact of fire regimes on populations of an endangered lizard in montane south-eastern Australia

2014 ◽  
Vol 40 (2) ◽  
pp. 170-177 ◽  
Author(s):  
Sarsha Gorissen ◽  
Jacqueline Mallinson ◽  
Matthew Greenlees ◽  
Richard Shine
Keyword(s):  
Fire Regimes ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

scholarly journals Applying seed germination studies in fire management for biodiversity conservation in south-eastern Australia

Web Ecology ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 47-54 ◽  
Author(s):  
T. D. Auld ◽  
M. K. J. Ooi
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Fire Regimes ◽  
Functional Trait ◽  
Strong Response ◽  
South Eastern ◽  
Germination Response ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Abstract. We examine the patterns of germination response to fire in the fire-prone flora of the Sydney basin, south-eastern Australia, using examples from several decades of research. The flora shows a strong response to fire-related germination cues. Most species show an interaction between heat and smoke, a number respond only to heat, whilst a few are likely to respond only to smoke. Many recruit in the first 12 months after fire and show no obvious seasonal patterns of recruitment, whilst several species have a strong seasonal germination requirement, even in this essentially aseasonal rainfall region. Key challenges remaining include designing future seed germination studies within the context of informing the germination response surface to smoke and heat interactions, and incorporation of the impact of varying soil moisture on seed germination post-fire, including its affect on resetting of seed dormancy. An understanding of the resilience of species to frequent fire also requires further work, to identify species and functional types most at risk. This work must ideally be integrated within the framework of the management of fire regimes that will change under a changing climate. We suggest that the functional classification of plant types in relation to fire could be enhanced by a consideration of both the type of germination response to fire (type of cues required) and the timing of the response (seasonally driven in response to seed dormancy characteristics, or independent of season). We provide a simplified version of such an addition to functional trait classification in relation to fire.

The introduction of earthworms to an ameliorated, irrigated duplex soil in south-eastern Australia and the influence on macropores

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 807 ◽  
Author(s):  
PS Blackwell ◽  
J Blackwell
Keyword(s):  
Wheat Straw ◽  
Air Permeability ◽  
Clay Soils ◽  
Aporrectodea Caliginosa ◽  
Pore Connectivity ◽  
South Eastern ◽  
Eastern Australia ◽  
Summer Fallow ◽  
Gypsum Application ◽  
South Eastern Australia

Two species of lumbricid, Aporrectodea caliginosa and Aporrectodea longa and a megascolecid, Eukerria saltenis were introduced, during the winter, to a duplex soil (transitional red-brown earth) ameliorated by either gypsum-enriched slots or beds formed after deep ripping and gypsum application. Some were introduced to areas enclosed by mesh within the slots, others were released in adjacent unenclosed areas. The enclosed areas had the equivalent of 0, 5 or 10 t ha-l of wheat straw on the surface, the unenclosed areas had 5 t ha-1. The enclosed areas were excavated in the spring, 17 weeks after earthworms were introduced. Proportionally more Eukerria adults were recovered than Aporrectodea adults (4040% compared with 10-30%). At 20-45 cm depth, Eukerria adults were four times more common than Aporrectodea. Cocoons and immature forms of Aporrectodea were very common, especially near the surface. Nine months after the introduction, even after a drier than average summer fallow, earthworms were still present. More Eukerria than Aporrectodea adults were found in the sample from the unenclosed areas. The smaller species, Eukerria, (about 1 mm diameter and 30 mm long) may be better adapted to survive in these ameliorated clay soils, but further research is needed. In the enclosed areas, soil macroporosity was unaffected by the 17 weeks with earthworms, but air permeability through the macropores was significantly increased, probably due to the burrows increasing vertical pore connectivity within 0 . 3 m depth.

scholarly journals Determining the impact of the Holocene highstand at the coastal-fluvial interface, Shoalhaven River, south-eastern Australia

2013 ◽  
pp. n/a-n/a ◽  
Author(s):  
Stephanie J. Kermode ◽  
Martin R. Gibling ◽  
Brian G. Jones ◽  
Tim J. Cohen ◽  
David M. Price ◽  
...  
Keyword(s):  
The Holocene ◽  
South Eastern ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

Wheat roots proliferate in response to nitrogen and phosphorus fertilisers in Sodosol and Vertosol soils of south-eastern Australia

Soil Research ◽  
2009 ◽  
Vol 47 (1) ◽  
pp. 91 ◽  
Author(s):  
S. J. Officer ◽  
V. M. Dunbabin ◽  
R. D. Armstrong ◽  
R. M. Norton ◽  
G. A. Kearney
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Fine Roots ◽  
Root Diameter ◽  
Soil Types ◽  
Alkaline Soil ◽  
South Eastern ◽  
Eastern Australia ◽  
Root Responses ◽  
South Eastern Australia

Root growth responses to separately placed of bands of N and P fertiliser were examined at the 3-leaf (GS13) and stem extension growth stages (GS30) for wheat (Triticum aestivum L. cv. Yitpi) growing in 2 major alkaline soil types from the rainfed (375–420 mm) grain production regions of south-eastern Australia. Intact cores of a Sodosol and a Vertosol were destructively sampled and changes in root length density (RLD) and root diameter distribution within the soil profile were examined using restricted maximum likelihood analysis and principal component analysis, respectively. At GS13, RLD increased in the Vertosol when only P was applied, although there was no shoot growth response. The root response to P consisted of a spatially generalised increase in RLD, rather than a specific increase in the vicinity of the P fertiliser band. There was a substantially greater, but still generalised, increase in RLD in the Vertosol when both N and P fertiliser were applied, although there was no response to N fertiliser (without P). The distribution of root length in diameter classes changed with depth in the profile at GS13 but was otherwise similar, regardless of soil types and fertiliser treatment. The root responses to fertiliser at GS30 also consisted of a generalised proliferation of RLD in the topsoil, with no detectable fertiliser-specific changes in the location or structure of the root system. Shoot and root growth increased to a similar level at GS30 when plants were supplied with N, irrespective of P, and root diameter distributions were again insensitive to fertiliser treatment. Plants responded to N by increasing the RLD of relatively fine roots (100–250 μm), which was a P style of acquisition strategy that was possibly triggered by moisture limitations. Consequently, the root responses to fertiliser under realistic semi-arid conditions did not follow expectations based on nutrient acquisition studies. Instead, wheat plants responded to N or P fertiliser with a generalised proliferation of fine roots, apparently to better compete for finite water and nutrients.

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