Determination of 2,4-d amine in soils using anion-exchange membranes

Non-Peer ReviewedA new method for the quantitative determination of 2,4-D in soils by use of anion-exchange membranes with GC detection was developed. Preliminary investigation of ion-exchange properties of pure 2,4-D acid on the membranes revealed that whe11 a suitable solvent system is used, a quantitative recovery of 2,4-D acid can be achieved. Linear relationships between 2,4-D acid removed by the membrane and 2,4-D concentration in solutions, soil suspensions and soils were obtained within the range tested. The developed method was successfully applied for the determination of 2,4-D amine from a commercial formulation on soil surfaces. The method was tested in two concentration ranges representing a typical farm spraying application rate and a spill. The relationship between amount of 2,4-D amine detected by membranes and the spike level on the soil surface was linear for both concentration ranges. The applicability of the method was examined for a degradation study of 2,4-D amine after a spill. The low detection limit and the simplicity of the procedure make this method very suitable for 2,4-D determination in soils

Mobility of flucarbazone in two prairie soils

Non-Peer Reviewe

Bioavailability of metsulfuron and sulfentrazone herbicides in soil as affected by amendment with two contrasting willow biochars

Non-Peer Reviewe

Effect of soil pH on pyroxasulfone bioactivity in soil

Non-Peer Reviewe

Are barley yields on eroded calcareous soils restricted by low zinc supply?

Non-Peer ReviewedCalcareous knolls are often relatively unproductive locations in a field landscape. This may be attributed to lack of moisture as well as limited nutrient supplies. A growth chamber study was initiated to investigate the role of micronutrient deficiencies in yield limitations observed on calcareous knolls. Three rates of zinc (Zn) fertilizer were applied to calcareous soils collected from both an Asquith and Amulet association. In addition, macronutrients were applied in sufficient quantities as to not limit plant yields. Barley was grown in the treatments, harvested, and the treatments were compared. Results indicated a highly significant barley dry matter yield response to Zn fertilizer

Developing a herbicide bioassay for the detection of flucarbazonesodium in three Saskatchewan soils

Non-Peer ReviewedIn this study, a bioassay for determination of flucarbazone residues in soils has been investigated. The response of five crops grown on soils (0-10cm) from three landscape positions was examined in the Brown soil zone. Lentil, field pea, tame oats, chickpea and oriental mustard were grown for five days in soils spiked with 1,3,5,10 and 20 ppb of flucarbazone. Root and shoot length and shoot dry weight were measured and percent growth inhibition was calculated. Root length inhibition provided the most sensitive and consistent indication of herbicide presence in the soil. Of the investigated crops, oriental mustard was the most sensitive in revealing root inhibition from of flucarbazone in the soil with detectable inhibition down to 1 ppb. The mustard also showed the highest degree of inhibition, up to approximately 70% as compared to approximately 50% for the other crops. Percent root growth inhibition was soil dependent; the highest degree of inhibition was observed in the upper slope soil and the lowest in the lower slope soil, indicating that soil properties affect the phytotoxicity of the herbicide in the soil

Factors affecting the phytotoxicity and persistence of Group 2 herbicides in prairie soils

Non-Peer ReviewedAdvantages of Group 2 herbicides include low use rates, broad spectrum weed control and low mammalian toxicity. However,Group 2 herbicides often persist in soil and cause damage to subsequent crops in rotation. Phytotoxicity and persistence are the two parameters that determine the potential damage that could occur from these herbicides. These parameters are affected by soil properties, both chemical and physical, and by environmental factors. Phytotoxicity is often increased and persistence extended by low soil organic matter contents. If the compound is susceptible to hydrolysis, low pH can cause increased rates of dissipation due to this chemical process. Microbial activity and the environmental factors that influence decomposition also play a large role. Increased moisture and temperature typically result in increased microbial activity and decreased persistence. Identifying the factors which are most influential in the phytotoxicity and persistence of Group 2 herbicides is important in managing crop rotations and reducing potential for crop damage

Testing root length bioassay for assessment of herbicide resistance in wild oat (Avena fatua L.)

Non-Peer Reviewe

Effect of soil properties on pyroxasulfone bioactivity and field application rates

Non-Peer ReviewedThe relationship between pyroxasulfone bioactivity and soil properties has not been investigated in a wide range of soils typical of western Canada. In this study, 47 soils from Saskatchewan, Manitoba and Alberta, with varying organic matter content (1.5 to 22.1%), pH (5.0 to 7.9), and clay content (6.8 to 59.4%) were used to evaluate the effect of soil properties on pyroxasulfone bioactivity and its relevance to field application rates. Bioactivity was assessed by measuring the reduction of sugar beet shoot length after 7 days in response to 0, 92, 184, and 368 μg ai kg-1 pyroxasulfone concentration in soil. Multiple regression analysis showed that pyroxasulfone bioactivity was related to soil organic matter content, pH and clay content. Grouping the soils according to these properties allowed for a summarization of pyroxasulfone field application rates required to achieve bioactivity based on the magnitude of sugar beet shoot length inhibition (%). The estimated field application rates ranged from less than 120 to 480 g ai ha-1

Application of a mustard root bioassy to assess phytotoxicity of Group 2 herbicides

Non-Peer ReviewedGroup 2 herbicides exhibit high bioactivity at low concentrations in soil and may persist into the next growing season causing crop injury. A bioassay that is suitable for the detection of a range of Group 2 herbicides was developed; in this bioassay, a root growth inhibition of oriental mustard is used for the determination of the herbicide concentration in soil. The Group 2 herbicides included were: Everest (flucarbazone-sodium), Frontline (florasulam), Sundance (sulfosulfuron), and Odyssey (imazamox + imazethapyr). This bioassay was used to examine the degree of root inhibition by simultaneous application of two Group 2 herbicides. Application of varying levels of flucarbazone or sulfosulfuron combined with Odyssey resulted in root length inhibition that was comparable to the root length inhibition caused by application of flucarbazone alone or sulfosulfuron alone and Odyssey alone, possibly indicating an additive effect of these pairs of herbicides. Further studies are needed to examine which combinations of Group 2 herbicides under what environmental and soil conditions may result in “stacking” causing increased plant injury