From high herbicide/no tillage to no herbicide/high tillage: how do crops respond?

Non-Peer ReviewedIn general, zero-till systems resulted in higher yields and yields declined as the intensity of tillage was increased. The High Herbicide/Zero Tillage system always resulted in the highest yield. The Medium Herbicide/Zero Tillage, Low Herbicide/Zero Tillage and Medium Herbicide/Medium Tillage systems always resulted in similar yields just slightly lower than the HH/ZT system. Canola yields declined the most and barley and pea yields the least when herbicide inputs were reduced. Management system had little or no effect on crop quality characteristics and weed biomass tended to be greatest when herbicides were not used. As herbicide intensity decreased, weed biomass increased and yield decreased in all crops. Application of fungicide generally increased seed yield of barley, wheat and field pea with the greatest increases occurring in barley. In most cases where yield responses were significant, the magnitude of the increase was relatively small and so the economic impact of fungicide application was often not positive. The greatest response to fungicide occurred in the wetter years of 1999 and 2000. Fungicide application increased seed weight of all crops except for canola, tended to reduce protein concentration of cereals and field pea and increased barley plumpness

Broadleaf weed control in chickpea (Cicer arietinum) and lentil (Lens culinaris) with fall application of pursuit

Non-Peer ReviewedBroadleaf weed control options in chickpea and lentil are very limited. Preliminary trials found that spring applied Pursuit at rates from 0.25X to 0.5X resulted in severe injury to chickpea in some years. The objective of these trials was to evaluate fall application of Pursuit in chickpea and lentil, at rates from 0.25X to 0.5X, for both crop tolerance and weed control efficacy. A 4-replicate trial was set up at Saskatoon, Sask. in 2000, 2001 and 2002 and at Scott, Sask. and Swift Current, Sask. in 2002. Pursuit was surface applied, with no incorporation, in the fall, at rates of 0.25X, 0.33X, 0.4X and 0.5X. Edge (2000) or Poast Ultra (2001, 2002) were applied to improve grassy weed control. The trials were direct seeded with low disturbance openers. There was excellent crop tolerance to fall applications of Pursuit in both chickpea and lentil at all location-years. Some visual crop injury was evident at the higher rates of Pursuit; however, yield was not reduced. Broadleaf weed control was inconsistent at the 0.25X rate. Rates higher than 0.33X rates resulted in excellent control of stinkweed (Thlaspi arvense L.), wild mustard (Sinapsis arvensis L.), wild buckwheat (Polygonum convolvulus L.), lamb’s-quarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), Russian thistle (Salsola kali L.) and cleavers (Galium aparine L.) at all location-years. When compared to a post-emergence application of Sencor, fall applied Pursuit at 0.33X to 0.4X rates resulted in similar to 20% higher seed yields in lentil and chickpea, respectively. Fall applied Pursuit at 0.33X to 0.4X rate resulted in consistent broadleaf weed control, low crop injury, and high crop yield

Effect of timing of isoxaflutole application on weed control in desi chickpea (Cicer arietinum)

Non-Peer Reviewe

Interactions of soil residual ALS inhibiting herbicides

Non-Peer ReviewedALS inhibiting herbicides exhibit high bioactivity at low concentrations and may persist in the soil. To examine possible interactions between two different residues present together in the soil, field and lab tests were performed in three contrasting Saskatchewan soils. Field plots using Roundup Ready canola were used to assess residual effects of combinations of ALS inhibiting herbicides applied to peas and wheat in the previous two years. A root length inhibition bioassay based on oriental mustard was used to test for residual herbicide phytotoxicity in samples of soil from field and lab-spiked soils from the three study sites. The field plots were sprayed initially with imazamox/imazethapyr, and followed by imazamethabenz, flucarbazone-sodium, sulfosulfuron, or florasulam in the second growing season. Soil samples were taken from the plots after the second growing season for the bioassay test. To determine the interactions (antagonistic, additive, or synergistic) between the herbicides investigated, Colby’s equation was applied to the bioassay results. In field samples, the results to date have indicated additive and potential synergistic interactions for the same herbicide combinations in different soils

In search of new herbicide chemistries for the prairies

Non-Peer ReviewedThere are a limited of herbicide groups for use in western Canada so there is a need introduce different modes of action to manage herbicide resistant weeds. In addition, many broadleaf crops such as chickpea have limited broadleaf weed control options. Sulfentrazone, a Group 14 PPO inhibitor has been screened in a number of broadleaf crops. Chickpea has exhibited excellent tolerance to sulfentrazone, while the tolerance of other broadleaf crops can be summarized as follows: sunflower and fababean (fair to good); field pea, and narrow-leaved lupin (fair); dry bean (poor) and lentil (very poor). Isoxaflutole is a Group 27 carotenoid biosynthesis inhibitor that may have potential for use in chickpea, tame buckwheat, and narrow-leaved lupin. Sulfentrazone effectively controls many broadleaf weeds but is weak on cruciferous weeds such as wild mustard. Isoxaflutole also controls a number of broadleaf weeds but does not control wild buckwheat. Both sulfentrazone and isoxaflutole are soil-applied herbicides with potential to carry-over and injure rotational crops. Preliminary results from field trials indicate that combined low rates of sulfentrazone and isoxaflutole can result in excellent broad spectrum weed control in chickpea. Carfentrazone-ethyl, a contact non-residual PPO inhibitor has been shown to be an effective pre-seed burndown partner for glyphosate. This would allow for the control of volunteer Roundup-ready canola prior to the seeding of broadleaf crops

Roundup ready canola control in roundup ready soybean

Non-Peer Reviewe