Effects of crop management on leaf spots of wheat in eastern Saskatchewan

Non-Peer Reviewe

Landscape-scale variability of N2 fixation by pea

Non-Peer ReviewedThe landscape-scale variability of N2 fixation by pulse crops is an important part in the intensity of N cycling in a hummocky terrain. A 100-gridpoint landscape-scale research design was established at a site in the thick Black Soil Zone in the spring of 1993. At the time of seeding, grid points classified as footslope landform complexes had 6.4% more water and 21.7 kg ha-1 more available N than those classified as shoulder. Pea seed yield ranged from 400 to 3750 kg ha-1 and straw yield ranged from 1900 to 12500 kg ha-1. Median seed yield on footslopes was 35% lower than that on shoulders, while median straw yield was 18% greater on footslopes in comparison to shoulders. Total N2 fixed in pea straw and seed ranged from 0 to 239 kg N ha-1. Median N2 fixed on shoulders was 116 kg N ha-1 and 91 kg N ha-1 on footslopes, despite the fact that total N did not show a spatial pattern. Spatial variability of available N, controlled by the redistribution of water, was considered to be the major process controlling the landscape-scale variability of N2 fixation

Row spacing and seeding rate: management practices that influence flax production

Non-Peer ReviewedA three year study (1988-90) assessed the potential of row spacing and seeding rate to maintain flax yield in the presence of weeds. Flax seed yield was measured in three row spacings (9, 18, and 27 cm) and three seeding rates (300, 600, and 900 seeds m-2) of flax. Poor growing conditions in 1988 and 1989 resulted in small differences in flax seed yield among row spacings, seeding rates and types of weed competition. In 1990, a 900-seeds m-2 seeding rate increased seed yield in those types of weed competition that had the lowest average seed yield. A 9-cm row spacing increased seed yield in the absence of broadleaf weeds. Mechanisms of competition and practical implications of the results are discussed

Survey of herbicide-resistant wild oat (Avena fatua L.) in two townships in Saskatchewan

Non-Peer ReviewedThe objective of this study was to determine the nature and occurrence of herbicide resistance in wild oat in the Grassland and Parkland regions of Saskatchewan in 1997, based on a systematic survey of fields in two randomly selected townships. The survey found that: 1) over one-half of fields in both townships had populations resistant to Group 1, 2, and/or 8 herbicides; 2) fields in the Parkland township had higher mean levels of Group 1 resistance (% resistant seeds) than fields in the Grassland township, suggesting they were subjected to more Group-1 herbicide applications; and 3) single- (Groups 1, 2, or 8) and multiple-group resistance (1,2; 1,8; 2,8; 1,2,8) were exhibited in populations in fields in both townships. The proportion of fields with populations exhibiting Group 1 (single) resistance was higher, and Group 2 and Groups 1,2 resistance were lower in the Parkland compared to that in the Grassland township. In both townships, farmers with more land (within the township or total farmed) tended to have a greater proportion of that land infested with Group 1- or 2-resistant wild oat compared to those with less land. The nature of resistance in wild oat populations in Saskatchewan is more diverse, differences in distribution and abundance of resistant biotypes between Grassland and Parkland regions are generally less apparent, and occurrence of resistance is more prevalent than previously documented

Yellowfeed production in Saskatchewan

Non-Peer ReviewedYellowfeed is a harvesting method where an annual cereal crop grown for forage is sprayed with glyphosate at the milk-soft dough stage and allowed to stand until dry. Once dry the crop can be cut and then immediately baled. A study was conducted at 16 site by crop combination to monitor oat and barley forage yield and quality. After the application of glyphosate, dry matter yield was maximized at 20 days and protein concentration was minimized at 25 days. ADF, NDF, and TDN did not vary after glyphosate application. Yellowfeed is a viable alternative harvesting method when annual cereals are harvested for hay

The impact of phosphorus fertilizer placement on crop production

Non-Peer ReviewedImproved phosphorus (P) fertilizer management is viewed as a way to improve yields in highly productive cropping system. A study was conducted at numerous sites during the 1990’s to assess plant density and yield of canola (Brassica napus L.), barley (Hordeum vulgare L.), spring wheat (Triticum aestivum L.), and winter wheat respond to greater P fertilizer rates (0, 15, 30, 45, and 60 kg P ha-1) when seed placed and side banded. We did find that canola stand was insensitive to rates of P tested when banded, but greater rates of seed-placed P caused stand thinning. It is thought the compensatory growth of canola was the reason why canola yield did not respond to P treatment. Both barley and winter wheat yielded most when the greatest rates of P were applied. Spring wheat showed a similar response when P was side banded, thus indicating improved tolerance with P placed away from seed. Therefore, spring wheat was the only crop that fit with our hypotheses; side banding P will allow crops to respond positively to greater rates of P fertilizer. The fact the cereal crop density was unresponsive to P management indicates that seedlings show early-season better tolerance than canola. Unlike canola, yield-forming factors for cereal crops responded to greater rates of P

Tillage system and cropping sequence effects on common root rot of barley in eastern Saskatchewan

Non-Peer ReviewedFusarium head blight (FHB) in barley has been spreading on the Canadian Prairies for the last decade. Fusarium spp. causing FHB can also cause crown/root rot of cereal crops. It is therefore of interest to determine the impact of agronomic practices on fungal populations associated with root rot of barley. From 1999 to 2001, 137 barley crops were sampled in eastern Saskatchewan for severity of subcrown internode discoloration and percent isolation of fungi. Cochliobolus sativus was the most commonly isolated fungus, whereas the most commonly isolated Fusarium spp. included the FHB pathogens F. avenaceum, F. culmorum and F. graminearum. Discoloration caused by C. sativus was favored by conventional-till, whereas Fusarium spp. increased in reduced tillage systems. Barley grown after a cereal-summerfallow (or summefallow-cereal) sequence under conventional- or minimum-till had increased levels of C. sativus. Fusarium spp. were most affected by the previously grown crop(s); they were more common in barley grown after a noncereal than a cereal, and after two noncereals, or a noncereal alternated with summerfallow. Previous glyphosate applications were associated with lower C. sativus, and higher Fusarium spp., levels in barley grown under minimum till. This suggests changes in fungal communities; however, the mechanism(s) responsible for these changes in fungal levels are not known. Increased infection of ground/underground tissue by FHB pathogens might contribute to its development in succeeding cereal crops, therefore measures aimed at reducing root/crown infections by Fusarium spp. might also help reduce FHB development

Tillage system and cropping sequence effects on Fusarium head blight in barley in eastern Saskatchewan

Non-Peer ReviewedFusarium head blight (FHB) in barley is well established in the eastern Canadian Prairies and appears to be moving westward. A survey of 192 barley crops in eastern Saskatchewan was conducted to determine the impact of agronomic practices on FHB (1999-2002) and Fusarium damaged kernels (FDK) (2000-2001). The most common species isolated from spikes/kernels were F. sporotrichioides, F. avenaceum, and F. graminearum, followed by F. poae and F. culmorum. Disease tended to be higher under minimum- than conventional- and/or zero-till. F. sporotrichioides was favored by a previous cereal crop, whereas F. avenaceum was higher after a pulse crop, and F. graminearum decreased after a pulse but not an oilseed crop. The latter two pathogens were also more prevalent after diversified cropping sequences than after two cereal crops. Summerfallow, or summerfallow alternated with cereals, decreased FDK. Previous glyphosate (Group 9 herbicides) use was associated with increased infection by all Fusarium spp., whereas Group 1 herbicides were associated with increased infection by F. poae and F. sporotrichioides. Number of previous glyphosate applications was also correlated with FHB caused by F. avenaceum and F. graminearum. We concluded that in eastern Saskatchewan, barley grown under minimum-till where glyphosate had been sprayed and following diversified cropping sequences would sustain the greatest damage due to FHB/FDK caused by F. avenaceum and F. graminearum

Management practices influencing herbicide resistance in wild oat (Avena fatua)

Non-Peer ReviewedA 3-year study was conducted in Wheatland County, Alberta to determine if agronomic practices of growers influenced the occurrence of herbicide resistance in wild oat. Wild oat seeds were collected in 33 fields in 1997, and in 31 fields in each of 1998 and 1999 (one field per grower). Seedlings were screened for resistance to two acetyl-CoA carboxylase (ACCase) inhibitors (Group 1), imazamethabenz, an acetolactate synthase (ALS) inhibitor (Group 2), and triallate, a thiocarbamate herbicide (Group 8). A questionnaire on herbicide resistance awareness and management practices was completed by each grower. Both ACCase and ALS inhibitor resistance in wild oat were linked to a lack of crop rotation diversity. In addition, ALS inhibitorresistant wild oat was associated with conservation-tillage systems and recent use of herbicides with that mode of action. Results of this study suggest that timely tillage and inclusion of fall-seeded and perennial forage crops in rotations will effectively slow the selection of resistance in this grass species

Impact of crop management systems on Fusarium populations in spring wheat and barley on the Canadian prairies

Non-Peer Reviewe