The Rise and Fall of Water Net (Hydrodictyon reticulatum) in New Zealand

During the late 1980s to early 1990s a range of aquatic habitats in the central North Island of New Zealand were invaded by the filamentous green alga, water net Hydrodictyon reticulatum (Linn. Lagerheim). The alga caused significant economic and recreational impacts at major sites of infestation, but it was also associated with enhanced invertebrate numbers and was the likely cause of an improvement in the trout fishery. The causes of prolific growth of water net and the range of control options pursued are reviewed. The possible causes of its sudden decline in 1995 are considered, including physical factors, increase in grazer pressure, disease, and loss of genetic vigour

Gujba: A new Bencubbin-like meteorite fall from Nigeria

Gujba is a new Bencubbin-like meteorite fall enriched in N-15 and consisting (in vol.%) of 41% metal nodules, 20% large light-colored silicate nodules and 39% dark-colored, C- and silicate-rich matrix

Increasing yield and profit by straight-cutting canola

Non-Peer ReviewedStraight combining canola (Brassica napus) can save producers time, fuel costs, and equipment wear. Research was undertaken at three locations to determine if straight combining shatter losses would be reduced sufficiently with higher yield potential to make straight combining viable in western Canada. This research employed a randomized complete block design. Treatments included crop density (low and high), fertility (low and high), time of weed removal (early and late), and harvest time (early and late). Factors were selected to offer a range of yields to evaluate the relationship between potential yield and shatter loss. Overall, factors causing shatter loss and crop yield differed between locations. Not surprisingly, crop density was affected by target crop density and percent green seed was affected by harvest timing

Soil microorganisms and crop yields after cattle manure, hog manure, or fertilizer application

Non-Peer ReviewedSoil biological properties can be significantly impacted by land management. Cattle manure, hog manure or inorganic fertilizers were applied annually or triennially to a Gray Wooded soil at Falher, Alberta, over three years. A control treatment without manure or fertilizer was also included. Canola (Brassica napus) was grown in Year 1, hulless barley (Hordeum vulgare) in Year 2, and wheat (Triticum aestivum) in Year 3. Where effects were significant, cattle manure increased soil microbial biomass C (MBC) by 26-86%, hog manure by 31%, and inorganic fertilizers reduced MBC by 20%. Similar effects, except the reduction by inorganic fertilizers, were observed for functional diversity of soil bacteria (Shannon index, H’). Crop N uptake from hog manure was higher than that in other treatments in Year 1, when hog manure increased grain yields by 75%, cattle manure by 49%, and inorganic fertilizers had no significant effect. However, cattle manure out-yielded other treatments in Years 2 and 3 (25-50% increase over the control) even though N uptake from inorganic fertilizers was the highest in Year 2. This implies that factors other than nutrient uptake also influenced crop yields. Frequency of application usually had no effects on MBC or H’, but the triennial application rate of inorganic fertilizers reduced crop yields relative to annual applications in Year 1

Increasing yield and profit by straight-cutting canola

Non-Peer ReviewedStraight combining canola (Brassica napus) can save producers time, fuel costs, and equipment wear. Research was undertaken at three locations to determine if straight combining shatter losses would be reduced sufficiently with higher yield potential to make straight combining viable in western Canada. This research employed a randomized complete block design. Treatments included crop density (low and high), fertility (low and high), time of weed removal (early and late), and harvest time (early and late). Factors were selected to offer a range of yields to evaluate the relationship between potential yield and shatter loss. Different components of potential yield were important in determining yield and seed losses before and during harvest operations. In Lacombe, fertility has been the most important factor. In Vegreville, timing of weed removal was paramount in 2006. At Scott in 2006, it appears that all operations must be conducted under best management practices or there is a substantially increased probability of reduced yield when straight-cutting. These results generally fit the hypothesis that ability to straight-cut is dependent upon maximizing potential yield. Under higher-yielding conditions, a key factor has led to success at straight-cutting. Under low-yielding conditions, all factors contributing to increased potential yield must be used to ensure feasibility of straight-cutting

How much phosphorus do crop residues release under conventional and zero tillage systems?

Non-Peer ReviewedIn a field experiment conducted at Fort Vermilion in north-western Alberta, we used the litter bag method to quantify phosphorus (P) release from red clover green manure, field pea, canola and wheat residues under conventional tillage and zero tillage. Wheat residues added significantly less P (1.7 kg ha-1) to the soil than the other residues (5.6-8.5 kg P ha-1). Tillage had no significant effect on residue P applied, but the trend was for slightly greater amounts under ZT than under CT. Clover released the most P (3.8 kg ha-1 under CT and 2.8 kg ha-1 under ZT, compared with 1.4 kg ha-1 or less from the other residues). There were no significant tillage effects on the amounts released by clover, pea and canola residues, but wheat immobilized 0.2 kg P ha-1 under ZT compared with 0.4 kg P ha-1 released under CT. Soil phosphate contents were not significantly different between tillage systems. Phosphate contents decreased with soil depth, especially under ZT. However, there was no tillage by soil depth interaction with canola residues, where soil phosphate was greater (although not significantly) under ZT than under CT at all depths. Uptake of P by wheat was significantly greater where pea and, to a lesser extent, canola residues had been applied than where clover and wheat residues had been applied, and tillage had no significant effects on P uptake

Management of fertility in the pulse-based cropping systems of western Canada

Non-Peer Reviewe

Effect of “starter” N and P on nodulation and seed yield in field pea, lentil, and chickpea in semiarid Canadian prairies

Non-Peer Reviewe

Update on fall dormant seeded canola research

Non-Peer Reviewe

A decade of herbicide-resistant crops in Canada

Non-Peer ReviewedThis review examines some agronomic, economic, and environmental impacts of herbicide-resistant (HR) canola, soybean, corn, and wheat in Canada after 10 years of growing HR cultivars. The rapid adoption of HR canola and soybean suggests a net economic benefit to farmers. HR crops often have improved weed management, greater yields or economic returns, and similar or reduced environmental impact compared with their non-HR crop counterparts. There are no marked changes in volunteer weed problems associated with these crops, except in zero-tillage systems when glyphosate is used alone to control canola volunteers. Although gene flow from glyphosate-HR canola to indigenous populations of bird’s rape in eastern Canada has been measured, enrichment of hybrid plants in such populations should only occur when and where herbicide selection pressure is applied. Weed shifts as a consequence of HR canola have been documented, but a reduction in weed species diversity has not been demonstrated. Reliance on HR crops in rotations using the same mode-of-action-herbicide and/or multiple in-crop herbicide applications over time can result in intense selection pressure for weed resistance and consequently, greater herbicide use in the future to control HR weed biotypes. History has repeatedly shown that cropping system diversity is the pillar of sustainable agriculture; stewardship of HR crops must adhere to this fundamental principle