Volume 38, Number 14 | SEPTEMBER 2012
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PRACTICAL PRODUCTION TIPS FOR THE PRAIRIE FARMER
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Sulphur is essential Don’t let anyone tell you that you don’t need to worry about sulphur. Especially if you’re growing canola BY ANGELA LOVELL
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cross most of Western Canada, if you do grid sampling, large areas of the field can actually be sulphur responsive even when the bulked soil tests say you don’t have to worry,” says Elston Solberg, president of Agri-Trend Agrology and an acknowledged expert in sulphur nutrition. This is especially true for canola, particularly in the Parkland region. Soil organic matter is the primary source of plant-available sulphur. Soil type and topography can play a significant part in the amount of sulphur that is present. Sandy soils, soils low in organic matter and upper to mid-slope positions are especially prone to sulphur deficiency. “Because of this, sulphur is probably the most variable nutrient across the landscape and it’s a challenge to get a reliable soil test result,” says Solberg. “For example, high sulphur levels are often associated with salinity and if just one core sample in 20 is a saline patch, that core can pollute the other 19 samples and give you a false positive result for sulphur content and false confidence. If a plant is Publications Mail Agreement Number 40069240
growing in that saline patch it will have access to oceans of sulphur, but a plant growing up the slope 100 feet away may be growing in a sulphur desert. “I put virtually no confidence in soil test sulphur levels unless they come back low — then you know you have a problem. If they come back adequate to high sulphur content, you are not really sure if that’s real or you hit a hot spot, so that’s when I rely on tissue samples to tell me if the plant has enough sulphur or not.”
SAMPLING FOR SULPHUR Many fertilizer recommendations for sulphur are based on samples taken from a zero- to six-inch depth, but this can also provide a misleading recommendation because there may be additional sulphur available in the subsoil. Taking additional samples at depths of six to 12 and 12 to 24 inches will give a more accurate interpretation of the sulphur status of the soil. While getting a representative sample is a challenge, soil sampling just before seeding will determine the soil-available sulphur present. Fall sampling can provide reliable
fertilizer recommendations — again if the sample is truly representative — when taken after the surface soil temperature drops below 5 C and microbial activity slows.
SULPHUR IS CRUCIAL Sulphur is an essential plant nutrient, but it’s particularly crucial for canola, which has the highest content of sulphur amino acids and sulphur compounds than most other plants. Canola is also much more sensitive to sulphur deficiency than cereals and other crops. Sulphur is a key component of two essential amino acids, cysteine and methionine, and is needed for protein and chlorophyll production. Methionine is the initiating amino acid in the synthesis of virtually all plant and animal proteins. A lack of methionine will have a negative impact upon the formation of other essential amino acids. “In other words, when sulphur is limited, methionine production is limited and this shortcircuits overall amino acid production,” says Solberg. The ability to produce these key amino acids in the right amounts is
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PHOTOS: AAFC
When canola is sulphur deficient, leaves may take on a cupped appearance.
Leaves may redden from the leaf margins. Flowers are small and pale.
In This Issue
Wheat & Chaff ..................
2
Features ............................
6
Columns ........................... 32 Cattleman’s Corner .......... 17 Machinery & Shop ............ 38 FarmLife ............................ 44
Fungicides and Soil Life
ANGELA LOVELL PAGE 6
Winter wheat can produce good returns
Crop Advisor’s Casebook
48
LEE HARTY PAGE 8
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12-08-24 3:37 PM