Grainswest - Winter 2019

Winter 2019 Grains West 48 Soil testing cited as the key to optimizing yield Do it inthedirt GRAIN SCIENCE NEWS THOUGH RELATIVELY FEW farmers do it regularly, agronomists emphasize there is great value in soil testing. And it may be particularly so following two growing seasons in which dry conditions diminished yields. Coupled with cropping and management history, determining how much nitrogen, phosphorous, potassium and sulphur remain in a given field as a result may well suggest reducing inputs for the 2019 growing season. “If a producer has been applying 40 pounds of phosphate in each of the past couple of years, for example, and the crop has only removed about 20 pounds, they might be able to cut back to 15 to 20 pounds this coming year and with decent growing conditions achieve their target yields,” said Matt Gosling, founding part- ner of Premium Ag Solutions, an agro- nomics consultancy based at Strathmore. Adjusting input rates can increase produc- tion efficiency and profitability. Gosling has long recommended annual soil testing under all growing conditions. “The soil is a living biological creature that is very changeable,” he said. Soil tests eliminate agronomic guesswork. He explained it comes down to knowing what you have. “I’ve always said a soil test is the cheapest input on the farm. Deciding whether to soil test should never be about the cost.” Depending on the lab and degree of analysis, soil test costs can vary from $50 to $200. “Even if it cost $200 for a soil test, you’re on the land with equipment that costs anywhere from $300,000 to $500,000 per unit and overall inputs are costing maybe $200 per acre,” said Gosling. “That $200 for information on nutrients required to achieve your target yield is an investment rather than a cost.” Despite the recognized value, industry surveys continue to show only about 30 per cent of farmers routinely test their fields. Some agronomists say perhaps 50 per cent test every three to five years. Old habits, concern about time and cost, misinformation and lack of confidence in soil test recommendations are among the reasons cited for this lack of uptake. While some concerns are valid, the experts say that if the soil samples are collected properly, analyzed by a reputable lab, with results evaluated by an experienced professional, they can be a valuable tool in optimizing yield. “Soil testing isn’t without its pitfalls,” said Rigas Karamanos, a senior agrono- mist with Koch Fertilizer Canada. “But they are still the best measure of soil nutrient levels on the farm. The tests are working with a natural system that can have wide variability. Even with just a gram of soil you are looking at more than 12 million microorganisms. A soil test recommendation might say you need 10 pounds of a nutrient plus or minus, or you might need 50 pounds plus or minus, but at least it is an indication of where to start.” Karamanos said he can understand why farmers might be leery about the value of soil tests. He describes the process as both a science and an art. The art is in applying the results to the management planning process. He noted that research Farmers Edge digital ag intern Zach Smith assists agronomist Jack Payne with the installation of a soil moisture probe in an Alberta farmer’s field.