Внесение дренажа в поля Манитобы заставляет фермеров пересматривать стратегии внесения удобрений

Got tile drainage? Have your 4R fertilizer plans changed to match? Tile drainage can give back big yield potential for the farmer, but that also means revisiting fertilizer plans and the right decisions for 4R nutrient management A growing number of Manitoba farmers installing tile drainage systems are also rethinking how and when they apply fertilizer, with agronomists saying better water management can change every aspect of the 4R nutrient stewardship framework. Why It Matters Tile drainage attracts farmers for its potential to recover unproductive acres. Manitoba farmers are finding their old fertilizer programs may no longer fit their fields. Ernie Sirski, board member with the Manitoba Pulse and Soybean Growers, said his family’s operation near Dauphin made significant changes after installing tile drainage in 2021. “Number one, we do not apply fall fertilizer anymore, and that was a conscious decision based on the fact that we didn’t want it to be leeched out into the groundwater through the tiles,” Sirski said at a July research tour on his farm. Instead, the farm now applies fertilizer in the spring. The farm also adopted variable-rate fertilizer applications after discovering highly saline areas. “This whole area was nothing but salinity,” he said. “Kochia didn’t grow on these fields.” Within five years, those acres had become some of the farm’s best performing land. The transformation, he said, has been nothing short of dramatic. “It was worse than the ocean, and now you can literally drink the water that’s coming out of those pipes,” Sirski said. Better drainage, better production potential For Kevin Thompson, a mixed grain and cattle producer near Ochre River and former agronomist, tile drainage changes the economics of fertilizer because it changes yield expectations. Thompson said removing excess water reduces nitrogen losses. “We’re reducing the risk of denitrification,” he said. As a result though, fertilizer recommendations may need to be revised upward, and the right source might change. “Now all of a sudden, the right rate can be different, because now we’re shooting for higher yields,” he said. Producers often notice the biggest changes in areas that once produced little or nothing, he added. Improved drainage on Thompson’s farm allows soils to function differently from the beginning of the growing season. “We start the year with air in our soil,” he said, adding that this encourages roots to grow deeper and use moisture more efficiently. “We’re using a full soil profile.” The benefits became especially apparent during this year’s wet conditions in June. Not only is his crop still growing, despite the flooding that rocked the Parkland, but some of the moisture actually ended up being useful. How tile drainage changes nutrient decisions Tile drainage uses underground perforated pipes to remove excess water from below the crop root zone. The argument is that by lowering the water table, the systems help fields dry and warm more quickly in the spring, encourage deeper rooting and can reduce yield losses caused by excess moisture. The systems discharge collected water through outlet pipes into drainage networks or waterways. That, however, makes nutrient management an important consideration in a world where farmers are being increasingly pushed to be more efficient with fertilizer. Marla Riekman, soil fertility specialist with Manitoba Agriculture, also noted how improving water management changes the goalposts on the best nutrient decisions. “The rate really does change, because your yield changes with the management of the water,” Riekman said. Reclaiming saline areas in particular takes time, but can return big payoffs in recovered yield potential, she noted. Better-drained fields also give farmers more flexibility in when they can apply nutrients. “If we are looking at managing our water a little bit better, we can see more targeted application of nutrients in other times of the year, moving away from fall fertilizer on soils that allow for that to happen,” Riekman said. Those improvements extend across all four components of nutrient stewardship, she added. “We can dial in around the time and the place, and then the rate really does change because you’re really changing with that management of the water, and so we have the ability to decrease that extra water stress at different points in time, or get onto a field a little earlier.” Is tile right for your field? Before installing tile drainage, Manitoba Agriculture soil health specialist Megan Westphal said producers should carefully assess whether fields are suitable. “We also look around for any stone on the surface, and any potential salinity issues that we could be seeing on the surface, and then once we take note of that, we start digging down and put our head into the soil, because there’s various soil characteristics we look at,” Westphal said. These include soil texture, natural drainage, parent material and calcium carbonate. These all help determine whether tile drainage is appropriate. Recommendations remain site-specific, and the four Rs will need to be tailored to each soil type and each situation. Current best management practices from Manitoba Agriculture’s website recommend matching fertilizer applications to soil test results and crop needs, avoiding applications on saturated soils or before heavy rain and placing nutrients below the soil surface whenever practical to reduce losses through tile drainage.