b'a greater potential for environmental losses, but theadequate P early in the growing season, especially if the extra fertilizer applied becomes a wasted input, limitingsoil is cold and dry at seeding time. economic gains. Understanding STP trends through regular soil testing allows one to balance P fertilizer based on long term crop Balanced Inputs, Better Outcomes rotations, rather than responding to annual requirements. Regular soil testing also helps to track long-term trends.If STP is low, it is important to invest in P during times of Are P levels declining, holding steady, or increasing? Aslow fertilizer and/or high commodity prices. If STP has a general rule, soil test phosphorus (STP) will increasebeen built up to a medium to high level, then it is possible one part per million (ppm) for every 20-30 pounds ofto be more reactionary to high fertilizer prices in the P applied over and above what the crop removes. Thisshort term without the same long-term consequences. could mean a single-year P application of 60 poundsA few years of starter P rates may slowly deplete STP; per acre (~115 pounds of MAP per acre) may only raisehowever, if one has concentrated on building STP when soil test levels by ~1 ppm. Building P levels may not befertilizer is affordable, then a short-term reduction in P feasible during times of high fertilizer prices or tightrates wont devastate those STP reserves.margins, but maintaining a good soil P supply can pay offTo determine crop removal rates for balancing P in the in the long term. rotation, visit prairienutrientcalculator.info. Crop response to P fertilizer is a game of probabilities. If STP is below 10-12 ppm, the probability of a yieldFertility Planning with a Long-Term Lensresponse is high. When STP is above 18-20 ppm, theGiven the continued volatility in fertilizer prices and the probability of a yield response is low. The sweetpressure of tight profit margins, producers must make spot is generally in the 12-18 ppm range, where it iseconomic decisions that maintain yield potential without recommended to apply P at crop removal rates tocompromising soil fertility. Regular soil testing provides maintain that same STP level going forward.critical insights into nutrient availability, guiding precise If STP is below 10-12 ppm, then it may be beneficialapplication rates and preventing both over- and under-to build STP levels by applying P at a rate greater thanapplication. Strategic nutrient planning, grounded in crop removal. When STP is high, its still recommended toagronomic data and economic analysis, is essential for SEC_PBRNOTICE25_SM_SEC_PBRNOTICE25_SM.qxd2025-10-1711:28 AMPage 1apply P at starter rates to ensure the crop has access tosustaining profitability into the future. Ad Number: SEC_PBRNOTICE25_SM Publication: Seed Manitoba Size: Half Page 7.25 x 5DID YOU BUY SEEDFROM YOUR NEIGHBOUR?ITS PROBABLY ILLEGAL.Produced for: SeCan Product: PBR Plant Breeders Rights Date Produced: October 2025To report illegal activity contact: seedwatch@seeds-canada.caFor more information visit: pbrfacts.caSeed Manitoba 2026 11 Ad Number: SEC_PBRNOTICE25_SM'