Рост цен на азот заставляет фермеров Миссури пересчитывать экономику внесения удобрений

High nitrogen prices force a closer look at the numbers Published 12:30 am Tuesday, September 1, 2026 Stockpiled tall fescue remains one of Missouri’s strongest competitive advantages in the beef industry, with the low-cost fall and winter feed allowing producers to extend grazing deeper into the winter than producers in most other cattle states. Maximizing that advantage starts with smart fertility decisions in August, according to University of Missouri Extension state forage specialist Carson Roberts. Applying nitrogen in mid- to late August traditionally has been a reliable way to boost stockpile yield. But nitrogen prices have risen more than 40% in the past six months because of supply disruptions tied to the Iranian conflict. That increase has many producers asking if fall nitrogen still makes economic sense. MU Extension research over the past three years shows that a 60-pound-per-acre fall nitrogen application has increased tall fescue yield by an average of about 35%, Roberts said. Response varies widely with rainfall – drought years often produce only 8 pounds of additional forage per pound of nitrogen applied, while in years with favorable moisture, the increase can reach 20 to 25 pounds. To decide whether fall nitrogen is a better buy than buying hay, Roberts recommends a quick formula: -Divide 2,000 by expected pounds of forage produced per pound of nitrogen. -Multiply that result by the current cost of nitrogen per pound. -Compare that number to the delivered price of average-quality fescue hay. If the calculated fertilizer cost per ton is higher than local hay prices (around $85 per ton for average fescue hay in many markets), buying hay is the lower-cost option. Buying and feeding hay on pasture also affects fertility, Roberts said. A typical ton of fescue hay contains about 32 pounds of nitrogen, 12 pounds of phosphorus and 18 pounds of potassium, plus valuable micronutrients. When hay is fed strategically across pastures, much of that fertility returns to the soil and can reduce the need for commercial fertilizer over time. The key to capturing the fertility benefit of hay without damaging stands is proper feeding management. “When unrolling hay or bale grazing, move the feeding site with each new bale,” Roberts said. Soybean tentiform leafminer MU Extension state crops entomologist Ivair Valmorbida has confirmed a second finding in Missouri of a new pest, soybean tentiform leafminer. Missouri’s second confirmed case was in Macon County on Aug. 19. The first case of the pest in the state was in a Cooper County soybean field in August 2025. Valmorbida encourages farmers to scout soybean fields and to contact a local MU Extension agronomist if the pest is suspected. Soybean tentiform leafminer was detected feeding on soybean in Minnesota in 2021 and since has been detected in South Dakota, North Dakota, Iowa and Nebraska. The pest is a small white larva that turns pale green as it matures. The adult moths are less than ¼-inch long and have orange and white wings with gray-black marks. Adults lay eggs on the underside of soybean leaves. Larvae feed inside the leaves and tunnel to create “mines” that do not cross the midribs or main lateral veins of the leaves. The mined tissue eventually dies, resulting in less leaf area. On the underside of the leaves, mines enlarge to become elongated, oval white blotches. On the upper side of leaves, these mines become tentiform – slightly raised, or tented. There are no well-established management practices for this insect, but University of Minnesota researchers report that several parasitic wasps, natural enemies of the soybean tentiform leafminer, and translaminar insecticides could provide control.