The latest research from the University of Kentucky highlights emerging challenges and innovative strategies in agriculture, focusing on Italian ryegrass management, the complexities of sulfur deficiency diagnostics, green stem syndrome in soybeans, and weather service rainfall reporting accuracy.
Fall Residual Herbicides & Cover Crops Can Help with Ryegrass
Research has demonstrated that Italian ryegrass is becoming a significant problem for grain producers in the state, challenging traditional spring burndown strategies. Experiments showed that fall-applied residual herbicides, especially those containing pyroxasulfone or S-metolachlor, provide over 94% control of ryegrass into the spring, far surpassing the effectiveness of a spring burndown alone. Additionally, combining these residual herbicides with cover crops like wheat or cereal rye not only maximizes ryegrass control but also mitigates soil erosion risk. Based on these findings, recommendations for managing Italian ryegrass include using a fall application of certain herbicides, potentially in combination with cover crops, followed by a spring burndown to control any escapes.
Mehlich III Extractable Sulfur and S Deficiency: Some Additional Considerations
In Kentucky, soil testing is deemed crucial for detecting nutrient deficiencies, yet its effectiveness varies across nutrients, with nitrogen (N) tests being notably weaker, and sulfur (S) tests presenting complications. Recent research sponsored by the Kentucky Small Grain Growers Association across two growing seasons revealed a generally negative yet weak correlation between soil test sulfur values and wheat yield response, with variations depending on specific soil characteristics. Particularly in the Inner Bluegrass region, high phosphate soils disrupted the expected negative correlation, highlighting the need for region-specific interpretations of soil S tests. While deeper soil samples suggested a potential for more accurate S availability assessment, the study concluded the current lack of a reliable soil test for sulfur, suggesting the importance of further research and possibly integrating plant tissue analysis for a more comprehensive nutrient management strategy.
Green-stem Syndrome in Soybean
Green stem syndrome in soybeans, characterized by the presence of green stems on plants at harvest time, has been linked to a variety of factors including viruses, insect damage, and environmental stressors. The syndrome was experimentally induced by researchers Bill Bruening and D.B. Egli through pod removal treatments (25% and 50%) during the early seed-filling stage, which consequently showed more green stems in the 50% removal group. These treatments highlighted that reduced pod load prevents the normal senescence and redistribution of sugars and nitrogen within the plant, keeping the stems green while the pods mature normally. This finding reorients the focus from what causes the green stems to what reduces the pod load, suggesting varied and potentially complex management strategies for addressing this issue in fields.
Assessing the Accuracy of Rainfall Reporting by Weather Services
Robbie Williams, a farm business owner, and researcher from the University of Kentucky tested the accuracy of rainfall reporting from three agricultural weather services by comparing their data to direct rain gauge measurements in Henderson, Kentucky. They found significant variations in accuracy among the services, with Climate FieldView and John Deere’s Operation Center often overestimating rainfall, while Beck’s Hybrid’s FarmServer displayed varying degrees of bias based on the amount of rainfall. These discrepancies could lead to considerable water deficits in precision agriculture applications, such as irrigation planning, where accurate rainfall data is crucial for managing water budgets and ensuring crop health. The study underscores the importance of ground-truthing technology for reliable estimations in high-precision farming practices.
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