Eric Yu, Extension Educator – Crops, Beatriz Bizzuti, Extension Forage Specialist, Troy Salzer, Extension Educator – Ag Production Systems, Tim Gieseke, Extension Educator – Ag Water Management
Forage producers across Minnesota are making important management decisions as the first alfalfa harvest is underway and grazing season ramps up. During the University of Minnesota Extension Strategic Farming: Field Notes webinar on June 3, Dr. Beatriz Bizzuti, Extension Forage Specialist, discussed factors to consider before first-cut alfalfa harvest, while Troy Salzer, Extension Educator, provided updates on pasture conditions and grazing management. Tim Gieseke, Extension Educator – Agricultural Water Management, joined the second half of the session to discuss precision drainage and emerging opportunities for managing water more efficiently across agricultural landscapes. The webinar was moderated by Eric Yu, Extension Educator – Integrated Pest Management.
Healthy alfalfa stands should generally have more than 40 stems per square foot or at least five plants per square foot. In addition to counting stems and plants, producers should dig several plants and examine crown and root tissue. Healthy crowns and roots should have a creamy white interior, while dark brown discoloration may indicate root rot and winter injury.
Understanding how well a stand overwintered, along with the age of the stand, can help producers determine the best management strategy for the season ahead. For additional information on identifying and evaluating winter injury in alfalfa, see the University of Wisconsin Crops and Soils article on alfalfa winterkill.
One management option is early harvest. Cutting alfalfa can help reduce weevil populations by exposing larvae to hotter and drier conditions within the canopy. However, Bizzuti noted that early harvest involves tradeoffs.
During winter, alfalfa plants rely on stored carbohydrate reserves in roots and crowns to survive. In spring, plants replenish those reserves through photosynthesis. Harvesting too early can interrupt this process, potentially reducing drought tolerance, affecting subsequent cuttings, and decreasing stand persistence. Additional information on alfalfa weevil identification, scouting, treatment thresholds, and management strategies is available in the Minnesota Crop News article on alfalfa weevil management.
When deciding on harvest timing, producers should consider stand age, winter injury, pest pressure, and overall farm goals. Depending on the operation, priorities may include maximizing forage quality, increasing seasonal yield, extending stand life, or balancing all three objectives.
Annual forage crops such as sorghum-sudangrass may provide an opportunity to replace lost forage production, particularly under dry conditions. Late-planted corn intended for silage may also be an option in some situations.
Across much of the state, livestock have already been turned out onto pasture. Salzer noted that some pastures are being grazed very short, and many grasses have headed out earlier than expected. Clipping mature seed heads can help return grasses to a vegetative growth stage, improving forage production and quality later in the season.
Strategic rotational grazing can also improve pasture productivity by allowing plants time to rebuild root reserves and recover between grazing events. Overgrazed pastures often struggle with weed pressure, shallow root systems, and reduced productivity. Providing adequate rest periods can improve plant vigor and help maintain forage availability throughout the growing season.
In situations where pastures need additional recovery time, temporarily moving livestock to a dry lot and feeding stored forage may help preserve long-term pasture productivity.
Bizzuti added that overseeding perennial grasses into damaged stands may also be a viable option, particularly in younger stands where maintaining productivity for future years remains a priority.
According to Gieseke, traditional drainage systems often followed low-lying areas of fields, while modern pattern tile systems typically use evenly spaced tile lines across large areas. Precision drainage takes a more site-specific approach by adjusting tile spacing and layout based on soil type, drainage intensity, and topography.
The goal is to create more uniform drainage conditions across a field. He noted that poorly drained soils may require narrower tile spacing, while lighter soils with greater water movement can function effectively with wider spacing.
Precision drainage systems are designed to manage both horizontal and vertical water movement. By accounting for changes in elevation and soil characteristics, these systems can help create more consistent soil moisture conditions, improve field trafficability, and reduce variability across fields.
In dry periods, maintaining a slightly higher water table may help provide additional moisture to crops through capillary movement. However, careful management is required because maintaining elevated water tables can increase the risk of waterlogging if significant rainfall occurs.
New technologies are making these systems easier to manage. Automated control structures, soil moisture sensors, and remote monitoring tools allow producers to adjust water levels and monitor conditions using mobile devices. Gieseke noted that these technologies continue to evolve as interest in conservation drainage and water management increases.
University of Minnesota's Strategic Farming: Field Notes webinar series, offered Wednesday mornings from 8:00 to 8:30 a.m. through August, provides timely, research-based information on crop production issues throughout the growing season. For more information and to register, visit the Strategic Farming website.
Thanks to the Minnesota Soybean Research and Promotion Council and the Minnesota Corn Research and Promotion Council for their generous support of this program.
Forage producers across Minnesota are making important management decisions as the first alfalfa harvest is underway and grazing season ramps up. During the University of Minnesota Extension Strategic Farming: Field Notes webinar on June 3, Dr. Beatriz Bizzuti, Extension Forage Specialist, discussed factors to consider before first-cut alfalfa harvest, while Troy Salzer, Extension Educator, provided updates on pasture conditions and grazing management. Tim Gieseke, Extension Educator – Agricultural Water Management, joined the second half of the session to discuss precision drainage and emerging opportunities for managing water more efficiently across agricultural landscapes. The webinar was moderated by Eric Yu, Extension Educator – Integrated Pest Management.
Evaluating alfalfa stands before first harvest
As producers prepare for first-cut alfalfa, Bizzuti emphasized the importance of assessing stand health and winter survival. Stand evaluations conducted in early spring can provide valuable information for harvest timing and season-long management decisions.Healthy alfalfa stands should generally have more than 40 stems per square foot or at least five plants per square foot. In addition to counting stems and plants, producers should dig several plants and examine crown and root tissue. Healthy crowns and roots should have a creamy white interior, while dark brown discoloration may indicate root rot and winter injury.
Understanding how well a stand overwintered, along with the age of the stand, can help producers determine the best management strategy for the season ahead. For additional information on identifying and evaluating winter injury in alfalfa, see the University of Wisconsin Crops and Soils article on alfalfa winterkill.
Balancing harvest timing and alfalfa weevil management
Reports of alfalfa weevil infestations have increased in several areas of Minnesota this spring. Alfalfa weevil larvae feed on leaves, reducing forage yield and quality. Because leaves contain the highest concentrations of crude protein and digestible nutrients, significant defoliation can have a substantial impact on forage value.One management option is early harvest. Cutting alfalfa can help reduce weevil populations by exposing larvae to hotter and drier conditions within the canopy. However, Bizzuti noted that early harvest involves tradeoffs.
During winter, alfalfa plants rely on stored carbohydrate reserves in roots and crowns to survive. In spring, plants replenish those reserves through photosynthesis. Harvesting too early can interrupt this process, potentially reducing drought tolerance, affecting subsequent cuttings, and decreasing stand persistence. Additional information on alfalfa weevil identification, scouting, treatment thresholds, and management strategies is available in the Minnesota Crop News article on alfalfa weevil management.
When deciding on harvest timing, producers should consider stand age, winter injury, pest pressure, and overall farm goals. Depending on the operation, priorities may include maximizing forage quality, increasing seasonal yield, extending stand life, or balancing all three objectives.
Pasture management considerations
Salzer reported that winter injury has also affected some forage stands used for grazing, contributing to reduced first-harvest yields in certain areas. Producers should evaluate whether damaged stands remain productive enough to justify keeping them in place or whether alternative forage options should be considered.Annual forage crops such as sorghum-sudangrass may provide an opportunity to replace lost forage production, particularly under dry conditions. Late-planted corn intended for silage may also be an option in some situations.
Across much of the state, livestock have already been turned out onto pasture. Salzer noted that some pastures are being grazed very short, and many grasses have headed out earlier than expected. Clipping mature seed heads can help return grasses to a vegetative growth stage, improving forage production and quality later in the season.
Strategic rotational grazing can also improve pasture productivity by allowing plants time to rebuild root reserves and recover between grazing events. Overgrazed pastures often struggle with weed pressure, shallow root systems, and reduced productivity. Providing adequate rest periods can improve plant vigor and help maintain forage availability throughout the growing season.
In situations where pastures need additional recovery time, temporarily moving livestock to a dry lot and feeding stored forage may help preserve long-term pasture productivity.
Options for winter-injured stands
For producers dealing with winter-killed alfalfa stands, both annual and perennial forage species may provide recovery options. Salzer highlighted annual forage crops as one approach for replacing lost production during the current season.Bizzuti added that overseeding perennial grasses into damaged stands may also be a viable option, particularly in younger stands where maintaining productivity for future years remains a priority.
Precision drainage aims to improve water management
The second half of the webinar focused on precision drainage, an emerging approach that combines advances in drainage design, soil mapping, and water management technology.According to Gieseke, traditional drainage systems often followed low-lying areas of fields, while modern pattern tile systems typically use evenly spaced tile lines across large areas. Precision drainage takes a more site-specific approach by adjusting tile spacing and layout based on soil type, drainage intensity, and topography.
The goal is to create more uniform drainage conditions across a field. He noted that poorly drained soils may require narrower tile spacing, while lighter soils with greater water movement can function effectively with wider spacing.
Precision drainage systems are designed to manage both horizontal and vertical water movement. By accounting for changes in elevation and soil characteristics, these systems can help create more consistent soil moisture conditions, improve field trafficability, and reduce variability across fields.
Looking ahead to drainage water management
Precision drainage can also serve as a foundation for drainage water management systems. Water control structures installed within tile systems allow producers to raise or lower the water table based on crop needs and weather conditions.In dry periods, maintaining a slightly higher water table may help provide additional moisture to crops through capillary movement. However, careful management is required because maintaining elevated water tables can increase the risk of waterlogging if significant rainfall occurs.
New technologies are making these systems easier to manage. Automated control structures, soil moisture sensors, and remote monitoring tools allow producers to adjust water levels and monitor conditions using mobile devices. Gieseke noted that these technologies continue to evolve as interest in conservation drainage and water management increases.
Join us Wednesday mornings!
Join us this week when University of Minnesota Extension specialists discuss soybean stand assessments and postemergence herbicide considerations.University of Minnesota's Strategic Farming: Field Notes webinar series, offered Wednesday mornings from 8:00 to 8:30 a.m. through August, provides timely, research-based information on crop production issues throughout the growing season. For more information and to register, visit the Strategic Farming website.
Thanks to the Minnesota Soybean Research and Promotion Council and the Minnesota Corn Research and Promotion Council for their generous support of this program.
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