I have enjoyed the mild, warmer than normal, fall weather and grass is still growing in my pastures and lawn. I much prefer mowing grass to plowing snow so I could take a couple more months of this mild weather and then be ready for spring.
Grass hay and pasture stands can still benefit from 40-50 pounds of nitrogen per acre applied now, helping to overcome summer stresses and go into winter in a more healthy condition. University of Maryland fertilizer recommendations for grass hay and pasture (less than 25 percent legumes) were changed several years ago to have 40-50 pounds of nitrogen per acre applied mid-October to mid-November, depending upon location. This 40-50 pounds of nitrogen was removed from the late winter/early spring green up application, thus the total annual nitrogen recommendation has not changed — only the timing of applications has changed, as illustrated in the tables.
Why the change? Why late season nitrogen on cool-season grasses?
• It increases root growth. Enhanced root growth aids in uptake of water and nutrients, helps carbohydrate buildup in stem bases, and promotes winter survival and initiation of spring growth.
• It increases plant density by enhancing formation of crown buds and subsequently new tillers the following spring.
• It increases drought tolerance.
• It decreases summer weeds.
In summary, low rates of nitrogen in fall set up the plant for winter (winterize) and for healthy early spring growth.
What are the principles of late season nitrogen fertilization?
• Applying 40-50 pounds of nitrogen per acre from mid-October to mid-November (in Maryland) results in little top growth but root growth is still active. Nitrogen is taken up by roots even though shoot growth has stopped.
• Nitrogen increases chlorophyll content. Increased chlorophyll content results in increased photosynthesis and increased photosynthesis results in an increased level of sugars.
• The plants are not growing at this time of year, so the sugars are not used for growth — they are stored to enhance winter survival and spring recovery.
• The stored sugars make grass plants less susceptible to freezing.
• Late season nitrogen applications promote deep rooting during the fall, so deeper, healthier roots the following spring and summer.
When is late season in Maryland? It obviously varies by location:
• Mid- to late October in mountains of western Maryland.
• Late October to mid-November elsewhere in Maryland.
• Roughly around the time of the average killing frost date.
Highly soluble sources of nitrogen should be used for this late season application — organic sources do not provide the same effect. And while this application may replace some or all of the late winter/early spring green-up nitrogen application, depending upon yield goals, it does not replace or substitute for the late spring and summer applications, as shown in the accompanying tables.
If you haven’t done it yet, hurry, time is running out. And if you just can’t get it done in the time remaining this fall, at least put it into your schedule of management practices for next year.
As I wrote last month, we are in the midst of planning the Maryland-Delaware Forage Council’s series of Hay and Pasture conferences to be held in January. These conferences will focus on soil health along with hay and pasture management strategies for higher yields and improved utilization. Featured speaker will be Doug Peterson, rancher and USDA NRCS regional soil health specialist for Missouri and Iowa. Peterson will discuss how soil health affects virtually all natural resource processes and the management practices necessary to effectively improve soil health.
In a second presentation, Peterson will discuss healing the land with high-density grazing, often referred to as mob grazing. Other topics to be covered include herbicide resistant weeds in pasture and hay, metabolic disorders associated with pastures, mower-conditioner and baler tune-up, and pasture fertility.
Reserve the dates on your calendar. The Delmarva conference will be held Jan. 9 at the Delaware State Fairgrounds in Harrington, the Southern Maryland conference Jan. 10 at the Baden Volunteer Fire Department, Brandywine, Maryland, and Tri-State conference Jan. 11, location to be determined.
Look for more details on these conferences in the coming months.